Another study on positive feedback mechanisms: Peatlands

Following up on my previous post on the potential positive feedback mechanism of cloud cover, a new study in Nature (Dorrepaal, et al., Carbon Respiration from Subsurface Peat Accelerated By Climate Warming in the Subarctic, 460 Nature 616-620 (2009)) reveals another potentially massive positive feedback mechanism: accelerated carbon release as a consequence of enhanced peatland respiration induced by warming trends. The field study, conducted in a subarctic petland, indicated that a 1°C increase in temperature would accelerate respiration rates by 60% in spring and 52% in the summer on the site, a much greater rate than projected in previous studies. While the researchers express appropriate caution about projections from studies of this nature given their short duration and correlative nature, they conclude that a 1°C increase in temperature  could result in a release of an additiona 38-100 megatons of carbon per year. Put in perspective, the EU Kyoto Protocol target for emissions reductions is approximately 92 megatons of carbon per year.

For those of you that include a science component in your courses, this is a very good case study of how warming may indeed beget substantially more warming, and again, the importance of operationalizing the precautionary principle.

New Study on Cloud Feedbacks Not Encouraging

Climate researchers have consistently emphasized that the response of clouds to climate change will play a critical role in the future of the globe’s climate, but assessing the magnitude, and direction, of this feedback mechanism has proven extremely problematic in climate change modeling. A new study in the journal Science, Clement, Burgman & Norris, Observational and Model Evidence for Positive Low-Level Cloud Feedback, is a valuable contribution in this context, assessing the two best, long-term records of cloud behavior over a rectangle of ocean that nearly spans the subtropics between Hawaii and Mexico.  The study’s conclusions are sobering. During a warming episodes, that started around 1976, ship-based data showed that cloud cover—especially low-altitude cloud layers—decreased in the study area as ocean temperatures rose and atmospheric pressure fell. This, in turn, appears to result in more sunlight being let in, further warming the ocean, an apparent positive, and potent, feedback mechanism.

Another implication of the study is in the context of the accuracy of global climate models. The study tested 18 GCMs to ascertain if they were accurately modeling the cloud positive feedback mechanism, and concluded that only two of them were, with the stand out in this context being the HadGEM1 model from the U.K. Met Office’s Hadley Center in Exeter. This is not particularly good news since this model is among the most sensitive of the 18 models to added greenhouse gases. When carbon dioxide is doubled, the model warms the world by 4.4°C; the median of the models for a doubling is 3.1°C.

This study is thus a good way to demonstrate to students the importance of seeking to operationalize the precautionary principle in the UNFCCC. As the lead author of the study concluded, “We tend to focus on the middle of the range of model projections and ignore the extremes . . . I think it does suggest serious consideration should be given to the upper end of the range.”

Interdisciplinary Climate Change Research Symposium

Interdisciplinary Climate Change Research Symposium
13-20 March 2010
Saguaro Lake Ranch, AZ

Application Deadline
31 August 2009
Participation limited to thirty-four early career scholars
Airfare and on-site expenses supported by the National Science Foundation

The Dissertations Initiative for the Advancement of Climate Change Research (DISCCRS, pronounced discourse), connects natural andsocial scientists engaged in research related to climate change, impacts and solutions. The goal is to broaden perspectives and establish a collegial peer network to address climate challenges at the interface of science and society. A report and list of participants from the mostrecent symposium is available at

During the week-long symposium — held in the Tonto National Forest near Phoenix, Arizona — participants will present and discuss their research, hone interdisciplinary communication and team skills, and discuss emerging research, societal and professional issues with each other and with established researchers invited to serve as mentors. Confirmed mentors include Julia E. Cole (University of Arizona), Jonathan T. Overpeck (University of Arizona), Billie L. Turner (Arizona State University), and David A. Randall (Colorado State University).

Participation will be limited to thirty-four early career scholars identified by an interdisciplinary committee of research scientists based on review of submitted applications.

PhD requirements completed April 1, 2007 – July 31, 2009. Selection will favor applicants who plan to engage in interdisciplinary research careers in any subject within or relevant to climate change, its impacts and solutions. We encourage applicants from the natural and social sciences, economics, mathematics, engineering, or any other field so long as the research focus relates to climate change, its impacts or solutions. While the emphasis is on the U.S. research system, we welcome applicants from all countries who are interested in learning about the U.S. research system and connecting with U.S. researchers.

