Early Warning Signs for James Hansen’s Superstorms Visible — North Atlantic Cool Pool As Harbinger to “All Hell Breaking Loose”

Extreme weather. It’s something that’s tough to predict 2 weeks out, much less 2 decades. But for more than twenty years Dr James Hansen has been warning that the out-flush of cold water from glaciers in Greenland and Canada into the North Atlantic could set up a storm-producing weather pattern the likes of which human civilization has never seen. An atmospheric wrecking ball in the form of an intense cold-hot dipole that, once firmly established over Atlantic Ocean waters between North American and Europe, would carry on in brutally destructive fashion for decades and decades. In other words, as Dr. Hansen says in the below video, “all hell would break loose.”

His recent and, what might well be called, earth-shattering paper on the subject — Ice Melt, Sea Level Rise, and Superstorms — takes a good, hard look at both the potential for exponentially ramping rates of ice melt and sea level rise over the coming decades and the impact those thousands of cubic kilometers of fresh water ramming out into the North Atlantic would have in producing a barrage of increasingly intense superstorms.

(Hansen addresses his concerns about the potential for increasingly severe storms and rapid sea level rise if human fossil fuel emissions do not stop soon in the above video.)

Early Evidence That All Hell is Starting to Break Loose

How could this happen? And what might it look like?

These are questions Hansen valiantly attempts to tackle. And according to him, in addition to a growing number of top climate researchers like Dr. Jason Box and Dr. Stephan Ramhstorf (please see Dr. Jason Box’s very salient take on the new Hansen study here), we may already be starting to witness signs of the wrenching oceanic and atmospheric shift that would produce these terrible weather systems.

For what we see now is the visible formation of a large cool pool in the North Atlantic. One that appears to be developing due to an increasingly rapid rate of Greenland melt. One that may be setting up atmospheric conditions for the age of storms that Hansen has feared could arise. An event resulting from a rampant human fossil fuel emission and a related very rapid injection of heat into the Earth System.

North Atlantic Cool Pool

(Composite global temperature anomaly data from NOAA for 2013 through 2015 provides evidence of the early start to the formation of a possible superstorm-producing North Atlantic cool pool. Image source: Climate Crocks.)

How might this cool pool become such a powerful storm generator? It could well be thought of as an ironic matter of atmospheric and ocean physics. Ironic in the sense that overall global heating produces a severe weather hazard in the form of a large area of cool ocean surface water.

Increased warming of the Earth results in more rapid warming at the poles, especially in the Northern Hemisphere. In turn, this polar amplification sets off a number of feedback loops in which ice in Greenland and West Antarctica begin to melt faster and faster. The ironic atmospheric relationship to large slabs of ice sliding off the great ice sheets and into the ocean begins to come into play. For a thin veil of fresh water from these increasingly massive volumes of melting ice begin to lock more and more heat into the local ocean system.

Over hundreds of thousands of square kilometers, the fresh water begins to cut off the ocean’s ability to ventilate heat into the airs above. As a result, the surface of the ocean and the local atmosphere cools. More heat is shoved into the deeper waters — where it can melt the sea facing glaciers ever more rapidly even as it gets to doing the dangerous work destabilizing carbon stores on the sea bed. Dangerous — not only for its potential to add more greenhouse gasses to the world atmosphere, but also for its ability to develop anoxic dead zones in the ocean depths and to expand those life-killing layers toward the sea surface.

Climate Change’s War Between Hot and Cold — Understanding the Warning Signs

In scientific terms, we call this a stratified ocean state. But in plainer words, we could think of it as a big mechanism for heat exchange and ocean and atmospheric chemistry change.

Where Hot and Cold Collide

(Anyone who knows anything about ocean and atmospheric physics should be concerned about this picture. Here we see the April 8, 2016 ocean surface temperature anomaly reanalysis provided by Earth Nullschool and developed from data collected by NCEP and the National Weather Service. Here we see a large swath of Gulf Stream waters ranging from 5-8 C above average temperatures coming into collision with waters in a North Atlantic cool pool ranging from 1-10 C below average. It is the increasing difference in temperature, or thermal gradient, between these two ocean zones that Hansen and others identify as having a high potential for very severe storm generation.)

Changing the ocean’s heat relationship with the atmosphere is bound to alter the weather. And Hansen’s paper points toward a serious risk that this fundamentally altered relationship will result in much more powerful storms. A cooler North Atlantic will collide with all kinds of expanding heat from various regions. A backed up Gulf Stream will warm up — it already has. The tropics will begin to heat up, increasing the temperature gradient between the lower Latitudes and the cool pool in the North Atlantic. Such conditions amp up the atmospheric storm potential by producing an abundance of what storms feed on — very extreme differences in temperatures, related strong winds and atmospheric vortexes, strong south to north and north to south air flows that link the tropics to the pole, and an ever-growing abundance of moisture bleeding off the record warm waters that come into increasing collision with the expanding pool of cold to the north. Such conditions risk the development of extraordinarily powerful storms in this region. Storms the likes of which our civilizations have never seen before. Storms that may leap the boundaries of their formation zones to have far broader impacts.

Hansen, in his paper found evidence that such conditions may well have existed during the last warm period between ice ages around 115,000 years ago. Back then, a huge flush of ice bergs running out from a melting Greenland during the peak period of warmth appears to have produced terrible storms in the North Atlantic. Storms powerful enough to pluck 2,000 ton boulders up out of the sea bed and hurl them 100 feet above sea level before depositing them onto the hills of places like Bermuda and the Bahama islands.

During that period, the rate of warming was slower. So the pace of melt was likely also slower than what we would see due to human warming. The atmospheric changes were thus milder than those we are likely to experience if human warming continues along its current path and sets the dramatic melt and related atmospheric wrenching into motion. Already, we see storms the likes of which history has never seen running into the UK and Ireland, aiming their increasingly powerful winds and rains at Western Europe. Already we see climate change enhanced superstorms. New forms of severe weather. Hellacious mergings of devastating hurricanes with extraordinary nor’easters.

But what we see now is nothing compared to what we will see if Hansen’s research is anywhere near the mark and if human fossil fuel burning continues unabated. What we risk, and what Hansen has warned us about in what he considers to be his most important work of science, is setting off a severe chain of events that includes rapid sea level rise and powerful, powerful storms. In addition, the ocean stratification that is the cause of all this atmospheric and oceanic trouble would set off further consequences not touched on in Hansen’s work — hitting ocean health hard and, likely, liberating more carbon stores from the Earth System to add to the troubles that humans (and particularly the fossil fuel special interests) are already rapidly bringing to the fore.

One final point — the Hansen paper has and will continue to generate a huge controversy in the science. But from the point of view of this threat analyst, there is a high potential for dangerous outcomes similar to those the Hansen paper warns of together with a number of additional troubles so long as the human-forced warming continues. And we already see visible evidence of those kinds of dangerous atmospheric and ocean changes starting to happen now.

Links:

Ice Melt, Sea Level Rise, Superstorms

The Storms of My Grandchildren

Human Warming Pushing Seas to Exponentially Rise

Dr Jason Box’s Take on the New Hansen Study

Earth Nullschool

NCEP

National Weather Service

Hurricane Sandy — the Storm that Climate Change Wrought

 

Tumbling Down the Rabbit Hole Toward a Second Great Dying? World Ocean Shows Signs of Coming Extinction.

The last time Earth experienced a Great Dying was during a dangerous transition from glaciation and to hothouse. We’re doing the same thing by burning fossil fuels today. And if we are sensitive to the lessons of our geological past, we’ll put a stop to it soon. Or else doesn’t even begin to characterize this necessary, moral choice.

*    *    *    *    *

The Great Dying of 252 million years ago began, as it does today, with a great burning and release of ancient carbon. The Siberian flood basalts erupted. Spilling lava over ancient coal beds, they dumped carbon into the air at a rate of around 1-2 billion tons per year. Greenhouse gasses built in the atmosphere and the world warmed. Glacier melt and episodes of increasingly violent rainfall over the single land mass — Pangaea — generated an ocean in which large volumes of fresh water pooled at the top. Because fresh water is less dense than salt water, it floats at the surface — creating a layer that is resistant to mixing with water at other levels.

