We are losing sunlight. No, I am serious. Over the past 4 decades, studies in the developed countries(and some not so developed) have found various degrees of decrease in sunlight.
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(mostly because you know, the world has been getting, I don't know, hotter?). 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.
Global dimming creates a cooling effect that may have partially masked the effect of greenhouse gases on global warming.
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.
Dimming appears to be caused by yep, you guess it, air pollution. The usually smog, smoke emissions, planes flying in the air... the same little devils of greenhouse responsible for making this world just a bit hotter. This little buggers reflect 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(that would be us). "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(as well as giving Bushies more excuse to stall environmental laws).
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(wrongly) 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.
This means, we are screwed.
As Dr. Peter Cox puts it, "This is bad news."
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, (like Malaysia). |
At 4:32 PM,
We are royally screwed! The end is coming.....eventually. So let's party like mad before the lights go out.
Looking out of the 68th Floor today I truly believe in the dimming, I can barely see 5 feet away. Its those 'hotspots' in Indonesia I tell ya!!
Given up hope already, even when it comes to disposing of my trash. What's the point when I neatly throw my garbage away and everyone else tosses it all over the place.
We need to colonize Mars. And what's with you Siriuz? Didn't you say our blog posts have been too depressing as of late. Post some sun shiny stuff man ;)