Carbon Sinks in Crisis — It Looks Like the World’s Largest Rainforest is Starting to Bleed Greenhouse Gasses

Back in 2005, and again in 2010, the vast Amazon rainforest, which has been aptly described as the world’s lungs, briefly lost its ability to take in atmospheric carbon dioxide. Its drought-stressed trees were not growing and respiring enough to, on balance, draw carbon out of the air. Fires roared through the forest, transforming trees into kindling and releasing the carbon stored in their wood back into the air.

These episodes were the first times that the Amazon was documented to have lost its ability to take in atmospheric carbon on a net basis. The rainforest had become what’s called carbon-neutral. In other words, it released as much carbon as it took in. Scientists saw this as kind of a big deal.

This summer, a similar switch-off appears to be happening again in the Amazon. A severe drought is again stressing trees even as it is fanning wildfires to greater intensity than during 2005 and 2010. Early satellite measures seem to indicate that something even worse may be happening — the rainforest and the lands it inhabits are now being hit so hard by a combination of drought and fire that the forest is starting to bleed carbon back. This gigantic and ancient repository of atmospheric carbon appears to have, at least over the past two months, turned into a carbon source.

Amazon carbon dioxide

(High levels of carbon dioxide, in the range of 410 to 412 parts per million, and methane in the atmosphere over the Amazon rainforest during July and August of 2016 is a preliminary indicator that the great forest may be, for this period, acting as a carbon source. Image source: The Copernicus Observatory.)

Carbon Sinks Can’t Keep Up

Though the story of human-forced climate change starts with fossil-fuel burning, which belches heat-trapping carbon dioxide into the atmosphere, sadly, it doesn’t end there. As that burning causes the Earth to heat up, it puts stress on the places that would, under normal circumstances, draw carbon out of the atmosphere. The carbon-absorbing oceans, boreal forests, and great equatorial rainforests all feel the sting of that heat. This warming causes the oceans to be able to hold less carbon in their near-surface waters and sets off droughts and fires that can reduce a forest’s ability to take in that carbon.

In the context of the global cycle of carbon entering and being removed from the Earth’s atmosphere, oceans and large, healthy forests serve to take in greenhouse gasses. We call these carbon sinks, and throughout the past 10,000 years of our current epoch, the Holocene, they’ve helped to keep these gasses, and by extension, Earth’s temperatures, relatively stable.

carbon sinks

(Without the ability of forests, soils and oceans to take in carbon — to act as carbon sinks — global atmospheric CO2 would have already risen well above 500 parts per million by 2009 due to fossil-fuel burning. These sinks are a helpful mitigating factor to the insult of human carbon emissions, but if they become too stressed, they can become sources of carbon instead. Image source: IPCC/CEF.)

However, for a long time now human fossil-fuel emissions have far exceeded the ability of the world’s carbon sinks to draw in excess carbon and keep greenhouse gas levels stable. Though these sinks have taken in more than half of the great volume of carbon emitted from fossil-fuel burning, the total portion of heat-trapping CO2 has risen from 280 ppm to more than 400 ppm. The oceans acidified as they strained beneath the new carbon overburden. And the forests took in this carbon even as they fought off expanding deforestation. As a result of all the excess carbon now in the atmosphere, the Earth has warmed by more than 1 degree Celsius above 1880s levels. And combined with the already strong stress imposed by clear-cutting and slash and burn agriculture, the added heat is a great strain on an essential global resource.

Global Warming Causes Carbon Sinks to Switch Off, or Worse, Turn into Sources

In this tragic context of heat, drought, ocean acidification and deforestation, it appears that the grace period that the Earth’s carbon sinks have given us to get our act together on global warming is coming to an end. Heating the Earth as significantly as we have is causing these sinks to start to break down — to be able to draw in less carbon, as was the case with the Amazon rainforest in 2005 and 2010. At these points in time, the sink was carbon-neutral. It was no longer providing us with the helpful service of drawing carbon out of the atmosphere and storing it in trees or soil. But, more ominously, in 2016, it appears that the Amazon may also to be starting to contribute carbon back to the atmosphere.

High Surface Methane Amazon August 4

(High surface methane readings over the Amazon in excess of 2,000 parts per billion is a drought and wildfire signature. It is also a signal that the rainforest during this period was emitting more carbon than it was taking in. Image source: The Copernicus Observatory.)

After each of these brief periods of failing to draw down carbon in 2005 and 2010, the Amazon carbon sink switched back on and began to function again for a time. But by 2015 and 2016, record global temperatures had again sparked a terrible drought in the Amazon region. According to NASA officials, the new drought was the worst seen since at least 2002 and was sparking worse fire conditions than during 2005 and 2010 — the last times the Amazon’s carbon sink switched off. In July of 2016, the Guardian reported:

“Severe drought conditions at the start of the dry season have set the stage for extreme fire risk in 2016 across the southern Amazon,” Morton said in a statement. The Brazilian states of Amazonas, Mato Grosso, and Pará are reportedly at the highest risk.

