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Study: Climate-driven vegetation change by boreal forests is yet another positive, amplifying feedback

By Joe Romm on March 28, 2011 at 7:18 pm

"Study: Climate-driven vegetation change by boreal forests is yet another positive, amplifying feedback"


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Co-author: “What we’re seeing is a system kicking into overdrive. Warming creates more warming.”

Russia’s boreal forest – the largest continuous expanse of forest in the world, found in the country’s cold northern regions – is undergoing an accelerating large-scale shift in vegetation types as a result of globally and regionally warming climate. That in turn is creating an even warmer climate in the region, according to a new study….

That’s from the University of Virginia news release for a new Global Change Biology study (abstract here).

Back in 2005, Science published an analysis, “Role of Land-Surface Changes in Arctic Summer Warming,” which explained how reduced snow cover and albedo (reflectivity) in the summertime Arctic landscape, caused by global warming, has added local atmospheric heating “similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric CO2” (Science, subs. req’d).

That same Science study warned “Continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating 2-7 times.”

The new study looks at a completely different effect:

The Great Russian forest, which includes much of Siberia, is the size of the contiguous United States. It has experienced significant documented warming over the last several decades. As a result, tree species that are more tolerant of warmer weather are advancing northward at an increasing rate as species that are less tolerant to a warmer climate are declining in number.

“We’ve identified that the boreal forest, particularly in Siberia, is converting from predominantly needle-shedding larch trees to evergreen conifers in response to warming climate,” said the study’s lead author, Jacquelyn Shuman…. “  This will promote additional warming and vegetation change, particularly in areas with low species diversity.”

…  “What we’re seeing is a system kicking into overdrive,” said co-author Hank Shugart, a U.Va. professor of environmental sciences. “Warming creates more warming.”

The researchers used a climate model to assess what would happen if evergreens continued to expand their range farther north and larch species declined. The “positive feedback” cycle of warming promoting warming showed an increase of absorbed surface warming. The model takes into account detailed information about tree growth rates, and the results agree with actual field studies documenting changes in cone production and movement of evergreen treelines northward….

The Russian boreal forest sits over a tremendous repository of carbon-rich soil frozen in the permafrost. As the forest changes in species distribution from larch to evergreens, warming of the ground surface would cause decomposition of the soil, releasing huge quantities of carbon dioxide into the atmosphere – possibly as much as 15 percent of the carbon dioxide currently in the atmosphere.

“This is not the scenario one would want to see,” Shugart said. “It potentially would increase warming on a global scale.”

Well, actually, the permafrost permamelt contains a staggering “1.5 trillion tons of frozen carbon, about twice as much carbon as contained in the atmosphere, much of which would be released as methane.  Methane is 25 times as potent a heat-trapping gas as CO2 over a 100 year time horizon, but 72 times as potent over 20 years!


Going back to the 2005 Science study, the point is that if you convert a white landscape to a boreal forest, the surface suddenly starts collecting a lot more solar energy. That trend is occurring now, as seen in these two photos from a recent ScienceNews article, “Boreal forests shift north.”

“Upper photo taken in 1962 shows tundra-dominated mountain slope in Siberian Urals. A 2004 photo of the same site, below, shows conifers were setting up dense stand of forest.”

A 2008 study warns that the warming-driven northward march of vegetation poses yet another threat to the tundra.  That study, “Frequent Fires in Ancient Shrub Tundra: Implications of Paleorecords for Arctic Environmental Change,” finds:

“¦ greater fire activity will likely accompany temperature-related increases in shrub-dominated tundra predicted for the 21st century and beyond. Increased tundra burning will have broad impacts on physical and biological systems as well as on land-atmosphere interactions in the Arctic, including the potential to release stored organic carbon to the atmosphere.


The concern is not so much the direct emissions from burning tundra. As the article concludes:

“¦ studies of modern tundra fires suggest the possibility for both short- and long-term impacts from increased summer soil temperatures and moisture levels from altered surface albedo and roughness, and the release soil carbon through increased permafrost thaw depths and the consumption of the organic layer.

The image hows just how much the fire changes the albedo (reflectivity) of the tundra landscape.

A new, very conservative study by NOAA and the National Snow and Ice Data Center — which doesn’t even consider these various amplifying feedbacks in the region — finds that that the thawing permafrost feedback will turn the Arctic from a carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100.

