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BBC on Global Dimming
linoleo writes "The BBC reports that the amount of solar energy reaching the Earth's surface has declined significantly between the 1950s and the 1990s, apparently due to particulate air pollution. Scientists are worried that this global dimming may be disrupting the pattern of the world's rainfall. Most alarmingly, it may have led us to greatly underestimate the greenhouse effect: with particulate pollution being brought under control, a global temperature rise of 10 degrees Celsius by 2100 could be on the cards, rendering many parts of the world uninhabitable." The lengthy transcript of the show is available.
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.
I like when news outlets use this type of language. "Woke up". As if the other scientists were slope-headed morons rejecting some obvious truth just because they did something sooooo horrible as wait for independent confirmation of one guy's conclusions.
Because we all know that science has advanced the world over the last 4000 years or so by jumping on every statement made by anybody who ever put forward a hypothesis.
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.
In addition, this is quite a conclusion to jump to. There are many, many factors involved in climate changes on Earth. To suggest that little or no climate changed is being "caused" by something man made without backing it up goes beyond the bounds of irresponsible journalism to the point that I'd have to question whether the individual who wrote this story ought to be left in the employ of the BBC.
I just love reading the pop-sci crap that gets fed to the public. We observe less solar radiation all over the world, and the next thing you know, we're jumping straight into the conclusion that two man made pollutants are cancelling each other out and keeping the greenhouse effect - an incredibly complicated process to discuss - in check.
I love the media. It's so much fun. Too bad it's about as informational as repeatedly banging your head against a brick wall.
P.S.: The expression is "in the cards", not "on the cards".
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Let me get this straight... we are getting less sunlight, but the world is getting hotter?
The unofficial
Really, this article jumps to far too many conclusions with far too little data.
And with exactly the same certainty as this statement expresses, if I dance around in a circle every Thursday night, an average rainfall increase of 17 inches could be in the cards!
lets all screw up our environment.. we may as well speed it up .. start using more coal and gas based turn off all clean nuclear power stations (yes they are clean until the end product is required). and then we can go and increase the capacity of our engines 10 fold.. no worries.. lets all be selfish and not give a shit!!!..
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rendering many parts of the world uninhabitable.
OK, I call BS! Human beings seem to be fully capable of inhabiting locations on earth from -60 F to +115 F. While it may change the mixture of life present in places all over the world, this cycle called the ice ages has been doing the same damned thing for millions of years.
A ten degree increase in temperature, by itself, will not appreciably impact the ability of human beings to survive anywhere on the globe.
Other impacts, like sea level increase, may necessitate moving populations around, but worst case places like Arizona and Utah would then be more inhabitable with increased rainfall.
The sky is NOT falling, and we are not all doomed!
I saw the actual programme, and it was far from Pop Science. In paticular the 9/11 data was fairly stark in underlining the impact of removal of aeroplanes from the skys for just two days over the US.
But of course, we could all just bury our heads in the sand and claim it is pop science.
The programme went into a "light" amount of detail, but mainly said this was something that required more research but was on the scary side of its implications. They certainly didn't say it was cancelling out the greenhouse effect, they claimed it was MASKING its impact, a very different claim.
The real trouble is that anything that claims there is a global warming problem caused by pollution comes up against one basic problem:
The US Energy Policy.
To my mind these elements equate to the old "the odds of this thing going critical if I drop it are pretty low" school of porting nuclear materials. The odds may be low, but the cost is huge, hence the reason you don't just lob the stuff about.
So it was a lightweight programme, well yes it wasn't the Open University, but "Pop Science", not really. It definately played for some dramatic effect, but there was evidence for those who were watching.
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Would you buy stock in IBM now based on its performance in 2100?
"No, of course not," you'd say. "I don't know anything about the year 2100. IBM might not exist. Hell, computers may not exist."
Yet this very attitude is used all the time in quasi-scientific studies. Look -- if we had asked scientists 100 years ago what the biggest danger to pollution was, they probably would have said "horse dung."
In 100 years, I guarantee you that not only will technology have changed, but people will have changed as well. Articles such as this one resort to fear-mongering to try and increase the celebrity of their idea. We live in an age where the popularity of one's hypothesis is more important than its correctness.
There are many factors that go into creating the temperature of the planet. Reflectivity of the atmosphere, distance to the sun, atmospheric composition, etc. The greenhouse effect from CO2 is predictable and provable. Just because we have had global temperatures fluxuating does not disprove that CO2 is an atmospheric insulator and traps solar energy. Unless this CO2 is being drawn back out of the atmosphere (by plantlife, by carbon deposition, water absorption, or whatever else it can do), continually ramping up CO2 production into the atmsophere may cause the density to increase to the point where it becomes a problem. Thing is, once it's a problem, how long will it take to fix it, and depending on how hot it gets (10 degrees C hotter? more?) will we have time to do so before we get cooked?
