Global Dimming 637
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."
Well of course (Score:4, Funny)
badum DUM
Re:Well of course (Score:2)
Re:Well of course (Score:5, Funny)
"1000 points of light...and we get the dim one"
Re:Well of course (Score:3, Funny)
Re:Well of course (Score:5, Interesting)
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.
Re:Well of course (Score:5, Insightful)
In laboratory animals, chronic consumption of preservatives and free glutamate affects the hypothalamus and causes obesity, among a large number of other problems. The amount of this in our food has skyrocketed enormously over the last 50 years. In certain countries, such as the US, we eat nearly toxic levels of these compounds without taking notice.
sorry everyone (Score:5, Funny)
i'll set it back to the way i found it
So instead (Score:2, Interesting)
Re:So instead (Score:5, Insightful)
Re:So instead (Score:2, Funny)
It's all these damn enviro-hippies and their solar power! They're sucking in all the light that used to hit the ground and keep the earth warm. STOP IT.
Re:So instead (Score:5, Informative)
Not quite right either. The amount of sunlight reaching the top of the Earth's atmosphere is still the same. The amount reaching the ground is over 10% less than during the 60's. It is not clear how much of the sunlight is being absorbed and then re-emitted as IR within the atmosphere, and how much is being reflected back into space. Snow and clouds both reflect a lot of energy back out of the atmosphere. You mention reflection, but you don't seem to think it could result in net energy loss.
What I'm trying to get at is that if some factor (say cloud seeding from aircraft exhaust, a known phenomenon) is causing more cloud cover, it could well be that the total solar energy absorbed by the ground+atmosphere is substantially less than it used to be. The article wasn't clear on this point.
Re:So instead (Score:3, Interesting)
This is the exact thought that i had. I remember reading some analysis that said there was a significantly larger temperature range recorded due to the reduction in cloud cover over the US in the days following Sept 11th, as all the planes were grounded. Link [findarticles.com]
It makes sense that on average the increase in cloud would also reduce the solar radiation.Has anyone plotted, global flight hours of jet aircraft against year on year dimming effect? Sounds like a likely answer to m
Re:So instead (Score:4, Informative)
Yes it is. You haven't actually read the article, have you?
It states -
Sorry to be sarcastic, but you could at least have searched the text for, say, 'violet' before commenting.
Re:So instead (Score:2, Informative)
Re:So instead (Score:3, Interesting)
Re:So instead (Score:3, Insightful)
Re:So instead (Score:3, Funny)
Re:So instead (Score:5, Funny)
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
Re:So instead (Score:4, Insightful)
Not necessarily. Venus, hottest planet in the system, is completely covered in clouds. They act as a blanket to keep heat in (cloudy nights are warmer).
Interesting Statistic (Score:5, Interesting)
On a similar note, the US could obtain all energy from the sun if it were to install a 200 mile square solar installation (assuming 15 percent efficiency... easily doable today). I say, put a dime of tax on each gallon of gas and use this money to subsidize solar generation - one of the only energy producers out there with net positive energy (more energy produced in the cell's lifetime than it takes to produce the cell itself). Hydro, wind and solar... I can't wait for the day.
On yet another related note, I'm in the process of building a solar/NiMH PC. I'm simply going to use store-bought NiMH rechargables to store excess daytime solar input. It certainly won't be cost effective but it'll be pretty high on the geek factor.
Re:Interesting Statistic (Score:4, Interesting)
Where do you want to dump the highly toxic chemicals that would be the result of the 200 square mile solar installation? Where are you going to put it that wouldn't make environmentalists, homeowners, or farmers go crazy and is still safe from natural disasters?
Wind is nice and clean, but it takes a lot of windmills to generate enough power to replace a power plant. Windmill farms are regarded as many to be ugly so people don't want them around their houses.
Hydro sounds like a great idea, but many people have a bias against hydrogen because of past mistakes with it. We can handle it much safer now, but it is still more dangerous than gasoline.
Also remember that the bigger you make something, the more difficult is to maintain. Snow, ice, earthquakes, tornados, and hurricanes can cause havoc on large equipment.
Everyone knows the nasty side effects of using oil & coal energy.
