Climate change 'irreversible', warn scientists

Climate change is irreversible and projects to prevent temperature rises will have no impact for at least thousand years, scientists have warned.

Last Updated: 12:39PM GMT 27 Jan 2009

Halting carbon emissions will not see temperatures reduce before the year 3000, according to the US-based National Oceanic and Atmospheric Administration's Earth System Research Laboratory.
Contrary to popular opinion, halting carbon emissions will not see temperatures reduce before the year 3000, according to the US-based National Oceanic and Atmospheric Administration's Earth System Research Laboratory.
Nevertheless, Susan Solomon, who led the research, said cutting emissions remained important.
She added: "People have imagined that if we stopped emitting carbon dioxide the climate would go back to normal in 100 years, 200 years - that's not true."
Ms Solomon is lead author of an international team's paper reporting irreversible damage from climate change, published today in Proceedings of the National Academy of Sciences.
She defines irreversible as change that would remain for 1,000 years even if humans stopped adding carbon to the atmosphere immediately.
Ms Solomon said: "Climate change is slow, but it is unstoppable - all the more reason to act quickly, so the long-term situation does not get even worse."
In recent years Britain has seen regular instances of flash flooding.
The latest findings were announced as US President Barack Obama ordered reviews that could lead to greater fuel efficiency and cleaner air, saying the Earth's future depends on cutting air pollution.
Alan Robock, from Rutgers University in New Jersey, agreed with the research, adding: "It's not like air pollution where if we turn off a smokestack, in a few days the air is clear.
"It means we have to try even harder to reduce emissions."
In her paper Ms Solomon, a leader of the International Panel on Climate Change and one of the world's best known researchers on the subject, noted that temperatures around the globe have risen and changes in rainfall patterns have been observed in areas around the Mediterranean, southern Africa and south-western North America.
Warmer climate also is causing expansion of the ocean, which is expected to increase with the melting of ice on Greenland and Antarctica, she said.
"I don't think that the very long time scale of the persistence of these effects has been understood," Ms Solomon added.
Global warming has been slowed by the ocean, but that good effect will wane over time with seas eventually helping keep the planet warmer, she said.
Climate change has been driven by gases in the atmosphere that trap heat from solar radiation and raise the planet's temperature.
Carbon dioxide is the most important of those gases because it remains in the air for hundreds of years.