Climate change preparations must focus on health disparities

Abstract

Quantification of the likely costs to health of temperature increases is one of the key reasons why the Stern review, an analysis of the economic cost of climate change, commissioned by the UK Government and published on Oct 30, sounds more pessimistic than previous estimates. Instead of just totting up the numbers of people who will be exposed to malaria in future, the Stern review factors in more frequent extreme weather events—a cause of malnutrition as well as of temperature-related deaths—and estimates that mortality related to climate change will reach 300 000 a year by 2030.Slightly paradoxically, however, the short-term effects of climate change on mortality might actually be positive. The limited evidence suggests mortality may follow a U-shaped curve, decreasing during the initial rise in temperature but then increasing sharply once the temperature exceeds what human beings can cope with. But in the long run, there is no doubt that health will be affected—and those already disadvantaged will suffer most. The Stern review cites a WHO estimate that climate change during the past 50 years has already caused an extra 150 000 deaths a year, mainly due to diarrhoea, malaria, and malnutrition. Further temperature rises will increase malnutrition and heat stress, in addition to facilitating the spread of vector-borne diseases, such as malaria and dengue fever, in places currently free from these illnesses. One estimate quoted by Stern suggests that even a 2°C increase in temperature could expose 40–60 million more people to malaria in Africa—a 9–14% increase over today's numbers.Stern concludes, however, that the picture painted in the report is essentially an optimistic one because if “we act now and act internationally” the consequences can be averted. But for health, the pessimism stems not from the shaky estimates of temperature-related excess deaths, but from the certainty that this mortality burden will not be equally distributed around the world. Climate change will amplify disparities between rich and poor countries. Resolving these disparities is therefore where preventive efforts must be concentrated. Quantification of the likely costs to health of temperature increases is one of the key reasons why the Stern review, an analysis of the economic cost of climate change, commissioned by the UK Government and published on Oct 30, sounds more pessimistic than previous estimates. Instead of just totting up the numbers of people who will be exposed to malaria in future, the Stern review factors in more frequent extreme weather events—a cause of malnutrition as well as of temperature-related deaths—and estimates that mortality related to climate change will reach 300 000 a year by 2030. Slightly paradoxically, however, the short-term effects of climate change on mortality might actually be positive. The limited evidence suggests mortality may follow a U-shaped curve, decreasing during the initial rise in temperature but then increasing sharply once the temperature exceeds what human beings can cope with. But in the long run, there is no doubt that health will be affected—and those already disadvantaged will suffer most. The Stern review cites a WHO estimate that climate change during the past 50 years has already caused an extra 150 000 deaths a year, mainly due to diarrhoea, malaria, and malnutrition. Further temperature rises will increase malnutrition and heat stress, in addition to facilitating the spread of vector-borne diseases, such as malaria and dengue fever, in places currently free from these illnesses. One estimate quoted by Stern suggests that even a 2°C increase in temperature could expose 40–60 million more people to malaria in Africa—a 9–14% increase over today's numbers. Stern concludes, however, that the picture painted in the report is essentially an optimistic one because if “we act now and act internationally” the consequences can be averted. But for health, the pessimism stems not from the shaky estimates of temperature-related excess deaths, but from the certainty that this mortality burden will not be equally distributed around the world. Climate change will amplify disparities between rich and poor countries. Resolving these disparities is therefore where preventive efforts must be concentrated.