Climate change is real and the result of man-made greenhouse gases, the U.S. Environmental Protection Agency said Thursday in response to skeptics that include Virginia Attorney General Ken Cuccinelli.

At the request of Virginia and 15 other states, the EPA re-examined its position on greenhouse gases and came to the same conclusion it reached in December -- they threaten human health and should be more tightly regulated.

Cuccinelli filed a legal challenge in February to the EPA's initial determination, saying it was based on flawed data from the Climate Research Unit at the University of East Anglia in England.

In what Cuccinelli called "the explosive revelations of climate-gate," hacked e-mails from researchers at the school suggested that they tampered with data to exaggerate the threat of climate change while suppressing academic dissent of their views.

But those arguments were based on "selectively edited, out-of-context data and a manufactured controversy," EPA Administrator Lisa Jackson said Thursday in a statement.

An analysis of the e-mails by EPA found them to be "simply a candid discussion of scientists working through issues that arise in compiling and presenting large complex data sets," the statement read.

The same conclusion has been reached by other reviews, including a UK government investigation that found no evidence of the data being manipulated to show that human activity is causing climate change.

Cuccinelli said the battle is far from over.

An appeals court "is likely to find the [EPA] decisions fatally flawed procedurally because the agency has reviewed and weighed new information without notice or comment from the public," Cuccinelli spokesman Brian Gottstein said.

Cuccinelli now has the option of going back to the U.S. Court of Appeals in Washington, which earlier this year placed on hold a complicated legal dispute while the EPA reviewed its position.

At stake, among other things, is the agency's authority to regulate exhaust emissions from new automobiles.

Of more than 30 states that have joined the case, slightly more than half are supporting the EPA's position, according to Morgan Butler, a senior attorney for the Southern Environmental Law Center in Charlottesville.

"EPA made the right call here in rejecting the stall tactics that Attorney General Cuccinelli and others are using to try to stop action on climate change," Butler said. (The law center has intervened in the case in support of the EPA.)

"Since the so-called 'climate-gate' incident, some half-dozen independent analyses have concluded that the science demonstrating climate change and human causation has not been cast in doubt," Butler said.

Skeptics, however, have pointed to scientific studies that they say cast doubt on the EPA's position. Any global warming that may be happening is a natural occurrence, they say.

Climate change is one of several issues over which Cuccinelli has challenged the federal government since taking office in January. He is also trying to block the health care reform act passed by Congress and has backed a strict immigration law in Arizona that is being opposed by the U.S. Justice Department.