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Extinctions Due to Global Warming Predicted
PizzaFace writes "A study being published today in Nature predicts that global warming will doom 15 to 37 percent of plants and animals to extinction by 2050, according to various news sources. The study looked at how predicted warming would affect the suitability of the areas that particular species inhabit, and whether displaced species would be able to migrate to suitable habitat. Many of the unlucky species are being caught between the hammer of global warming and the anvil of habitation destruction." The BBC has a story about climate engineering: long-range planning on making major changes in order to reduce the effects of global warming.
This is not true. You can look at the atmospheric CO2 concentrations before and after any major eruption in the last 50 years (the time during which CO2 has been continually monitored around the world) and see that the amount of CO2 you are talking about was not released into the atmosphere.
Over the past 100 years, fossil fuel burning has released somewhere around 170 gigatons of carbon into the atmosphere. If a volcanic eruption released this much carbon, it would increase the CO2 concentration from 360 parts per million to 440 parts per million. That didn't happen.
You can also go back 500,000 years using glacial ice cores and see that the CO2 concentration never approached its current value during that time, even though there were many portions of that time span during which volcanic activity was much greater than it is today.
Also, water vapor is a more effective greenhouse substance than CO2
But the concentration of water vapor is limited by the saturation vapor pressure. If I dump a whole lot of water vapor into the atmosphere, the excess will precipitate out. The residence time of a water vapor molecule is quite short.
On the other hand, CO2 is not a vapor at room temperature, it's a gas. Its atmospheric residence time is much longer, so CO2 emitted today will be around for 50-100 years.
Finally, becauee small warming caused by increased CO2 causes the saturation vapor pressure of water vapor to rise, the water vapor effect amplifies the effect of CO2, causing approximately double the warming we would see with CO2 alone. This has been experimentally verified in studies of the troposphere following the Mt. Pinatubo eruption.
Finally, I would point out that chemical analysis of glacial ice cores demonstrates that over the past 500,000 years, whenever CO2 concentrations were high, temperatures were high. Whenever CO2 concentrations were low, temperatures were low. During ice ages, CO2 concentrations were exceptionally low. During interglacial periods, CO2 concentrations were high.
Today, CO2 concentrations are about 30% higher than they were during any time in that 500,000 year record. Because the oceans take a long time to heat up, we will not see the full warming due to the current CO2 concentration for many decades, but it is a great stretch to assume that the mechanisms that regulated the ice ages will suddenly stop working and fail to deliver substantial warming over the next century.