Is Climate Change the “Defining Challenge of Our Age†?

Climate change, some claim, is this century's most important environmental challenge. Mortality estimates for the year 2000 from the World Health Organization (WHO) indicate, however, that a dozen other risk factors contribute more to global mortality and global burden of disease. Moreover, the state-of-the-art British-sponsored fast track assessments (FTAs) of the global impacts of climate change show that through 2085–2100, climate change would contribute less to human health and environmental threats than other risk factors. Climate change is, therefore, unlikely to be the 21 st century's most important environmental problem. Combining the FTA results with WHO's mortality estimates indicates that halting climate change would reduce cumulative mortality from hunger, malaria, and coastal flooding, by 4–10 percent in 2085 while the Kyoto Protocol would lower it by 0.4–1 percent. FTA results also show that reducing climate change will increase populations-at-risk from water stress and, possibly, threats to biodiversity. But adaptive measures focused specifically on reducing vulnerability to climate sensitive threats would reduce cumulative mortality by 50–75 percent at a fraction of the Kyoto Protocol's cost without adding to risks from water stress or to biodiversity. Such “focused adaptation†would, moreover, reduce major hurdles to the developing world's sustainable economic development, lack of which is the major reason for its vulnerability to climate change (and any other form of adversity). Thus, focused adaptation can combat climate change and advance global well-being, particularly of the world's most vulnerable populations, more effectively than aggressive GHG reductions. Alternatively, these benefits and more — reductions in poverty, and infant and maternal mortality by 50–75%; increased access to safe water and sanitation; and universal literacy — can be obtained by broadly advancing sustainable economic development through policies, institutions and measures (such as those that would meet the UN Millennium Development Goals) at a cost approximating that of the Kyoto Protocol. However, in order to deal with climate change beyond the 2085–2100 timeframe, the paper also recommends expanding research and development of mitigation options, reducing barriers to implementing such options, and active science and monitoring programs to provide early warning of any “dangerous†climate change impacts.