Per NASA’s Amazon fire forecast, the wildfire risk for July to October now exceeds the risk in 2005 and 2010 — the last time the region experienced severe drought and wildfires raged across large swaths of the rainforest. So far, the Amazon has seen more fires through June 2016 than in previous years, which NASA scientists said was another indicator of a potentially rough wildfire season.

Extensive Wildfires Over Brazil and Amazon on August 5 2016

(Extensive wildfires over the southern Amazon and Brazil coincide with apparent atmospheric methane and CO2 spikes. Indicator that the Amazon carbon sink is experiencing another period of failure. Image source: LANCE MODIS.)

At the same time that drought and related wildfires were starting to tear through the Amazon, atmospheric carbon monitors like the The Copernicus Observatory were picking up the signal of a carbon spike above the Amazon with methane levels higher than 2,000 ppb (which is often a drought and wildfire signature) and carbon dioxide levels in the range of 41o to 412 ppm. It was a spike comparable to those over industrial regions of the world like eastern China, the U.S. and Europe.

In context, these Amazon carbon spikes are occurring at a time of record atmospheric CO2 increases. For the first seven months of 2016, the average increase in CO2 versus 2015 was 3.52 ppm. 2015’s overall rate of CO2 increase in the range of 3.1 ppm year-on-year was the fastest annual increase ever recorded by NOAA and the Mauna Loa Observatory. So far this year, the rate of atmospheric gain in this key greenhouse gas is continuing to rise — this in the context of carbon spikes over a region that should be drawing in CO2, not spewing it out.

Links:

Drought Shuts Down Amazon’s Carbon Sink

Amazon Could Face Intense Wildfire Season This Year, NASA Warns

The Keeling Curve

The Copernicus Observatory

NOAA ESRL

IPCC/CEF

LANCE MODIS

Hat tip to Colorado Bob

Hat tip to DT Lange

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Climate Change Pushing Extreme Events into Higher Gear: PAC 2013 Enters 4th Week, Greenland Melt Hits 27%, US Sees Powerful Storms Spawned by Derecho, and Ongoing Western Drought Spawns 3rd Record Colorado Fire

This past week has hosted a variety of extreme and unprecedented weather events. In the US, storms pummeled a region from the Dakotas to the US East Coast while Colorado suffered its worst wildfire ever recorded, the third time such a dubious record has been broken in the past year. And, in the Arctic, a persistent cyclone (PAC 2013) ended its 3rd week of ice thinning as Greenland melt blew through the usual summer maximum with hardly a pause.

US Derecho, Severe Storms

A storm system that spawned numerous severe thunderstorms, high wind events, hail, heavy rain, and sporadic tornadoes swept through a broad swath of the northern, central, and eastern United States from Tuesday through Thursday. Major power outages were reported over this broad region and, sadly, one death occurred when a little boy lost his life to falling trees in Virginia on Thursday.

This combined derecho and severe thunderstorm event, though less severe than last year’s June 29th ‘Hurricane over Land,’ still resulted in major impacts. According to Jeff Masters, from Weather Underground:

NOAA’s Storm Prediction Center (SPC) logged 376 reports of damaging thunderstorm wind gusts in the 15 hours ending at 11:25 pm EDT Thursday night, and three of these gusts were 74 mph or greater. SPC is now acknowledging that Wednesday’s bow echo that traveled 600 miles from Indiana to New Jersey was a low-end derecho, with over 150 damaging wind reports. The most impressive thunderstorm winds from the derecho occurred in Wabash County, Indiana, where a “macroburst” produced winds of 90 – 100 mph across an area seven miles long and three miles wide, destroying three buildings and causing extensive tree damage. Total damage from the two-day severe weather outbreak over the Midwest and Mid-Atlantic will likely run into the hundreds of millions of dollars.

You can view the progression of yesterday’s derecho in the NOAA/National Weather Service radar sequence here:

derecho_jun12

Western Drought and Colorado Fires

Meanwhile, the western drought, still covering over 44% of the US, spawned the most damaging fire in Colorado history. Again.

The Black Forest Fire has now destroyed nearly 400 homes, killed 2 people, forced nearly 40,000 people to evacuate, and burned over 18,000 acres. Last year, the High Parks Fire and then the Waldo Canyon Fire each successively broke the record, set in 2002 for the most damaging fire in Colorado history. Now, just one year later, the Black Forest Fire has again taken the record.

Three record damaging fires in one year is anything but normal. But, according to climate forecasts, things are going to get much worse for Coloradans. According to this US Department of Agriculture study, under a ‘moderate global warming scenario’ in which Colorado temperatures rise by an additional 1 degree Celsius by 2050, the area burned by forest fires would increase by 2.8 to 6.6 times the current level.

Fuel for the Colorado fires is provided by an embedded drought which has persisted in the region since last spring. Unfortunately, a switch to mild La Nina conditions in the Pacific may indicate that the US drought is set to expand once more.

