Global Dimming
Research has suggested that the burning of fossil fuels has contributed to a phenomenon known as Global Dimming. Essentially, the dust, soot, ash and particulates resulting from said burning is masking the earth from the actual strength of solar radiation. It could, in fact, be masking the true effects of global warming, whether man-made or NOT.
Most scientists agree (whether alarmed by global warming or not) that global cooling is caused by dust particles in the atmosphere, principally from volcanic eruptions, but also from air pollution. Scientists have found that despite increased solar activity, the amount of solar energy getting to the ground is lessened. Dr. Gerald Stanhill of the Agricultural Research Organisation in Israel has been measuring the amount of sunlight getting to the ground and comparing it with figures from the 1950s.
The results suggest a 22% drop in solar radiation getting to the ground. He figured that there must be a mistake somewhere, despite the testing system being identical to the earlier experiment.
Meanwhile, Dr. Beate Liepert of the Lamont-Doherty Earth observatory found similar results over the Bavarian Alps, but was just as skeptical as Dr. Stanhill. The coincidence seemed unbelievable to them and so working independently of each other they read through as many journals, publications and meteorological records as possible to try to get data from around the world. The figures they found were of drops in solar radiation getting to the ground all over the world (9% less in Antarctica, 10% in the USA, 30% in Russia and 16% in Britain).Dr. Stanhill called the phenomenon “Global Dimming”.
Still the results were viewed with disbelief by most climatologists, because as THEY knew, the climate is warming.
However, two biologists in Australia, Dr. Michael Roderick and Professor Graham Farquhar, were intrigued by another paradoxical result - the world-wide decline in the pan-evaporation rate.
PROF GRAHAM FARQUHAR (Australian National University): It’s called pan evaporation rate because it’s evaporation rate from a pan. Every day all over the world people come out in the morning and see how much water they’ve got to add to a pan to bring it back to the level it was the same time the morning before. It’s that simple.
In some parts of the world, people have been taking the same measurements for over a hundred years, so the figures are incredibly valuable. The paradox is that despite the global mean temperature rising, the pan-evaporation rate has fallen. The key factor in pan-evaporation is sunlight, although humidity and wind also play a part. They found, through extending their study, that pan-evaporation in Russia, the US and Eastern Europe had declined by an average of 100 millimetres (about 4 inches) in the last thirty years. They were able to calculate how much energy was required to evaporate this 100 millimetres of water at 250 mega-joules. This correlated exactly with the decline in solar radiation from the previous study.
Dr. Veerabhadran Ramanathan of the University of California spearheaded a study called Project INDOEX, which set out to measure the impact of air pollution on the amount of sunlight getting to sea-level. He chose the Maldives, because while the northern islands were in the direct path of pollution clouds from India, the southern islands were in a stream of clean air from Antarctica.
In a multi-national effort over four years they found interesting results. The pollution was causing a 10% drop in sunlight reaching sea-level.
Despite the pollution attracting water particles, forming clouds and therefore reflecting more sunlight back into space, it didn’t increase rainfall, because the droplets were forming around particles, but not getting heavy enough to fall to earth. To stop pollution preventing sunlight getting to earth, all we (as a race, not the West) need to do is burn our fuel more cleanly.
Dr. David Travis of the University of Wisconsin, Whitewater, has long been speculating that aeroplane contrails in the high atmosphere could have an effect by reflecting sunlight back into space. He figured there was no way to study this however, because planes never stop flying.
It was the terrible events of 9/11 that gave him the opportunity to test his theory. He not only gathered the temperatures (which can vary a lot from day to day), but the temperature ranges (the difference between the highest temperature during the day and the lowest at night). During the 3 day period when commercial flights were grounded, he found the temperature range jumped by over a degree celsius, the largest temperature swing of this magnitude in the last thirty years. By removing just one form of pollution, there was a dramatic change.
And that’s not all. Climatologists like Peter Cox have begun to worry that Global Dimming has led them to underestimate the true power of global warming. They fear that the Earth could be far more vulnerable to greenhouse gases than they had previously thought.
DR PETER COX: We’ve got two competing effects really, that we’ve got the greenhouse effect, which has tended to warm up the climate. But then we’ve got this other effect that’s much stronger than we thought, which is a cooling effect that comes from particles in the atmosphere. And they’re competing with one another. And we know the climate’s moved to a warmer state by about point six of a degree over the last hundred years. So the whole thing’s moved this way. If it turns out that the cooling is stronger than we thought then the warming also is a lot stronger than we thought, and that means the climate’s more sensitive to carbon dioxide than we originally thought, and it means our models may be under sensitive to carbon dioxide.
