EPA Report Blames Human Activity for Global Warming

A variety of environmental phenomena show that the earth is warming due to greenhouse gas emissions from human activities, according to a recent report by the Environmental Protection Agency.

A variety of environmental phenomena show that the earth is warming due to greenhouse gas emissions from human activities, according to a recent report by the Environmental Protection Agency.

"Warming of the climate system is well documented, evident from increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level," EPA says in the report, "Climate Change Indicators in the United States." The buildup of greenhouse gases in the atmosphere "is very likely the cause of most of the recent observed increase in average temperatures, and contributes to other climate changes," the report adds.

The report presents 24 indicators, each describing trends related to the causes and effects of climate change, it said. Among the indicators included are changes in sea level, temperatures and greenhouse gas emissions.

"These indicators show us that climate change is a very real problem with impacts that are already being seen," said Gina McCarthy, EPA's assistant administrator for air and radiation, in a statement. "The actions Americans are taking today to save energy and reduce greenhouse gas emissions will help us solve this global challenge."

According to EPA, the report will inform policy decisions and will help in evaluating the success of efforts to mitigate climate change. The data were collected by several government agencies, academic institutions, and other stakeholder organizations. EPA plans to update the report periodically.

Increases in greenhouse gas emissions are mainly due to fossil fuels used to generate electricity, to power motor vehicles, and to provide energy for industry.

The report said annual U.S. greenhouse gas emissions increased 14 percent from 1990 to 2008, to a total of 6.957 billion tonnes. Global emissions increased 26 percent between 1990 and 2005, to 38 billion tonnes.

Average temperatures have risen since 1901 in the lower 48 states, the report said, and seven of the top 10 warmest years have occurred since 1990. Average global temperatures show a similar trend, the report said, with 2000-2009 being the warmest decade on record.

The intensity of tropical storms and hurricanes has increased since 1990, with six of the 10 most active hurricane seasons occurring since the mid-1990s. The increase is closely related to variations in sea surface temperature in the tropical Atlantic. Sea surface temperatures increased steadily over the 20th century, the report said.

Sea levels have risen an average of six-tenths of an inch each decade since the 1870s, the report said, but are now rising an average of an inch a decade. From 1993 to 2008, sea levels rose twice as fast as the long-term trend.

2007 had the least Arctic sea ice of any year on record, the report said, followed by 2008 and 2009.

Glaciers in the United States and around the world have shrunk since the 1960s, the report said. The rate of melting appears to have accelerated over the last decade. Glaciers worldwide have lost more than 2,000 cubic miles of water since 1960, the report said, contributing to the observed rise in sea level.

Page 1 of 51
Next Page