When the Great Ice Sheets Start Going Down — Approaching the Age of “Storms”

The great ice sheets are melting with increasing velocity. Melt ponds are forming over Greenland, then pounding heat down through the ice like the smoldering hammers of ancient Norse fire giants. Warming mid-depth ocean waters are eating away at the undersides of Antarctica’s great ice shelves. Pools of fresh water are expanding outward from the bleeding glaciers, flooding the surface zones of the world’s oceans. Sea level rise rates have jumped to 4.4 millimeters per year (see study here). And the North Atlantic Overturning Circulation (AMOC) is slowing down.

Ice mass loss all glaciers

(Accelerating ice mass loss from Antarctica, Greenland and other continental glaciers and ice caps [GICs]. Image source: Geophysical Research Letters.)

Keeping all this in mind, let’s talk a little bit about the ugly transition to phase 2 climate change. A transition it now appears we’re at the start of. The — you should have listened to Dr. James Hansen and read The Storms of My Grandchildren — phase of climate change. The awful, long, stormy period in which the great glaciers really start going down.

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In an effort to organize how human-caused climate change may proceed, it helps to break the likely progression of human-caused climate change down into three basic phases. For this simplification we have phase 1 — polar amplification, phase 2 glacial melt and storms, and phase 3 — runaway hothouse and stratified/Canfield Oceans. For this article, we’ll focus mostly on phase 1 and 2.

Phase 1 — Polar Amplification

During the first phase, human greenhouse gas emissions gradually add heat to the atmosphere. This causes general warming that is most intense at the polar regions, especially in the Northern Hemisphere. Called Polar Amplification, this added heating at the poles occurs due to greenhouse gasses’ ability to increase the atmosphere’s heat trapping efficiency at night, when the sunlight angle is low, or during periods of dimmer light (cloudiness etc). In addition, snow and ice melt cause albedo loss at the poles and greenhouse gasses sequestered within frozen carbon stores may release during warming as ice thaws adding another kick to polar amplification (amplifying feedbacks). Due to lower volumes of continental ice, more low-albedo land mass, more vulnerable carbon stores, and closer proximity to human greenhouse gas emissions sources, the Northern Hemisphere polar zone is most vulnerable to increased rates of warming during phase 1 climate change.

Weather impacts during phase 1 include a slowing down of the jet stream due to loss of polar ice, a multiplication of slow moving weather systems, an increasing prevalence of drought and heavy rainfall events, and a slow ratcheting of the intensity of powerful storms. Phase 1 continues until ice sheets begin to become heavily involved and melt outflows greatly increase. At that point, we begin a transition to a more unstable period of human-caused climate change — phase 2.

Phase 2 — An Age of Storms

During phase 2, ever-increasing volumes of cold, fresh ice and water pulse out from the world’s glaciers. In essence, the great mountains of ice really get moving and there’s nothing left to stop them. The glacial heat content has reached a critical point and the glaciers start moving and crumbling on a massive scale. A seaward avalanche that has essentially become unstoppable due to basic inertia.

Due to highest levels of ice concentration, the regions seeing the greatest impact are areas adjacent to Greenland and Antarctica. Cold, fresh water and ice hitting these local ocean zones have numerous influences. The first is that the local fresh water acts as a lid on ocean-to-atmosphere heat transfer. As a result, atmospheric temperatures in the region near large glacial melts will tend to cool. Warm, saltier surface waters near the glacial outflows are pushed downward by the lighter, fresh water — heating the ocean bottom zone and continuing to melt the underbellies of sea facing glaciers. Ultimately, the meridional ocean circulations in the North Atlantic and in the Southern Ocean are cut off.

Deep water formation is driven toward the equator. This stops heat transport toward the poles in a number of regions resulting in equatorial heat amplification. Meanwhile, the impact of the fresh water ocean lid results in local atmospheric cooling near the glaciers — a counter-trend to a larger global warming.

Weather-wise, we see a reverse of the trends first apparent during phase 1. The cooling of surface zones near the great glaciers puts a damper of phase 1 polar amplification. Meanwhile, the southward progression of fresh surface waters shuts down the oceanic coveyors transporting heat into the polar zones. As a result we see heat building up through a kind of ocean heat transport train-wreck in low latitude regions near the equator. The combined equatorial heating and near glacier cooling increases temperature gradients and amplifies the storm track.

