A poll of more than 1,000 likely voters in the United States released this week showed that in the last two years Americans have become more convinced that global warming is happening.

An increasing number also believe there is a link between the increase in temperature and severity of weather events, such as hurricane Katrina, which has affected many and etched unpleasant memories in people's minds.

The poll was conducted by Zogby International for the National Wildlife Federation. The results:

74 percent are more convinced that global is happening than they were two years ago, while only one in five are now less convinced.70 percent of respondents also linked severe weather to global warming.68 percent thought that hurricanes such as Katrina were influenced by the increase in global temperatures. (Scientists say no single hurricane can be taken as evidence of global warming, and while the topic is very controversial among experts, some scientists argue that global warming has contributed to the intensity of hurricanes in recent decades. Hurricanes are not the only potential indicators of global warming. Also, a period of lower than usual hurricanes doesn't imply that global warming has been curbed.)The summer's heat wave was blamed on climate change by 65 percent of participants. (Again, scientists have modeled a climate future in which extremes will become more extreme, but no single heat wave is a clear sign of any change.)58 percent of participants think there is a link between more wildfires and the planet's higher temperature. (A recent study agreed.)More than 65 percent of those surveyed found global warming responsible for an increase in droughts and less snowfall.72 percent thought reducing industrial greenhouse gas emissions could improve the environment without affecting the economy.Democrats (87 percent), Independents (82 percent) and Republicans (56 percent) are much more convinced that global warming is happening than they were two years ago."Global warming isn't about right or left, it's about right or wrong," said Larry Schweiger, National Wildlife Federation president. "American's believe we have a moral responsibility to confront global warming to protect our children's future."

A poll conducted by the federation earlier this year found that the majority of hunters and fishermen think the country is on the wrong track with its energy policy and should be a leader in combating global warming.

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