One year prior to James Hansen testifying to Congress in 1988 he was 99% certain that man-made global warming was occurring, a paper published in Nature indicated that global warming would cause negative feedback from increased cloud cover to cool the Earth by more than the alleged warming effect of CO2.
Sunday, June 26, 2011
Buying carbon offsets to assuage your green guilt? Study says don't bother
Study: trees not cure for global warming
BY MARGARET MUNRO, POSTMEDIA NEWS JUNE 18, 2011
Planting trees may help appease travellers' guilt about pumping carbon into the atmosphere.
But new research suggests it will do little to cool the planet, especially when trees are planted in Canada and other northern countries, says climatologist Alvaro Montenegro, at St. Francis Xavier University in Nova Scotia.
"There is no magic bullet" for global warming, says Montenegro, "and trees are certainly not going to be providing it."
He assessed the impact of replanting forests on crop and marginal lands with Environment Canada researcher Vivek Arora. Their study, published Sunday in Nature Geoscience, concludes "afforestation is not a substitute for reduced greenhouse-gas emissions."
The United Nations, environmental groups and carbon-offset companies are invested heavily in the idea that planting trees will help slow climate change and global warming. International authorities have long described "afforestation" as a key climate-change mitigation strategy.
But the study says the benefits of tree planting are "marginal" when it comes to stopping the planet from overheating.
Trees do suck carbon [dioxide] out of the air, but the study highlights that their dark leaves and needles also decrease the amount of solar radiation that gets reflected by the landscape, which has a warming effect.
Cropland - especially snow-covered cropland - has a cooling effect because it reflects a lot more solar energy than forests, the scientists say. This so-called "albedo effect" is important and needs to be incorporated into assessments of tree planting programs and projects, the researchers say.
Montenegro and Arora stress that planting forests has many benefits - trees provide habitat for wildlife and prevent soil erosion. And planting forests does help reduce atmospheric levels of carbon dioxide because carbon is locked into wood as trees grow.
But planting trees will have only a modest effect on the global temperature, according to their study, which used a sophisticated climate modelling system developed by Environment Canada. [see Top 10 Reasons Why Climate Model Predictions are False]
BY MARGARET MUNRO, POSTMEDIA NEWS JUNE 18, 2011
Planting trees may help appease travellers' guilt about pumping carbon into the atmosphere.
But new research suggests it will do little to cool the planet, especially when trees are planted in Canada and other northern countries, says climatologist Alvaro Montenegro, at St. Francis Xavier University in Nova Scotia.
"There is no magic bullet" for global warming, says Montenegro, "and trees are certainly not going to be providing it."
He assessed the impact of replanting forests on crop and marginal lands with Environment Canada researcher Vivek Arora. Their study, published Sunday in Nature Geoscience, concludes "afforestation is not a substitute for reduced greenhouse-gas emissions."
The United Nations, environmental groups and carbon-offset companies are invested heavily in the idea that planting trees will help slow climate change and global warming. International authorities have long described "afforestation" as a key climate-change mitigation strategy.
But the study says the benefits of tree planting are "marginal" when it comes to stopping the planet from overheating.
Trees do suck carbon [dioxide] out of the air, but the study highlights that their dark leaves and needles also decrease the amount of solar radiation that gets reflected by the landscape, which has a warming effect.
Cropland - especially snow-covered cropland - has a cooling effect because it reflects a lot more solar energy than forests, the scientists say. This so-called "albedo effect" is important and needs to be incorporated into assessments of tree planting programs and projects, the researchers say.
Montenegro and Arora stress that planting forests has many benefits - trees provide habitat for wildlife and prevent soil erosion. And planting forests does help reduce atmospheric levels of carbon dioxide because carbon is locked into wood as trees grow.
But planting trees will have only a modest effect on the global temperature, according to their study, which used a sophisticated climate modelling system developed by Environment Canada. [see Top 10 Reasons Why Climate Model Predictions are False]
CO2 levels have risen at the same rate for past 18,000 years
While climate alarmists claim CO2 levels have risen at an unprecedented rate since the industrial revolution, extrapolation from ice core data shows the rate of rise has been steady since the peak of the last ice age about 18,000 years ago. This shows that man-made CO2 (~3% of total emissions) has had little effect on atmospheric levels of CO2, which instead are driven by outgassing from the oceans during interglacial periods; interglacial periods are driven by solar insolation, not CO2.
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| Atmospheric CO2 from 3 ice-core studies shown on vertical axis, thousands of years ago shown on horizontal axis. Linear extrapolation from the peak of the last ice age ~18,000 years ago shows that the rate of rise in CO2 has not changed over the past 18,000 years. Notations in red added. Graph source. |
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