Earth's climate has changed many times over
the course of the planet's history, ranging from ice ages to long periods of intense heat. Until now, these changes have
occurred in response to natural events, like volcanic eruptions or variations in the amount of energy produced by the
sun. However, in the 18th century, during the time of the Industrial Revolution, human activities began to significantly
contribute to a worldwide warming trend.1 People began to burn fossil fuels like coal and oil and deforest
the land at rates unprecedented in Earth's history.2 These activities have changed the composition of the
atmosphere and are therefore almost certainly changing Earth's climate.
Climate change is a complex problem stemming from unsustainable policies and practices in almost every corner of the
world. Yet the basic science behind climate change is quite simple. The sun radiates vast amounts of energy onto
Earth. Most of the energy bounces off the surface of the planet and returns to space. But some of the energy is
trapped by greenhouses gases, like carbon dioxide and methane, which form a sort of buffer around the planet. The
heat-trapping effect is vital for life to exist because it keeps the planet far warmer than it otherwise would be.
Without greenhouse gases, the planet would be far too cold to inhabit.3
Naturally occurring levels of greenhouse gases allow life to flourish on Earth. Yet over the past two centuries,
certain human activities have caused an overabundance to build up in the atmosphere. Carbon dioxide, a by-product
of burning fossil fuels, is one major contributor to climate change. This problem is intensified by deforestation:
cutting down the trees that use carbon dioxide to grow. Because all plants are made of carbon, forests are one
of the most important storehouse of carbon on the planet.4 Countless human activities, like
transportation, livestock management, and agriculture, add more greenhouse gases to the atmosphere every year.
As concentrations increase, too much heat is trapped around the planet. This leads to rising global temperatures,
and countless other associated effects. According to the National Oceanic and Atmospheric Administration (NOAA)
and National Aeronautics and Space Administration (NASA), the average surface temperature of Earth has risen
about 1.2° Fahrenheit (F) in the last 100 years.5 The warmest year ever recorded occurred in
2005.6 While such a small change may seem insignificant, Earth's delicate balance has been disrupted,
leading to rapid environmental change. If climate models are accurate, the average temperature of Earth's surface
will only continue to rise. Models predict that the global average temperatures will increase from 3.2° to
7.2° F above 1990 levels in the next 90 years.7
The site gives an overview of the widespread environmental consequences that may result from climate change. To find out more,
visit the Resources page for a comprehensive list of web resources.
- Batturbury, S. (2008). Anthropology and global warming: The Need for environmental engagement. Australian
Journal of Anthropology, 19(1), 62-68. Retrieved from Academic Search Premier database.
- Friedman, T. (2008). Hot, flat, and crowded. New York: Farrar, Straus, and Giroux.
- U.S. Environmental Protection Agency. (2009). Climate change basic information. Retrieved July 1, 2009
from U.S. Environmental Protection agency website: www.epa.gov/climatechange/basicinfo.html
- Ingerson, A. (2007). U.S. forest carbon and climate change. Washington, DC: The Wilderness Society.
- National Aeronautics and Space Administration [NASA]. (2006). 2005 warmest year in over a century.
Retrieved July 1, 2009 from NASA website: http://www.nasa.gov/vision/earth/environment/2005_warmest.html
- Pachauri, R.K. & Reisinger, A. (Eds.) (2007). Climate Change 2007: Synthesis Report. Contribution of
Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate
Change. Geneva, Switzerland: IPCC.