No. 49, May/June 2001
Linkages between Climate Change and Desertification
by Katherine Waser
These days, most of the debate on climate change seems to center around U.S. President George W. Bush's abrupt repudiation of the Kyoto Protocol in March 2001. Argument currently rages about whether Kyoto is or is not "dead" without U.S. participation; more immediately, it's anybody's guess what will happen in July 2001 when meetings are resumed of the 6th Conference of the Parties (COP-6) to the U.N. Framework Convention on Climate Change.
Meanwhile, residents of the world's drylands, affected as seriously and immediately by land degradation and desertification as they are by climate change, live every day with questions that lie at the intersection of these two serious phenomena:
These questions of potential linkages between climate change and desertification can be considered on at least three different levels: Scientific/technical; social and institutional; and procedural and organizational. (1) Even here there are linkages among the various levels, as the articles in this issue of the Arid Lands Newsletter illustrate.
Of most basic concern is the issue of scientific linkages. That climate change can directly contribute to desertification is widely accepted and in fact incorporated into the U.N.'s definition of desertification as "resulting from various factors, including climatic variations... ." (2) But, as it turns out, these linkages are more intricate than one might infer from this definition. As Dr. Martin A.J. Williams points out in his overview article on the interactions between these two phenomena, "Climate and desertification interact at a variety of scales through a complex and still only partially understood series of feedback loops."
For example, climate change could contribute to desertification not only because of increasing temperatures but also because of its effects on the composition of the atmosphere. Carbon dioxide (CO2), one of the major greenhouse gases (GHGs) linked with climate change, is of course crucial to plant life. In drylands, generally characterized by relatively sparse vegetation, the question of how increasing atmospheric CO2 levels might affect plant growth patterns, and consequently patterns of desertification, is of extreme interest. Scientists at the Free Air CO2 Enrichment facility in Nevada have been studying these questions; the article by Drs. Stan Smith and Travis Huxman outlines their results to date.
Perhaps because desertification effects tend to be local (especially in terms of human activities) whereas climate change effects tend to be global, it is easier to discern potential effects of climate change on desertification than it is to identify potential effects of desertification on climate change. Yet, it is crucial to begin to specify how and on what scale these latter effects exist. Two of the articles in this issue offer strong evidence that land degradation, land use change, and desertification can, indeed, influence local and regional-scale climate systems.
First, Dr. Christopher Taylor, of the Centre for Ecology and Hydrology (in the U.K), considers feedback loops between land surface and atmosphere in the Sahel--specifically, the effects of such loops on regional precipitation levels and their potential role in causing the droughts that have plagued the Sahel in recent decades. The data suggest that land surface conditions do influence rainfall in the region, in that rainfall patterns, once established, tend to persist longer than could be accounted for by chance. These results, coupled with other conditions such as increasing land use changes, suggest that climate instability in the region is likely to continue. (This, in turn, suggests that developing appropriate and effective adaptation strategies is of particularly immediate importance in the Sahel.)
Next, Dr. Daniel Rosenfeld of the Hebrew University of Jerusalem examines the effects of aerosols (particulate emissions) on the ability of clouds to form precipitation and produce rainfall. Many of these aerosols are produced by human activities, some of which (e.g. field burning, deforestation, and erosion resulting from both) directly contribute to land degradation as well. The research indicates that such aerosols can immediately and materially reduce the amount of rain that clouds produce. It is not difficult to predict that the resulting lack of rain would tend to increase pressures on the land, potentially resulting in human activities that cause even more aerosol emissions. This suggests a strong positive feedback loop, indeed. At the same time, however, the possibility exists for mitigation strategies with an immediate beneficial effect.
More broadly, the existence of such strong linkages between climate change and desertification processes suggests that mitigation strategies could be designed and coordinated to address aspects of both of these problems at once.In fact, there is strong evidence that one potential strategy, already much discussed in the context of the Kyoto Protocol, might be particularly appropriate for drylands. That strategy is carbon sequestration. The idea behind this strategy is to "lock up" carbon in vegetation and soils (that is, in "carbon sinks") in order to help offset rising CO2 emissions from human activities.
Many skeptics feel that this would merely allow industrial countries to continue emitting pollutants without restraint, and there is certainly merit to this criticism. Industrial countries should definitely not be let off the hook: there is no question but that such countries must seriously work towards reducing greenhouse gas emissions--preferably without whining or preaching about the supposedly "sacred" and "blessed" nature of grossly overconsumptive lifestyles.
On the other hand, the reasoning that carbon sequestration should be rejected outright because it will probably only offset rising GHG emissions in the relatively short term, is itself flawed. In fact, many arid lands researchers suggest that carbon sequestration, hitherto considered primarily as a strategy for temperate forests, could have significantly fewer drawbacks and greater benefits if implemented in drylands agroecosystems and soils.
