by Crazy Horse
Tue Sep 14th, 2010 at 01:19:23 PM EST
A friend turned me on to the concept of Global Dimming. While i'd been through some of the accompanying literature a bit, and while i've read some about the effect of jet contrails, i'd never seen it put together like this. Yet i have no idea of where this science stands.
I'm sure there are people at ET who are far more familiar with this research. I'd like to get a handle if there is any validity here. I'm using a BBC show from 2005 as a base for discussion, but have no idea of where this research has gone over the past five years.
NARRATOR: Instead we have to take urgent action to tackle the root cause of both global warming and Global Dimming - the burning of coal, oil and gas. We may have to make very difficult choices, about how we live and how we generate our electricity. We have been talking about such things for 20 years. But so far very little has been done in practical terms. The discovery of Global Dimming makes it clear that we are rapidly running out of time.
the story begins with measurements from the three days after 9/11 when flights were grounded.
DR DAVID TRAVIS: We found that the change in temperature range during those three days was just over one degrees C. And you have to realise that from a layman's perspective that doesn't sound like much, but from a climate perspective that is huge.
Then comes solar measurement from Israel.
NARRATOR: A 22% drop in solar energy was simply massive. If it was true surely Israelis should be freezing. There had to be something wrong. So when Gerry published his results they were ignored. DR GERALD STANHILL: I must say the publications had almost no effect whatsoever on the scientific community.
NARRATOR: But in fact Gerry was not the only scientist who had noticed a fall in sunlight. In Germany a young graduate climatologist called Beate Liepert found that the same thing seemed to be happening over the Bavarian Alps too. DR BEATE LIEPERT (Lamont-Doherty Earth Observatory): I was the same, I was as sceptical as any other climatologist. But then, um, I, I saw the same results er in Germany, so um I believed him.
By now i'm thinking if there were something here, we would be discussing it. or perhaps i'm just lazy, and Dimming is part of the global discussion, i'm just not aware of it.
DR MICHAEL RODERICK: And then one day, just by accident, I had to go to the library to get an article out Nature. As you do, I couldn't find it. And I just glanced at a, through the thing, and there was an article called Evaporation Losing Its Strength. Which reported a decline in pan evaporation over Russia, United States and Eastern Europe. And there in the, in the measurements, they said that the, the pans had on average, evaporated about a hundred millimetres less of water in the last thirty years.
Project INDOEX, as it was called, was a huge multinational effort. For four years every possible technique was used to sample and monitor the atmosphere over the Maldives. INDOEX cost twenty-five million dollars, but it produced results - and they surprised everyone.
PROF VEERABHADRAN RAMANATHAN: The stunning part of the experiment was this pollutant layer which was three kilometre thick, cut down the sunlight reaching the ocean by more than 10%.
So the scientists detect an effect which is 10X what the models predict.
DR PETER COX: We've got two competing effects really, that we've got the greenhouse effect, which has tended to warm up the climate. But then we've got this other effect that's much stronger than we thought, which is a cooling effect that comes from particles in the atmosphere. And they're competing with one another. And we know the climate's moved to a warmer state by about point six of a degree over the last hundred years. So the whole thing's moved this way. If it turns out that the cooling is stronger than we thought then the warming also is a lot stronger than we thought, and that means the climate's more sensitive to carbon dioxide than we originally thought, and it means our models may be under sensitive to carbon dioxide.
Long story short, if there's something here, you'd think this would be getting some attention. So i'm assuming there's been discrediting research done of which i'm unaware. (no time to check, barely found time to do this diary, so let's use the resources of ET.)
NARRATOR: At this point, whatever we did to curb our emissions, it would be too late. Ten thousand billion tons of methane, a greenhouse gas eight times stronger than carbon dioxide, would be released into the atmosphere. The Earth's climate would be spinning out of control, heading towards temperatures unseen in four billion years. But this is not a prediction - it is a warning. It is what will happen if we clean up pollution while doing nothing about greenhouse gases. However, the easy solution - just keep on polluting and hope that Global Dimming will protect us - would be suicidal.