Again, the people out there who think R&D or an energy quest is going to stop us from multiple catastrophes are deluding themselves and others.  We need to start aggressive mitigation now as every major independent study concludes.

Related posts and amplifying feedbacks:


Stephen Colbert: Nuclear reactors are as safe as oil, coal, and bank-robbing windmills

Editorials defending the EPA

18 Responses to Study: Climate-driven vegetation change by boreal forests is yet another positive, amplifying feedback

  1. Arkitkt says:

    A study published by the University of Virginia? The authors better know Cuccinelli will be digging through their emails trying to find any “lefty” leaning information on them,for publishing valuable science related research.

  2. Mike Roddy says:

    Few media publications address the effects of industrial logging in northern climates. Photos of natural landscapes are shown, but only about 5% of primary forests remain in the US, and roughly 30% in Canada, where primary forest logging continues.

    When you clearcut a site and burn the slash, a tremendous amount of carbon is released, and only about 15-20% ends up in wood products. Direct or implied policies to “manage” the remaining site for high fiber species results in simplification, making the area less resistant to climate stresses. Grassland or even desert can result, ecosystems that sequester far less carbon.

    We don’t read much anymore about temperate forest destruction through either logging or pollution, but forests are going to play a big role in our climate future.

  3. Richard Brenne says:

    Sometime when you’re not busy(!) Joe it’d be interesting to see all the observed and potential positive feedbacks to warming listed and compared with all the observed and potential negative feedbacks.

    My guess is that the positive feedbacks are kicking the negative feedbacks behinds at somewhere between a 10 to 1 to 100 to 1 or more ratio, and that this ratio will only increase. Your guess would be more educated and I’d love to hear it, together with the educated guesses of others. . .

  4. Mark says:

    Bizarre we keep applying tension to the equlibrium guitar string with all these feedbacks… what happens when there’s a sudden contribution from the earth?


    “Helo and fellow researchers from McGill, the Monterey Bay Aquarium Research Institute, and the Woods Hole Oceanographic Institution, have been able to prove that explosive eruptions can indeed occur in deep-sea volcanoes. Their work also shows that the release of CO2 from the deeper mantle to Earth’s atmosphere, at least in certain parts of mid-ocean ridges, is much higher than had previously been imagined.

    Given that mid-ocean ridges constitute the largest volcanic system on Earth, this discovery has important implications for the global carbon cycle which have yet to be explored.”

  5. Davos says:

    I tried to click on the tundra fire picture, but it took me to an error msg.

    [JR: Sorry. They didn't keep up their links!]

  6. Michael Tucker says:

    Nothing that I have seen or heard from any for our leaders leads me to think we will be able to accomplish anything to avoid future:
    Climate catastrophes
    Oil blow-out catastrophes
    Nuclear catastrophes

    Or really catastrophes of any kind…

    Let’s go ahead and rely on 30 year old nuclear reactors, blow-out preventers that have design flaws, and the EPA to control GHG. Let’s expand coal mining and ultra-deep oil drilling. Let’s depend on the stability of OPEC for the furure of our economy. Then let’s wait for the next disaster. That is all we have been able to do so far and I am very afraid that is all we can ever expect from our government.

    Is New Orleans ready for another Katrina? After seeing our government in action after Katrina are we convinced that they will be able to respond any better next time?

    They are completely inept because, for our leaders, it is all a political game and not a human issue of monumental proportion.

  7. Mike Roddy says:

    Richard Brenne,

    Good suggestion, I’d like to see feedbacks listed and quantified too, instead of being described in general terms. EIA and IPCC have reams of data on emissions, but very little on feedbacks.

    Michael Tucker,

    I agree, lots of us are frustrated as hell. Given the performance of our politicians, I only see a change if there is a big catastrophe that is both telegenic and directly affects food supplies. Then, maybe whoever is president could do his job and inspire the nation to act. This day is inevitable, but it might come too late.

    Even this isn’t certain- Russia is still hoping to drill in the Arctic after the recent collapse of their grain harvest. Unfortunately, there are no other events I can think of that will change anything. In the meantime, I’m going to keep finessing the inner struggle between despair and action.

  8. Joan Savage says:

    It really puts the focus on damping down the fossil contribution before these other positive feedbacks crank even faster.

    As recently as 1999 some researchers predicted that with global warming, carbon storage in the Arctic would increase. How wrong.

