A new study examining carbon exchange in the Amazon rainforest following extremely hot and dry spells reveals tropical ecosystems might be more sensitive to climate change than previously thought.
The findings, published online on April 28 in the journal Global Change Biology, have implications for the fate of the Amazon and other tropical ecosystems if greenhouse gas emissions continue to climb.
“There have been a lot of projections of what might happen in the Amazon in the future as global warming intensifies,” said study co-author Noah Diffenbaugh, an associate professor of Earth Systems Science at Stanford’s School of Earth, Energy & Environmental Sciences. “In this study, we are bringing together many different data sources to take a more comprehensive and detailed look at how the Amazon has responded to severely hot and dry conditions that happened in the recent past.”
Net Biome Exchange
Land ecosystems “breathe” carbon dioxide (CO2) in and out during growth and decay, and the amount of CO2 taken up or released by biomes can offer important insights into how ecosystems could be affected by global warming. Because of their vast potential to store and release carbon, tropical ecosystems play a major role in regulating the Earth’s climate. If climate change causes tropical forests to emit large amounts of CO2 into the atmosphere, that carbon loss could amplify the global warming effects of fossil fuel emissions.
The study’s lead author, Caroline Alden, began the study at the University of Colorado’s Cooperative Institute for Research in Environmental Sciences (CIRES) and continued the research as a postdoctoral researcher working with Diffenbaugh at Stanford.
Alden and her colleagues developed a data analysis that combines weather data with CO2 measurements gathered by airplane surveys to calculate how much atmospheric carbon exchange, also known as net biome exchange (NBE), is happening across the Amazon basin. This new analysis allowed the researchers to track down the sources of CO2 absorption and emission in the rainforest during each month over a three-year period.
“By gathering many observations of CO2 in the atmosphere, we gain a sense of how CO2 is distributed above the Amazon, and how that changes in response to extreme climate events,” said Alden, who is currently a research associate at the University of Colorado. “By combining that knowledge of CO2 in the atmosphere with knowledge of where the winds came from in the days preceding the measurements, we can track down the sources of the signals that we see in the air.”
The analysis Alden’s team developed is the first to look at NBE variations month-by-month on regional scales that cover several million square kilometers, filling in a critical gap between very small-scale and larger-scale studies and helping to improve understanding of Amazon climate-carbon interactions.
Shifting Carbon Balance
For their analysis, the scientists calculated NBE flux in the Amazon for the three-year period spanning 2010 to 2012. In 2010, a major drought and unusually high temperatures affected much of the Amazon basin, but conditions had returned closer to normal by 2011 and 2012.
Alden and her team found evidence of very large shifts toward carbon loss to the atmosphere in the Amazon after periods of extreme heat and drought in 2010. What’s more, the shifts were surprisingly fast.
“We see that the carbon balance in the Amazon can change quickly in response to climate events,” Alden said, “Heat anomalies during the wet season are strongly correlated with increased carbon loss in the same month, and lower-than-average rainfall during the wet season is correlated with increased carbon loss in the following month.”
Increasing Heat Stress
It was already known that the 2010 drought had caused large carbon loss from the Amazon. However, the more detailed information developed in the new study allowed the researchers to analyze both the carbon and climate conditions that occurred in different parts of the Amazon as the drought evolved. This new analysis suggests that the loss of carbon may have preceded the onset of drought conditions, when the climate was unusually hot but not yet unusually dry.
“We have very strong evidence that severe heat has been increasing in the Amazon, and that more global warming will intensify this effect,” said Diffenbaugh, who is also a senior fellow at Stanford’s Woods Institute for the Environment. “Our findings suggest that regardless of changes in precipitation, the Amazon could be vulnerable to the increasing heat stress that we know is very likely to accompany further global warming.”
The group also found that in the eastern Amazon, CO2 was still being emitted to the atmosphere in large pulses throughout 2011, months after the severe heat and drought events had occurred. This “legacy” effect could indicate that tropical rainforests can take several years to recover from a major drought, Alden said.
Taken together, these results suggest the Amazon may be more sensitive to heat and drought conditions than previously thought – a finding that does not bode well for tropical ecosystems in the coming decades as the effects of climate change are expected to intensify.
“The Amazon ecosystem is a critical part of the global climate and carbon system, and home to unparalleled biodiversity,” Alden said. “These findings highlight how much more we still have to learn about tropical carbon-climate interactions, and underscore the importance of continued monitoring of the atmosphere in tropical regions.”
The findings also show that carbon emissions from the Amazon have tremendous capability to affect global climate, said John Miller, a study co-author and CIRES researcher at the time of the analysis and now a scientist at the National Oceanic and Atmospheric Administration.
