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Global Dimming
wiredog writes "The Guardian reports on research which shows that the amount of sunlight reaching the Earth's surface has decreased by 10% in 30 years. This has implications for global warming models and, especially, agricultural output."
my landlord told me not to touch that dial on the wall, but i couldn't resist
i'll set it back to the way i found it
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
No. The amount of sunlight reaching earth is still the same. The amount reaching the ground is what is decreasing. It is being absorbed elsewhere or being reflected.
I prefer the "u" in honour as it seems to be missing these days.
I always felt that the world was a brighter place when I was a kid, now I have proof!
Each year less light reaches the surface of the Earth. No one is sure what's causing 'global dimming' - or what it means for the future. In fact most scientists have never heard of it. By David Adam
Thursday December 18, 2003
The Guardian
In 1985, a geography researcher called Atsumu Ohmura at the Swiss Federal Institute of Technology got the shock of his life. As part of his studies into climate and atmospheric radiation, Ohmura was checking levels of sunlight recorded around Europe when he made an astonishing discovery. It was too dark. Compared to similar measurements recorded by his predecessors in the 1960s, Ohmura's results suggested that levels of solar radiation striking the Earth's surface had declined by more than 10% in three decades. Sunshine, it seemed, was on the way out.
The finding went against all scientific thinking. By the mid-80s there was undeniable evidence that our planet was getting hotter, so the idea of reduced solar radiation - the Earth's only external source of heat - just didn't fit. And a massive 10% shift in only 30 years? Ohmura himself had a hard time accepting it. "I was shocked. The difference was so big that I just could not believe it," he says. Neither could anyone else. When Ohmura eventually published his discovery in 1989 the science world was distinctly unimpressed. "It was ignored," he says.
It turns out that Ohmura was the first to document a dramatic effect that scientists are now calling "global dimming". Records show that over the past 50 years the average amount of sunlight reaching the ground has gone down by almost 3% a decade. It's too small an effect to see with the naked eye, but it has implications for everything from climate change to solar power and even the future sustainability of plant photosynthesis. In fact, global dimming seems to be so important that you're probably wondering why you've never heard of it before. Well don't worry, you're in good company. Many climate experts haven't heard of it either, the media has not picked up on it, and it doesn't even appear in the reports of the Intergovernmental Panel on Climate Change (IPCC).
"It's an extraordinary thing that for some reason this hasn't penetrated even into the thinking of the people looking at global climate change," says Graham Farquhar, a climate scientist at the Australian National University in Canberra. "It's actually quite a big deal and I think you'll see a lot more people referring to it."
That's not to say that the effect has gone unnoticed. Although Ohmura was the first to report global dimming, he wasn't alone. In fact, the scientific record now shows several other research papers published during the 1990s on the subject, all finding that light levels were falling significantly. Among them they reported that sunshine in Ireland was on the wane, that both the Arctic and the Antarctic were getting darker and that light in Japan, the supposed land of the rising sun, was actually falling. Most startling of all was the discovery that levels of solar radiation reaching parts of the former Soviet Union had gone down almost 20% between 1960 and 1987.
The problem is that most of the climate scientists who saw the reports simply didn't believe them. "It's an uncomfortable one," says Gerald Stanhill, who published many of these early papers and coined the phrase global dimming. "The first reaction has always been that the effect is much too big, I don't believe it and if it's true then why has nobody reported it before."
That began to change in 2001, when Stanhill and his colleague Shabtai Cohen at the Volcani Centre in Bet Dagan, Israel collected all the available evidence together and proved that, on average, records showed that the amount of solar radiation reaching the Earth's surface had gone down by between 0.23 and 0.32% each year from 1958 to 1992.
This forced more scientists to sit up and take notice, though some still refused to accept the change was real, and instead blamed it on inacc
So the pollution that pumps out of power stations is making it too dark to switch to solar power. How convenient.
Not at all. The problem these days is not quantity of food, but lack of effective distribution thereof.
Hokey statistics and ancient misconceptions are no match for a good thought in your head, kid!
Quite weird - there was an elderly farmer saying much the same thing this morning on my bus to work.
I'm pretty sure he wasn't a guardian reader, it's just something he'd noticed over the years.
At the time, I thought he was talking crazy talk...
sounds like complete bull to me... If ANYTHING there would be MORE now since the 70's when they implemented all the anti-smog and pollution laws. Whoever came up with these results is likely just trying to make a name for themself. Sounds like a pathetic attempt...
... the math ain't hard.
Did you RTFA? That's almost exactly the reaction a lot of senior scientists had, but it looks like the evidence is pretty overwhelming. (With the usual caveats about popular journalism being hard to trust when it comes to science reporting, etc.) The thing about pollution laws is, they've helped a lot, but a) a lot of pollution comes from Third World countries that have no pollution laws, or don't enforce the ones they have, and b) the effects of the laws have been pretty much overwhelmed by the fact that we have a lot more people now than we did two or three decades ago.