Dr. Lennart Olsson and his colleagues weigh in first with an article promoting the possibility of carbon sequestration in semi-arid agroecosystems in developing countries. Such projects, if properly designed, could also provide significant social benefits by enhancing smallholder food security and rural livelihoods. This in turn would tend to promote better habitat conservation. Thus, carbon sequestration projects in drylands could enhance the goals not just of the UN Framework Convention on Climate Change and UN Convention to Combat Desertification, but also of the UN Convention on Biological Diversity. As the authors point out, this could truly be a "win-win-win" situation and should be seriously considered in future international climate change negotiations.
Another strong proponent of carbon sequestration is Dr. Rattan Lal of Ohio State University, who considers its potential in the drylands soils of the USA. Like Dr. Olsson, Dr. Lal is convinced that this is a strategy that must be pursued. Readers of these two articles will note that the specific methodologies the two authors propose are, in some cases, diametrically opposed. This does not, however, indicate "fuzzy science" or "weak scientific evidence." Rather, it reflects the differences between low-input agriculture systems, typical of developing countries, and high-input agriculture systems, typical of developed countries, and suggests that there is no "one size fits all" approach to designing mitigation strategies.
The article from Petra Tschakert, Ph.D. candidate in Arid Lands Resource Sciences at the University of Arizona, provides further evidence that this is so. Tschakert's research focuses on the potential human actors in the landscape. The notion that local "ownership" of projects is crucial to their long-term success is widely recognized; her research provides a model of how to ensure such a sense of ownership when it comes to carbon sequestration: a concept that is still largely a technological abstraction to most non-scientists. Working in the Old Peanut Basin of Senegal, Tschakert is opposed to evaluating mitigation strategies solely for their potential to sequester the most carbon at the least cost. Rather, she argues convincingly for "a shift in rationale to identify areas where local populations can derive social, economic and environmental benefits from sequestering carbon while, at the same time, contributing to desertification control and climate change mitigation."
This need to link policy with practice is also the broad theme of Siri Eriksen's two-part article. Focusing on study sites in Kenya and Tanzania, she and her colleagues are looking at how climate change and desertification can most effectively be addressed at the local level. The first part of the article focuses on physical and social linkages; the second part reviews how these local linkages and related actions are incorporated into government policies. The article also considers how resulting policy frameworks could be strengthened through implementation of the UN Conventions on Climate Change and on Desertification, and how these conventions might help provide financial and technical assistance for implementing practical measures. (3)
Finally, reminding us that climate change and desertification issues affect all regions of the globe, Dr. Michael Glantz and colleagues present a plea to the Chinese government that "creeping environmental problems" be addressed as part of that country's Western Region Development Strategy. Creeping environmental problems are defined as "changes that are imperceptible from one day to the next, but over some period of time they become noticeably worse. By then, however, attempts to address them have become more difficult as well as more costly." This of course sums up a central policy problem on a global scale (and in particular of countries that are major GHG producers): it is all too easy to postpone actions that may be expensive and politically unpopular, but doing so will only make things worse in the long run.
At this point, the fate of the Kyoto Protocol is uncertain. What the articles in this issue suggest, however, is that there are still many other avenues of action to explore, perhaps particularly in drylands. In these regions, precisely because of the strong linkages between climate change and desertification, there are many potential points and levels at which appropriate adaptation or mitigation strategies could be implemented, and much potential for well-designed actions to have multiple positive effects. In short, to paraphrase Rattan Lal, all of this needs to be done. The potential consequences of not so acting are grim, indeed.
(1) For more detail on this categorization scheme and ideas on creating linkages between the Climate Change and Desertification Conventions, see: Hoffmann, Hanna B. 2000. Linkages between climate change and desertification: Opportunities of an integrated approach. GLOBE Southern Africa Newsletter 2, March-April 2000. Internet: http://www.globesa.org/news200.htm; accessed 8 June 2001. (back to text)
(2) The full definition, codified in the UN Convention to Combat Desertification, Part 1: Introduction, Article 1, is as follows: '"desertification" means land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities.' More information is available from the UNCCD web site at http://www.unccd.int/. (back to text)
(3) In another move to strengthen possible linkages between policies and actions at the convention level, the Global Environmental Facility (GEF; the funding arm for the Climate Change and Biodiversity conventions) is moving towards establishing land degradation as a fifth focus area. This would provide a mechanism for the GEF to fund desertification mitigation activities directly. More details on the GEF and how it functions are available from the GEF web site, http://www.gefweb.org. For more details on the GEF's move to establish a new focus area, see: GEF 2001. Options to Enhance GEF Support for the Implementation of the United Nations Convention to Combat Desertification. Report GEF/C.17.5. Internet: http://www.gefweb.org/Documents/Council_Documents/GEF_C17/C.17.5.pdf; accessed 7 June 2001. Also available as a Word document at URL: http://www.gefweb.org/Documents/Council_Documents/GEF_C17/C.17.5.doc. (back to text)
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