Posted on 05/06/2005 7:19:39 AM PDT by .cnI redruM
Our planet's air has cleared up in the past decade or two, allowing more sunshine to reach the ground, say two studies in Science this week.
Reductions in industrial emissions in many countries, along with the use of particulate filters for car exhausts and smoke stacks, seem to have reduced the amount of dirt in the atmosphere and made the sky more transparent.
That sounds like very good news. But the researchers say that more solar energy arriving on the ground will also make the surface warmer, and this may add to the problems of global warming. More sunlight will also have knock-on effects on cloud cover, winds, rainfall and air temperature that are difficult to predict.
The results suggest that a downward trend in the amount of sunlight reaching the surface, which has been observed since measurements began in the late 1950s, is now over.
The researchers argue that this trend, commonly called 'global dimming', reversed more than a decade ago, probably following the collapse of communist economies and the consequent decrease in industrial pollutants.
The widespread brightening has remained unnoticed until now simply because there wasn't enough data for a statistically significant analysis, says Martin Wild, an atmospheric scientist at the Swiss Federal Institute of Technology in Zurich and an author on one of the reports.
Sunny days
Wild and his team looked at data on surface sunshine levels from hundreds of devices around the planet. They found that since the 1980s there has been a transition from decreasing to increasing solar radiation nearly everywhere, except in heavily polluted areas such as India and at scattered sites in Australia, Africa, and South America1.
A second study, led by Rachel Pinker from the University of Maryland, College Park, found a similar trend by looking at satellite data, although their research suggests the extent of the brightening is smaller2. Unlike ground stations, satellites can sample the whole planet, including the oceans. However, satellite data are difficult to calibrate, and so are considered less accurate than measurements from the ground.
Surprisingly, Wild's study shows a brightening trend in China, despite the fact that there is a booming, fossil-fuel-intensive industry in that country. Wild says he can only speculate that the use of clean-air technologies in China might be more widespread and efficient than has been thought.
In contrast, India's vast brown clouds of smog, which result from wildfires and the use of fossil fuels, have reduced the sunlight reaching the ground.
Just warming up
Researchers will now focus on working out the long-term effects of clearer air. One thing they do know is that black particulate matter in the air has been contributing a cooling effect to the ground. "It is clear that the greenhouse effect has been partly masked in the past by air pollution," says Andreas Macke, a meteorologist at the Leibniz Institute of Marine Sciences in Kiel, Germany.
Uncertainties remain part of the game because scientists have only a limited ability to track cloud cover and particulates, says Macke. Increased cooperation in programmes such as the NASA-led International Satellite Cloud Climatology Project should help to close the gaps in our knowledge of how dirty air affects climate, he says.
IT'S ALL BUSH'S FAULT.
"Personally, I'm still waiting for the ice age we were promised back in the 70s"
Amazing how many don't remember, or weren't around when those claims were made.
I cannot believe the desperation of those who want to run other people's lives. Everything is indeed a symptom of global warming. If the average temperature of the earth dropped 3 degrees, they'd find a way to link that to global warming!
I'm sick of junk science.
Chicken is good for you.
Chiken is bad for you.
Coffee is bad for you.
Coffee is good for you.
Being slightly overweight will shorten your life.
Being slightly overweight will lengthen your life.
Eggs are bad for you.
Eggs are good for you.
Newsflash: researchers admit that they know absolutely nothing for sure, and are in search of a clue.
What is the global effect of millions of large scale wind turbine farms that work by removing energy from the wind and thus slowing down the wind?
This slow down will affect the air and weather circulation patterns worldwide.
Where do I sign up for the government's free money to study this problem?
"It's the end of the world as we know it, and I feel fine."
ITS Bush's fault, him and his d*mn clean skies initiative.
It's also Ronald Reagan's fault, for destroying communism.
Its always something.
If the air is cloudy, it is proof positive that we are all going to die from global warming caused by George W. Bush and SUVs.
If it is warm outside, it is proof positive that we are all going to die from global warming caused by George W. Bush and SUVs.
If it is cold outside, it is proof positive that we are all going to die from global warming caused by George W. Bush and SUVs.
If the sun rises in the east, it is proof positive that we are all going to die from global warming caused by George W. Bush and SUVs.
If the sun sets in the west, it is proof positive that we are all going to die from global warming caused by George W. Bush and SUVs.
Anyone else beginning to notice a pattern here?
I think you might get a larger grant if you studied the extent to which wind-farms are slowing the rotation of the Earth.
And, BTW, we have already started having longer days.
When I was a kid, I was awake from 7AM to 9PM. Now I'm awake from 5:30 until 11PM.
What further proof do you need?
Now, of course, I was probably the only kid in the class room thinking, "COOL!" and I came up with this fantasy about being sort of this cave girl of the frozen tundra (of Florida), wearing animal skins and riding a wooly mammoth, hunting my food with spears, etc. I'm still waiting for that damn mammoth.
" I came up with this fantasy about being sort of this cave girl of the frozen tundra (of Florida), wearing animal skins and riding a wooly mammoth, hunting my food with spears, etc. "
Well, if it's any consolation, you've just contributed to a fantasy for me! :)
You read my mind!
If they are, it's because of Global Warming.
Hot d*mn! My mom always said patience pays.
Still, I'm wondering if there's anything in the Homeowners Association by-laws about having an animal like this. I wonder if they'd be considered livestock.
No! The pressure is building, we're all DOOMED!
Please send taxpayer grant money to study this potential environmental disaster to the Volcano Watch Society c/o Nancy Pelosi, Washington DC.
If you look good and wear skimpy furs while riding around on your mammoth, you can count on the man vote in your Homeowners Association.
I better rake out the Abdominizer if I'm going to fit into that sabre tooth bikini by swim suit season...
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.