“Better understanding of NBE in the Amazon will continue to help scientists resolve major unknowns in future climate projections,” Miller said, “namely how tropical forest sensitivities to future changes in temperature, rainfall and drought patterns may accelerate global climate change.”
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Didn’t someone put up a satellite to measure CO2? No need for airplane surveys of ‘several million square kilometers’.
“Heat anomalies during the wet season are strongly correlated with increased carbon loss in the same month”
Heat and water means more rot.
To think that these guys actually claim to be scientists.
Technically, they are correct. Today, it’s weather. Tomorrow, it’s climate. Let’s keep our fingers crossed for this continued span of favorable, semi-stable conditions.
The scientific frame of reference has an indeterminate period and scope with accuracy inversely proportional to the time and space offsets from an established frame.
Just like that extreme climate event that confined the MWP to that small region of the globe for 300+ years.
Color me a true believer in the supernatural.
Back in the real world-
“Normal weather conditions prevailed”
“U.S. farm income experienced a golden period during 2011 through 2014, driven largely by strong commodity prices and agricultural exports-
Wrap Up of U.S. Agriculture for 2015
Normal weather conditions prevailed in most major growing regions around the world in 2015”
“Amazonian rainforest was created just 2,000 years ago by climate change that wiped out ancient farmers
Area was grassland until a natural shift to wetter climate 2,000 years ago
Researchers say the find sheds new light on the Amazon’s history – and show it was a savannah rather than the high forest it is today”
http://www.dailymail.co.uk/sciencetech/article-2685049/Amazonian-rain-forest-just-2-000-years-old-previously-SAVANNAH-tended-farmers-researchers-find.html
‘extreme climate events’
It’s Climate English.
”What emerged, say linguists, was a nograj called Climate English [CE].
Historically, the problem with scientific jargon is that it only makes
sense if you understand science. CE, by contrast, only makes sense if
you don’t.’
http://joannenova.com.au/2016/04/the-illusion-of-debate-a-history-of-the-climate-issue-part-1/#more-47135
Sounds like a variant of Orwell’s “Newspeak”. Control the language, control the mind.
In my view, an “extreme climate event” should be an event that covers at least a 30 year period relative to a longer period of a hundred years or more and preferably a thousand years or more. For example, a 30-year period with extreme drought compared to other 30-year periods over hundreds of years. Another example is our current Holocene, which is an unusually warm event relative to the last half million years and has lasted almost 12,000 years. During the Holocene, global average temperatures have been running at least 4C to 6C above the 500,000 year mean. The most recent glacial maximum from about 36,000 to 16,000 years ago when global average temperatures were about 4C to 6C below the 500,000 year mean is another good example of an “extreme climate event”.
On a longer time scale, our current ice age that began with the Pleistocene about 2.6 million years ago is easily the coldest period within to the entire Cenozoic Era that began about 66 million years ago, and thus could be considered an extreme cold long-term climate event. For most of the Cenozoic, from about 10 million to 66 million years ago, global average temperatures were about 4C to 14C higher than the most recent 100 years. Thus, our current Holocene warm interglacial period is “cold” relative to most of the Cenozoic period. Even the most extreme alarmist visions of global average temperature about 8C above the pre-industrial average by 2100 would only put temperatures back where they were for 20 million years, from about 20 to 40 million years ago, and well below the Eocene optimum about 50 million years ago that was about 14C higher.
Most alarmists are much too short-sighted. Our next major “extreme climate event” will likely be the next glacial period that could gradually start any time during few thousand years. A little warming might help to delay it. Below is a graph comparing estimated global average temperatures during our current interglacial as compared to the previous four, based on the EPICA ice core proxy. Only one of the last four was longer than our current interglacial, which is not very good odds.
I conclude you are the author of this graph (I checked your website). Excellent graph. Reminds me of El Nino’s piled on top of each other. Now isn’t that interesting.
Pamela thanks, yes I made the graph showing a comparison of the current and last four interglacial warm periods. The broken icon in my comment is to a PNG graph on Wiki showing estimated global temperature anomalies back 500 million years (apparently Word Press does not create a thumbnail for PNG images like it does for GIF and JPG images but you can still click on the broken icon to see the PNG graph at Wiki).
After looking at my graph again, I realized that I misspoke and that only two of the last four interglacials were shorter than our current interglacial. The most recent previous interglacial lasted about 2,000 years longer and the fourth one back lasted about 12,000 years longer. However, the fourth one back seems to match the pattern of the current interglacial better than any of the others. It also had a peak more than 2C warmer than present with a sharp rise after about 13,000 years and then stayed at or above 2C warmer for about 7,000 years … all from natural causes. Probably the best we can estimate from this long-term persistence forecast is that our current interglacial could end at any time in the next few thousand years, or if humanity is very lucky, it might last another 10 to 12 thousand years at most.