Algae Blooms and Red Tides in the Stratified Ocean

This stratified ocean state began to cut the life-giving thread of the world’s great waters. Reduced mixing meant the great ocean currents slowed. Oxygen transport into the depths declined. Moreover, a constant rain of debris in the form of particulate matter from burning forests and nitrogen oxides from the smoldering coal beds fertilized the ocean surface. Food for algae also came from increasing continental run-off. And a spike in iron loading due to glacial melt added yet more fertilizer. Great microbial blooms covered the world ocean, painting its face neon green, blue, or blood red.

antarctic-algae-bloom-terra

(Stratified Ocean waters hosting massive algae blooms. It’s a combination that can quickly rob ocean waters of oxygen. During the Permian, a transition to stratified and then Canfield Ocean conditions led to the worst mass extinction event in the history of life on Earth. Today, the Southern Ocean’s waters are increasingly stratified due to glacial melt run-off of fresh water. In addition, these waters also host very large algae blooms like the ones seen above in a NASA satellite shot from 2012. Image source: NASA and Live Science.)

Rising CO2 levels increased ocean acidification even as the blooms spread toxins through the waters. When the blooms finally exhausted all the available food in their given region, they died off en masse. And by decay they further robbed the waters of life-giving oxygen. At this point the strains to ocean life became extreme and the first mass deaths began to occur. The stress opened pathways for disease. And the warming, de-oxygenating waters forced migrations to different Latitudinal zones and ocean depths. What life there was that couldn’t move, or couldn’t move fast enough died in place.

Transitioning to a Canfield Ocean

At first, ocean deaths appeared prominently in the bottom regions that saw the most rapid declines in oxygen levels and the swiftest increases in temperatures. For not only did the fresh water at the surface of the world’s oceans prevent mixing — it also prevented the oceans from ventilating heat into the air. Instead, the ocean heat was increasingly trapped at depth. Aiding this process of heat transport into the world’s deeps was a bottom water formation that issued from the hot Equator. There, evaporation at the surface increased saltiness. The heavier, hotter, saltier waters sank — carrying with them the Equatorial surface heat which they then delivered to the ocean bottom.

The hot, low oxygen bottom water became increasingly loaded with methane as the heat activated frozen stores. It created an environment where a nasty little set of primordial, hydrogen sulfide producing, creatures could thrive.  These little microbes cannot live in oxygen rich environments. But warm, anoxic bottom waters are more like the ancient environments from which they emerged. Times long past when the world was ruled by microbes in conditions that were simply deadly to the more complex and cold-loving life forms of later times. To most life, the hydrogen sulfide gas produced by these little monsters is a deadly toxin.

Ancient ocean conditions

(Oxygen, iron and hydrogen sulfide content of the world’s oceans over the past 4 billion years. Ancient oceans were hotter than today. They were rich in iron and densely populated with hydrogen sulfide producing bacteria. They were also anoxic. During hothouse events, oceans can again lapse into these ancient ocean states. Called Canfield Ocean environments and named after Dr. Donald Canfield who discovered them, these states are extremely deadly to ocean life. If they become too deeply entrenched, Canfield Oceans can also transform the global atmosphere, resulting in extinctions of land animals as well. Such an event was thought to be the primary killing mechanism during the Permian Extinction. Image source: Nature.)

The rotten-eggs stinking, hydrogen sulfide filled waters at first did their dirty work in silence at the bottom of the warming world ocean. But, steadily, anoxia progressed upward, providing pathways for the hydrogen sulfide producing bacteria to fill up the oceans. Death expanded from the bottom toward the surface.

In all the great mass extinction events but, possibly, one, this heat-driven filling up of the world ocean with deadly hydrogen sulfide gas during hothouse periods represents the major killing mechanism. The other impacts of hothouse waters — ocean acidification and habitat displacement — do provide killing stresses. But the combined zero oxygen environment filled with a deadly gas generates zones of near absolute death in which few things but microbes and jellyfish can live. In rock strata, the anoxic, zones are marked by regions of black as the hydrogen sulfide producing bacteria-filled waters eventually take on the color of tar. In the lesser extinctions, these black zones are confined to the lower ocean levels. In the greater ones, they rise higher and higher.

During the Great Dying, the oceans brimmed full of the stuff. Black, purple and neon green waters bubbled to the surface to belch their lethal loads of hydrogen sulfide gas into the airs. The gas was deadly toxic to land plants and animals alike. And it eventually wafted into the skies, turning it from blue to green and eating away at the protective ozone layer.

In this terrible way, more than 99 percent of all living things were killed off. Of species, about 95 percent of ocean forms were lost with around 80 percent of the land forms being wiped out.

Early Signs of a New Ocean Extinction

The Great Dying of the Permian Extinction 200 million years ago should be a warning to anyone still enamored with the notion that today’s terrifying fossil fuel burning results in any future that is not horrible, wretched, bleak. Today, we dump 11 billion tons of carbon into the air each year — at least six times faster than during the Great Dying. Today, the great melting glaciers are beginning the painful process of ocean death by spreading out their films of stratifying, iron-loaded fresh water. Today fossil fuel industry, industrial farming and warming all together are fertilizing the ocean surface with nitrous oxides, particulates, phosphates flushed down rivers, and an overall increased runoff due to a multiplication of extreme rainfall events.

(The hot blob in the Pacific Ocean is setting off the largest red tide on record. Just one of many dangerous impacts to sea life due to this large region of abnormally warm water.)

And the impacts are visible to anyone who cares to look. In the Pacific Ocean, a climate change related blob of hot water is resulting in mass ocean creature die offs. Low oxygen waters beneath the blob are wrecking large zones of ocean productivity and risking the proliferation of deadly hydrogen sulfide producing bacteria. The largest red tide on record has spun off the hot blob. Covering waters 40 miles wide and 600 feet deep, it has left piles and piles of dead shellfish rotting on beaches across the North American West Coast.

Across the Continent, the Chesapeake Bay suffers a proliferation of dead zones and greatly reduced productivity. There’s a rising risk that, during coming years, increased warming will deliver a heavy blow to life in the Bay and turn one of the world’s greatest estuaries into a large hydrogen sulfide production zone similar to the Baltic Sea. In the Gulf of Mexico, a similar dead zone emerges near the outlet of the Mississippi. And out in the Atlantic Ocean, mobile dead zones now swirl providing a roving surface hazard to both the deep open waters and to the coastal regions that now sit in the firing line.

In the Arctic, recently ice-freed waters are now the host of massive blue and green Algae blooms.

Barent Algae Bloom July 2015

(Large blue and green algae bloom covering the southern Barents Sea during late July of 2015. Large algae blooms are now a frequent feature of previously ice covered waters in a warming Arctic. Image source: LANCE-MODIS.)

Ever since the mid 2000s a massive algae bloom like the one pictured above has dominated the Barents Sea during summer time. Often running as deep as 400 feet, this sprawling mat can rapidly deplete northern waters of vitalizing oxygen and result in mass fish kills. Waters around Greenland, in the East Siberian Sea, the Chukchi, and the Beaufort have also hosted large, and potentially ocean-health threatening algae blooms.

And, in the polynyas and open waters off a melting Antarctica, massive algae blooms are also starting to form. Some of the blooms are so dense they emit a nasty rotten-eggs smell — a sign that sulfide producing bacteria may already be active in some of these waters. Fed by iron from melting glaciers, these immense blooms represent rapid explosions of life that can equally rapidly deplete waters of nutrients and then oxygen as they die off.

The blooms and the related expanding, low oxygen dead zones now range the entire world ocean. And where we see the red, the neon green, the cloudy light blue what we see are the signs of another ocean extinction in the making. An extinction that is likely building faster than at any time in the geological past. But we may still be able to avoid another great dying. The amount of carbon we’ve emitted into the world’s airs is immense, but it is still but a fraction of the carbon explosion that resulted in the Permian die-off. It is still a tiny fraction of the carbon that remains in the ground. The carbon that could be burned but shouldn’t. And a rapid cessation of fossil fuel burning now should, hopefully, be enough to prevent another hothouse spurred great dying in the oceans and upon the lands.

As for continued burning of fossil fuels — that results in ever greater risk of unleashing the horrors of the ancient hothouse. A set of now stirring monsters that we should carefully allow to fall back into slumber — leaving them to rest in dreams of the great long ago where they belong.

Links:

A Deadly Climb From Glaciation to Hothouse: Why the Permian-Triassic Extinction is Relevant to Current Warming

Antarctic Glaciers are Loading the Southern Ocean Up With Iron (Not the Good News Some Are Making it Out to Be)

Large Algae Blooms off Antarctica

Under A Green Sky

Awakening the Horrors of the Ancient Hothouse

Canfield Oceans

Nature

K-T Extinction — Impact or Hothouse Caused?