20121230_iceberg_cooling_effect_Hansen_Sato

(Model runs showing temperature anomalies under A1B [near RCP 6.0] scenario warming with 0.6 meter global sea level rise from glacial outflows by 2065 and 1.44 meter global sea level rise by 2080 vs only thermal expansion based sea level rise [right frame images]. Note that A1B implies about 550 ppm CO2 — a bad scenario but no-where near the worst case. Also note that these models do not include carbon store response feedbacks. Finally, the models were adjusted by adding fresh water outflows from glaciers, so this is not a prediction of rate of sea level rise, only a projection of atmospheric impacts under a given melt and ghg scenario. Image source: Greenland Melt Exponential?)

In the Northern Hemisphere, the North Atlantic sees the greatest counter-trend cooling influence in atmospheric regions due to glacial melt. Meanwhile, Arctic regions continue to see (somewhat slowed) warming conditions. The result is a shift of the center of cold air to an off-set zone more toward Greenland and a screaming storm track running oblong over the polar zone and centering over a trough in the North Atlantic. Amazing temperature differentials between the continents, the Polar zone, Greenland, the North Atlantic, the equatorial Atlantic and Africa result in the potential for continent-sized storms packing the strength of hurricanes according to a recent study by Hansen.

The storms would spin up as the unstable cold air over Greenland ravels and unravels in great frontal wings of cold air encountering the hot air roiling at the equator and building in sections of the Arctic and over the continents. Tropical storms forming adjacent to cold core storms would increase the potential for hybrid storm events. And extreme temperature gradients would provide high octane atmospheric fuel for baroclinic systems. Finally, the great melt pulses themselves would supply periods of high global thermal variance. The pre melt pulse times would see rapid warming, while the post melt pulse times would see cooling. This up-down would periodically load and then wring the global atmosphere of moisture, resulting in high risk for extreme deluge events.

Heating the Deep Ocean Sets Stage for Phase 3

Meanwhile, heat at the ocean surface is driven toward the deep ocean by the fresh water melt pulses issuing from the glaciers. So the melt outflows and storms of phase 2 climate change act as an amazing mechanism for atmosphere-to-ocean heat transfer. Which is really bad news for the health of the world ocean system.

This phase 2 climate change age of storms lasts so long as large glacial outflows still issue from Greenland (in the North) and Antarctica (in the South). Since even under the most rapid pace of human-caused warming it would take hundreds of years for the great ice sheets to go down, what we are looking at is a period of possibly centuries. Avoiding phase 2 climate change, on the other hand, involves avoiding rapid destablization of Greenland and Antarctica’s ice sheets. An issue we may have already pushed too hard to prevent at least some of these storm, ocean, and weather destabilization impacts.

As for phase 3 climate change — that’s a transition to a runaway hothouse and a stratified/Canfield Ocean state. And we really don’t want to see that either. But before we get there, it’s a transition to an age of glacial melt and tremendously potent storms.

Links:

Hat Tip to Colorado Bob

Why Greenland’s Huge Melt Lakes are Vanishing

Global Sea Level Rise, Ice Melt, El Nino

An Increase in the Rate of Sea Level Rise Since 2010

What’s Going on in the North Atlantic?

Geophysical Research Letters

Greenland Melt Exponential?

The Storms of My Grandchildren

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2013 4th Hottest Year on Record, Deep Ocean Warming Fastest, NASA, NOAA Find No Pause in Long-Term Warming Trend

2013 4th Hottest On Record

(Global temperature anomalies for 2013. Image source: NOAA)

With the readings coming in for 2013 — atmosphere, ocean surface and the deep ocean — it becomes increasingly obvious that anyone saying planetary warming has slowed down is clearly misinformed.

Criticisms of the misinformed aside, according to reports from NOAA’s National Climate Data Center, 2013 was the world’s 4th hottest on record since temperature measures began in 1880. All this despite ENSO conditions remaining neutral in the Eastern Pacific and deep ocean heat content continuing to rapidly rise while sucking a portion of that heat out of the atmosphere.

