Tropical climate

Definition

The tropics are the equatorial region between the Tropic of Cancer (23.5° north latitude) and the Tropic of Capricorn (23.5° south latitude). Because of an atmospheric circulation pattern known as the Hadley circulation, the tropics tend to be warm and wet. This region contains a variety of ecosystems, including deserts, rainforests, savannas, as well as several major islands. Although each of these ecosystems resembles the others in having generally hot weather (with the exception of a few mountains, such as Kilimanjaro in Tanzania, which lies only a few degrees south of the equator), they differ widely in average annual rainfall. In parts of Asia, Latin America, and Africa, rainforests are common, with average rainfall of more than 250 centimeters per year. The Sahara Desert also falls within the tropics, and some parts of it have the driest climate in the world. Some savanna regions, such as those in Kenya, have moderate amounts of rainfall. Indeed, some savannas are at a high enough altitude that they have a fairly wide daily temperature range during some parts of the year. The tropics also include several important coral reefs, such as those off the northern coast of Australia.

Significance for Climate Change

One aspect of concern related to global climate change is that many of the tropical nations are among the poorest on Earth. These developing nations will be less able to adapt to climate change than the industrial nations of Europe and North America. All the scenarios generated by the researchers connected with the Intergovernmental Panel on Climate Change (IPCC) indicate that global warming will have less of an impact on the temperature of the tropics than on the temperatures of regions at higher latitudes. Nonetheless, even minor temperature changes coupled with other factors can produce dramatic results.

In 1912, the average snow cover on Mount Kilimanjaro was 12 kilometers thick, yet by 2007, the snow cover had decreased to an average of only 1.5 kilometers thick. If the climate warms, in some places rainfall is expected to increase a great deal, while in other regions, such as northern Australia, drought conditions will intensify. In tropical rainforests in parts of Africa and South America, the intensity of rainstorms is predicted to increase, causing further erosion in cleared regions of the forests. Because many tropical ecosystems are quite fragile, even small changes in temperature, precipitation, and wind patterns will produce large adverse impacts on the affected nations. The major impacts in the tropics will come less from direct increases in temperature and more from changes in precipitation patterns, wind currents, and indirect impacts combining these two with temperature increases.

The impact of climate change on the tropics will differ from region to region, but it will become increasingly severe as global warming increases. For example, the IPCC projects that a 3° Celsius increase in global temperature will lead to a major loss of tropical rainforests, and, with this increase, as many as one-third of all species will become extinct. A 4° Celsius increase in temperature could lead to as many as 70 percent of all species worldwide, many in the tropics, becoming extinct. A temperature increase of this magnitude is also likely to lead to increased ocean acidification and the bleaching and ultimate death of most coral reefs, many of which are found in the tropics.

Increased rainfall and the resulting runoff in tropical countries could lead to extensive flooding, a problem exacerbated in low-lying nations such as Bangladesh by coastal flooding. Coastal flooding in southern India is projected to threaten the water supplies of many communities by the latter part of the twenty-first century. Because most hurricanes are found in the tropics, tropical peoples have long been concerned by the number and magnitude of hurricanes. Several scientists predict that increasingly warmer oceans would be likely to spawn more hurricanes and cyclones of greater magnitude than in the past.

A combination of climate change and concomitant socioeconomic changes is likely to produce several negative social and economic effects for societies in the tropics. In Nigeria, for example, many people may be forced to migrate from the interior to already-crowded coastal cities. Increasing temperatures combined with precipitation changes (either too little or too much) are likely to have a negative impact on the food supplies of tropical regions. In some cases, diseases such as malaria are likely to become more common because of increased standing water.

The various scenarios for climate change accepted by most scientists project an average increase in temperature of between 3° and 7° Celsius by the end of the twenty-first century. Although the temperature is projected to increase less in the tropics than in the temperate zones, the impact is likely to be severe. Many tropical nations lack the resources to adapt to climate change, so there is likely to be widespread suffering, in addition to extensive ecosystem damage.

Bibliography

Intergovernmental Panel on Climate Change. Climate Change, 2007—Impacts, Adaptation, and Vulnerability: Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Ed. by Martin Parry et al. New York: Cambridge U P, 2007. Print.

Lomborg, Bjørn. Cool It. New York: Random House, 2007. Print.

Mann, Michael E., and Lee R. Kump. Dire Predictions. New York: D.K., 2008. Print.

"Tropical Weather Systems." National Oceanic Atmospheric Administration (NOAA), 26 July 2023, www.noaa.gov/jetstream/tropical. Accessed 10 Dec. 2024.

"Tropics Feel the Heat of Climate Change." Scientific American. Scientific American, 31 Jan. 2014. Web. 20 Mar. 2015.