Climate Change Happening Faster Than Scientists Predicted

How Global Warming Sets off Extreme Weather

Hot Pacific Ocean Runs Bloody

Pacific Algae Bloom is The Biggest Red Tide We’ve Ever Seen

Chesapeake Bay Dead Zones

The Atlantic Ocean’s Whirlpool Dead Zones

LANCE-MODIS

Warning From Scientists — Halt Fossil Fuel Burning Fast or Age of Superstorms, 3-20 Foot Sea Level Rise is Coming Soon

First the good news. James Hansen, one of the world’s most recognized climate scientists, along with 13 of his well-decorated fellows believe that there’s a way out of this hothouse mess we’re brewing for ourselves. It’s a point that’s often missed in media reports on their most recent paper — Ice Melt, Sea Level Rise, and Superstorms. A paper that focuses on just two of the very serious troubles we’ll be visiting on ourselves in short order if we don’t heed their advice.

The way out? Reduce global carbon emissions by 6% each year and manage the biosphere such that it draws carbon down to 350 ppm levels or below through the early 22nd Century. To Hansen and colleagues this involves a scaling carbon fee and dividend or a similarly ramping carbon tax to rapidly dis-incentivize carbon use on a global scale. Do that and we might be relatively safe. Safe, at least in the sense of not setting off a catastrophe never before seen on the face of the Earth. That’s pretty good news. Pretty good news when we consider that some of the best climate scientists in the world see an exit window to a hothouse nightmare we’re already starting to visit upon ourselves.

The bad news? According to Hansen and colleagues, even if we just continue to burn fossil fuels and dump carbon into the atmosphere at a ‘moderate’ pace some of the terrifically catastrophic impacts of human caused climate change are not too far off.

A Moderate Pace of Burning

The new Hansen paper takes a look into both our geological past and our climate future in an attempt to give us an idea what may be in store. In this scenario, model, and paleoclimate based study, Hansen and colleagues assume two things about global human civilization. The first assumption is that we don’t follow the worst case, business as usual carbon emissions policies that lead to around 1000 ppm CO2 in the atmosphere by 2100. It is instead assumed that some effort is given to reducing coal, oil, and gas consumption. That some renewable energy, increased efficiency and behavior changes replace a significant portion of future fossil fuel emissions. But the most effective solution — a complete transition away from fossil fuel burning over the next few decades — fails.

A1B1

(A1B is a ‘moderate’ emissions scenario that, according to model essays, is likely to see between 2.5 and 3.5 C warming by the end of this Century and around 700 ppm of CO2 accumulation. That is, without the kind of major ice sheet response indicated in the new Hansen study. Image source: Knutti and Sedlacek.)

As a result, we end up with around 700 parts per million carbon dioxide in the atmosphere by 2100. In such a case we’ve followed what the IPCC community terms as the A1B or ‘moderate’ fossil fuel emissions scenario.

A Question of Melt Rate Doubling Time

It is in this context that the Hansen paper attempts to determine a key factor that will have wide-ranging impacts on ocean health, the continued existence and lifespan of coastal cities, and on the severity of the weather itself. That factor is captured by a single simple question — if we continue a moderate pace of fossil fuel burning, then how rapidly will ice sheet and ice shelf melt double?

To Hansen this is a critical question. One he has already done quite a bit of work to answer over recent years. And according to his findings it looks as if land ice melt rates for both Greenland and West Antarctica could now be doubling every 5-20 years. It’s a doubling rate that may find a historical allegory in the milder yet still intense glacial outflows of times long past. And it’s something that, according to Hansen, is being directly driven by an extreme pace of human-based greenhouse gas accumulation.

The Eemian — Significant Sea Level Rise and Terrible Storms Under Far Lower CO2 Forcing

To this point, Hansen’s new paper takes a dive into the paleoclimate study of an ice age interglacial that bears some stunning similarities to our own, human warmed, time period. He looks at the Eemian, a warm period that occurred 130,000 to 115,000 years ago. A period that featured temperatures in the range of 1-2 C above 1880s values (we’re in the process of hitting 1 C above 1880s values this year). A period in which CO2 levels were in the range of 285 parts per million (about 15 parts per million higher than the Holocene average before humans spiked that level to 400 parts per million during recent years). And a period that, according to Hansen’s broad study of past research, included numerous Heinrich type glacial outburst and melt events.

Back then, at 285 parts per million CO2 levels, seas were as much as 5-9 meters (16 to 30 feet) higher than they are today. The global climate, on the other hand, was much stormier. For two Heinrich type events that Hansen investigated were found to have dramatic impacts on severe storms in the North Atlantic during the Eemian. Hansen found large boulders propelled up onto the islands of Bermuda and the Bahamas by what appear to be powerful storm waves. Hansen also noted chevron shaped wave channels carved into the calcified sand beds in the Bahama Island Chain.

Heinrich Event

(Heinrich events included major glacial outflows like the one seen here at Jacobshavn, Greenland. Note the significant ice volume outflow through the channel at center frame. Also note the white dots in Baffin Bay indicating ice berg discharge. For reference, bottom edge of frame is about 100 miles. In past Heinrich Events outflows like the one seen above hit high gear as glaciers released armadas of ice bergs into the oceans which generated ocean and atmospheric changes. As the ice bergs melted, they deposited rocks on the sea bed. These piles of ice raft debris then became a signature geological feature of Heinrich events in the ancient past. Image source: LANCE MODIS.)

It paints an overall picture of very stormy weather in the North Atlantic as a result of these Heinrich ice sheet melt episodes affecting Greenland and West Antarctica. These melt events drove fresh water out into the North Atlantic and the Southern Ocean at the rate of about 0.5 to 1 meters of sea level rise per century. The expanding cold, fresh water along the surface zones in the upper latitude waters shut off heat exchange between the ocean and the atmosphere by generating a stratified ocean state. This fresh water wedge interrupted the plunging of heavier, salt-laden waters in the North Atlantic and the Southern Ocean. A loss of heat exchange that resulted in the cooling of airs directly over the fresh water outflow pools.

Meanwhile, since heavy, saltier waters were no long diving to the ocean bottom in these regions — broader ocean circulation was interrupted. As a result, heat from the equator was no longer traveling poleward. The equator warmed. The cold, fresh water outflow regions cooled. And this high temperature gradient subsequently became a powerful storm generator — providing extreme baroclinic potential energies for the storms that likely reshaped the ocean bottom and deposited massive boulders upon islands throughout the North Atlantic.

It’s worth noting that the 5-9 meter sea level rise during the Eemian occurred in the context of global temperatures that are now similar to our own (1-2 C above 1880s values). But it’s also worth considering that the underlying CO2 and greenhouse gas conditions for the current age are far, far worse. Peak global CO2 during the Eemian never hit higher that 285 parts per million. For the Anthropocene age we are now leaving the 400 parts per million CO2 level in the dust. Meanwhile, the pace at which we are warming is also more than 10 times faster than the pace of warming to peak Eemian heat values. And it’s these two factors — an extreme greenhouse gas overburden combined with a very rapid pace of warming that has Hansen and colleagues very concerned about our climate situation over the next 10-80 years.

Land Ice Below Sea Level — Amplifying Feedback For Melt

Turning to the current day, there’s a growing number of reasons why we should be concerned that rapid land ice melt, large fresh water outflow to oceans, and resulting superstorms could be in our future. First, we’ve learned that the topography of Greenland and Antarctica include numerous channels that tunnel deep into its great glaciers at depths well below sea level. When oceans warm, and they’re warming as you read this, the submerged, sea-facing slopes of glaciers are confronted with more and more heat gnawing away at their under-bellies. Just a 0.1 C increase in water temperature can melt away a meter of ice over the course of a year. Multiply that by glaciers with faces that are submerged hundreds of feet deep whose sea fronting cliffs extend for many miles and you can end up with quite a lot of melt due to very little warming. As more of the undersides of glaciers melt, more of the water tunnels inland and large masses of ice are rafted away from the central ice exposing still more of the land anchored ice to a warming ocean flood.

image

(Image from Hansen Paper shows how land ice melt generates ocean stratification which is an amplifying feedback that enables ocean bottom warming and more land ice melt. Note — AABW stands for Antarctic bottom water, NADW — North Atlantic down welling. Image source: Ice Melt, Sea Level Rise, and Superstorms)

As bad as this dynamic may sound, the process includes one more wrinkle that makes it even worse. As the undersides of ice shelves erode and more fresh water laden ice bergs are pulled out into the ocean, these ice bergs begin to melt en mass. This massive ice melt develops into an enormous and expanding pool of fresh water at the surface. And its this troublesome demon that traps heat in the deeper ocean levels. So, in other words, as the ice from the land glaciers floats away and melts it traps and focuses more heat at the base of these great glaciers. It’s an amplifying feedback. A very serious kind that doesn’t even require the human forced kick to create severe trouble. One that during the Eemian really wrecked the weather and caused massive surges in ocean height.