Symposium Application instructions:

Register your PhD dissertation and search for other recent climate change dissertations:
(over 900 PhDs have added their dissertation abstract on climate change to this database).

Electronic newsletter:
with jobs and other time-sensitive announcements is available to those who register dissertations.

Public webpage:
includes the dissertation registry, numerous early career resources, and symposium application instructions.


Ronald B. Mitchell, University of Oregon; Paul H. Yancey, Whitman College; Jennifer R. Marlon, University of Oregon; and Ruth A. Ladderud, Whitman College.

This Symposium is funded by the U.S. National Science Foundation through grants to the University of Oregon and Whitman College.


For a printable color poster of information about DISCCRS V in PDF format, please go to: — please distribute widely.

Ruth Ladderud

Administrative Assistant to C. Susan Weiler

Whitman College

345 Boyer Ave.

Walla Walla, WA 99362

509-527-4986    FAX 509 527-5961

Climate Lectures Online

Here’s an excellent set of videotaped lectures on Climate Change Law & Policy on the Academic Earth site, by William Collins.  If you put in the search term “climate change,” the site pulls up several others by UC-Berkeley faculty.

New Study on Long-Term Climate Solutions by Belfer Center

In a new Op-Ed, How to Set Greenhouse Gas Emission Targets for All Countries, Professor Jeffrey Frankel of Harvard’s Belfer Center outlines an interesting approach to how to develop a post-2012 climate regime. The study may be an interesting reading for students when juxtaposed with proposals that focus more on other criteria, e.g. equitable considerations or economic efficiency. The full study is also available.

Frankel argues that any viable long-term solution requires participation by all major emitters in the developed and developing world, must develop a path for emissions reductions for a century, and must not impose exorbitant costs that would preclude participation or lead to withdrawal from the regime in the future. Frankel  disparages current proposals, however, indicating that they have focused on science, equity and economic cost-benefit analysis, but have failed to take into account critical political considerations.

Frankel indicates that any future climate change agreement needs to grapple with six “political constraints”

  1. The US will not commit to quantitative targets if China and other major developing countries do not commit to quantitative targets at the same time, due to concerns about economic competitiveness and carbon leakage.
  2. China and other developing countries will not make sacrifices different in character from those made by richer countries that have gone before them.
  3. In the long run, no country can be rewarded for having “ramped up” its emissions high above the levels of 1990.
  4. No country will agree to participate if the present discounted value of its future expected costs is more than, say, 1% of GDP.
  5. No country will continue to abide by targets that cost it more than, say, 5% of GDP in any one budget period.
  6. If one major country drops out, others will become discouraged and the system may unravel.

To address these constraints, Frankel proposes the following broad criteria for a post-2012 regime:

  1. Rich nations immediately begin to make emissions cuts in line with targets to which their leaders have already committed;
  2. Developing countries agree to maintain their business-as-usual emissions in the first decades, but over the longer term agree to binding targets that ultimately reduce emissions well below business-as-usual
    • However, the prescribed emissions cuts are no greater than the cuts made by rich nations earlier in the century, accounting for differences in per-capita income, per-capita emissions, and baseline economic growth.
  3. There is a “catch-up factor” for nations that did not agree to binding targets under Kyoto to make gradual emissions cuts to account for their additional emissions since 1990. This is intended to preclude latecomers from being rewarded with higher targets, or providing them with an incentive to ramp up emissions prior to signing the agreement

Under Frankel’s formula, global carbon emissions peak in 2035, and atmospheric concentrations of carbon dioxide stabilize at 500ppm by the last quarter of the century. Frankel indicates that most countries would only sustain losses of under 1% GDP for the first half of the century.

I find Frankel’s proposal problematic in many different aspects:

  1. It is by no means clear that a concerted program to facilitate technology transfer to developing countries could effectuate substantial reductions in emissions, and at a lower cost than that projected by Frankel under his proposal. See, e.g.: den Elzen, Differentiation of Countries’ Future Commitments in a Post-2012 Climate Regime, 10 Environmental Science & Policy (2007).
  2. Frankel’s projections for temperature increases under these scenarios are questionable for several reasons:
    • He fails to take into account non-carbon dioxide emissions, which from a forcing perspective result in about half of the projected warming. When one takes into account optimal carbon dioxide equivalent targets, it’s hard to see how we could permit developing countries to increase their emissions beyond 2010 without seriously risking an overshoot of 3-4 degrees C
  3. If economic considerations are important, the study fails to seriously take into account either: a. the huge economic implications of potential non-linear responses of the climate change system once we pass the 2 or 3 degree C threshold; and b. Ignores the fact that delays in implementing meaningful cuts will substantially increase many of the costs of mitigation, which may make this framework much less politically palatable in the long term.

