American voters tend to see Global Warming as a serious problem but are divided as to whether it’s caused by human activities or long-term planetary trends.

A Rasmussen Reports telephone survey of 1,000 Likely Voters found that 45% consider Global Warming a “very serious” problem while another 28% say it is “somewhat serious.”

Forty-six percent (46%) of American voters believe that Global Warming is caused primarily by human activities. Thirty-five percent (35%) say it is the result of long-term planetary trends. Eight percent (8%) say there is some other cause while 11% are not sure.

Fifty-six percent (56%) of Democrats say human activity is the cause while 51% of Republicans identify long-term planetary trends as the culprit.

As with most issues, the understanding of why something is happening has a huge impact on perceptions about the issue. Among those who believe human activity is the primary cause of Global Warming, 71% consider it a Very Important issue. Among those who believe long-term planetary trends are causing the warming, just 17% rate the issue Very Important.

Also, those who see human activity as the cause of Global Warming are more likely to see a conflict between environmental protection and economic growth. Overall, 47% see a conflict between those goals while 29% do not.

Thirty-two percent (32%) of America’s Likely Voters say that President Bush has done a good or an excellent job on environmental issues. Twenty-five percent (25%) say he’s done a fair job while 42% say poor.

Overall, 53% of Americans say that environmental issues will be Very Important in terms of how they will vote in Election 2008. At the beginning of Election 2006, Health Care, the Economy, Government Corruption, and Iraq were rated as Very Important by at least 60% of Americans.

Earlier surveys by Rasmussen Reports have found that Americans strongly prefer development of alternative energy sources rather than conservation efforts. Most also support development of new nuclear power plants.