Jim Manzi, noting that global warming will have relatively modest impacts on global economic product, argues for a DARPA-like government-supported program to expand technological options (e.g., developing backstop options such as geoengineering or “visionary biotechnology”) as a relatively cheap hedge in case the impacts of warming turn out be worse than generally expected. However, Joseph Romm argues that “immediate action is required” and that the costs of staving off the risk of “self destruction” would be modest.
I will assume that Romm is right in that something should be done about climate change beyond Manzi’s research approach, although I don’t share Romm’s faith in the results of climate modeling and in their implications for action. First, there are unanswered questions regarding the quality and integrity of surface temperature data that must necessarily be used to develop, calibrate, verify, and validate climate models (See Watts 2007, Watts 2008, Hale et al. 2006 (subscription required), Pielke et al. 2007a (pdf), Pielke et al. 2007b (subscription required), and McKitrick and Michaels 2007 (pdf)). Second, it’s unknown how much confidence, if any, should be placed not only on climate models (Koutsoyiannis et al. 2008) but also biophysical (Botkin et al. 2007 (pdf)) and socioeconomic models (Goklany 2007 (pdf)) that use the outputs of these climate models to estimate future impacts. Typically, they aren’t verified and validated at the appropriate geographical scales with observational data outside of that used to develop the models themselves. Third, projections extending beyond a few decades are inherently suspect (see Goklany 2008a).
While Romm’s approach essentially focuses on climate change to the exclusion of other problems, I’ll take a broader perspective. First, I’ll examine whether climate change is the most important problem facing the world today and in the foreseeable future. Next I’ll address how we can most effectively reduce damages from climate change while also advancing human and environmental well-being.
My analysis uses results of studies by scientists who are in good standing with the IPCC. Specifically, it uses mortality estimates from the World Health Organization (WHO) and estimates of the global impacts of climate change from the British-government sponsored “Fast Track Assessments” (FTAs) which were extensively referenced in the Stern Review and the IPCC’s latest assessment. In fact, many FTA authors were major contributors to the IPCC’s latest assessment. Cost estimates are taken from the IPCC and the United Nations Millennium Project. Details on the analysis can be found in my paper “What to Do about Climate Change” (Goklany, 2008b).
With respect to the first issue, the WHO’s analysis indicates that climate change is responsible for less than 0.3 percent of the present-day global health and mortality burden (Goklany 2008c). In fact, a dozen other environmental, food, and nutrition-related risk factors contribute more to the global death toll than climate change. For example, hunger’s annual contribution is over twenty times larger, unsafe water’s is ten times larger, and malaria’s is six times larger. With respect to ecological factors, habitat conversion continues to be the single largest demonstrated global threat to species and biodiversity. Thus climate change is not the most important problem facing today’s population.
With respect to the foreseeable future, which optimistically may extend to 2085 (if then), the FTAs indicate that under the IPCC’s warmest (A1FI) scenario, which the Hadley Center’s HadCM3 model projects will increase average global temperature by 4°C between 1990 and 2085, climate change will contribute about 10 percent of the cumulative death toll from hunger, malaria — a surrogate for vector-borne diseases in general — and flooding (figure 1).
Figure 1: Cumulative mortality in 2085 under various IPCC scenarios. The IPCC’s labels for these scenarios (A1FI, A2, B2, B1) and the corresponding Hadley Center estimate of average global temperature increase between 1990 and 2085 are shown under each bar.
Surprisingly, climate change would reduce the net global population at risk of water stress (Goklany 2008a).
Regarding environmental well-being, the FTA results indicate that in 2100, under the same scenario, despite a population increase, cropland could decline from 11.6 percent in the base year (1990) to less than half that (5.0 percent) (Goklany 2008d). That is, climate change may well relieve today’s largest threat to species and biodiversity! Also, non-climate-change related factors will dominate the global loss of coastal wetlands between 1990 and 2085.
Clearly, other problems outrank climate change now and through the foreseeable future, whether the concern is human well-being or global ecology. And thus these other environmental and public health problems should take precedence over climate change.
Let’s now examine what’s the most effective method of reducing damages from climate change, while also advancing well-being.
Since climate change contributes 10 percent of the global mortality from hunger, malaria, and coastal flooding in 2085 (under the warmest scenario), rolling back climate change to its 1990 level (i.e., “maximum mitigation”) would at most reduce mortality from these three risk factors by 10 percent. Thus, even if we eliminate climate change, annual mortality would vary from 2 million to 6 million in 2085, depending on the IPCC scenario employed. The Kyoto Protocol, on the other hand, would reduce climate change by less than 10 percent in 2085-2100. Hence, as a first approximation, had the United States participated and if all nations had met their obligations fully, the protocol would have reduced mortality by less than 1 percent (i.e., 10 percent of 10 percent) in 2085.
By contrast, if we focus our efforts on reducing societies’ vulnerabilities to hunger, malaria, and coastal flooding today, we would reduce not only the 10 percent of the problem due to climate change, but also the remainder of the problem, the 90 percent due to other factors, in the 2085 worst-case scenario. For example, with respect to malaria, worldwide vulnerability could be reduced through the development of a malaria vaccine, more effective insecticides, or improved therapies. Such measures would target the total malaria problem and reduce its toll regardless of whether it was caused by climate change or other factors.
