Survey results published by the Brookings Institution, a prominent Washington think tank, offer insights on factors most likely to influence public attitudes on climate change.

Based on a telephone poll conducted in Michigan and Pennsylvania in late 2007, researchers said they found that two significant factors prompt belief in manmade global warming: evidence of declining polar ice and glaciers, and personal experience with rising local temperatures.

In Michigan, for example, 57 percent of survey respondents said reduced polar ice and glaciers had a “strong effect” on their “view that the Earth is getting warmer.” In Pennsylvania, the comparable number was 55 percent.

Forty-two (42) percent of those surveyed in Michigan and 40 percent in Pennsylvania assigned “strong effect” status to higher temperatures in their own areas.

Computer modeling, Hurricane Katrina, and Al Gore’s “An Inconvenient Truth” film all were named by smaller numbers of respondents in both states as having a “strong effect” on their views.

Party affiliation was also found to be linked to patterns of response:

“Democrats were significantly more likely than their Republican counterparts to indicate that the factors we included in the study strongly affected their views on global warming,” wrote the two scholars who conducted the survey, Christopher B. Borick of Muhlenberg College and Barry G. Rabe of Brookings and the University of Virginia.

Other factors such as gender and age were also found to be linked to responses, but the authors wrote that those effects seem less obvious.

“It remains unclear whether public belief in global warming translates into support for new policies that may impose long-term economic and behavioral changes,” they concluded.

A promised follow-up report “will examine the receptivity of Michigan and Pennsylvania residents to a diverse set of policy options at both federal and state levels, ranging from regulatory approaches such as renewable energy mandates to more market-based strategies such as cap-and-trade and carbon taxes.”