Don't get me wrong, I (like you) am looking forward to the day when I can throw away all gasoline powered devices, but we are not quite there yet. Hopefully it will be very soon.
Re:Interesting Statistic (Score:3, Insightful)
I don't believe this statement is factual. Source, please.
C//
Re:Interesting Statistic (Score:4, Informative)
I did a quick google search & found this. Very informative.
http://www.e-sources.com/hydrogen/safety.html
Thanks for catching me on this. I can say I learned something new today.
Re:Interesting Statistic (Score:3, Informative)
Observations of the incident show evidence inconsistent with a hydrogen fire: (1) the Hindenburg did not explode, but burned very rapidly in omnidirectional patterns, (2) the 240-ton airship remained aloft and upright many seconds after the fire began, (3) falling pieces of fabric were aflame and not self-extinguishing, and (4) the very bright c
Re:Interesting Statistic (Score:3, Informative)
They painted the entire fabric skin of the ship with explosively flammable paint/sealant and they were suprised when it burned so readily.
Helium in the envelope wouldn't have saved the Hindenburg. But it was a convenient explanation at the time.
Regards,
Ross
wind is quickly on its way to dominance (Score:4, Interesting)
Actually, the entire electricity requirements of the United States could be served by wind turbines with a combined land-use footprint of only 14,000 acres, including enough grid redundancy to provide 99.5% uptime through long grid transmission to areas experiencing calm winds. (The remaining 0.5% backup could be hydro or whatever.) That area is only twice the size of the Stanford campus, and as large as the amount of Oak forest that California loses each year.
Some people consider turbines ugly at first glance, but more people want wind turbines in their neighborhood than want mercury-spewing coal smokestacks in their state.
Wind power is the fastest growning renewable industry [awea.org] and is expected to be the dominant form of power production in less than 30 years [google.com].
Please see the Windpower FAQ [windpower.org] for more information.
Re:Interesting Statistic (Score:3, Informative)
Re:Interesting Statistic (Score:3, Insightful)
How else do you think, the following produciton plant is possible. Even if it only gets 10-20% of the energy from the solar panels on the building, it still produces far, far more panels than are installed on the building.
Solarfabrik [solarfabrik.de]
And also see this study [uni-kassel.de].
The energetic amortization for a solar powerplant is 6-7 years!!! And this is a pessimistic study, others even say it is only 3 years.
Re:So instead (Score:4, Informative)
I AM an optical scientist, so I'll fill in a few gaps that are not covered in the article, and are often misrepresented. The phenomenology of propagation through the atmosphere is very different for longwave infrared, visible (& shortwave infrared), and ultraviolet (UV). That is why it is possible to have global warming with decreasing sunlight, and increasing UV.
NOTE: when I say 'atmosphere,' I mean the part where most of the air is, i.e., just the stratosphere and troposphere. Don't be a snot about the "exosphere".
1. Most of the energy reaching the earth from the sun is in the visible and near IR wavelengths. The atmosphere is nearly transparent to these wavelengths, so a lot of the sun's energy reaches the surface of the earth. Scattering from particulates (e.g. pollution, volcanic material, water particles, etc.) is the primary loss mechanism for sunlight. Most of these particulates are close to the ground, or well-distributed through the atmosphere. Therefore, nearly all of the sunlight gets close to the earth.
2. Dangerously short wavelengths (cosmic rays, x-rays, gamma rays, hard UV) are scattered and absorbed at the cusp of earth's atmosphere. Almost none reaches even the lower atmosphere. Soft UV is predominantly absorbed by ozone. The atmosphere itself scatters short wavelengths very well (thus, blue sky).
3. Excepting a few 'windows', the atmosphere is opaque to longwave infrared light. Earth emits long-wave IR light due to its low temperature. Longwave IR light from is absorbed in the atmosphere, preventing the earth from cooling itself. This is the 'greenhouse effect.' Since the atmosphere is so opaque to longwave-IR, the greenhouse 'panes' are pretty much at the edge of the atmosphere.