The NCDC measure found numerous regions in which temperatures were the hottest ever recorded including a large swath of Australia, a broad stretch of the Pacific Ocean adjacent to New Guinea and the Philippines, an area larger than Texas at the heart of the Asian Continent, and multiple other locations ranging from south of Svalbard to East Africa to the Indian Ocean to the Northern and Southern Pacific. Aside from these record hot zones, over 70 percent of the land and ocean surface measured came up either hotter than average or much hotter than average while 28% of the globe experienced average temperatures and less than 2% of the Earth’s surface experienced cooler than average temperatures.

Notably, no regions of the globe saw record coldest temperatures and the only zone coming up cooler than normal cropped up in the Southern Ocean just north of Antarctica.

NASA found 2013 to be the 7th hottest on record and the 2nd hottest non El Nino year on record.

Helpfully, NASA also put together a graph of global temperature averages as measured since 1950 showing that atmospheric warming has continued unabated despite much false and inaccurate press coverage of a ‘global warming hiatus.’

gistemp_nino_s

(GISS temperature measurements with trend lines for El Nino, La Nina and all years. It’s worth noting that this temperature graph indicates no pause in warming since 1950. Instead, what we see are inexorable global surface temperature increases. Image source: NASA GISS)

Deep Ocean Warming Measures Far More Dire

Recent news reports have also falsely claimed that more heat going into the deep ocean, as measured by NASA, NOAA, the Trenberth study, and others, is an indication of lowered global climate sensitivity. To the contrary, a warming ocean contains two very dire consequences that, if set into play, could both enhance warming, and create an ecological nightmare for first the oceans and finally the surface world.

The first, a growing risk of subsea methane release, is greatly enhanced by a rapidly warming ocean. We have covered the risks and consequences of methane release (both seabed and terrestrial methane) in numerous posts over the past year. For your convenience I’ve linked them below. But, suffice it to say that a warming ocean puts at risk the more rapid release of hundreds of gigatons of methane, an amount that could greatly amplify the already powerful and ongoing signal of human warming. More worrisome, initial indications show that at least some of this methane is already destabilized and venting into the world ocean system and atmosphere.

The second consequence involves growing ocean hypoxia and anoxia as the oceans warm, become more stratified and as major ocean current systems are disrupted and altered. Growing ocean hypoxia and anoxia results in, among other terrible impacts, ocean sea bottoms that are less and less able to support a diversity of life and that, more and more, come to support dangerous hydrogen sulfide producing bacteria.

A third consequence includes the basal melting of ocean contacting ice sheets. Such melting has already destabilized the massive Pine Island Glacier which, according to a recent scientific study, is on the path to an inevitable collapse into the Southern Ocean.

Yet, according to these excellent graphs produced by Larry Hamilton for The Arctic Ice Blog, world ocean heat content has been rising by leaps and bounds over the past few years, especially in the deep ocean where warming puts at risk the most dangerous of outcomes — methane release and anoxia.

OHC_7an

OHC_2an

(Image source: L Hamilton. Image data: NOAA. Produced for The Arctic Ice Blog. Note the extraordinarily steep slope indicating deep ocean warming since 1985.)

The top graph shows ocean heat content increases in the first 700 meters of ocean water. The bottom graph shows ocean heat content in the first 2000 meters of ocean water. Note that ocean heat content gains for the deep ocean (2000 meter graph) are more rapid by 25% than heat content gains in the shallower ocean. Meanwhile, both graphs show a very rapid accumulation of heat, especially through recent years during which the so-called global warming hiatus was in effect.

If we could find a place to put the majority of heat from human-caused climate change, the deep ocean would be the last place any sane ecologist would look. Warming the deep ocean is a worst-case disaster in the making. It puts added stress on methane hydrate stores and it pushes the very dangerous consequences of ocean stratification and anoxia along at a much more rapid pace.

These are not optimistic measures. In my view, this is much closer to an absolute worst case.

Mixed Outlook for 2014

Early indications for 2014 show an increased chance of La Nina for the first three months of the year. That said, ocean surface heat in the Eastern equatorial Pacific appears to be on the rise, especially in areas closest to coastal South America.

sst.daily.anom

(Image source: NOAA)

Should ENSO tip the scale to El Nino, it is almost certain we will see a hottest year on record for surface temperatures during 2014. Should conditions remain neutral or tip to La Nina, we’ll still likely experience a top ten hottest year on record (atmosphere) even as ever more heat is transferred to the deep ocean.