It’s a process that Hansen and his colleagues believe make both Greenland and West Antarctica very vulnerable. A process that could, when combined with the high velocity human heat forcing, produce melt rates that double every 20, 10 or even every 5 years. But of the two — Greenland or Antarctica — which is worst off?

Greenland topography

(Topographic map of Greenland sans its great ice sheet. Most of central Greenland’s mass is now below sea level. It’s a basin that now holds a miles high ice mountain. Various channels allow ocean water access to the central ice mass should the channel openings melt due to warming oceans. Such an invasion could set off a rapid sea level rise driven by Greenland melt. Image source: Livescience.)

Greenland, for its part, is little more than a great Archipelago held together by its stunning ice mass. Remove the ice and the interior of Greenland would flood, leaving a ring of islands as a final remnant. Though deep, most of these channels run up slope. And this feature, according to the Hansen study, may be one saving grace for potential Greenland ice melt pace. Up slope channels limit the impact of basal melt by serving to check rates of catastrophic destabilization. So though Greenland is certainly vulnerable to ice melt due to the fact that many channels cut hundreds of feet below sea level and into the island’s glacial heart, it is not as vulnerable as West Antarctica.

There, many channels cut deeper beneath the Antarctic ice mass. But not only are they below sea level by hundreds of feet as with Greenland, they slope down. They slope down and not for just a little ways under the ice sheet — some of these ocean heat skids extend in down-sloping fashion for hundreds of miles beneath the Antarctic ice. The result is a kind of skid, that once unlocked by initial melt, can continue to expose larger and large chunks of bottom ice to the warming ocean. Allowing, ultimately, the creation of new warming seas underneath the ice and floating it away in very rapid fashion.

In West Antarctica, ice shelves facing the Weddell and Ross seas both feature these dangerous retrograde slopes. In East Antarctica, the Totten Glacier is likewise vulnerable as are many other glaciers surrounding the vast periphery of Antarctica.

Retrograde slope Ross ice shelf

(Retrograde slopes behind ice sheet grounding lines are just one reason why Antarctic land ice is so unstable. Image source: Ice Sheet Mass Balance and Climate Change.)

Finally, in addition to being surrounded by the warming, deeper waters of the Southern Ocean, in addition to featuring dangerous retrograde slopes that channel warming sea water further and further inland and beneath the ice sheets, West Antarctica itself sits on a geological hot bed. Though not mentioned in the Hansen study, recent work also highlighted that West Antarctica rests atop a geologically active zone that had formed numerous sub-glacial lakes warmed by geological activity. This added geological heat makes West Antarctica that much less stable — an instability that when given the shove of human heated oceans is leading the Larsen B Ice Shelf to completely collapse by 2020. It makes Antarctic land ice that much more vulnerable to the added heat human beings are forcing into the oceans and opens up the ominous possibility that melt rate doubling times for West Antarctica could become quite extreme indeed.

Modeling Land Ice Melt’s Impact in the 21st Century — Facing A Coming Age of Superstorms

So what does all this mean? In the worst case (5-10 year melt rate doubling times), it’s possibly 3 meters of sea level rise by mid Century, perhaps 7 meters by end Century under business as usual fossil fuel emissions. Even in the more moderate cases (10-20 year melt rate doubling times), 1 meter of sea level rise by mid Century and 3 meters or more of sea level rise by end Century is not entirely out of the question, according to Hansen’s new research. These potentials are markedly different than the more conservative rates outlined by IPCC which is still calling for a less than 1 meter sea level rise under even the worst case human carbon emissions scenarios (1000 parts per million CO2, in the range of 1200 ppm CO2e).

So much fresh water hitting the oceans would cause a rapid stratification. A rapid loss of ocean to atmosphere heat exchange in the regions impacted. A train wreck of heat backing up at the equator. Such a train wreck would result in temperature extremes and gradient differences that would make the Eemian Heinrich events (mentioned above) seem moderate and slow by comparison.

Hansen has been working on global atmospheric models for tracking these events for a number of years now. And this new study is an improvement on his earlier, model-driven “Storms of My Grandchildren” work. Hansen’s new model runs are imperfect simulations of what may happen given large melt pulses from Greenland and Antarctica. The models, according to Hansen, mix the ocean water too much, reducing the overall impacts of stratification through the mechanism of the fresh water wedge. However, even with this imperfection, the temperature gradients displayed by these models are absolutely stunning. A clear warning to anyone who still wants to keep burning fossil fuels that they’re really grabbing the dragon by the tail.

image

(A mid range simulation including 10-20 year melt rate doubling times and 6 feet of sea level rise by 2080 — half Greenland, half Antarctica — shows enormous weather impacts in the form of a severe, superstorm generating, temperature gradient. Image source: Ice Melt, Sea Level Rise, Superstorms.)

In the above image we can see just one of these model runs. The model assumes a 10-20 year doubling time for rate of land ice melt. It contributes equal portions of melt from Greenland in the north and Antarctica in the south. Greenhouse gas accumulation is considered to be along the moderate case A1B track. By 2080 we have about six feet of sea level rise globally and about 600 parts per million CO2 in the atmosphere. The more rapid rate of melt has put a temporary damper on the rate of global atmospheric warming which has dipped to 1.11 C above 1880s values (just slightly higher than today). But much of this cooling is localized to the Southern Ocean and to an extreme cold pool in the North Atlantic between Northwestern Europe and Greenland.

There a massive outflow of fresh water has shut down the ocean’s ability to exchange heat with the atmosphere. AMOC has been vastly weakened. The Gulf Stream is backed up along the US East Coast and into the Gulf of Mexico. Heat is building in the Arctic opposite Greenland and all along the Equator. Temperature anomalies in the range of 17 degrees Celsius below average occur over the ocean fresh water pool. This drop is enough to generate year round winter like conditions in the cold pool region even as other sections of the atmosphere around it continue to warm or retain severe excess heat.

Energy imbalance at the top of the atmosphere rockets to between 2 and 4 Watts per meter squared. What this means is that, in failing to ventilate heat to the atmosphere in the North Atlantic and Southern Ocean, the world ocean system has continued to accumulate a massive amount of heat. Heat that is now going to work warming the ocean bottom and hitting the bases of the already rapidly melting land ice.

Sandy

(More superstorms in our future. If Hansen’s new research is correct storms like Sandy will grow both more powerful and more common as Greenland dumps ever increasing volumes of fresh water into the North Atlantic. Image Source: NASA.)

For the North Atlantic, it is the greatest of understatements to say that an area of perpetual winter surrounded by warming airs and sitting atop a warming deep ocean is a major storm generator. Summer time temperature deltas between the center of the cold pool will range from near zero C to 20s, 30s and 40s C over nearby ocean and continental land masses. It’s like taking the High Arctic and shifting it to Scotland while all the adjacent airs warm. Temperature gradient and baroclinic (pressure gradient) energy for storm generation will be on the order of something that modern humans have never experienced. The potential for superstorms in this model simulation will, notably be quite high.

Final Notes — Superstorm Conditions Could Emerge Sooner than Models Indicate

The point to consider here is that large scale land ice melt sets in place forces that result in a weather wip-lash of epic proportion. It’s been the heart of Hansen’s work for many decades and it’s an issue that we really need to consider as time goes forward. A dwindling time for response that may well be much shorter than even Hansen’s models indicate. First, ice sheet vulnerability may well be higher than IPCC officials imagine and we could well be on a slope of melt rate doublings in the range of 5-20 years now.

global sea level change

(Global sea level rise keeps hitting a steeper and steeper slope. Image source: Dr. James Hansen, Columbia University)

Second, Hansen’s models likely capture the atmospheric impact of such large-scale land ice melt later than would happen in the real world. This later capture is due to the fact that his low resolution models mix the ocean heat more with the atmosphere than would occur under the kinds of ocean stratification events that we are likely to see due to these doubling times. Third, and finally we return again to the paleoclimate time of the Eemian where there is ample evidence that a mere 0.5 to 1 meter per century rate of sea level rise due to melting Greenland and West Antarctic ice during that time set in place conditions to generate superstorms with high enough peak intensity to deposit massive boulders upon islands in the Atlantic and to carve the impression of gigantic, long-period waves into the sea bed.

