The Environmental Protection Agency said on Monday that U.S. greenhouse gas emissions linked to global warming increased 16 percent over a 15-year period.
The report found that emissions did not rise between 1990 and 2005 as much as the U.S. economy, which grew 55 percent during the same period.
Overall U.S. emissions in 2005, the most recent year examined, increased by less than 1 percent from the year before to the equivalent of 7,260 million metric tons of carbon dioxide.
In 1990, emissions stood at 6,242 million tons.
Electricity generation mostly from coal-fueled power plants spewed 41 percent of the carbon dioxide emissions from fossil fuel combustion in 2005, the EPA said.
The inventory report also looked at carbon dioxide emissions taken out of the atmosphere by so-called "sinks," such as forests, vegetation and soils that absorb carbon.
The final report will be sent to the United Nations to meet the United States' annual requirement as a party to an international treaty on climate change.
The United Nations Framework Convention on Climate Change, which was ratified by the United States in 1992, sets out an overall framework for governments to tackle climate change.
President Bush pulled the United States out of the subsequent Kyoto global warming treaty, arguing the accord's limit on annual emissions would hurt the U.S. economy.
Instead, the Bush administration has pushed its program to have companies voluntarily take steps to cut their greenhouse gas emissions.
But rather than reducing total emissions, the administration is focused on cutting the amount of emissions per every $1 increase in the U.S. economy. The White House goal is to reduce greenhouse gas intensity by 18 percent by 2012.
Many lawmakers in the new Democratic-controlled Congress argue that policy is not good enough and are pushing legislation to impose specific reductions in total U.S. greenhouse gases.