  9. John McGraw says:

    Someone needs to email this post to our Speaker of the House John Boehner. He said that since carbon dioxide isn’t a carcinogen we don’t need to worry about climate change. Senator Michelle Bachmann’s contribution is to tell us over and over that we don’t need to worry since carbon dioxide is a “natural” gas. With the large number of severely science challenged Republicans currently in office, there is zero chance of getting anything done.

  10. adelady says:

    Groundhog Day.

    This feels like that ‘phytoplankton moment’ all over again.

  11. Solar Jim says:

    Notice the recurring theme of Meltdown, a euphemism of the Atomic Age.

    Permafrost Meltdown, Clathrate Meltdown, Financial Meltdown, Arctic Meltdown, Cryosphere Meltdown, Atomic Meltdown.

    It makes one feel there is nothing solid about industrial civilization anymore, except the hubris, tax exemption, limited liability and indemnification of nation-state sanctioned globalized corporations.

    Speaking of solid, referring to uranium and coal as “energy” seems like solid hubris of contamination. Pardon our clean meltdowns.

  12. Tony says:

    Cue Ronald Reagan and his remarks about the Killer Trees!

  13. Brad Pierce says:

    Solar Jim, to slow the melting, it would help to cut black carbon (BC) emissions. According to http://www.igsd.org/news/documents/PR_EPABCreport_25March.pdf

    “Cutting BC is an essential strategy for vulnerable regions like the Arctic and Himalayas. If we don’t cut the BC emissions that end up in these vulnerable regions, we risk triggering positive feedback mechanisms that accelerate warming.”


    In the U.S. and other developed countries, most BC is from diesel use in the transport sector. For these sources, BC emissions can be reduced with ultra-low sulfur diesel, along with new engine standards and retrofits of existing engines. In developing countries, BC emissions are from residential cookstoves, as 3 billion people worldwide still cook with biomass or coal in rudimentary stoves or open fires. This source of BC pollution not only causes significant regional warming, it also causes 2 million deaths a year, mostly women and children.

  14. malcreado says:

    I agree with Mike; “forests are going to play a big role in our climate future”

    reforestation is geo-engineering that works

  15. Jay Alt says:

    This is the type of work some climate model critics said has been lacking. They say it is too simplistic to model the forcings mostly with GHGs. The emphasis of their own work on weather phenomenon makes them reluctant to trust methods that have given only limited local and regional results. Well, here it is boys and girls in terms you can understand. Unfortunately, I suspect most of the RJPSrtypes will simply jump-start their excuses assembly line.

  16. Lewis C says:

    Richard and Mike – there is only one of the major feedbacks for which I’ve heard a recent credible quantification, namely albido loss. According to the report on it a few months ago its current forcing is equivalent to that of around 30% of current anthro-CO2 outputs. The authors made the point that their study justified this estimate despite its being about twice the previous estimates by specialists in cryosphere dynamics.

    This raises a series of issues. First, with intensifying climate and anthro-impacts on soils and forests, and with the edge of permafrost having already shifted northward by some 140kms in places, it seems predictable that these and other feedbacks will also already be contributing significantly to airborne CO2e (as CO2 &/or methane), if not on the scale of the forcing from albido loss.

    With the planet’s natural carbon sinks declining – such as by forest desiccation and wildfire, soil desiccation, plankton decline, etc, the 20% to 50% of anthro emissions the sinks have been recovering annually plainly cannot be maintained. In fact, if the albido loss study is correct, we are probably at or near the point of those sinks being swamped by the combined contribution of the feedbacks.

    Given the additional pipeline-warming reflecting the last three or four decades of rising GHG pollution, and its resulting continued acceleration of the feedbacks, passing that ’swamping-point’ seems plainly unavoidable – at least without recourse to rapid planetary temperature moderation by geo-engineering in the form of albido restoration.

    Passing that point means of course that even a total overnight cessation of anthro-GHG outputs would not decelerate the feedbacks. Once they can fill the sinks with just a little to spare to increase airborne GHG stocks, our emissions control is irrelevant to their continued self-reinforcing acceleration.

    Finally there is the issue of their interactivity – the advance of the thruput of one feedback empowers all the rest – which has to be a bit problematic for modellers – How exactly would one start to model the interaction of a variety of feedbacks both with each other and with the evolving all-sources track of global temperature rise ? For a start this would mean incorporating a planet-sized set of variables and linkages to provide even a moderately credible outcome.