The easy solution - just keep on polluting and hope that Global Dimming will protect us - would be suicidal.
First posted as a comment in http://sayanythingblog.com/readers/entry/the_great_global_warming_swindle_new_documentary/#comments
The results suggest a 22% drop in solar radiation getting to the ground. He figured that there must be a mistake somewhere, despite the testing system being identical to the earlier experiment.
Meanwhile, Dr. Beate Liepert of the Lamont-Doherty Earth observatory found similar results over the Bavarian Alps, but was just as skeptical as Dr. Stanhill. The coincidence seemed unbelievable to them and so working independently of each other they read through as many journals, publications and meteorological records as possible to try to get data from around the world. The figures they found were of drops in solar radiation getting to the ground all over the world (9% less in Antarctica, 10% in the USA, 30% in Russia and 16% in Britain).Dr. Stanhill called the phenomenon “Global Dimming”.
Still the results were viewed with disbelief by most climatologists, because as THEY knew, the climate is warming.
However, two biologists in Australia, Dr. Michael Roderick and Professor Graham Farquhar, were intrigued by another paradoxical result - the world-wide decline in the pan-evaporation rate.
PROF GRAHAM FARQUHAR (Australian National University): It’s called pan evaporation rate because it’s evaporation rate from a pan. Every day all over the world people come out in the morning and see how much water they’ve got to add to a pan to bring it back to the level it was the same time the morning before. It’s that simple.
In some parts of the world, people have been taking the same measurements for over a hundred years, so the figures are incredibly valuable. The paradox is that despite the global mean temperature rising, the pan-evaporation rate has fallen. The key factor in pan-evaporation is sunlight, although humidity and wind also play a part. They found, through extending their study, that pan-evaporation in Russia, the US and Eastern Europe had declined by an average of 100 millimetres (about 4 inches) in the last thirty years. They were able to calculate how much energy was required to evaporate this 100 millimetres of water at 250 mega-joules. This correlated exactly with the decline in solar radiation from the previous study.
Dr. Veerabhadran Ramanathan of the University of California spearheaded a study called Project INDOEX, which set out to measure the impact of air pollution on the amount of sunlight getting to sea-level. He chose the Maldives, because while the northern islands were in the direct path of pollution clouds from India, the southern islands were in a stream of clean air from Antarctica.
In a multi-national effort over four years they found interesting results. The pollution was causing a 10% drop in sunlight reaching sea-level.
Despite the pollution attracting water particles, forming clouds and therefore reflecting more sunlight back into space, it didn’t increase rainfall, because the droplets were forming around particles, but not getting heavy enough to fall to earth. To stop pollution preventing sunlight getting to earth, all we (as a race, not the West) need to do is burn our fuel more cleanly.
Dr. David Travis of the University of Wisconsin, Whitewater, has long been speculating that aeroplane contrails in the high atmosphere could have an effect by reflecting sunlight back into space. He figured there was no way to study this however, because planes never stop flying.
It was the terrible events of 9/11 that gave him the opportunity to test his theory. He not only gathered the temperatures (which can vary a lot from day to day), but the temperature ranges (the difference between the highest temperature during the day and the lowest at night). During the 3 day period when commercial flights were grounded, he found the temperature range jumped by over a degree celsius, the largest temperature swing of this magnitude in the last thirty years. By removing just one form of pollution, there was a dramatic change.
And that’s not all. Climatologists like Peter Cox have begun to worry that Global Dimming has led them to underestimate the true power of global warming. They fear that the Earth could be far more vulnerable to greenhouse gases than they had previously thought.
DR PETER COX: We’ve got two competing effects really, that we’ve got the greenhouse effect, which has tended to warm up the climate. But then we’ve got this other effect that’s much stronger than we thought, which is a cooling effect that comes from particles in the atmosphere. And they’re competing with one another. And we know the climate’s moved to a warmer state by about point six of a degree over the last hundred years. So the whole thing’s moved this way. If it turns out that the cooling is stronger than we thought then the warming also is a lot stronger than we thought, and that means the climate’s more sensitive to carbon dioxide than we originally thought, and it means our models may be under sensitive to carbon dioxide.
The easy solution - just keep on polluting and hope that Global Dimming will protect us - would be suicidal.
First posted as a comment in http://sayanythingblog.com/readers/entry/the_great_global_warming_swindle_new_documentary/#comments
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