The results of rising sea levels on human and animal populations could be catastrophic. The gases that are primarily causing global warming include simple water vapor and carbon dioxide. To sustain life, some degree of a greenhouse effect is necessary or else most of the sun's warmth would be dissipated into space. The rapid increase of greenhouse gases in the atmosphere due to industrialization...

Therefore, global warming is at least enhanced by human causes. Emissions of carbon dioxide and other greenhouse gases are exacerbating the earth's natural warming process.
Solving the problems associated with climate change requires wholesale changes to the ways human beings produce goods on a large scale. Simply shutting off lights at night might help but the key remains in developing new technologies that reduce emissions at their greatest sources: factories and vehicles including automobiles and airplanes.

References

National Oceanic and Atmospheric Administration. "Global Warming Frequently Asked Questions." National Climatic Data Center. Retrieved May 26, 2008 at http://www.ncdc.noaa.gov/oa/climate/globalwarming.html#q1

United States Environmental Protection Agency. "Climate Change." Retrieved May 26, 2008 at http://www.epa.gov/climatechange/basicinfo.html