Source: University Corporation for Atmospheric Research (UCAR) ad the National Oceanic and Atmospheric Administration (NOAA), Reports to the Nation: Our Changing Climate (UCAR, Boulder, Colorado, 1997), p. 20.

The graph above shows fluctuations in the global temperature.  Even looking as far as 140 years back, the temperature has stayed with a range of just over two degrees Fahrenheit from then until the present day.

It is also obvious from the graph that the global temperature has been increasing in recent years.

There is considerable debate among scientists, environmentalists, and government policy makers about what is causing this global warming.  Some people say it is caused by natural environmental dynamics, while others attribute it to human activities.

If it is being caused by human activities, then global warming can probably be prevented.  Governments might have to begin working much harder to reduce global warming in the future if these current trends continue.