Chapter 7 - Can Climate Change Save Lives? A Comment on “Economy-Wide Estimates of the Implications of Climate Change: Human Health”

Summary

In a 2006 article published in the journal Ecological Economics, Francesco Bosello, Robert Rosom and Richard Tol make the remarkable prediction that one degree of global warming will, on balance, save more than 800,000 lives annually by 2050. They introduce enormous, controversial monetary valuations of mortality and morbidity, varying with income; they then focus primarily on modeling the much smaller, indirect economic effects of the changes in health outcomes. Their calculations, large and small, are driven by the huge projected reduction in mortality – an estimate that Bosello et al. fail to substantiate. They rely on research that identifies a simple empirical relationship between temperature and mortality, but ignores the countervailing effect of human adaptation to gradual changes in average temperature. While focusing on small changes in average temperatures, they ignore the important health impacts of extreme weather events. They extrapolate the effects of small changes in average temperature far beyond the level that is apparently supported by their principal sources, and introduce arbitrary assumptions that may bias the result toward finding net health benefits from warming.

Introduction

Could a little bit of global warming have wonderful consequences for human health? In their article, “Economy-wide Estimates of the Implications of Climate Change: Human Health,” (2006, 579–91), Francesco Bosello, Roberto Roson and Richard Tol make the surprising prediction that the first stages of global warming will, on balance, save a large number of lives. As shown in their Table 1 (582), Bosello et al. estimate that in the year 2050 a global mean temperature 1.03°C higher than today's will result in 1,760,000 fewer deaths due to cardiovascular disease, only partially offset by 910,000 additional deaths due to malaria, diarrheal diseases and respiratory illness. The net effect is 850,000 avoided deaths, a huge change in worldwide mortality in a single year.

The estimate of reduced mortality is only the starting point for the ambitious set of calculations offered by Bosello et al. They seek to determine both the value of the direct welfare impacts of changes in mortality and morbidity due to climate change, and the indirect economic impacts of those changes in human health, including productivity losses and increased healthcare costs attributable to illness.