Anyone reading this work and considering the notion that some of the greatest scientific minds this age has birthed could be right is immediately confronted with the realization that the gargantuan forces we are playing with are not to be trifled with. And yet, the trifling continues despite the wise and well considered scientific warning to relent.

Links:

Hansen Paper: Ice Melt, Sea Level Rise and Superstorms

Dr. James Hansen, Columbia University, Former NASA GISS Lead Scientist

Knutti and Sedlacek: Robustness and Uncertainties in Climate Model Projections

The Eemian

LANCE MODIS

Livescience — Topographic Map of Greenland Sans Ice Sheet

Ice Sheet Mass Balance and Climate Change

NASA: 10,000 Year Old Ice Shelf to Collapse by 2020

IPCC Sea Level Change

NASA Earth Data

Storms of My Grandchildren

 

Steaming Equatorial Pacific Sees Winds Blowing Toward Monster El Nino

Last year, we raised a warning that the 2014-2015 El Nino could develop into a monster event. And, unfortunately, there is some indication that conditions may well be continuing in that direction.

*   *   *   *

All across the broad belt of the Equatorial Pacific, sea surface temperatures are running in the hot-to-extraordinarily hot range. Starting just north and east of New Guinea, 1 C + above average temperature anomalies run uninterrupted to a zone near the date line where they encounter a hot pool in the range of +2.6 to +3.1 C above average. Running eastward, these high heat anomalies gradually taper off to +1.4 to +1.7 C along a 5,000 mile stretch before they again spike to +3 to +4 C above average just off the west coast of South America.

A massive zone of above average sea surface temperatures encompassing almost the entire width of the Equatorial Pacific:

image

(Pacific Ocean showing extreme heat anomalies across most regions. Image source: Earth Nullschool.)

Hot equatorial waters in a Pacific Ocean that, from Arctic north to Austral south, from East Asian shores to the west coasts of the Americas is a morass of record high temperatures. An ocean zone featuring few and dwindling pools of lower than average readings. Oceans undergoing rising rates of heat-related sea creature die offs in waters that, when they warm, lose vital oxygen and host toxin-producing microbes that thrive in hot water.

It’s a freakishly hot Pacific. A strange ocean. One that we aren’t quite accustomed to. One in the grips of what is already a moderate strength El Nino. An El Nino that, combined with an extraordinary human greenhouse gas heat forcing, has pushed global surface temperatures into record high range for 2014 and the first three months of 2015 thus far. An El Nino which is now threatening a new leap to monster status.

For a powerful Kelvin Wave is presently lending heat to equatorial surface waters after receiving a boost from gale force westerly winds associated with the strongest Madden Julian Oscillation on record this past March. An raging equatorial heat engine that is now drawing yet more energy from a second set of strong westerlies developing this week.

image

(Strong westerlies emerging in the Western Pacific on May 6 may provide yet another boost to the 2014-2015 El Nino. Image source: Earth Nullschool.)

In the above GFS summary, we find sustained winds in the range of 30 mph with gale force gusts in a region along and just north of the Equator near New Guinea. The winds are in association with a developing cyclone, one that models indicate will reach strong Typhoon status later this week. The westerlies stretch westward along the back of New Guinea and on toward the Philippines. There, they receive a boost from another cyclone — Tropical Storm Noul.

The result is a brisk set of westerlies running against the trades along hundreds of miles of open ocean. The kind of event with the potential to further strengthen an El Nino that is already at respectable intensity.

This week’s CFSv2 NOAA forecast models continued to indicate an extreme strength El Nino by later this year. Weighted models are now showing seasonal anomalies in the Nino 3.4 zone peaking out at +2.3 C. Weighted monthly models are showing peaks in the range of +2.5 C above average for Nino 3.4. And unweighted models are showing peak averages that now exceed +3.1 C. This is a jump from last week’s CFSv2 forecast. Another set in a continued trend for higher intensity.

Monster El Nino forecast

(NOAA’s forecast models show potential for extreme El Nino starting in June and extending into January. Image source: NOAA.)

Should such an event emerge it would truly be a monster. Something far worse than even the Super El Nino of 1998.

An extraordinary El Nino of this kind would have far-reaching climate and weather related impacts. It would push global temperatures into ever more dangerous ranges. It would strain global carbon sinks. And it would worsen drought and/or set off heavy precipitation events in various, already vulnerable regions of the globe. With model forecasts continuing to hit higher values, with so much available heat to fuel El Nino ranging the Pacific, and with strong westerlies continuing to reinforce the current El Nino, this is a situation that bears very serious continued monitoring.

Links:

Monster El Nino Emerging From the Depths

NOAA’s Climate Prediction Center

Earth Nullschool

March Shows Strongest Madden Julian Oscillation on Record

Starving Sea Lion Pups and Liquified Starfish

 

 

 

 

World Ocean Heartbeat Fading? ‘Nasty’ Signs North Atlantic Thermohaline Circulation is Weakening

Scientists call it Atlantic Meridional Overturning Circulation (AMOC). But we may as well think of it as the heartbeat of the world ocean system. And when that heartbeat begins to slow down, we’d best sit up and start paying attention:

(New video produced by climate hawk Peter Sinclair and featuring top scientists Stefan Rahmstorf, Michael Mann, and Jason Box, issues warnings about an observed disruption to ocean circulation due to water freshening in the North Atlantic. This is the kind of work I mentioned last week in my KPFA interview. The kind that should be showing on major network news every single night. Since that probably won’t happen, I urgently ask you to spread this video, together with its critical information, as far and as wide as possible.)

Global Warming Poses Risk to Ocean Circulation, Life Support

For nearly three decades now, prominent climate scientists have been warning policymakers that salt and heat driven circulation of the world ocean system (called thermohaline — thermo for heat and haline for salt) could be disrupted by cold water outflows from Greenland. There, in the North Atlantic, salty, dense, ocean water issuing from the tropics along the Gulf Stream begins to cool. The heavier water, burdened with salt, sinks to the bottom in the North Atlantic. This sinking, in turn, drives a massive ocean conveyer belt. It delivers colder, oxygenated water to the deep ocean. It dredges less oxygen rich bottom waters to the surface where they can be reinvigorated. And it drives this ocean revitalizing train of currents through every major corner of the world ocean.

A disruption of this ocean water mixing machine would ripple through the world oceans like a gunshot to a vital circulatory organ, reducing oxygen levels throughout the whole ocean system, and greatly reducing the oceans’ ability to support life. It would be a major shift toward a stratified, less life supporting ocean, and one step closer to the nightmare ocean state called a Canfield Ocean (named after its discoverer — Dr. Donald Canfield).

Warmer, salty water cooling and sinking in the North Atlantic is an essential cog in the wheel of this massive ocean water overturning machine. It has also been described (as Dr Box notes in the video above) as the Achilles Heel of global ocean circulation.

But I like to think of it more as the world ocean’s beating heart. The reason is that any disruption of the overturning process in the North Atlantic basically kills off a life-giving circulation to the entire world ocean system.

Cooling in Exactly the Wrong Place

AMOC Temperature Trend

(Linear temperature trend from 1900 through 2013 produced by Stefan Rahmstorf in his new study. Note the anomalous cool pool just south of Greenland. That’s exactly the kind of temperature signature you don’t want to see. One that is indicative of cold, fresh water outflows from Greenland interfering with North Atlantic and World Ocean Circulation. Also see: RealClimate.)

Now, a new 2015 report headed by Dr. Stefan Rahmstorf finds that the world ocean system is cooling in exactly the wrong place — the North Atlantic just south and east of Greenland. This cooling is an indicator that a high volume outflow of cold, fresh water is entering this region of ocean. A cold, fresh outflow that comes directly from the melting glaciers of Greenland itself. A cooling and freshening that creates a physical block to salt water down welling in the North Atlantic. The kind of block that can directly disrupt the Gulf Stream and the rest of ocean circulation on down the line.

Dr Rahmstorf explains the findings of his study in his notes at RealClimate:

The North Atlantic between Newfoundland and Ireland is… the only region of the world that has defied global warming and… cooled. Last winter [this region] was the coldest on record – while globally it was the hottest [such period] on record. Our recent study (Rahmstorf et al. 2015) attributes [ anomalous North Atlantic cold water] to a weakening of the Gulf Stream …, which is apparently unique in the last thousand years.

