WASHINGTON - The White House on Monday dismissed as "silly" the notion that global warming science had been compromised by emails exposing a row between top climate scientists.

The emails have been pounced on by climate skeptics, particularly in the United States to suggest the scientific community is hyping the threat from carbon dioxide emissions ahead of the Copenhagen climate conference.

"I think everybody is clear on the science," White House spokesman Robert Gibbs told reporters.

"I think scientists are clear on the science. I think many on Capitol Hill are clear on the science. I think that this notion that there is some debate ... on the science is kind of silly."

Gibbs spoke hours before President Barack Obama was due to meet climate change campaigner and former vice president Al Gore at the White House, as he prepares to head for Copenhagen next week.

Earlier, a top US negotiator in Copenhagen slammed the emails controversy, dubbed Climategate, as "opportunistic."

"It just happens to be the topic of the moment," said Jonathan Pershing, the deputy head of the US delegation at the December 7-18 UN talks.

"It is a misrepresentation of the robustness of science. What we end with is that our understanding of the issues is not different... I look at this and I think to myself, it's opportunistic."

Some of the thousands of emails purloined from scientists at Britain's East Anglia, a top center for climate research, expressed frustration at the scientists' inability to explain what they described as a temporary slowdown in warming.

They also discussed ways to counter the campaigns of climate naysayers. The Copenhagen meeting, which will end with a December 17 summit of more than 100 heads of state, including Obama, is tasked with forging a deal to tame global warming and help poor countries cope with its consequences.