|01-20-2005, 10:13 AM||#1|
Angling in the Deep
Join Date: Oct 2003
Location: Texas Riviera, Southern Mountains
Makes sense as we keep throwing more and more man made particles into our atmosphere, blocking more sunlight from reaching earth, that world temperatures would start to cool. These scientists findings are very interesting and somewhat disturbing.
Globe Grows Darker as Sunshine Diminishes 10% to 37%
by Kenneth Chang
In the second half of the 20th century, the world became, quite literally, a darker place.
Defying expectation and easy explanation, hundreds of instruments around the world recorded a drop in sunshine reaching the surface of Earth, as much as 10 percent from the late 1950's to the early 90's, or 2 percent to 3 percent a decade. In some regions like Asia, the United States and Europe, the drop was even steeper. In Hong Kong, sunlight decreased 37 percent.
No one is predicting that it may soon be night all day, and some scientists theorize that the skies have brightened in the last decade as the suspected cause of global dimming, air pollution, clears up in many parts of the world.
Yet the dimming trend — noticed by a handful of scientists 20 years ago but dismissed then as unbelievable — is attracting wide attention. Research on dimming and its implications for weather, water supplies and agriculture will be presented next week in Montreal at a joint meeting of American and Canadian geological groups.
"There could be a big gorilla sitting on the dining table, and we didn't know about it," said Dr. Veerabhadran Ramanathan, a professor of climate and atmospheric sciences at the University of California, San Diego. "There are many, many issues that it raises."
Dr. James E. Hansen, director of the NASA Goddard Institute for Space Studies in Manhattan, said that scientists had long known that pollution particles reflected some sunlight, but that they were now realizing the magnitude of the effect.
"It's occurred over a long time period," Dr. Hansen said. "So it's not something that, perhaps, jumps out at you as a person in the street. But it's a large effect."
Satellite measurements show that the sun remains as bright as ever, but that less and less sunlight has been making it through the atmosphere to the ground. (continued)
Why the Sun seems to be 'dimming'
By David Sington
We are all seeing rather less of the Sun, according to scientists who have been looking at five decades of sunlight measurements.
They have reached the disturbing conclusion that the amount of solar energy reaching the Earth's surface has been gradually falling.
Paradoxically, the decline in sunlight may mean that global warming is a far greater threat to society than previously thought.
The effect was first spotted by Gerry Stanhill, an English scientist working in Israel.
Comparing Israeli sunlight records from the 1950s with current ones, Dr Stanhill was astonished to find a large fall in solar radiation.
"There was a staggering 22% drop in the sunlight, and that really amazed me." Intrigued, he searched records from all around the world, and found the same story almost everywhere he looked.
Sunlight was falling by 10% over the USA, nearly 30% in parts of the former Soviet Union, and even by 16% in parts of the British Isles. (continued)
NARRATOR (JACK FORTUNE): This is a film that demands action. It reveals that we may have grossly underestimated the speed at which our climate is changing. At its heart is a deadly new phenomenon. One that until very recently scientists refused to believe even existed. But it may already have led to the starvation of millions. Tonight Horizon examines for the first time the power of what scientists are calling Global Dimming.
NARRATOR: September 12th 2001, the aftermath of tragedy. While America mourned, the weather all over the country was unusually fine. Eight hundred miles west of New York, in Madison, Wisconsin a climate scientist called David Travis was on his way to work.
DR DAVID TRAVIS (University of Wisconsin, Whitewater): Around the twelfth, later on in the day, when I was driving to work, and I noticed how bright blue and clear the sky was. And at first I didn't think about it, then I realised the sky was unusually clear.
NARRATOR: For 15 years Travis had been researching an apparently obscure topic, whether the vapour trails left by aircraft were having a significant effect on the climate. In the aftermath of 9/11 the entire US fleet was grounded, and Travis finally had a chance to find out.
DR DAVID TRAVIS: It was certainly, you know, one of the tiny positives that may have come out of this, an opportunity to do research that hopefully will never happen again.
NARRATOR: Travis suspected the grounding might make a small but detectable change to the climate. But what he observed was both immediate and dramatic.
DR DAVID TRAVIS: We found that the change in temperature range during those three days was just over one degrees C. And you have to realise that from a layman's perspective that doesn't sound like much, but from a climate perspective that is huge. (continued)