It happens to be just that area for which climate models predict a cooling when the Gulf Stream System weakens (experts speak of the Atlantic meridional overturning circulation or AMOC, as part of the global thermohaline circulation). That this might happen as a result of global warming is discussed in the scientific community since the 1980s – since Wally Broecker’s classical Nature article “Unpleasant surprises in the greenhouse?” Meanwhile evidence is mounting that the long-feared circulation decline is already well underway. (emphasis and a little clarity added)

To Dr Rahmstorf’s point that the North Atlantic was experiencing a Gulf-Stream threatening record cold while the world was under a pall of record warmth, we need only look at NOAA’s Land-Ocean temperature anomalies map for the winter of 2014-2015 below:

NOAA land ocean temperatuer anomalies

(NOAA Land Ocean temperature anomalies map for 2014-2015 shows extraordinary record cold pool of water south of Greenland in a record warm world. The smoking gun for large glacial outflow and thermohaline disruption in the North Atlantic. Image source: NOAA via ClimateCrocks and MeltFactor.)

Other Concerns Regarding North Atlantic Cooling

Unfortunately, an expanding pool of cold, fresh water in the North Atlantic is not just a threat to ocean health. It also represents a zone of anomalous cold in a region surrounded by atmospheric and ocean warming. As such, it represents a zone of likely expanding atmospheric instability — one involved in the shift of the cold center of circulation from the polar zones and more toward Greenland and Canada. Parcel to the kinds of weather disruptions that have been described in the theories of Dr. Jennifer Francis and during some of the later works of Dr. James Hansen (alluded to in The Storms of My Grandchildren).

As such, cold water bleeding from the great glaciers of Greenland not only poses a threat to ocean circulation, it also poses a risk for generating significant disruptions to atmospheric winds and related weather as well. Ones that could set off increasingly intense storm events in the Northern Hemisphere similar to what was seen for the US Northeast this winter (but likely worsening with time) and the extraordinarily powerful barrage of storms hitting England during the winter of 2013-2014.

Dr. Hansen in his Greenland Ice Sheet Loss: Exponential? paper warned of the potential for continent-sized frontal storms packing the strength of hurricanes under some rapid Greenland melt scenarios by mid-century.

Hollywood dramatizations aside, this is more than enough real world weather and climate trouble to pose serious cause for concern. And as Dr. Rahmstorf, Peter Sinclair, Dr. Jason Box and Dr. Mann allude to the header video — the policy makers were warned well in advance.

Links:

A Nasty Surprise With the Greenhouse

What’s Going on With the North Atlantic?

Exceptional 20th Century Slowdown in North Atlantic Overturning Circulation

Unpleasant Surprises in the Greenhouse

NOAA

MeltFactor

Greenland Ice Sheet Loss: Exponential?

Linking Weird Weather to Rapid Warming in the Arctic

Canfield Ocean

Hat tip to Today’s Guest Is…

New Study Finds 3-4 Meter Sea Level Rise From Antarctica May be Imminent

Ocean stratification. A condition characterized by the separation of layers of water of different temperatures and chemical make-up. A condition that has serious impacts to the geophysical nature of the worlds oceans, to the ability of oceans to support life, and to the stability of the vast glaciers of Antarctica — whose faces plunge as deep as hundreds of feet into the Southern Ocean.

In the Antarctic, today, what we see is a cold surface layer and a heating bottom layer. The cold surface layer is fed by an expanding pulse of chill, fresh water issuing from the melting glaciers of Antarctica. Over the years it has become more uniform, sequestering cold near the surface as warmth builds up in the depths below. The deeper hot layer is fed by warmer water issuing in from the tropics and heated to temperatures not seen for tens of thousands of years. This hot water bears a heavy burden of salt. So it is denser and it dives beneath the expanding fresh water layer. The insulating fresh, cold water layer prevents mixing between the bottom layer and the surface. Such mixing would cool the bottom layer. But instead the heat builds and builds and builds.

Difference in Ice mass Between now and last glacial maximum

(Antarctica — visual difference in ice mass between now [right] and last glacial maximum [left]. By mid century, atmospheric greenhouse gas concentrations driven by humans could be high enough [550 ppm CO2e+] to melt all the remaining ice upon this now-frozen continent. Image source: NASA/Goddard Space Flight Center.)

Ocean currents bring the deep, hot water in contact with the base of Antarctica’s massive glaciers. And this intensely focused heat engine goes to work to rapidly melt the ice.

It is this condition of ongoing and intense melting of the ice sheet’s bases that terminate in faces of ice cliffs, hundreds of feet high and deeply submerged in the sea, that is driving the irreversible collapse of many glaciers in Antarctica. Already, due to this irreversible fall, the entire flank of West Antarctica is under collapse — locking in at least three feet of sea level rise from this region alone going forward.

But now, a new study finds that these conditions — the same conditions we observe today — led to the release of enough glacial ice from Antarctica alone at the end of the last ice age to raise sea levels by 3-4 meters (10-13 feet) in just 1-3 centuries.

From Nature Communications:

“The reason for the layering is that global warming in parts of Antarctica is causing land-based ice to melt, adding massive amounts of freshwater to the ocean surface,” said ARC Centre of Excellence for Climate System Science researcher Prof Matthew England an author of the paper.

“At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers on Pine Island and Totten. It appears global warming is replicating conditions that, in the past, triggered significant shifts in the stability of the Antarctic ice sheet.”

The last time this happened was 14,000 years ago as the Earth slowly warmed out of the end of the last ice age. But the result was anything but gradual:

“Our model simulations provide a new mechanism that reconciles geological evidence of past global sea level rise,” said researcher UNSW ARC Future Fellow Dr Chris Fogwill.

“The results demonstrate that while Antarctic ice sheets are remote, they may play a far bigger role in driving past and importantly future sea level rise than we previously suspected.”

“The big question is whether the ice sheet will react to these changing ocean conditions as rapidly as it did 14,000 years ago,” said lead author Dr Nick Golledge, a senior research fellow at Victoria’s Antarctic Research Centre.

These are critical questions. Ones that have serious impacts for the more than 700 million people now living within 10 meters of current sea level.

Antarctic Ice Shelf Thickness Changes

(Antarctic Ice Shelf thickness changes. Note the thinning of almost all the ice shelves along the margin of Antarctica. Ice shelves anchor interior ice, keeping it from rushing out through deep channels into the Southern Ocean. Rapidly thinning ice shelves is a precursor to glaciers rushing toward the sea. Image source: Nature Pritchard et al. 2012)

To this point it is worth noting that the pace of warming 14,000 years ago was on the order of 0.05 degrees Celsius each century. The current pace of human-driven warming over the past century was 20 times faster. This century, the warming is predicted to be as much as 500 times faster (3-5 C warming by 2100). So the question may we be — will Antarctica respond as ‘slowly’ as it did at the end of the last ice age? Slow as in ice outbursts that lead to sea levels rising by as much as 14 feet during one century.

Links:

Change Antarctic Conditions Could Trigger Steep Rise in Sea Levels

Antarctic Contribution to Meltwater Pulse 1A From Reduced Southern Ocean Overturning

Weighing Change in Antarctica

It’s All About Fresh Water — Rapid Sea Level Rise Points to Glacial Melt in Antarctica

Human-Destabilized Antarctica Capable of Glacial Outbursts Contributing to Sea Level Rise of 14+ Feet Per Century

Antarctic Ice Sheet Loss Driven by Basal Melting of Ice Shelves

(Hat Tip to Colorado Bob)

 

 

 

 

 

It’s All About Fresh Water — Rapid Sea Level Rise Points To Massive Glacial Melt in Antarctica

It’s all about fresh water. In this case, massive freshwater outflows from the vast glaciers covering Antarctica.

This week, a new scientific report published in the Journal Nature found that from 1992 through 2012 freshwater outflow from Antarctica’s massive glaciers exceeded 400 gigatons each year. An immense flood of cold, fresh water. One that helped push sea levels rapidly higher around the Antarctic continent.

But with glacial melt on the rise and with mountains of ice now inexorably sliding seaward, these freshwater flows may just be the start of even more powerful outbursts to come. And such prospective future events have far-ranging implications for sea level rise, global weather, sea ice, human-caused climate change, and world ocean health.

Flood of Fresh Water Drives More Sea Level Rise Than Expected

The researchers discovered the tell-tale signature of this vast freshwater flood through chemical analysis of the seas surrounding Antarctica. The analysis pointed to a broad and expanding fresh water layer over-riding a warmer, saltier current issuing in from the Southern Ocean.

