(NaturalNews) Preventing irreversible climate disaster will require carbon dioxide emissions reductions big enough not only to prevent the atmosphere's carbon load from increasing, but to allow the amount of carbon in the atmosphere to actually decrease, according to a warning issued by scientists at the 2007 meeting of the American Geophysical Union.
"We're a lot closer to climate tipping points than we thought we were," said James Hansen, director of the Goddard Institute for Space Studies at the National Aeronautics and Space Administration (NASA). "If we are to have any chance in avoiding the points of no return, we're going to have to make some
changes."
A tipping point is the point at which the damage to a system, such as a climate or ecological system, becomes irreversible.
The scientists warned that
climate change is occurring much more rapidly than anticipated. Since the 1970s, every glacier on the planet has already shrunk, and the Arctic ice sheet over the North Pole has shrunk from roughly the size of the continental United States to less than the size of the states west of the Mississippi River. In summer 2007, ships were able to sail across portions of the Arctic Ocean that had always before been covered by ice.
The atmospheric concentration of
carbon dioxide, which is currently increasing by two parts per billion each year, now stands at 380 parts per billion. According to the scientists' warning, levels must be reduced to 350 parts per billion to stabilize the climate.
While a certain amount of
carbon dioxide is removed from
the atmosphere by natural processes, the pace of
emissions has rapidly outstripped the planet's ability to clean the atmosphere. Roughly 20 percent of the carbon emitted by burning coal, for example, remains in the atmosphere for 1,000 years or more.
The minor temperature changes that have already seen may be enough to irreparably damage many of the planet's ecosystems, the
scientists said.
"The only hope for a recovery is considerable and persistent atmospheric cooling," said Josefino Comiso, of NASA's Goddard Space Flight Center.
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