Reduction of malaria vulnerability is an example of what I call “focused adaptation,” and this approach can be generalized to other climate-sensitive risks that non-climate-change-related factors also contribute to. Under focused adaptation, we would focus our efforts on enhancing resilience and reducing vulnerability to climate-sensitive problems that are urgent today and that could be exacerbated by future climate change. These include problems such as malaria and other vector-borne diseases, hunger, water shortages, threats to biodiversity, extreme weather events, and so forth. Significantly, focused adaptation would also begin to reduce current problems in short order (e.g., the annual death toll due to malaria, hunger, and flooding of 4 million), whereas any significant benefits from climate change mitigation would be delayed by decades because of the inertia of the climate system.
Significantly, the technologies and practices needed to deal with these problems today will be the basis for dealing with the same problems in the future whether they are caused by climate change or other factors.
Thus, focused adaptation would target all of the mortality due to hunger, malaria, and coastal flooding from now through the future, whereas maximal climate mitigation would target 0.3 percent (at most) of these problems today, rising to 10 percent in 2085.
The FTA results also indicate that mitigation could actually increase both the net global population at risk of water stress (Goklany 2008a), and habitat loss (Goklany 2008d). This illustrates a major, but often-ignored, drawback of mitigation, namely, that it reduces all impacts of climate change, whether good or bad, while adaptation allows us to be selective.
So through the foreseeable future, the potential benefits of focused adaptation far outweigh those from even maximum mitigation. But what about costs?
The Kyoto Protocol, despite its minimal effectiveness, is estimated to cost around $165 billion annually (in 2010-2015). Although the cost of maximum mitigation has never been estimated, suffice it to say that it would cost orders of magnitude more. I will assume a lower bound of $165 billion per year. As will become evident, the precise costs of mitigation don’t matter for this analysis because of the enormous mismatch between the cost-to-benefit ratios of the adaptive approach versus mitigation.
Regarding the costs of focused adaptation, the UN Millennium Project and the IPCC’s latest assessment indicate that by 2015, malaria could be reduced by 75 percent for $3 billion per year, hunger by 50 percent for $12-15 billion per year (e.g., through development of crops that would grow better in poor climatic or soil conditions such as drought, water-logging, and high salinity), and vulnerability to coastal flooding significantly reduced for $2-10 billion per year (e.g., through building and strengthening coastal defenses, insurance reform, and improving early warning systems).
Combining these estimates, and allowing for population increases, I estimate that focused adaptation could reduce mortality due to hunger, malaria, and flooding by 64 percent in 2085, at a cost of $34 billion annually, compared to a 10 percent reduction under maximum mitigation at an annual cost well above $165 billion, or simply a 1 percent reduction under the Kyoto Protocol at an annual cost of $165 billion.
There is another, broader method to reducing vulnerability to climate change. As Manzi notes, wealth and technology are the raw materials for developing future options. Also note that developing countries are most at risk from global warming not because they will experience greater climate change, but because they lack the adaptive capacity to cope with its impacts. Hence, another approach to addressing climate change would be to enhance their adaptive capacity by promoting broad development — economic development, human capital formation, and the propensity for technological change — which, of course, is the point of sustainable economic development.
Moreover, since the determinants of adaptive and mitigative capacity largely are the same, enhancing the former also should boost the latter. Perhaps more importantly, advancing economic development and human capital formation also would advance society’s ability to cope with all manner of threats, whether climate-related or not.
The costs and benefits of sustainable economic development can be estimated from work done on the UN’s Millennium Development Goals (MDGs), which were devised to promote sustainable development in the developing world. The benefits associated with these goals — halving global poverty, hunger, and the lack of access to safe water and sanitation; reducing child and maternal mortality by 66 percent or more; providing universal primary education; and reversing growth in malaria, HIV/AIDS, and other major diseases — would exceed the benefits flowing from the deepest mitigation and even focused adaptation. Yet, according to the UN Millennium Project, the additional annual cost to the richest countries of attaining the MDGs by 2015 is about $165 billion annually. That is approximately the same cost as that of the ineffectual — but expensive — Kyoto Protocol.
The following table summarizes the costs and benefits of the four mitigation and adaptation approaches discussed above. Note that red letters and negative numbers indicate a deteriorating situation:
Table 1: Costs and benefits of various mitigation and adaptation approaches.
The table shows that through the foreseeable future, vulnerability reduction will provide far greater benefits than even the deepest mitigation, and at a lower cost. And these conclusions hold regardless of the choice of discount rate, or fanciful scenarios beyond the foreseeable future.
Some have argued for mitigation as an insurance policy. Although mitigation (and R&D to expand mitigation options) makes sense so long as its implementation is neither mandatory nor subsidized, reducing vulnerability to current climate-sensitive problems and enhancing adaptive capacity is a far superior insurance policy. It will, unlike mitigation, pay handsome dividends now and in the future, whether or not the climate changes, or in whichever direction it does change. It will reduce risks faster, more effectively, more surely, and by a greater amount. No less important, it would provide the world the wherewithal to deal with a much wider array of future problems, whether they are related to climate or not. In short, vulnerability reduction allows us to solve the urgent problems facing today’s generations and improve their well-being while providing the best hedge for future generations as well.