Since fresh water is less dense than salt water, the freshwater layer expands at the ocean surface causing sea levels to rise more rapidly. Meanwhile, the heating of the deep ocean surrounding Antarctica is thought to result in additional thermal expansion of the water column.

The researchers note:

On the basis of the model simulations, we conclude that this sea-level rise is almost entirely related to steric adjustment [changes that effect atomic spacing], rather than changes in local ocean mass, with a halosteric [salt based] rise in the upper ocean and thermosteric [heat based] contributions at depth. We estimate that an excess freshwater input of 430 ± 230 Gt yr−1 is required to explain the observed sea-level rise. We conclude that accelerating discharge from the Antarctic Ice Sheet has had a pronounced and widespread impact on the adjacent subpolar seas over the past two decades.

Antarctic Sea level Trend

(Rate of sea level rise in the seas surrounding Antarctica since 1992. Aggregate sea level rise is indicated in black. Individual seas data is broken out by color. Image source: Nature.)

Previously, increased rates of sea level rise surrounding Antarctica were thought to have been set off by increasing winds around the continent. The winds were thought to push more water up against the ice faces forming a kind of perpetual, low-grade storm surge. But the current finding provides strong evidence that the source of the sea level rise is due to less dense fresh water over-topping saltier waters flowing in from the Southern Ocean combined with increasing heat along the Antarctic sea bed. And, notably, this is not the first study to find increasing freshwater flows spilling into the Southern Ocean. Last year, a KNMI expedition uncovered similar results.

More Evidence of Large-Scale Melt

The study comes on the back of other recent findings showing that warm water invasion at Antarctic glacier bases had led to more rapid than expected melt and destabilization. In May, two NASA studies showed that a broad section of West Antarctica had destabilized and was sliding at an ever more rapid pace toward the ocean (see reports here and here). These findings held stark implications for global sea level rise as large ice regions of Greenland and West Antarctica, containing enough water to raise seas at least 15 feet, are likely already in a state of irreversible collapse.

 

Regional Anomaly Sea level Antarctic

(Sea level rise anomaly of the region surrounding Antarctica compared with the rest of the Southern Ocean. Red indicates faster than normal sea level rise. Blue indicates slower than normal sea level rise. Image source: Nature.)

This intensifying glacial melt and associated freshwater cap expanding out from the pole has implications — not just for sea level rise, but for sea ice, weather, and world ocean system health.

Impacts For Sea Ice

Large outflows of glacial fresh water may well be involved in the recent observed expansion of sea ice in the zone surrounding Antarctica (see recent related study). Fresh water serves as an insulative cap on the ocean surface preventing warm water from entering the top layer from below. The warm, salty water, in the Antarctic instead pools near the bottom or at the base of the great ice sheets.

Fresh water also freezes at a higher temperature than salt water. So sea ice in an expanding freshwater zone around Antarctica would have naturally higher resiliency even to the rising temperatures now occurring due to human-caused warming. Eventually, however, human heat forcing would overwhelm the ice, but not before a period of related, localized negative feedbacks.

The Iceberg Cooling Effect

The fresh water is a haven for sunlight-reflecting sea ice. It is interspersed with ice bergs from the glacial discharge and the large ice bergs cool the surrounding air. The fresh water layer prevents warm water upwelling from the warm, deep waters surrounding Antarctica. And the leading edge of the fresh water would drive salt-water down-welling along its advancing front. This would push warmer waters toward the ocean bottom, resulting in a kind of heat sink. And this is exactly the kind of dynamic that appears to be ongoing in the Southern Ocean now. These combined impacts are what is known as the ice berg cooling effect associated with large-scale glacial outbursts known as Heinrich Events. And we may well be in the process of setting off one of these geological scale nightmares.

20121230_iceberg_cooling_effect_Hansen_Sato

(Iceberg cooling effect under a mid-range warming scenario when global climate models were set to include the effects of large freshwater outflows from polar glaciers at a fast enough rate to raise seas by 60 cm through 2060 and 144 cm through 2080 [left frames]. Note the cooler zones in the Southern Ocean and North Atlantic adjacent to Greenland. Right frames include mid range emissions/warming scenarios and IPCC projected rates of sea level rise. It is worth noting that the amplifying effects of potential additional ghg release from the global climate system, particularly from Arctic and world ocean carbon stores, are not included in these simulations. Image source: Hansen and Sato.)

For global weather, such events have major implications. Regional cooling in the zone of freshwater outflow would juxtapose regional warming in the southern hemisphere meridional zones. This temperature differential would increase with the strength of the fresh water outflow and the rising intensity of the human-driven warming. The result would be a powerfully intensified storm track. Both the intensified storm track and increased atmospheric moisture loading due to human warming would result in much more powerful weather events than we are currently used to and the potential for catastrophic storms would drastically increase.

Amplifying Feedbacks and a Blow to World Ocean Health

Lastly, the expanding flood of fresh water would result in an increasing stratification of the world ocean system. This stratification would drive warm, salty water toward the ocean bottom and deplete already low oxygen reserves in that region. In addition, the extra heat is more likely to destabilize deep-sea clathrates — releasing methane which will speed in the oxygen depletion of the abyssal waters even as it tips the world ocean system to stop storing carbon and to begin releasing it. A combined feedback that is both an ocean killer and an amplifier to the already extraordinarily powerful human heat forcing mechanism.

Links:

Rapid Sea Level Rise Along Antarctic Margins Due to Increasing Glacial Discharge

Important Role For Ocean Warming and Enhanced Ice Shelf Melt in Sea Ice Expansion

Update on Greenland Ice Sheet Mass Loss: Exponential?

Grim News From NASA: West Antarctica’s Entire Flank is Collapsing

Nature: Human-Destabilized Antarctica Capable of Glacial Outbursts Contributing to Up to 14 Feet of Sea Level Rise Per Century

 

Through The Looking Glass of The Great Dying: New Study Finds Ocean Stratification Proceeded Rapidly Over Past 150 Years

During the terrible mass extinction event at the Permian-Triassic boundary about 250 million years ago nearly all life on Earth was snuffed out. The event, which geologists have dubbed “The Great Dying,” occurred during a period of rapid warming on the tail end of a long period of glaciation (see A Deadly Climb From Glaciation to Hothouse: Why the Permian-Triassic Extinction is Pertinent to Human Warming). According to reports by Dr. Peter Ward, a prominent geologist specializing in causes of previous mass extinctions, the Permian extinction was composed of three smaller extinction events occurring over the course of about 50,000 to 80,000 years which together wiped out 96% of all marine species and 70% of all land species. Ward’s book “Under a Green Sky,” in my view, together with Hansen’s seminal “Storms of My Grandchildren” provide an excellent if terrible rough allegory of the climate beast we seem to be in the process of awakening.

A2 model run

(NCAR A2 model run shows global surface temperatures near those last seen during the PETM and Permian/Triassic extinction events by 2090 under a middle-range fossil fuel emissions scenario. A2 does include some added emissions via amplifying feedbacks from massive polar methane or CO2 stores along with other Earth Systems feedbacks. It is worth nothing that the P/T extinction occurred at the end of a glacial period while the PETM did not and was notably less pronounced. It also worth noting that global average temperatures are currently about .2 C above those seen in the 1990s.)

As noted above, Ward’s work focused on causes and what he found at numerous dig sites around the world was evidence of a ‘Great Dying’ that began at the ocean floor, proceeded upward from the depths, and eventually came to transcend the ocean boundary and inflict a similar, if less pronounced, lethality upon terrestrial organisms. The mechanism Ward proposed for the worst extinction in Earth’s geological memory involved how oceans and, in particular, living creatures in the oceans, respond to rapid warming. Ward found that during periods of high heat called hothouse states, oceans first became anoxic and stratified and then, during the worst events, transitioned to a deadly primordial state called a Canfield Ocean.

A stratified ocean is one in which the layers become inverted and do not mix. Warm water is avected toward the ocean bottom and a cooler layer on top keeps that warm layer in place. The warmer water beneath is oxygen poor and this results in more anaerobic microbes living in the deep ocean. Overall, global ocean warming also contributes to an anoxic state. Many of these microbes produce toxins that are deadly to oxygen dependent organisms. As they multiplied, the combined low oxygen/high toxicity environment created a layer of death that slowly rose up through the world ocean system.