4. The article presents research which raises the possiblity that increased pollution (possibly) is causing more solar energy to be absorbed in the lower atmosphere. Global warming is still possible since the lower atmposphere is still 'inside' the greenhouse, so the extra abosrbed energy is still contributing to heating. UV light is being absorbed by the particulates as well, but not enough to offset the damage done to the ozone layer.
6. Do I believe the article? A little bit. The main point is that a previously crazy idea was corroberated very well by a second, independent measurement (evaporation). Two improper experiments are much less likely than one. Still, 10% seems pretty big.
CV
Sunglasses (Score:2)
Rus
Re:Sunglasses (Score:5, Insightful)
Agricultural output (Score:2, Insightful)
Re:Agricultural output (Score:3, Informative)
Re:Agricultural output (Score:5, Informative)
Re:Agricultural output (Score:3, Insightful)
HIV drugs can be used to stave off the disease, but the cost of drugs deplete funds t
Re:Agricultural output (Score:2)
Re:Agricultural output (Score:5, Insightful)
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.
Re:Agricultural output (Score:5, Informative)
Good question, though not too hard to research as there's a volume of data and it's a hot issue. Of course, it's controversial, since much of the research is influenced by agribusiness (esp. here in Canada -- AgCan is in industry's pocket) and that means that research is overly reductionist or just plain skewed.
Keywords to look for in your reference search: loss of topsoil in green revolution scenarios (effects of tilling, bare soil, industrial watering, monocrops, heavy feeding crops, pesticides); dependence of farming on chemical inputs; loss of seed sovereignty; crop diversity reduction; the effects of large-scale monocropping on the environment; water usage; permaculture; loss of local knowledge (microclimates, local pest management, seed varieties --again--, plant companions, etc); misguided pest management (overused pesticides etc.); distribution and ownership models that reduce local food security; and so on.
Some good places to start looking outside of google:
Institute for Agriculture and Trade Policy [iatp.org]
Sustainable Farming Connection [ibiblio.org]
FarmFolk/CityFolk [ffcf.bc.ca]
The Ram's Horn [ramshorn.bc.ca]
World Resources Institute [wri.org]
WorldWatch Institute [worldwatch.org]
Pesticide Action Network [panna.org]
Sustainable Agriculture Network [sare.org]
Permaculture [ibiblio.org]
ETC Group [etcgroup.org]
There, that should get you started. You want evidence? there's plenty out there.
How will H usage affect this? (Score:3, Interesting)
Re:How will H usage affect this? (Score:5, Insightful)
Re:How will H usage affect this? (Score:2)
Re:How will H usage affect this? (Score:4, Funny)
Re:How will H usage affect this? (Score:5, Insightful)
Automobiles are one of the more dirty ways of converting fossil fuel energy into usable energy, specifically because really good filters, and very high temperature combustion are not desirable (for both portability and usefulness reasons).
However, if this is done at a plant, these issues go away. The burning process will be much cleaner.
Re:How will H usage affect this? (Score:2)
I would think that lots of clouds would block sunlight and make the earth cooler. Isn't that the idea behind nuclear winter?
Re:How will H usage affect this? (Score:2)
Re:How will H usage affect this? (Score:2, Informative)
Most H2 generated today comes from hydrocarbons. It takes energy to reform the hydrocarbons to make H2 (with CO, CO2, etc. as the usual byproducts). This extra energy produces more H2O (and CO2).
The net result is more H2O from H2 fuel compared to the hydrocarbon fuel used directly.
Re: (Score:2, Insightful)
Re: (Score:2)
I was so much younger then (Score:5, Funny)
Full Text (Score:5, Informative)
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
Now I'll have to stay out even longer ... (Score:2)
it's a conspiracy (Score:5, Funny)
Kind of emphasizes a major point. (Score:4, Insightful)
What it comes down to is, whose policies are most in favor with the scientific community will get results from that community supporting their position. Screw the fact they don't have all the facts, it doesn't prevent either camp from making claims.
Its Global Warming this pas 15 years, before then it was Global Cooling.
Environmentalism is much more about ideaology than realism.
Re:Kind of emphasizes a major point. (Score:5, Insightful)
From my point of view it is about:
Those seem pretty practical demands to me.
Old-style environmentalism (Score:5, Insightful)
Unfortunately, real environmental problems are usually created locally*. Fixing them means taking the economic hit locally -- losing factory jobs in your own city, reducing the fertilizer-driven crop yield on your own farm, having a smaller engine in your own car, whatever.
It's much better to deal with global environmental issues, which are, by definition, somebody else's fault. "It's not me, it's those darned Amazonian loggers! I can't do anything by myself, the world's governments need to get together and make everyone do things differently."
[* important exception: rivers. Rivers carry and in some cases even concentrate pollution from large distances upstream]
tomorrows weather, 20 and sunny. (Score:3, Interesting)
weird (Score:5, Interesting)
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...
Re:weird (Score:3, Interesting)
Re:weird (Score:3, Interesting)
Re:weird (Score:4, Funny)
It's better overall to have scientists shaking their heads, saying things like "if it's this significant, then it would have been reported before". After all, it's not possible to have something reported the first time. Nope, not at all. These scientist guys really know their stuff.
The unintended benefits of pollution (Score:5, Interesting)
The scary part comes if we reduce these forms of pollution, reduce cloudiness, and thus accelerate global warming. Whether we like it or not, humanity is changing the climate -- as attractive as it seems, preservation is impossible. At this point, it might be better to think about climate engineering -- deciding how we want to change the climate rather than holding on to the false hope that we can avoid changing the climate.
Re:The unintended benefits of pollution (Score:5, Insightful)
Re:The unintended benefits of pollution (Score:4, Interesting)
So I wouldn't see this as a benefit. I would think reducing pollution would increase light reaching the ground, but also help decrease how much heat is retained in the atmosphere.
I'm probably wrong, I suppose.
The science behind contrails (Score:3, Informative)
Scientists have been debating this one quite a bit -- whether cloud's reflection of the sun light creates more cooling than the cloud's night-time heat-trapping abilities. The suspension of airtravel around 9-11 gave scientists a chance to study this [sciencenews.org]. They found that the absence of contrails created pronounced h
Re:The unintended benefits of pollution (Score:5, Funny)
The Venusians apparently made the same assumption about their climate, unfortunately.
Re:The unintended benefits of pollution (Score:3, Informative)
Clear skies generally indicate high-pressure systems, usually coming from northern areas over land.
Cloudy skies generally indicate the approach of a differently-pressured system.
Come to the Washington, DC area. Cloudy days mean cooler weather, and usually rain.
If you are speaking of night-time effects, you are right that clear skies will indicate cooler temperatures than cloudy skies, but there is no "INCREASES" going on. The cloudy skies simply trap more of the day
Crude (correct or incorrect?) Analogy (Score:2, Interesting)
If this analogy is correct, we really do have a lot to fear. Not only will we continue to have global warming but it seems as if the humidity level of the planet may rise too. O
Heh. Human dimming (Score:2)
So the bigger problem here is that it's getting increasingly harder for information to penetrate the thick skulls of humans. Looks to me like the number of thickheads is growing at a rate faster than 3% a decade, more like 300%
To quote the Bloodhound Gang. (Score:2)
or perhaps a better quote from Futurama.
"I'm glad global warming never happened. It did, but nuclear winter canceled it out."
Animatrix (Score:4, Funny)
Rock On!!! (Score:5, Funny)
Now, I'm not a scientist, but this sort of implies to me that things will get more humid as well. So, we're setting up for living in a big ole' sauna. So, let's look at the ups and downs:
Good: We'll all have great skin for starts.
Bad: Lots of very fat men walking around in flip-flops with small towels around their waists.
Good: Girls will wear less clothing to cope with the heat & humidity--we'll have a population of nice-skinned chicks dressed like the love-slaves from planet Triton. Misquoting Mary Carey [marycareyforgovernor.com]: "Global warming? Never heard of it, but I guess we'll all have to wear less". Woo!
Bad: Killer hangovers, massive ring around the collar.
Re:Rock On!!! (Score:5, Interesting)
Actually, the article mentioned that it was visable and infrared light that was being blocked by an excess of clouds, not ultraviolet. Add to this the fact that our magnetic feild is becoming less polarized, in the process of flipping. As it does so there will be a bunch of little poles (places where the magnetic feild points into the earth not parrallel to it), guiding in additional radiation (and aroras, yay!). So if anything we will have more problems with bad skin not less.