I for one am not ready to concede that the only politically viable scenario now is one that puts us on a path of stabilizing atmospheric carbon dioxide concentrations at 500 ppm given the dire implications of the 3 degree (and perhaps much more) temperature increase this scenario would wrought. More meaningful exploration of no-regrets mechanisms, many of which haven’t been assessed in any meaningful fashion at this point, as well as other mechanisms that may give us a lot of bang for our buck, e.g. addressing black carbon, need to be considered before we raise the white flag on the grounds of political expediency.

New Study on How to Achieve Equity in Long-Term Policymaking on Climate

An interesting new study, Chakravarty, Shoibal, Ananth Chikkatur, Heleen de Coninck, Stephen Pacala, Robert Socolow, and Massimo Tavoni. “Sharing Global CO2 Emission Reductions Among One Billion High Emitters.” Proceedings of the National Academy of Sciences of the United States of America (July 6, 2009) could be an excellent reading for students in helping them determine what might constitute equitable, and politically viable, post-2012 regimes. The study advances the thesis that the concept of “common but differentiated responsibilities” should be construed from the perspective of the emissions of individuals instead of nations. The study establishes a cap on emissions based on a floor of 1 tCO2/yr, and then calculates national budgets based on the number of “high emitter” individuals in each country, and their aggregate emissions. The authors conclude that the formula achieves equity and fairness in climate change policy in the sense that: 1. countries with a large proportion of high emitters are required to do more; and 2. countries with similar emission profiles would have similar commitments.

Applying the formula, the study concludes that the United States and China would have the highest carbon dioxide abatement assignments, while India, already, or poised to be, the third largest emitter of greenhouse gas emissions, would largely get a “free pass.” Interestingly, the formula would impose fairly substantial commitments on Africa, due to high carbon intensity and inequality in South Africa and in North African nations with energy industries. Russia and the Middle East would also take on substantial assignments for the same reason. A similar approach is taken by the think-tank EcoEquity in its formulation of a Greenhouse Development Rights scheme, though differences between its approach and that of the proposal of Chakravarty, et al. on issues such as historical emissions, can help the students to grapple with the large number of considerations that are pertinent to formulating long-term climate change commitments.

WRI Annual Review of Climate Science

The World Resources Institute’s issue brief Climate Science 2008: Major New Discoveries has just been released. It’s an excellent resource for teaching the climate change science phase of climate courses, reviewing major scientific developments in four sections: Physical Science; Hydrological Cycle; Ecosystems and Ecosystem Services; and Climate Change Mitigation Technologies.   The brief summarizes key studies released in 2008, and discusses their implications. The brief also contains hyperlinks to the original sources for all studies.


The latest UNFCCC data on GHG emissions of Annex I Parties is now available for the period of 1990-2006. The site includes some excellent graphs on total aggregate GHG emissions both including and excluding LULUCF, as well as trends in emissions.

Good Interactive Tool for Students

The UNFCCC Secretariat is working with Google and the Danish Government, as the host of COP 15, to display official UNFCCC greenhouse gas (GHG) emissions data for Annex I Parties using Google Maps.

Users can select a world map displaying: total national GHG emissions or removals, as well as emissions or removals from various sectors; absolute numbers (in Gg CO2 equivalent); or relative changes in emissions (in percent compared to the base year level).

This data may be particularly valuable in negotiation simulations, where students “represent” individual countries or regions.

Permafrost Melting: Implications

A quintessential example of potential positive feedback mechanisms that threaten to substantially accelerate warming trends during this decade and beyond is melting of permafrost in the far northern hemisphere. A new study, summarized in Reuters, and published in the journal Global Biogeochemical Cycle, concluded that the amount of carbon locked away in frozen soils in the far Northern Hemisphere is double previous estimates. The lead author, Pep Canadell, executive director of the Global Carbon Project at Australia’s state-funded Commonwealth Scientific and Industrial Research Organisation, concluded that if just 10% of this ice melted, it could raise atmospheric levels of carbon dioxide by 80ppm, translating into an additional 0.7C temperature increase. Of course, increased temperatures will result in more melting of permafrost, and more releases of carbon dioxide, bumping up temperatures, and so one.