Climate change during the next century and beyond may exacerbate many of the health threats faced by human populations, especially in resource-poor countries. These threats include disruption of water and food supplies by extreme weather events and the enhanced spread of vector-borne diseases by increasing air and water temperatures.1 Even under the most optimistic scenarios for reducing greenhouse gas emissions, average global temperatures will likely rise at least 2.5°C to 3.0°C over the next few centuries.2 This is well above the threshold for substantially increasing climate-related health threats.3 Thus, an effective strategy must provide long-term policies to reduce emissions, decrease vulnerabilities, and ameliorate negative impacts.
The primary international response to global climate change is the 1992 United Nations Framework Convention on Climate Change (UNFCCC), which has been ratified by 186 nations.4 The objective of the UNFCCC is to "stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system," although this level is not specified. Because of resistance by the United States and other nations to binding targets, the UNFCCC called upon parties merely to "aim" to return their emissions to 1990 levels at an unspecified point in the future.
In the face of mounting evidence that parties to the UNFCCC were failing to voluntarily reduce their emissions and projections that emissions might increase by 40% from 1990 levels by 2010,5 the third conference of the UNFCCC parties drafted the Kyoto Protocol in 1997.6 The Protocol calls for industrialized nations to reduce their emissions by at least 5% below 1990 levels by the period 2008-2012.
The Bush Administration has stated that it will not submit the Protocol for ratification by the Senate.7 This decision effectively excludes the United States, responsible for approximately a quarter of the world's greenhouse gas emissions,8 from a major multilateral effort to confront global warming. President Bush recently announced a series of initiatives to address climate change, including additional funding for research and largely voluntary efforts to reduce the ratio of greenhouse gas emissions to economic output. The World Resources Institute predicted, however, that US emissions under the Bush plan will grow by an additional 14% or more over the next decade.9
Even if the Kyoto Protocol itself is fully implemented, it represents a small down payment on what the world must ultimately do to mitigate climate change. To stabilize greenhouse gas concentrations at twice preindustrial levels (a critical threshold according to many researchers), greenhouse gas emissions must be reduced by 60% to 70% below 1990 levels.3 This would demand immense political will on the part of both industrialized and developing countries to fundamentally restructure many sectors of their societies.
Given the likely inevitability of substantial climate change over the next few centuries, strategies to adapt to its potential impacts on human health are critical. Indeed the seventh conference of the UNFCCC parties recognized this need, and the European Union together with other developed countries agreed to collectively contribute $410 million annually by 2005 to a preliminary fund for adaptation initiatives.10 These measures include establishing stations to monitor sea-level rise and extreme weather risks, improving geographic information systems and other tools to track the spread of disease vectors, and promoting public awareness on climate change issues.
While the cost of developing adaptation programs will be substantial, it will likely pale in comparison to the cost of allowing climate change to proceed without intervention. The Kyoto Protocol goes far beyond the original UNFCCC by recognizing the immediacy of the problem and setting legally binding and verifiable emissions targets. It also establishes mechanisms to promote efficient and renewable energy technologies and to transfer them to developing countries willing to leapfrog the fossil-fuel route. Effective mitigation of climate change, however, will ultimately require the participation of the United States and its realization that the adoption of alternatives to fossil fuels is not only compatible with economic growth11 but is also a public health measure supported by a large body of peer-reviewed science.
Burns WCG. Climate Change and Human Health: The Critical Policy Agenda. JAMA. 2002;287(17):2287. doi:10.1001/jama.287.17.2287-JMS0501-6-1