The graph of temperature and CO2 from the EPICA ice core that you displayed in a comment above clearly indicates that CO2 remained elevated well after the end of most of the recent interglacial periods and lagged behind in dropping, which suggests that over these time scales it is temperature that controls CO2 and not the other way around. Consequently, increasing CO2 levels are not likely to prevent the next glacial cycle, but any warming that we get in the next hundreds of years from any cause might help to delay the onset. Trying to keep the Earth at a constant climate is a wild and impossible dream at this point.
Do trees hate CO2 now? And I thought “climate” was long-term and global, while “weather” was short term and local. So isn’t “climate event” just like “jumbo shrimp” or “honest politician”?
Typical terrible research.
Apparently, no control group.
One small session of observations and without preceding or post evidence they’re assuming all kinds of disasters and carbon losses.
No effort to actually make random flights of CO2 measurement in a CO2 generating machine applicable to all of the Amazon; except general assumptions.
No attempt here in 2016 to use the satellite measuring CO2 to validate measurement methods…
The whole pot of sour ash looks cooked from the start to prove their confirmation biases.
Glad there has never, ever been an extreme “climate event” before. I would have wiped out the Amazon.
Climate events now? I thought an event was, you know, weather. A lot of the Northern Hemisphere has been under heaps of snow lately, does that count as an extreme climate event? Oh, but of course that’s opposite of catastrophic warming. Never mind.
On the headline issue of ‘extreme climate events’, there is in fact a symmetrical historical precident. In 1972 the global cooling scare took off partly due to its promotion by geologists upon discovery of the 100 000 year interglacial cycle. But it also took off due to well advertised extreme weather that year. This lead to an unprecidented level of public and political interest in climatic change. This interest was quickly channelled into proposals for funding a US nation climate program where the extreme events of 1972 were much referred to and referred to as climatic events and as evidence of climatic changes that have already happened–and so as changes that presage other climatic changes ( that, presumedly would be experienced as extreme events). In other words, from the beginning of the global climatic change scares in the global cooling scare, extreme weather events have featured interpreted as, themselves, climatic changes.
there is no such thing a climate change event (i.e. a single storm) …
From the article: “For their analysis, the scientists calculated NBE flux in the Amazon for the three-year period spanning 2010 to 2012. In 2010, a major drought and unusually high temperatures affected much of the Amazon basin, but conditions had returned closer to normal by 2011 and 2012.”
In 2010, a major drought and high temperatures affected much of the central U.S., too. I wonder if there is a connection.
Yeah, the summer of 2010, was one of the hottest in my memory. I spent over $300 a month on water bills, trying to keep my thirsty trees alive.
Don’t know what the CO2 above my head was doing at the time. Probably the same thing it was doing over the Amazon.
Hmmm….since such changes in climate have happened before the Industrial Revolution (and some of the changes were rather drastic), we should be relieved because (according to GW theory) they don’t exist anymore? Why worry about what the models say can’t be there?
Seems to me that they’ve been searching, testing and grasping for the Holy Grail of climate “communication” for several years now – particularly in the years post-Climategate. And it could well be their multiple failures which have led to – or at the very least contributed to – the more recent desperation seen in their multifarious lawsuits. Not to mention the flurry of so-called scientific “papers” deserving of little more than scorn and/or laughter.
Might be… have implications IF… projections of what might happen… If climate change causes… that could amplify…analysis suggests… may have preceded…Our findings suggest… the Amazon could be vulnerable…very likely to accompany…This “legacy” effect could indicate… may accelerate global climate change… is correlated with increased carbon loss… suggests that the loss of carbon may have preceded… the effects of climate change are expected…
———–
Accompanied by the requisite appeal for more grant money-
“These findings highlight how much more we still have to learn about tropical carbon-climate interactions, and underscore the importance of continued monitoring…”
———-
Good grief.
Better understanding of the climate, that’s the idea we should all focus. As I often use to say, everybody is preoccupied by the climate change, but it is useless to discuss only the future without understanding the main cause of the climate transformation. My opinion is that the ocean and human activity on the ocean (mostly naval wars) has a big contribution in the matter. Aren’t we ignoring that? Shouldn’t we pay more attention to the ocean, besides the CO2 that is so much argued these days?
I love that the picture includes an insert of “Batboy”. I remember when he was a fixture on the supermarket tabloids. I wonder how many Alarmists are too young to remember when every trip to the grocery store was a chance to see headlines about alien abductions, Elvis sightings, and of course, “The World Wil End In (insert year)”.
The exact same tabloid-selling headlines that were considered a joke in the 70’s and 80’s are now considered mainstream today.