| Topic: |
Religions > Atheism |
| User: |
"maff" |
| Date: |
13 Jan 2005 09:31:50 PM |
| Object: |
Global Dimming |
Global Dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
Horizon producer David Sington on why predictions about the Earth's
climate will need to be re-examined.
Questions and answers about global dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_qa.shtml
Programme transcript
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_trans.shtml
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.
Science: Horizon
http://groups-beta.google.com/group/alt.atheism/msg/35466ec360dad786
Global Dimming
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| User: "Ian H Spedding" |
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| Title: Re: Global Dimming |
13 Jan 2005 10:20:04 PM |
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"maff" <maff91@yahoo.com> wrote in message
news:1105653213.625419.215670@z14g2000cwz.googlegroups.com...
Global Dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
Horizon producer David Sington on why predictions about the Earth's
climate will need to be re-examined.
Questions and answers about global dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_qa.shtml
Programme transcript
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_trans.shtml
I just saw it. I have to admit I had not heard of "global dimming" before
but it was a fascinating programme. The possibility of a runaway global
warming effect in as little as 25 years was alarming to say the least.
Ian
--
Ian H Spedding
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| User: "Rune Børsjø" |
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| Title: Re: Global Dimming |
14 Jan 2005 02:19:55 AM |
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On Thu, 13 Jan 2005 22:20:04 +0000 (UTC), "Ian H Spedding"
<harry@spedding53.fsnet.co.uk> wrote:
I just saw it. I have to admit I had not heard of "global dimming" before
but it was a fascinating programme. The possibility of a runaway global
warming effect in as little as 25 years was alarming to say the least.
This has been around since the 60's when they projected atmospheric
particles would block out the sun and create a new iceage within
decades.
I've said it before and I'll say it again... there are far too many
unmapped and unknown variables flying around to make any conclusions
other than the fact that 1) If we were smart we would be more careful
and 2) Kyoto is worthless as it stands.
.
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| User: "Denis Loubet" |
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| Title: Re: Global Dimming |
13 Jan 2005 10:56:33 PM |
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"maff" <maff91@yahoo.com> wrote in message
news:1105653213.625419.215670@z14g2000cwz.googlegroups.com...
Global Dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
Horizon producer David Sington on why predictions about the Earth's
climate will need to be re-examined.
Questions and answers about global dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_qa.shtml
Programme transcript
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_trans.shtml
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.
Aargh! I hate being whipsawed back and forth!
--
Denis Loubet
dloubet@io.com
http://www.io.com/~dloubet
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| User: "Uncle Buck" |
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| Title: Re: Global Dimming |
14 Jan 2005 12:13:20 AM |
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On Thu, 13 Jan 2005 22:56:33 +0000 (UTC) in alt.atheism, "Denis
Loubet" <dloubet@io.com> defied the status quo and scrawled upon the
toilet stall:
"maff" <maff91@yahoo.com> wrote in message
news:1105653213.625419.215670@z14g2000cwz.googlegroups.com...
Global Dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
Horizon producer David Sington on why predictions about the Earth's
climate will need to be re-examined.
Questions and answers about global dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_qa.shtml
Programme transcript
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_trans.shtml
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.
Aargh! I hate being whipsawed back and forth!
Especially while being fried alive by microwave radiation. That just
_really_ bites the big one.
.
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| User: "Uncle Buck" |
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| Title: Re: Global Dimming |
15 Jan 2005 01:58:17 PM |
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On Thu, 13 Jan 2005 22:56:33 +0000 (UTC) in alt.atheism, "Denis
Loubet" <dloubet@io.com> defied the status quo and scrawled upon the
toilet stall:
"maff" <maff91@yahoo.com> wrote in message
news:1105653213.625419.215670@z14g2000cwz.googlegroups.com...
Global Dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
Horizon producer David Sington on why predictions about the Earth's
climate will need to be re-examined.
Questions and answers about global dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_qa.shtml
Programme transcript
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_trans.shtml
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.
Aargh! I hate being whipsawed back and forth!
Especially while being fried alive by microwave radiation. That just
_really_ bites the big one.
.
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| User: "Uncle Buck" |
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| Title: Re: Global Dimming |
15 Jan 2005 02:14:10 PM |
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On Sat, 15 Jan 2005 13:58:17 +0000 (UTC) in alt.atheism, Uncle Buck
<UncleBuck@SpamMeNot.com> defied the status quo and scrawled upon the
toilet stall:
On Thu, 13 Jan 2005 22:56:33 +0000 (UTC) in alt.atheism, "Denis
Loubet" <dloubet@io.com> defied the status quo and scrawled upon the
toilet stall:
"maff" <maff91@yahoo.com> wrote in message
news:1105653213.625419.215670@z14g2000cwz.googlegroups.com...
Global Dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
Horizon producer David Sington on why predictions about the Earth's
climate will need to be re-examined.
Questions and answers about global dimming
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_qa.shtml
Programme transcript
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_trans.shtml
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.
Aargh! I hate being whipsawed back and forth!
Especially while being fried alive by microwave radiation. That just
_really_ bites the big one.
Wups. Thought this one got skipped in the posting department. Never
mind. Carry on. Nothing to see here. ;-)
.
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