The Energy Information Administration blamed last year's rise in greenhouse gas emissions in part due to the more than 14% drop in hydropower output.

A steep decline in hydropower output in the U.S. led to higher greenhouse gas emissions in 2007, the federal Energy Information Administration (EIA) said on Wednesday.

Emissions rose 1.4 percent from the year before, and were about 16.7 percent above 1990 levels.

The EIA report stated, that the increase was primarily due to two factors. Unfavorable weather conditions which increased the need for heating and cooling, and a “drop in hydropower availability that led to greater reliance on fossil energy sources (coal and natural gas) for electricity generation, increasing the carbon intensity of the power supply.”

U.S. hydropower output, which is an emissions free energy source, dropped 14.2 percent last year caused by droughts in the U.S. Southeast and in California.

President-elect Barack Obama has pledged to cut greenhouse gas emissions to 1990 levels by 2020. However, EIA spokesman Paul McArdle said that achieving Obama’s goals would be a “substantial task”.