Are Adaptation and Mitigation Substitutes?


Air conditioners for sale in Mumbai, India, where A/C has become “a new status symbol.”
Source: Kuni Takahashi for The New York Times

Humanity has at least two ways of dealing with climate change: adaptation and mitigation.  Adaptation means dealing with the effects of a warming planet, while mitigation means trying to prevent the planet from warming in the first place.

In an ideal world, we would do our best to mitigate and adapt as needed, but ours is not an ideal world.  In some respects, at least, it seems that efforts to adapt to climate change could come at the expense of mitigation, and vice versa.

Case in point, consider this NBER working paper about air conditioning, climate change, and mortality (emphasis added):

…we find that the mortality effect of an extremely hot day declined by about 80% between 1900-1959 and 1960-2004.  As a consequence, days with temperatures exceeding 90°F were responsible for about 600 premature fatalities annually in the 1960-2004 period, compared to the approximately 3,600 premature fatalities that would have occurred if the temperature-mortality relationship from before 1960 still prevailed… The adoption of residential air conditioning (AC) explains essentially the entire decline in the temperature-mortality relationship.  In contrast, increased access to electricity and health care seem not to affect mortality on extremely hot days.  Residential AC appears to be both the most promising technology to help poor countries mitigate the temperature related mortality impacts of climate change and, because fossil fuels are the least expensive source of energy, a technology whose proliferation will speed up the rate of climate change.

Certain mitigation policies, like carbon taxes and cap-and-trade schemes, are necessarily going to make air conditioning more expensive, and thereby make it harder for poor countries to deal not only with the effects of a warming planet, but even with a stable atmosphere that occasionally gets very hot.  Not all mitigation strategies will necessarily have this effect — a cost-effective carbon-capture technology need not raise air conditioning costs, for example — but carbon taxes and cap-and-trade schemes, two popular mitigation strategies, do unfortunately have this drawback.

An important implication is that adaptation and mitigation can interact in dangerous and sometimes unpredictable ways.  Any proposal to deal with climate change has to take those interactions into account to be predictable.

Another important implication is that greenhouse gas emissions are not the best measure of how well we’re dealing with climate change.  An approach to climate change that reduces greenhouse gas emissions to absolute zero would not be worth it, if it ultimately costs more lives than it saves (which a zero-emissions policy certainly would — though no one is actually proposing that).  By the same logic, even a technology that saves 3,000 lives per year for 50 years might not be worth using, if in the end it costs more than 3,000 lives per year via its effect on the frequency of droughts, hurricanes, etc.

The bottom line is that ultimately, the goal of any climate change policy should not be to reduce greenhouse emissions just for the sake of reducing emissions, but to maximize human welfare.  Things like mortality, welfare, and utility can be extremely difficult to measure given the complexity of social and environmental systems, but the point is that at the end of the day, what matters is life and maximizing the quality of life.  Intermediate factors like greenhouse gas emissions, arctic sea ice, sea levels, and air temperatures are only important via their effects on those two things.

A budding research community, including Sense & Sustainability’s own Jisung Park, is going beyond emissions and sea level rises, by measuring the connections between climate change, climate policy, mortality, and human welfare.  This paper on air conditioning is just one example, but there is a growing number of others like it — researchers are now studying things like how a warming planet might affect labor productivity, how classroom attendance and test scores are affected by temperature (which in turn is affected by access to air conditioning), how climate change and climate change policy interact with investment in everything from physical capital to R&D, and all the little hidden costs of extreme weather events either caused or enhanced by global warming.

The welfare impacts of climate change and climate policy are what matter, so I look forward to sharing more research along these lines.


This post has also been published on Jacob’s personal blog, with the generous permission of Sense & Sustainability.


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