Healthy Climate, Healthy People

This is the twenty-seventh of a continuing series of essays and interviews from Earth Institute scientists on the prospects for a global climate-change treaty. Check with us daily for news and perspectives, and to make comments, as events unfold throughout the Copenhagen meetings.

As leaders debate climate policy in Copenhagen, one essential dimension has been largely left out: human health. This is a mistake for two reasons. First, one of the most compelling reasons for aggressive action is to avoid the enormous long-term health impacts likely to be felt throughout the world if we continue to push our climate out of balance. Second, there is an emerging consensus among health scientists that most of the available strategies for reducing society’s long-term climate footprint carry with them substantial near-term health co-benefits. In other words, taking steps now to slow climate change can have immediate health benefits in the communities where such steps are taken.

Global warming will bring a range of extreme events, including more intense heat waves and storms. It will also change patterns of rainfall, food production, and vector-borne diseases. Flooding due to sea-level rise is already affecting coastal populations around the world. Recent scholarship has highlighted the dramatic health consequences these changes may bring, particularly for children, the elderly, and people made more vulnerable by pre-existing illness or poverty. According to a study by Australian National University professor Anthony McMichael, climate change was already responsible for 166,000 deaths in 2000, most of which occurred in developing countries due to increases in malaria, diarrhea, and malnutrition. But the threat is not confined to the developing world. Researchers at Columbia University’s Mailman School of Public Health estimate that heat-related deaths in the New York metropolitan region could increase by 50% to 100% by the 2050s. These widespread impacts provide a compelling rationale for aggressive action.

In an urbanizing world, human influences on the global climate increasingly operate via actions taken at the urban scale. Cities have significant opportunities to contribute to greenhouse gas mitigation by reducing their own carbon footprints. Many, such as reductions in motor vehicle use and emissions, carry substantial, immediate local health benefits. They will reduce air-pollution levels and increase physical activity, and thus hit at the roots of cardiac and lung diseases. A study that appeared this year in the medical journal The Lancet examined potential benefits in London and Delhi of policies to reduce motor vehicle emissions and encourage biking and walking. By 2030, the study estimated, these policies could achieve up to a 25% reduction in life lost due to heart attacks.

Mitigation strategies in other sectors–household energy, food production, electricity generation–also are likely to carry a range of associated health co-benefits. Careful analyses are beginning to show the sizes and geographic patterns of such benefits. As we develop this knowledge, we should focus on policies that have higher near-term health co-benefits while also achieving mitigation targets at comparable costs, over other strategies.

By putting health at the center of the discussion, over emission targets per se, we have the opportunity to maximize health benefits in both the near and long terms. If we do it right, climate change could present one of the best opportunities in a generation for global health improvement.