Also, as the earth has warmed we have seen an the wet places getting more precipitation and the dry places getting less. And the article said the dimming was not constant, just that we have had more clouds and the clouds obviously block light, but the deserts, with no precipitation will have fewer clouds and thus less dimming.
My prediction: the world will be divided into radsuit wearing deserts desert dwellers, and mutant frog men, who live in swamps.
Driving a Truck Through This One (Score:5, Insightful)
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).
Re:Driving a Truck Through This One (Score:3, Interesting)
2) Astronomers tools have been improving and changing alot over the time period in question, and as a result their measurements may not be consistant enough going back for them to compare and notice the trend, especially if they aren't looking for it.
3) It's not necessarily just absorbed by the atmosphere, it could be reflected back into space by increased cloud cover.
4) In the long run it could be consistant with either warming or cooling, depending on the mechanism that is reducing t
Re:Driving a Truck Through This One (Score:4, Funny)
IANAAP*, IAAIC**. But why would energy being soaked up by the atmosphere lead to a warmer planet than being soaked up by the ground which then heats the atmosphere? If anything it would just change the temperature gradient, not the mean temperature, making the surface temperature colder, no?
* I am not an atmospheric physicist
**I am an ignorant clod
Re:Driving a Truck Through This One (Score:3, Informative)
This made me think of... (Score:3, Interesting)
So I blame jet airplane contrails.
Que the argument from ignorance fallacies (Score:5, Insightful)
To me this makes just as much sense as rejecting biology as soon as scientists discover a new species. "See! The proves the bible was right!"
Not enough data (Score:5, Interesting)
Also, it seems that the assumption has been made that the sun produces constant output. I don't think we can make this assumption. The sun, as a system, is way bigger than our atmosphere. Until we have thousands of years worth of data, observed from outside the atmosphere, we can't prove that solar radiation is a constant. In fact, since solar flares temporarily increase solar output, you could postulate that thousand year trends in flare frequency and magnitude could affect the overall output of the sun.
So, while global dimming may or may not affect us in the short term (on the scale of centuries) and pollution is still bad (again very long term effects are unrecorded, but it's obviously very bad in the short term (again measured in centuries) and it is ugly), I'm still not all that concerned that the world is going to ice over or boil away any time soon.
Re:Not enough data (Score:3, Informative)
It's not constant [noaa.gov], and so it only took several decades to prove it.
The price of uncertainty. (Score:5, Insightful)
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 [noaa.gov]. 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.
It stands to reason (Score:5, Funny)
Some interesting details (Score:4, Interesting)
Please note here, much of this 10% is being reflected. There are people in this thread pointing out how untrue the observations must be because if 10% of the sun's energy was being absorbed by the atmosphere, the Earth would be getting a heck of a lot warmer than it is. Instead, the Earth should be getting 10% brigher from the moon or anywhere else in space. Particulates are reflecting and clouds are forming (which look very bright to me when I fly over them).
I've been wondering about this. Would global warming end up creating enough clouds to reflect enough energy from the sun that it balances itself out after a few decades? Or will global warming cause an imbalance in the sun's reflected energy after a few decades that causes a swing on the cold side? How much does the CO2 green house effect compare to the particulate / cloud reflector effect?
Seasonal addective Disorder (Score:3, Interesting)
I wonder if this will have any sort of noticeable effect on Seasonal Affective Disorder [discovery.com]. It has been shown that people feel more depressed with less exposure to the sun (this disorder is especially common in winter).
It's funny, everyone talks about how people seem sadder and grumpier "these days". I wonder if there could be an actual link to this "global dimming".
Why less light doesn't mean cooling down. (Score:3, Insightful)
First, less light == cooling down? "If that was the case then we'd all be freezing to death."
There isn't less radiation coming from the sun, just less reaching the earth's surface ("there has been a general increase in overall solar radiation over the past 150 years"). This means it's probably being absorbed in the atmosphere, probably being converted to heat. By preventing that sunlight from being converted to non-heat energy (photosynthesis, evaporation), this might be heating up the atmosphere even more. I don't know where this heat goes, but it *might* be possible that less surface light means increased global warming. I guess the real questions regarding surface light and temperature is: How does a decrease in surface light affect the amount of energy that escapes the earth?, and Are we storing energy and remaining cool, or letting more energy be converted to heat?