The primary lethal agent Ward proposed for this action was hydrogen sulfide gas. This deadly gas, which has an effect similar to that of cyanide gas, is produced in prodigious quantities by an anaerobic bacteria whose remnants lurk in the world’s deep oceans. In lower quantities they turn the water pink or purple, in greater quantities — black. Oxygen is toxic to these primordial bacteria. And so, in the mixed oceans of the Holocene all the way back to the PETM boundary layer, these little monsters were kept in check by a relatively high oxygen content. But start to shut down ocean mixing, start to make the oceans more stratified and less oxygen rich and you begin to let these dragons of our past out of their ancient cages. And once they get on the move, these creatures of Earth’s deep history can do extreme and severe harm.

Ward hypothesized that these ancient organisms and the gas they produced eventually came to fill the oceans and then spill out into the atmosphere.

An anoxic, stratified ocean full of anaerobic organisms and out-gassing hydrogen sulfide to the atmosphere is a primordial sea state known as a Canfield Ocean. And Ward found that such hot, toxic waters were the lethal agent that most likely snuffed out nearly all life 250 million years ago.

A Climate Hockey Stick for the World Ocean System: Oceans Show Marked and Rapid Stratification Over the Past 150 Years

Peter Ward’s tone was nothing if not fearful in his book ‘Under a Green Sky.’ He wrote with the wisdom of a man who has come face to face with terrible limits time and time again. He wrote with the wisdom of a man shocked by some of the hardest truths of our world. He also made a plea — could scientists and experts of different fields please work together to give humanity a better measure of the risks he saw to be plainly visible.

Chief among these risks, according to Ward, included a rapidly warming planet. Ward found that both extreme high heat conditions as well as a relatively rapid pace of warming, in geological terms, increased the speed of transition to stratified ocean and Canfield Ocean states. Ward acknowledged that high rates of water runoff from continents likely contributed to anoxia. Recent studies have also indicated that rapid glacial melt combined with rapid global heating may contribute to a an increasingly stratified and anoxic ocean system.

Now, a new study of deep ocean corals entitled Increasing subtropical North Pacific Ocean nitrogen fixation since the Little Ice Age and conducted by researchers at the University of Santa Cruz and published in Nature has discovered proxy evidence that ocean stratification over the past 150 years advanced at the most rapid pace in at least the last 12,000 years. The study analyzed the sediment composition of coral growth layers to determine changes in ocean states since the 1850s. As the corals sucked up the dead bodies of micro-organisms over the past 1,000 years, the researchers were able to analyze what was happening to the cyanobacteria at the base of the food web.

What they found was that the bacteria increased their rate of nitrogen fixation by about 17 to 27 percent over the past 150 year period. And that this pace of change was ten times more rapid than that observed at the end of the Pliestocene and beginning of the Holocene 12,000 years ago.

Nitrogen Proxy Records and Their Relationship to Climate Change

(The Ocean’s Hockey Stick? Nitrogen Proxy Levels and Their Relationship to Climate Change.)

Increasing nitrogen fixation is an indicator of ocean stratification because cyanobacteria species under stress evolve to fix higher amounts of nitrogen from the surface transfer boundary with the air if particulate nitrogen levels in their environment drop. In a healthy, mixed ocean environment, nitrogen from various sources (terrestrial, run-off, etc), is readily traded between ocean layers due to the mixing action of ocean currents. In cooler oceans, more nitrogen is also held in suspension. But as oceans become warmer and more stratified, a loss of mixing and solubility results in lower nitrogen levels.

The researchers believe that this increase in nitrogen fixation is a clear indication that the region of the Pacific they observed is rapidly becoming more stratified and that this rate of increase is probably an order of magnitude faster than what occurred during the last major transition at the end of the last ice age.

“In comparison to other transitions in the paleoceanographic record, it’s gigantic,” Lead author Sherwood noted. “It’s comparable to the change observed at the transition between the Pleistocene and Holocene Epochs, except that it happens an order of magnitude faster.”

A separate study analyzing the nitrogen content of sea bird bones also provided proxy indication of a shift among cyanobacteria toward greater rates of nitrogen fixation, providing some additional confirmation for the increased ocean stratification observation. (An excellent article providing a more in depth exploration of these studies is available here.)

These studies combine with numerous observations of declining ocean health, increasing ocean hypoxia and anoxia, and an increasing number of observed mechanisms that may result in a more and more stratified ocean state as human warming intensifies to increase concern that the worst fears of Dr. Peter Ward and colleagues may be in the process of realization. (See: Dead Dolphins,  Climate Change Devastating Ocean Fishermen, and Mass Starfish Die-off for more indicators of failing ocean health.)

Concerned Journalists and Terrified Ecologists

Put into various contexts, the current state of climate and environmental health does channel our worst fears that the Permian Extinction event may well be in for a human-caused repeat. The current estimated background extinction rate of 100-250 species per day is possibly the most rapid in all of geological history. The current CO2 level, near 400 parts per million, is higher than at any time during which human beings walked the Earth. The pace of greenhouse gas emissions is at least six times faster than at any time in the geological record. And the current, very large, forcing provided by humans does not yet include a probable powerful and unpredictable response from the Earth’s natural systems.

As Ecologist Guy McPherson notes — Nature Bats Last. And we should not be comforted by this notion. Because Nature carries the biggest stick of all. A consequence hanging over our heads that grows larger and more dangerous with each passing year during which our insults to her continue.

Among the pessimists regarding the end consequences of human caused climate change and related pollution, ecologists are the worst of the bunch. This is likely due to the fact that ecologists are very intimately involved in the study of how communities of organisms succeed or fail in natural settings. Among all groups of scientists, they are perhaps the ones most intimately familiar with the way in which all living things are connected to both one another and to the natural world. Ecologists know all too well that small shifts can mean huge changes to biodiversity, the rate of death among living beings, and the distribution of species in a given environment. But the changes humans inflict are not small in the least. They roughly ripple through the natural world in ways that ecologists know all too well have never before been seen.

Dr. McPherson is such an ecologist and one with such great conscience and concern that he, years ago, abandoned most of the luxuries of modern civilization to live in a fashion that produced the least harm possible. Not that this action has resulted in more optimism on his part. In fact, Guy is one of a growing group of people who believe that no action is likely to save humankind. That our insults to the natural world have already grown too great.

McPherson notes:

“We’ve never been here as a species and the implications are truly dire and profound for our species and the rest of the living planet.”

In this observation, Guy is probably right. But I sincerely hope that his and my own worst fears do not emerge.

It was Guy’s ongoing tracking of various dangerous alterations to world climate systems and assertion that human extinction may well be nigh that drew the attention of prominent journalist Dahr Jamail. Jamail recently penned the article: “The Great Dying Redux: Shocking Parallels Between Ancient Mass Extinction and Climate Change.

Reading professor emeritus Guy McPherson’s blog was enough to convince Mr. Jamail of the risk that current warming could result in an extinction event to rival that of the Great Dying so long ago. Mr. Jamail notes:

It is possible that, on top of the vast quantities of carbon dioxide from fossil fuels that continue to enter the atmosphere in record amounts yearly, an increased release of methane could signal the beginning of the sort of process that led to the Great Dying. Some scientists fear that the situation is already so serious and so many self-reinforcing feedback loops are already in play that we are in the process of causing our own extinction. Worse yet, some are convinced that it could happen far more quickly than generally believed possible — even in the course of just the next few decades.

And so we come full circle. Rapid human warming leads to troubling ocean changes that hint at those feared to have resulted in mass extinctions during the Permian-Triassic boundary event. And the very rapid human warming puts at risk the catastrophically rapid release of Arctic methane which would certainly consign Earth to a rapid jump from a glacial to a hothouse state and potentially produce the kind of Canfield Oceans Dr. Ward fears. It is a deadly transition for which we have growing evidence with almost each passing day, one that McPherson and others fear could truly make an end to us and to so many other living creatures on this world.

So many scientists, so much valid reason to be dreadfully concerned, and yet we continue on the path toward a great burning never before seen in Earth’s history…

Links (Read them!):

A Deadly Climb From Glaciation to Hothouse: Why the Permian-Triassic Extinction is Pertinent to Human Warming

Increasing subtropical North Pacific Ocean nitrogen fixation since the Little Ice Age

The Great Dying Redux: Shocking Parallels Between Ancient Mass Extinction and Climate Change.

Deep Sea Corals Record Dramatic Long-Term Shift in Pacific Ocean Ecosystem

Nature Bats Last

Colorado Bob’s Climate Feed

Dead Dolphins

Mass Starfish Die-off

Climate Change Devastating Ocean Fishermen

NCAR A2 Model Run

Hat Tip to David Goldstein

%d bloggers like this: