Australian Antarctic DivisionA US government-sponsored report has warned that many effects of climate change are already irreversible.

Even if carbon emissions were somehow stopped now, global temperatures could remain high for 1,000 years, concluded the scientists. The report, sponsored by the US Department of Energy, appears in the journal Proceedings of the National Academy of Sciences.

It comes on the day that Al Gore is scheduled to appear before the Senate Foreign Relations Committee, where he will urge the US to take “decisive action” on climate change. Senator John Kerry, who heads the Senate panel, said Gore will “put the heat” on lawmakers to take action. “That’s appropriate, and that’s what he ought to do.”

The lawmakers need to feel the heat as the news from the scientists is depressing. The US Department of Energy-sponosred team warned that, if carbon levels in the atmosphere continued to rise, there would be less rainfall in already dry areas of southern Europe, North America, parts of Africa and Australia.  The added that oceans that are currently slowing down climate change by absorbing heat, will eventually release that heat back into the air.

“People have imagined that if we stopped emitting carbon dioxide the climate would go back to normal in 100 years, 200 year – that’s not true,” said researcher Susan Solomon, the lead author of the report.

Just one small example of what this means in practice is that Emperor penguins, whose long treks across Antarctica have been immortalised by Hollywood, are heading towards extinction, another group of scientists have reported.

Based on predictions of sea ice extent from climate change models, the penguins are likely to see their numbers plummet by 95% by 2100. Though the penguins could avert disaster by shifting their breeding patterns with the climate, the study’s lead author Stephanie Jenouvrier said that was unlikely.

“Unlike some other Antarctic bird species that have altered their life cycles, penguins don’t catch on so quickly,” she said. “They are long-lived organisms, so they adapt slowly. This is a problem because the climate is changing very fast.”

She added: “I hope people will be sensitized by the effect of climate change on such a charismatic species and realize there are strong ecological consequences of climate change.”