Second, "I don't think that aerosols by themselves would be able to produce this amount of global dimming." Aerosols "by themselves" might not filter that much light, but pollution does lead to "bigger, longer lasting clouds." It sounds like the "global dimming" just means less direct sunlight, not necessarily dimmer direct sunlight.
Venus - No Direct Sunlight But Hottest Planet (Score:3, Informative)
Re:Bunk science (Score:3, Funny)
Re:Sunlight (Score:5, Insightful)
The light from the sun is absorbed by the junk we blow into the atmosphere and thus doesn't reach earth. The energy is still absorbed by the earth as a whole....
Jeroen
Re:So now... (Score:3, Interesting)
The article is about less sunlight reaching the earth's surface. Nothing about the earth cooling down....
Lets have an experiment:
1 Take a black (or very dark) plastic bag.
2 Go stand in the sun.
3 Pull the bag over your head (not to tight you are not going for a Darwin Award)
4 Stand for a while
You will notice the following:
1 You don't see much since the sunlight does not reach your eyes. (Lets call this 'dimming')
2 It gets hot in the bag. (Lets call this 'warming')
Conclusion:
You can have
Re:Sunlight (Score:3, Funny)
Maybe we already have that considering that the study has a margin of error of 10%
Re:Sunlight (Score:3, Funny)
Actually, when one puts it that way, it doesn't sound too bad ...
Re:yeah right (Score:2)
Jeroen
Re:yeah right (Score:5, Insightful)
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
Re:yeah right (Score:5, Informative)
Don't kid yourself. The US is responsible for a very large chunk of the greenhouse gas output of the world. It is something like 40%. That is despite the fact that the US has around 5% of the world's population.
Don't forget that average fuel economy of cars sold in the US is at its lowest level in 20 years. Think about that for a moment. The average car sold today has roughly the same fuel economy as a car sold in 1983! Why? Looser resrtictions on "light trucks", because they were used for work purposes. Then the automakers realized they could make glorified station wagons and call them SUVs and sell them as "light trucks", as though they were being used for work. Heck, the Chevy Suburban is so big that it isn't even considered a "light truck" and is therefore not subject to fuel economy regulations at all. For fuel economy purposes, a Suburban is treated as though it were the same type of vehicle as a dump truck.
Re:yeah right (Score:3, Funny)
Don't kid yourself. The US is responsible for a very large chunk of the greenhouse gas output of the world. It is something like 40%. That is despite the fact that the US has around 5% of the world's population.
Ok, then just replace "Third World country" by "country whose leader has not been democratically elected", and it again fits...
Re:yeah right (Score:3, Insightful)
Yeah, right! Sure it's those ultra-developed industries in unregulated Third World countries producing all the polution. I'm sure that the fact that countries like the USA or Russia are conveniently not abiding by the Kyoto Treaty has nothing to do with it.
Re:Global Cooling Theories (Score:5, Informative)
Re:Global Cooling Theories (Score:3, Redundant)
Less light to the ground does not mean a colder climate, the heath from the sun is simply absorbed somewhere else like in an atmosphere full of greenhouse gasses.
The global warming fad won't be put away. The new data will simply be integrated into the models and will likely proove we screwed our environment up even further than we thought.
Jeroen
Re:The First Church of Environmentalism (Score:3, Insightful)
From WordNet (r) 2.0
environmentalism
n 1: the philosophical doctrine that environment is more
important than heredity in determining intellectual
growth [ant: hereditarianism]
2: the activity of protecting the environemnt from pollution or
destruction
The inductive approaches to physics, biology, and chemistry are sciences. T
Nuclear decay == Remains of a supernova (Score:3, Informative)
As to saying that radioactive decay is non-renewable, that is rediculous. It will always be there (unless you're looking at millions/billions of years in the future, and you might as well be worried about the sun burning out or exploding by then. You might as well consider the sun to be non-renewable on that timescale, as well.