Many damaging effects of climate change are already basically irreversible, and even if carbon emissions can somehow be halted, temperatures around the globe will remain high until at least the year 3000.
"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," climate researcher Susan Solomon said in a teleconference. Solomon is a leader of the International Panel on Climate Change and one of the world's best known researchers on the subject. "I think you have to think about this stuff as more like nuclear waste than acid rain: The more we add, the worse off we'll be," Solomon continued.
The report, spearheaded by an international team of scientists from the National Oceanic and Atmospheric Administration's Earth System Research Laboratory in Boulder, Colo., defines "irreversible" as change that would remain for 1,000 years even if humans stopped adding carbon to the atmosphere immediately.
The findings were announced as 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.
Climate change has been driven by gases in the atmosphere that trap heat from solar radiation and raise the planet's temperature — the "greenhouse effect." Carbon dioxide has been the most virulent of those gases because it remains in the air for hundreds of years. While other gases are responsible for nearly half of the warming, they degrade more rapidly.
Temperatures around the globe have risen and changes in rainfall patterns have been observed in areas around the Mediterranean, southern Africa and southwestern North America. Warmer climate is also causing expansion of the ocean, and that is expected to increase with the melting of ice on Greenland and Antarctica. The study projects that several regions of the world -- including southwestern North America, the Mediterranean and southern Africa -- will face major droughts as bad or worse than the Dust Bowl of the 1930s, and global sea levels will rise by about three feet by the year 3000, a projection that does not factor in melting glaciers and polar ice sheets that would probably result in significant additional sea level rises.
The policy implications are clear: We need to act sooner because by the time the public and policymakers really realize and appreciate the changes in our atmosphere, it may be far too late to do anything about it. In fact, as the researchers point out, it is already too late for some effects.
A separate study in the same journal yesterday warns that melting sea ice may lead to the extinction of the iconic emperor penguins of the Antarctic by 2100. The animals depend on sea ice for breeding, foraging and molting habitat. To void extinction, the penguins would have to migrate or change the timing of their growth stages to avoid extinction. Chances are this won't happen.
And we should keep in mind that this is only ONE example of the hundreds, if not thousands, of species that would be exterminated as a result of global warming.