Links:

NASA Finds 2013 Sustained Long-Term Warming Trend

National Climate Data Center Global Analysis

Larry Hamilton CA The Arctic Ice Blog

The Arctic Methane Monster Continues its Ominous Rumbling

Arctic Methane Monster Shortens Tail

The Arctic Methane Monster Stirs

Through the Looking Glass of the Great Dying

Awakening the Horrors of the Ancient Hothouse — Hydrogen Sulfide in the World’s Warming Oceans

Warming Ocean, Upwelling to Make an End to Pine Island Glacier

Hat Tip to Colorado Bob

Global Heating Accelerates, Deep Ocean Warming Fastest; What Does it Mean For Methane Hydrates?

A new study published in Geophysical Research Letters, found that ocean heat content rose at its fastest rate ever recorded over the past 15 years. The study, written by Magdalena A. Balmaseda, Kevin E. Trenberth, and Erland Kallen, found that the deep ocean below 700 meters accounted for 30% of all global heat content increase over the past decade.

What this means is that total warming of the atmosphere-ocean system didn’t slow down as some global warming denier sources claim. Instead, total Earth warming accelerated.

According to the paper, the most recent period since 1999 was:

the most sustained warming trend in this record of OHC. Indeed, recent warming rates of the waters below 700m appear to be unprecedented. In the last decade, about 30% of the warming has occurred below 700 m, contributing significantly to an acceleration of the warming trend.

Over the past decade, La Nina events have predominated. And this, according to study authors, resulted in a large portion of global warming being retained in the oceans. The reason is that El Nino is a powerful mechanism of ocean heat transfer to the atmosphere. But over the past decade, El Nino events have been rare, keeping more human caused heating in the world’s oceans. Not only did upper levels of the ocean heat up, a massive amount of global warming telegraphed into the deepest regions of world ocean systems.

According to Keven Trenberth, one of the study’s authors and a leading climate scientist, “It means less short term warming at the surface but at the expense of a greater earlier long-term warming, and faster sea level rise.”

The reason is that rapidly warming oceans pump more water vapor into the atmosphere. Water vapor is a powerful greenhouse gas and a major amplifying feedback to human caused warming. In addition, rapidly warming waters leads to greater thermal expansion of the world’s oceans, accelerating sea level rise.

Bad News For Methane Hydrates

More rapid ocean heating also has another impact not directly mentioned in the new study. What it does is put more of the world’s deposits of methane hydrates at risk of destabilization.

Methane hydrate is a volatile mixture of methane and frozen water that can be found on seabeds around the world. It is estimated that as much as 10,000 gigatons of carbon lay locked in methane hydrate deposits around the globe. Methane is a powerful greenhouse gas. Over a century, it is 20 times more powerful by volume than CO2. Over ten years, it is 100 times more potent. Methane is also problematic because after it amplifies warming as methane, it then breaks down into CO2, adding to already high volumes of that gas. Were even a small fraction of this carbon to bubble up from the ocean bottom and reach the atmosphere, it would result in a powerful amplifying feedback to human caused climate change.

Over the past decade, instances of methane hydrate destabilization have been found in the Arctic, off the east coast of the United States, and in other regions around the globe. Many of these events appeared to be new. Of these, methane plumes found in the East Siberian Arctic Shelf were the most disturbing. There, plumes of methane a kilometer across were discovered. Though submerged tundra was also a likely contributor to massive methane plumes discovered on the shelf, hydrates are also known to have formed there.

Now, with oceans heating at a greater rate than the atmosphere, risks for large methane hydrate releases are also increasing.

Most Missing Heat Found, Look to Ice Sheets for Remainder

This new research finds most of the missing heat scientists have been looking for around the globe. And that heat, as previously suspected, ended up in the world’s oceans and, to great extent, in the deep oceans. That said, a much smaller measure of heat is still unaccounted for. It might not be a bad idea to look in the world’s ice sheets — which appear to be decaying at a much faster rate than expected. One speculates that the hearts of the great glaciers are more watery than anticipated and contain much of the remaining heat from human caused global warming not currently located.

Links:

In Hot Water: Global Warming Has Accelerated Over Past 15 Years, New Study of Oceans Confirms

Winter 2013 Shows Increasing Arctic Methane Feedback to Human Caused Warming

Oceans Sponging Up Warmth

Arctic Methane Release Sea Ice Melt Shows Amplifying Feedbacks to Human Caused Climate Change

 

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