    Thus while I too would greatly welcome provision of a list of the major feedbacks’ current CO2e forcing equivalents, I’d see it as most likely being a highly potent means of warning of the hazard we face, rather than as predictably showing the key components of a grand projection of this century’s warming. In terms of presentation, the list I’d covet would show the feedbacks’ past and current CO2 forcing equivalents numerically, with the latter also expressed in the more comprehensible metric of: a new China, a new USA, a new Europe, a new Brazil, and so on.

    As the then-head of the UNFCCC, Dr Mohammed Cutajar observed to me,
    “This information would be a bombshell for the negotiations.”

    I’d add to his words that it could also reframe the public climate debate -
    not merely by the greatly raised urgency it describes,
    but also by sourcing the danger as being from Nature
    (which most people know deep down can be bloody dangerous)
    rather than being solely from mankind
    (whom so many have been taught is far too puny to affect this vast planet dangerously).



  17. Mike Roddy says:

    Thanks, Lewis, good points, and I agree. There are a couple of reasons why feedbacks have not been well documented or quantified in either the literature or the media:

    First, as you pointed out, precision is not possible with respect to feedback timelines or intensity, and interactivity throws timelines off even more. Still, a range of effects is possible, as with emissions in IPCC charts. There would be more complexity, but so what? We’re grown up enough to grasp it.

    The second reason is more elusive. With the exception of Science, Climate Progress, and a few others, the tom tom drums in editorial rooms seem to say “don’t alarm the public without information that does not appear in current measurements and trend projections”. This is actually far more irresponsible than erring on the side of very dangerous outcomes, given the stakes. Reasons include all the human frailties that may doom us- cowardice, commercial relationships, and failure to go where facts, logic, and imagination lead us.

  18. Lewis C says:

    Mike – thanks for your response to mine at 16/.

    Considering the central observation of the comment, that:

    “Given the additional pipeline-warming reflecting the last three or four decades of rising GHG pollution, and its resulting continued acceleration of the feedbacks, passing [the sinks'] ’swamping-point’ seems plainly unavoidable – at least without recourse to rapid planetary temperature moderation by geo-engineering in the form of albido restoration.”

    - I think it’s high time that this recognition was deployed to help initiate a thorough review of the institutional capacities and applied technology research needed to ensure that albido restoration is done well and done soon, and is not abused as merely a means to permit continued avoidable GHG outputs. Either we’re in that negotiation, or we cede the field to the likes of Koch Bros et al – who know full well the climate disruption their operations now face, and who will predictably seek the least-cost means to divert that threat.

    Plainly the kneejerk reaction to geo-engineering of “Just say NO!” is patently counter-productive – it would run us further past the ‘swamping-point’, leading predictably, as climate-disasters mount, to emergency deployment of the cheap-&-filthy option of massive sulphate aerosol distribution as a fossil carbon offset – to the ecosphere’s great detriment.

    With regard to my doubts over the feasibility of modelling the acceleration of the feedbacks with the other components of the GCMs, I’d gladly admit that my modelling skills are rudimentary – I hope I’m wrong and that some very bright sparks can somehow incorporate the feedbacks into credible projections.

    Yet the difficulties seem to me more than merely complex: they include problems such as predicting the chaotic month to month evolution of organic systems, such as the weather. Take for instance the geo-spatial nature of the major terrestrial carbon banks, the great forests and the permafrost tundra. Recent years’ mega-droughts and heat-waves over the Amazon & Boreal forests and over the tundra of both Siberia & Canada are going to recur (sans Geo-E), but how often, how soon, and with what intensity and duration ? Just these early assumptions alone will generate a huge spread of projections of the feedbacks’ rates of acceleration, and thus a still wider range of their total forcings by the century’s end.

    However, I wish the modellers the best of luck in their efforts, which are certainly worthwhile.

    I suspect that it is the sheer difficulty of the project that has discouraged scientific research into the feedbacks prognosis rather more than the commercial influences on media that you posit. Which is not to say that it is anything but negligent for the IPCC to have failed to publish an annual gazette of all known feedbacks’ estimated forcings, along with the necessary translation into nation-state-output equivalents for the media to disseminate.

    So if the IPCC has had to serve the instructions of its governmental authorities, what other high-profile scientific body might be persuaded to take on the task ? Could we persuade Joe perhaps to champion it amongst his many contacts as a potentially seminal messaging tool ?