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GLOBAL DIMMING
Contributed by
steeleyes
on
Saturday, 15th January 2005 @ 02:59:27 PM in AEST
Topic:
NaturePoetry
|
Global Dimming
Have you heard the term?
Perhaps to you like me
It’s something new
It seems our pollution
Is holding down the heat
Well you say, with global warming
That’s rather neat
Sadly not
The polluting can’t go on
But it’s holding back the warming
And as we reduce that down
The warming looks set to soar
The Greenland ice sheet melt
And the cities flood
By ALL it will be felt
Rainfall will be disturbed
Droughts here, storms there
As pollutants fall and Co2 soars
This is not just another scare
Britain becomes a virtual desert
Africa uninhabitable
All cities flooded
It’s almost unimaginable
And all of this could be
Just twenty years away
What can be done
So our present world can stay?
-o-
On the days after 9/11
The skies above were clear
No vapour trails as usual
Fine weather amid the fear
One scientist made a check
What would the weather do?
With this pollution gone
Many changes or just a few
What he found made him stare
A one degree rise
In just three days
Without polluted skies
Then, when flights resumed
And vapour trails spread
The one degree was lost
His heart was filled with dread
These trails were relatively small
What if there was a bigger drop?
To what level would temperature go?
Where would it stop?
As pollution goes down
Global Warming rises
The future looks bleak
Full of dark surprises
This is solid scientific fact
It is not fantasy
We must lift heads from the sand
And face reality
Mass death is in prospect
Unstoppable climate change
And once it starts happening
Impossible to rearrange
The cycle gets even worse
As the forests spark alight
Warming is increased
A future full of fright
We have this one time
It is now already SO late
To avoid the global suicide
And our approaching fate
--O/O/--
Global Dimming
We are all seeing rather less of the Sun. Scientists looking at five decades of sunlight measurements 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, 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,' he says.
Intrigued, he searched out records from all around the world, and found the same story almost everywhere he looked, with sunlight 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. Although the effect varied greatly from place to place, overall the decline amounted to 1-2% globally per decade between the 1950s and the 1990s.
Gerry called the phenomenon global dimming, but his research, published in 2001, met with a sceptical response from other scientists. It was only recently, when his conclusions were confirmed by Australian scientists using a completely different method to estimate solar radiation, that climate scientists at last woke up to the reality of global dimming.
Dimming appears to be caused by air pollution. Burning coal, oil and wood, whether in cars, power stations or cooking fires, produces not only invisible carbon dioxide (the principal greenhouse gas responsible for global warming) but also tiny airborne particles of soot, ash, sulphur compounds and other pollutants.
This visible air pollution reflects sunlight back into space, preventing it reaching the surface. But the pollution also changes the optical properties of clouds. Because the particles seed the formation of water droplets, polluted clouds contain a larger number of droplets than unpolluted clouds. Recent research shows that this makes them more reflective than they would otherwise be, again reflecting the Sun's rays back into space.
Scientists are now worried that dimming, by shielding the oceans from the full power of the Sun, may be disrupting the pattern of the world's rainfall. There are suggestions that dimming was behind the droughts in sub-Saharan Africa which claimed hundreds of thousands of lives in the 1970s and 1980s. There are disturbing hints the same thing may be happening today in Asia, home to half the world's population. 'My main concern is global dimming is also having a detrimental impact on the Asian monsoon,' says Prof Veerhabhadran Ramanathan, one of the world's leading climate scientists. 'We are talking about billions of people.'
But perhaps the most alarming aspect of global dimming is that it may have led scientists to underestimate the true power of the greenhouse effect. They know how much extra energy is being trapped in the Earth's atmosphere by the extra carbon dioxide (CO2) we have placed there. What has been surprising is that this extra energy has so far resulted in a temperature rise of just 0.6°C.
This has led many scientists to conclude that the present-day climate is less sensitive to the effects of carbon dioxide than it was, say, during the ice age, when a similar rise in CO2 led to a temperature rise of 6°C. But it now appears the warming from greenhouse gases has been offset by a strong cooling effect from dimming - in effect two of our pollutants have been cancelling each other out. This means that the climate may in fact be more sensitive to the greenhouse effect than thought.
If so, then this is bad news, according to Dr Peter Cox, one of the world's leading climate modellers. As things stand, CO2 levels are projected to rise strongly over coming decades, whereas there are encouraging signs that particle pollution is at last being brought under control. 'We're going to be in a situation, unless we act, where the cooling pollutant is dropping off while the warming pollutant is going up. That means we'll get reduced cooling and increased heating at the same time and that's a problem for us,' says Cox.
Even the most pessimistic forecasts of global warming may now have to be drastically revised upwards. That means a temperature rise of 10°C by 2100 could be on the cards, giving the UK a climate like that of North Africa, and rendering many parts of the world uninhabitable. That is unless we act urgently to curb our emissions of greenhouse gases.
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
Copyright ©
steeleyes
... [
2005-01-15 14:59:27]
(Date/Time posted on
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Re: GLOBAL DIMMING
(User Rating: 1 )
by Pyrofungus on
Saturday, 15th January 2005 @ 05:03:32 PM AEST
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a Message)
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wow....very informative, that's good that you posted this...if only more people would take the time to read it and do more about it before the human race is wiped out...
summer |
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