Analyzing global warming

global warming

Greenhouse effect

is a warming of the lower atmosphere and surface of a planet by a complex process involving sunlight, gases, and particles in the atmosphere. On the earth, the greenhouse effect began long before human beings existed. However, recent human activity may have added to the effect. The amounts of heat-trapping atmospheric gases, called greenhouse gases, have greatly increased since the mid-1800's, when modern industry became widespread. Since the late 1800's, the temperature of the earth's surface has also risen. The greenhouse effect is so named because the atmosphere acts much like the glass roof and walls of a greenhouse, trapping heat from the sun.

Causes of climate change
Impact Global Warming
Limited Global Warming
Agreement on global warming
Analyzing global warming
Kyoto Protocol
Greenhouse effect
Scientific research
Why climates vary
Ocean problems
Southern Ocean
Pacific Ocean
Ozone hole
Environmental problems by petroleum
Changes in the atmosphere
Increasing Temperatures
Can Earth Explode ?
NASA Study
El Nino
The Procedure Of Implementation Afforestation And Reforestation Project Under The Clean Development Mechanism (CDM) In Indonesia
Reducing emissions from deforestation and forest degradation (REDD) in developing countries


Scientists use information from several sources to analyze global warming that occurred before people began to use thermometers. Those sources include tree rings, cores (cylindrical samples) of ice drilled from Antarctica and Greenland, and cores drilled out of sediments in oceans. Information from these sources indicates that the temperature increase of the 1900's was probably the largest in the last 1,000 years.

Computers help climatologists analyze past climate changes and predict future changes. First, a scientist programs a computer with a set of mathematical equations known as a climate model. The equations describe how various factors, such as the amount of CO2 in the atmosphere, affect the temperature of Earth's surface. Next, the scientist enters data representing the values of those factors at a certain time. He or she then runs the program, and the computer describes how the temperature would vary. A computer's representation of changing climatic conditions is known as a climate simulation.

In 2001, the Intergovernmental Panel on Climate Change (IPCC), a group sponsored by the United Nations (UN), published results of climate simulations in a report on global warming. Climatologists used three simulations to determine whether natural variations in climate produced the warming of the past 100 years. The first simulation took into account both natural processes and human activities that affect the climate. The second simulation took into account only the natural processes, and the third only the human activities.

The climatologists then compared the temperatures predicted by the three simulations with the actual temperatures recorded by thermometers. Only the first simulation, which took into account both natural processes and human activities, produced results that corresponded closely to the recorded temperatures.

The IPCC also published results of simulations that predicted temperatures until 2100. The different simulations took into account the same natural processes but different patterns of human activity. For example, scenarios differed in the amounts of CO2 that would enter the atmosphere due to human activities.

The simulations showed that there can be no "quick fix" to the problem of global warming. Even if all emissions of greenhouse gases were to cease immediately, the temperature would continue to increase after 2100 because of the greenhouse gases already in the atmosphere.

Michael D. Mastrandrea, B.S., Graduate Fellow, School of Earth Sciences, Geological and Environmental Sciences, Stanford University. Stephen H. Schneider, Ph.D., Professor of Biological Sciences, Stanford University.

Additional resources

Christianson, Gale E.Greenhouse: The 200-Year Story of Global Warming. Walker, 1999. Godrej, Dinyar.The No-Nonsense Guide to Climate Change. Verso, 2001. Johansen, Bruce E.The Global Warming Desk Reference. Greenwood, 2002. Stein, Paul.Global Warming. Rosen Pub. Group, 2001. Younger readers. -

Source : World Book 2005.