Pollution Problems

[andrewducker]

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.

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.

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.

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.

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 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 degree Celsius.

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 six degrees Celsius.

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.

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.

"That means we'll get reducing cooling and increased heating at the same time and that's a problem for us," says Dr Cox.

That means a temperature rise of 10 degrees Celsius 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.

Whole article here

Comments

[cheekbones3.livejournal.com]

I think that while their conclusions about the runaway greenhouse effect seem reasonable, their specific predictions such as Britain being like north Africa are very silly and probably flawed, being apparently based on a simplistic correlation between temperature and latitude. The global climate is way too complex for that sort of thing, and there are many thoughts that Northern Europe is much more likely to become very cold due to the melting of the Greenland ice-cap and subsequent effect on the Gulf Stream and North Atlantic Drift...

[andrewducker]

You are, of course, correct. But you can't expect a BBC article to be that in-depth.

In fact, if we lost the North Atlantic Conveyor _and_ got a 10 degree warm-up, we'd be pretty much back where we began...

[cheekbones3.livejournal.com]

Aye - trouble is they were peddling the same nonsense on tely last night. I find the TV documentaries so frustrating and unthorough these days...

[andrewducker]

That, sadly, is a symptom of knowing things.

I can't remember the last documentary I saw about computers where I didn't want to kick the TV out the window.

[cheekbones3.livejournal.com]

Mmm...I'm not sure I find anything more irritating than the little pieces of video, endlessly repeated, such as numbers scrolling on a screen when they're talking about research etc etc *grrr*

If only people weren't so thick :O)