From the NY Times

“The impact of a changing climate is already being felt across the United States, like shifting migration patterns of butterflies in the West and heavier downpours in the Midwest and East, according to a government study to be released on Tuesday.

“Even if the nation takes significant steps to slow emissions of heat-trapping gases, the impact of global warming is expected to become more severe in coming years, the report says, affecting farms and forests, coastlines and floodplains, water and energy supplies, transportation and human health.

“… The study, overseen by the White House Office of Science and Technology Policy, will be posted at www.globalchange.gov/usimpacts.

“Some of the effects being seen today and cited in the report are familiar, like more powerful tropical storms and erosion of ocean coastlines caused by melting Arctic ice. The study also cites an increase in drought in the Southwest and more intense heat waves in the Northeast as a result of growing concentrations of carbon dioxide and other climate-altering gases in the atmosphere. “