Unusual weather increases pro-environment votes in Congress


Members of Congress are more likely to take pro-environment stances on votes when their home states experience unusual weather, says a paper from the Harvard Environmental Economics Program.

"Although the effects we estimate are modest in size (as would be expected)...our results suggest that extreme local weather is one of many factors that legislators may consider when voting on environmental issues," write the paper's (.pdf) authors, Evan Herrnstadt and Erich Muehlegger, respectively a University of Michigan doctoral candidate and a Harvard University public policy professor.

They looked at variation among individual members' votes on environmental issues from 2004 to 2011, using data on 215 bills, motions and amendments tracked by the League of Conservation Voters. To measure the salience of climate change, the authors used Internet search data, having found that searches for climate change respond to weather deviations.

Democrats in particular were more likely to support pro-environment legislation when search activity related to climate change was high in their home states, the paper says.

Pro-environment votes by House members tended to correlate more with unusual weather in their home states than Senate votes. That may be because senators face re-election less often, making them "less responsive to short-lived changes in constituent interests," the paper says.

The correlation was also weaker for members of Congress whose League of Conservation Voters rating was below 50 on the group's 0-100 scale (where pro-environment lawmakers score higher). Similarly, members who almost always vote in favor of pro-environment legislation didn't tend to act differently when there was more unusual weather.

"Forming accurate beliefs about a long-term one-time event such as climate change places an enormous informational burden on the actor," the paper says. "A natural proxy for understanding climate change is a short-run weather event."

The effects of abnormal weather on Internet searches varied significantly by season. In the winter, searches related to climate change surged in response to both unusually cold and unusually warm weather. In spring, weather had no statistically significant effect on searches.

Unusually cold weather had a large effect on in fall and winter, while unusually warm weather correlated with increased searches only in winter and summer, the paper says.

States with major industries that are weather-dependent produced predictable search trends, the paper says. The 18 states where farming comprises more than 1 percent of gross state product showed a sensitivity to unusually cold spring weather, and the 13 states with the most ski resorts were sensitive to unusually low snow depth.

For more:
- download the paper, "Weather, Salience of Climate Change and Congressional Voting" (.pdf)

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