We've seen this on a small scale where I live, in Denver, the city that gave the world the phrase "brown cloud." When I was a kid in the Seventies, the population of the Denver metro area was about half what it is now, and the pollution was just terrible. During the Eighties, as tougher laws kicked in (AFAIK, Colorado was the second state in the western US, after California, to really get serious about this) things improved dramatically. But through the Nineties, air quality started to get worse again, and we're now just about back to where we were when the laws came into effect. Halve the average emissions, double the population
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Since those yields are not sustainable, we're headed for trouble with or without global dimming.
Saying industrial agriculture is the solution to feeding our overcrowded planet is rather like saying that getting more credit cards is the solution to personal financial problems.
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
I thought it was a commentary on the last US Presidential election...
"1000 points of light...and we get the dim one"
People in cars cause accidents....accidents in cars cause people
1. In general, studies of this type are very difficult to do. One has to take into account:
-
the non-continuity of the measurements (they're not measuring everywhere, they are probably tending to measure near cities; cities cause definite local effects over time, but they are only a small percentage of Earth's surface area.
- astonishingly few "scientists" actually understand how to use instrumentation. (Yeah, flame me - but it's true - I've done a lot of teaching and mentoring in this area). One of the problems of our age is that we all have access to sophisticated equipment, but few actually know what the results mean.
2. It occurs to me that if the Earth's atmosphere were soaking up all of that energy, astronemers (one group that actually does know how to use instrumentation) would have noticed spectral changes years ago. But we haven't heard from them. (They could be part of a vast right-wing conspiracy to prop up the Bush and Cheney crew, I suppose, and are just not telling us.)3. I haven't done the calculations (has anybody?) but it also occurs to me that if Earth's atmosphere were soaking up all of that energy, there'd be some SERIOUS global warming occuring.
4. In the article, the "discoverer" of our newest Earth-dooming catastrophe seems to indicate that he was amazed to have found this issue in the mid-80's when "there was undeniable evidence that our planet was getting hotter". As some of us will recall, the dominant paradigm in the mid-80's was global cooling. Global cooling in the '80s was as obvious and well-proven as global warming is today. And, actually, diminishing sunlight reaching the Earth would be consistent with global warming (see point 3).
The thing people always seem to forget is that climate stasis is impossible even if humans had never existed. This stuff changes with or without us. We may or may not be affecting the process, but no matter what, we can't make it stay the way it is forever.
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
The important point here is: we are altering the planetary system, but can not predict the effects.
There is no doubt that we are changing the planetary system. If nothing else, CO2 concentrations are rising dramatically and human activity is definitely the culprit. And global temperatures are definitely rising. Humans may or may not be the culprit, but a back-of-the-envelope calculation suggests that more CO2 should cause higher temps.
The problem is that we can't predict the effects of these changes. It isn't like there's a global thermostat that we can turn up or down a half-degree by altering our industrial output. Rather, it is like throwing random chemicals into a bowl in a closed room, hoping you don't create toxic fumes. You might, you might not, but you don't know one way or the other, and you can't get out in any case.
I spent several months looking into climate models and concluded that they're complete bunk. We can't predict the weather a week out, but people use the very same techniques to "predict" the climate a century out. Consider this: if you believe in a human activity-climate link, then in order to predict climate, you have to predict human activity. So predicting the behavior of the entire world economy is just one small source of the uncertainty in these models! They're garbage! Computer climate models just create a false sense of predictability about climate change.
So this leaves us in a scary place. Here we are on earth. If we screw it up, we have nowhere else to go. We're making changes, but we don't know the effects. Since we don't understand the planetary system, we can't necessarily undo the effects. It's like remodeling an aircraft in flight.
If we make it easier for the stupid people to survive, then of course Global Dimming will occur.
Play Well
/. readers and global domination.. I don't think so!
:)
geek1: 'we need a totalitarian state run by elite technocrats to rule the world'
geek2: 'totalitarian states blow goatse, your monopolistic society just prevents personal freedom and restricts innovation. a community-wide socialist state for the benefit of all is what's needed'
geek1: 'you commie, just like the inhabitants of Thabeza3 in trek:NG episode 7, your society will crumble under the weight of indecision and everyone making their own principalities'
Meanwhile.. the rest of the world will continue as normal
Although you probably meant this as a joke, it might be. The amount of light people recieve affects lots of physical things. Chronically light deprived people (such as those who work night shifts) are heavier on average than those who don't. Lack of sufficient light also affects alertness and mood, and not only in those who have seasonal affective disorder.
That being said, I don't think a 10% reduction in light would cause a significant increase in obesity, but it might be an interesting experiment.
I like my beverages with warning labels!