Droughts are also predicted to grow more severe for the southwestern and central US as global temperatures rise. And this projected increase in drought conditions not only has implications for increasing risk of fire, it also drastically impacts US food productivity.

Farmers already suffering from last year’s drought can still expect to face climate extremes over a large area of the US. And with La Nina increasing risks that drought will re-expand, it appears the beginning of a long era of damage to crops and increased risk of severe fire via the ratcheting effects of climate change is now starting to settle over the US.

Today’s US Drought Monitor tells that tale all too well:

dm_us_w525_h391.png

(Image source: US Drought Monitor)

Persistent Arctic Cyclone Enters 4th Week

Moving northward into colder climes we enter the epicenter of another ongoing tale of climate change tragedy. In this case, a Persistent Arctic Cyclone which has continued to batter and thin the northern polar sea ice has now entered its fourth week.

The storm is now a 985 mb low centered between Svalbard and the North Pole. Two smaller storms are now also incorporated into its larger circulation and are indicated by the two light blue circles on the map:

Persistent Arctic Cyclone Enters 4th Week

Persistent Arctic Cyclone Enters 4th Week

(Image source: DMI)

The storm continues to pull warmer air into the Central Arctic from the south. Now, much of the Arctic Basin is experiencing above freezing temperatures. Yesterday, Barrow Alaska, one of the coldest cities in the Northern Hemisphere, experienced a 65 degree high, about 26 degrees above average for this time of year.

The below weather map shows temperatures above the freezing point of sea water (-1.9 C) covering all but a few isolated locations. In one location on the coast of Siberia and bordering the Arctic Ocean, the temperature has risen to a balmy 27 degrees Celsius or about 81 degrees Fahrenheit.

synNNWWarctisJune14

(Image source: Uni-Koeln)

Forecasts for the storm have tended to trend for it remaining in the Central Arctic at least until late next week. If these forecasts bear out, by next Friday we’ll begin talking about the month-long storm.

With the storm continuing for so long, it is forecast to really begin digging deep into the Arctic sea ice by next week. US Navy models continue to show major thinning in a broad swath from the Laptev Sea to the North Pole and creeping on toward Svalbard. Such projections show continued, dramatic and rapid thinning ramping up all the way through June 21rst. At this point, PAC 2013 begins to look more like the nightmare scenario I discussed in The Warm Storm blog and less like the strong thinning event we’ve witnessed thus far.

The Warm Storm Begins?

The Warm Storm Begins?

(Image source: US Navy)

It is worth stating that we’ve never before witnessed a Persistent Arctic Cyclone thin the ice to any note-worthy extent during June. This particular storm is already unprecedented in its impacts and the fact that it continues and is projected to continue for at least the next ten days should be major cause for concern.

Simply put, the Arctic sea ice is in ongoing and deepening peril. Should these amazing thinning and melt values the Navy is predicting emerge next week, we’ll have to modify our ‘Ice Free Arctic’ prediction (currently at 10% for 2013) accordingly.

Meanwhile, a related warming and melt is now occurring in Greenland, may be set to challenge an extreme record 120 year melt seen just last year.

Greenland Melt Starting to Go Bonkers

Earlier this week, Greenland melt surpassed maximum summer melt values usually seen in mid-to-late July. Today, these melt totals proceeded to spike without hardly a pause.

Average maximum melt area for Greenland usually peaks at around 23% during mid-summer. By Friday, June 14th, about 27% of the Greenland ice sheet experienced melt. You can see this rapid and ongoing spike in Greenland melt in the graphic below:

greenland_melt_area_plotJun14

(Image source: NSIDC)

Current melt coverage is still below last year’s record of near 100%. However, those values didn’t emerge until July and current melt is proceeding at a rapid enough pace to raise concerns that the 2012 record could be challenged this year.

Greenland melt is a major driver of extreme weather events. Melt has currently reached an average of 500 gigatons from the Greenland ice sheet annually. This level is already three times that observed in the 1990s. But melt rates are still rising over time. This massive and growing volume of melt water has already slowed the Gulf Stream and is likely playing a role in severe winters and springs in Europe.

Combined with sea ice erosion, which Dr. Jennifer Francis has implicated in a slowing of the Northern Hemisphere Jet Stream, Greenland melt is a powerful driver of the extreme weather we expect to see as climate continues to change.

Of these four events, three — the Colorado fires, PAC 2013, and amplified Greenland melt — can be directly attributed to a warming climate. The derecho, on the other hand, was likely made worse by a combination of alterations to the global jet stream, increased atmospheric heating, and increased water vapor pumping up the thunderstorms it spawned. Together they provide a context of climate change. One we are just starting to see emerge and one that will likely grow far worse should we not rapidly reduce our use of fossil fuels.

Links:

Hurricane over Land

Weather Underground

National Weather Service

US Department of Agriculture Fire Study

US Drought Monitor

DMI

Uni-Koeln

US Navy

NSIDC

Arctic Ice Graphs

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