Climate Change and Malaria
Sir David A. King's claim that "Climate change is the most severe problem that we are facing today--more serious even than the threat of terrorism" ("Climate change science: adapt, mitigate, or ignore?", Policy Forum, 9 Jan., p. 176) is based, in part, on UK government-sponsored impacts analyses (1, 2) that estimate that by the 2080s, because "of continued warming, millions more people around the world may in future be exposed to the risk of hunger, drought, flooding, and debilitating diseases such as malaria. Poor people in developing countries are likely to be most vulnerable" (p. 176). But the very studies underlying the latter quote, and which King cites, show that, for the most part, many more millions would be at risk in the absence of climate change (2). For instance, the population at risk of malaria (PAR-M) in the absence of climate change is projected to double between 1990 and the 2080s, to 8,820 million (2). However, unmitigated climate change would, by the 2080s, further increase PAR-M by another 257 to 323 million (2).
Thus, by the 2080s, halting further climate change would, at best, reduce total PAR-M by 3.5% [=100 x 323/(323 + 8,820)] (3). on the other hand, reducing carbon dioxide emissions with the goal of eventually stabilizing carbon dioxide at 550 ppm would reduce total PAR-M by 2.8% (2) at a cost to developed nations, according to King, of 1% of GDP in 2050 (p. 177), or about $280 billion in today's terms (4). But malaria's current annual death toll of about 1 million could be halved at an annual cost of $1.25 billion or less, according to the World Health Organization, through a combination of measures such as residual home spraying with insecticides, insecticide-treated bednets, improved case management, and more comprehensive antenatal care (5).
Clearly, implementing such measures now would provide greater malaria benefits over the next few decades than would climate stabilization at any level. It would also reduce vulnerability to malaria from all causes--man-made or natural--now and in the future (3). Similarly, reducing present-day vulnerabilities to the other risk factors mentioned by King (i.e., hunger, water shortage, and flooding) could well provide larger benefits at lower costs over the next few decades than would climate change mitigation efforts that go beyond so-called "no-regret" actions, that is, actions that are worth undertaking on their own merits unrelated to any climate change-related concerns (e.g., elimination of subsidies for fossil fuel usage or land clearance) (3).
The World Bank estimates that with additional annual expenditures of $40 to $60 billion, the United Nation's Millennium Development Goals to advance sustainable development could be reached by 2015 (6, 7). Comparing these goals (e.g., at least halving poverty, hunger, illiteracy, child and maternal mortality, and the proportions of populations lacking safe water and sanitation) (6) against what can be expected from halting further climate change (2) indicates that no matter how serious climate change is compared to terrorism, it pales by comparison with the more mundane problems poor people in developing countries face today and over the next few decades.
Even advancing halfway toward those goals would provide greater benefits for environmental and human well-being from now through the 2080s, and do so more economically than would heroic mitigation efforts (2, 6). Thus, it would be far more beneficial, and cost-effective, at least for the next several decades, to reduce vulnerabilities to current problems, especially if they might be exacerbated by climate change (e.g., hunger, malaria, drought, and flooding) (3). Even with a lagtime of 50 years to account for the inertia of the climate and energy system, the aforementioned analyses suggest we may have at least a quarter century window (2080s minus 50 years) before deciding on the depth and extent of mitigation. Meanwhile, we should focus on improving mitigation and adaptation technologies and our knowledge of climate change science, economics, and res exacerbated ponses. This way we can advance sustainable development and solve the problems of today while furthering our ability to solve the problems of the day after tomorrow.
SirDavidAKing
Chief Scientific Adviser to Her Majesty's Government and Head of the Office of Science and Technology,1VictoriaStreet,London