Why is global warming a problem?
The cost and benefits of global warming will vary greatly from area to area. For moderate climate change, the balance can be difficult to assess. But the larger the change in climate, the more negative the consequences will become. Global warming will probably make life harder, not easier, for most people. This is mainly because we have already built enormous infrastructure based on the climate we now have.
People in some temperate zones may benefit from milder winters, more abundant rainfall, and expanding crop production zones. But people in other areas will suffer from increased heat waves, coastal erosion, rising sea level, more erratic rainfall, and droughts.
The crops, natural vegetation, and domesticated and wild animals (including seafood) that sustain people in a given area may be unable to adapt to local or regional changes in climate. The ranges of diseases and insect pests that are limited by temperature may expand, if other environmental conditions are also favorable.
The problems seem especially obvious in cases where current societal trends appear to be on a “collision course” with predictions of global warming’s impacts:
- at the same time that sea levels are rising, human population continues to grow most rapidly in flood-vulnerable, low-lying coastal zones;
- places where famine and food insecurity are greatest in today’s world are not places where milder winters will boost crop or vegetation productivity, but instead, are places where rainfall will probably become less reliable, and crop productivity is expected to fall;
- the countries most vulnerable to global warming’s most serious side effects are among the poorest and least able to pay for the medical and social services and technological solutions that will be needed to adapt to climate change.
In its summary report on the impacts of climate change, the Intergovernmental Panel on Climate Change stated, “Taken as a whole, the range of published evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time.”
(For specific information on the projected impacts of climate change in the United States, see the National Assessment Report by the U.S. Global Change Research Program.)
- United Nations Environment Programme, Division of Early Warning and Assessment. (2006). Emerging Challenges: New Findings, in P. Harrison (Ed.), Global Environment Outlook Year Book 2006 (59-70). Malta: Progress Press Ltd.
- McGranahan, G., Balk, D., and Anderson, B. (2007) The rising tide: assessing the risks of climate change and human settlements in low elevation costal zones. Environment and Urbanization, 19 (1), 17-37.
- Intergovernmental Panel on Climate Change. (2007). Summary for Policy Makers. In Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller (eds.)]. Cambridge, United Kingdom, and New York, New York: Cambridge University Press.