While admittedly, just because we exist, we are going to change the environment around us. I fail to see the benefit in assuming that nothing that we do can or will affect the global perspective, especially when we have countries around the globe working their industrial magic. We should seek to stave off problems before they occur. In the global scale, if it takes 100 years to stabilize the temperature again, and that's a short time, it may be insufficient for us to adapt to if the temperature increases too fast.
By the way, since you're quoting data, where exactally did that come from. Care to quote the source, too?
What odds would you want before taking action?
It's not a question of odds. How do you determine odds on something you don't understand?
I agree that this is a large jump to make. Just because the solar radiation isn't getting to the ground doesn't mean that the atmosphere isn't getting the full force of the solar radiation. It would seem IMO that the particulates that are absorbing the solar radiation would cause the atmosphere to get even hotter than if the ground were aborbing it, thus this is part of the greenhouse effect and not canceling it. Of course, IANAM (Meteorologist).
Ben Hocking
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I realize you're being slightly facetious, and it's all very well and fine stating that a proportion of people live in "edge conditions", but think about it this way: increased globalization is driving more and more people to living in heavily populated and/or growing cities.
Throw a ten degree temperature increase at a place (like New York) during the summer and you're in a world of trouble (never mind potentially higher sea-levels from melted Greenland ice boosting Manhattan's previously non-existant boat industry).
Yeah, the fit and the healthy might survive and adapt, but the old and the frail, along with young children can't adapt to the heat. I grew up in South Africa, with average summer temperatures of 30 to 40 degrees (celsius) and I left the first chance I had (the humidity is just deathly). Now we're talking about 40 to 50 degree summers? I'm not sure how most people will really cope, unless we're out to cull a few billion people for "the greater good" or something.
IMHO even over 50 years, we should be able to spot trends of that order of magnitude in our food crops.
Global temperature has risen, fallen, and risen since 1880, even though carbon dioxide levels have steadily risen.
There's no doubt that CO2 levels have risen. There's also no doubt that they're far above what they've ever been over thousands of years (ice core data).
Who cares what the temperature data says? We know we can't arbitrarily raise the CO2 levels in the atmosphere ad infinitum. Putting off reducing CO2 emissions is just procrastination (and dangerous, for economic reasons, but ignoring that...). We have to stop raising the CO2 levels in the atmosphere. Why put off doing it?
Also, as a completely separate point, it's a little silly to treat US data from 1880 to 1920 as valid, but not for other countries. The US from 1880 to 1920 was not the US today. The difference in technology between the US and third world countries today is gigantic compared to the 1880s. Unless there's a known, valid reason not to use a country's data, it's cherry-picking.
At the liklihood of being branded a heretic, it should be said that global warming, its causes, its effects, and its magnitude, if any, are not understood yet and this article just illustrates that. We have been assured for many years that rising atmospheric CO2 levels (which is factual) will cause the earth's temperature to increase due to the 'greenhouse effect' of carbon dioxide in the atmosphere which reduces heat radiation into space (also factual). Scientists have attempted to create all sorts of sophisticated computer models to predict the magnitude of the warming and its effects on the global climate. Other scientists have attempted to reconstruct the historical climate by looking at tree rings, glacial ice gas bubbles, sedimentary rock layers, etc. to determine what has happened in the past. So far, so good.
The problem with all of this is that we are modeling a very large amount of heat reaching the earth from the sun every day minus an equally large amount of heat leaving the earth every day which leaves a tiny little theoretical residue of heat remaining on the earth to allegedly warm us up. Our current computer modeling techniques are just too crude to be used to draw any conclusions from. This article points out that the amount of heat reaching the earth has decreased significantly due to particulates in the atmosphere but also from increased cloud cover, caused by the particulates, or occuring independently of them. It is also possible, even likely, that the output from the sun is declining, which happens to be the currently-popular theory for explaining the cause of recent, and periodic, 'ice ages.'
What we are seeing is that even with a significant decline in solar radiation, the effect on temperatures has been relatively small. The fans of the global warming models will, of course, claim that the carbon dioxide effects have almost exactly balanced out the solar radiation decline but another, much more likely, conclusion, is that the earth's climate has a feedback control in the circulation of ocean currents, the amount of water evaporated, and the degree of cloud cover and that the computer models we currently have are not nearly sophisticated enough to give us any idea at all of what will happen in the future due to changes in solar radiation or carbon dioxide levels.
The next ice age might be just beginning or we might be on the verge of catastrophic warming but we simply do not know.
This article is probably the one that will turn people from "concerned" to "worried." We are talking about making the planet uninhabitable. On any continent. It's amazing that people are talking about this as "pop science garbage." How comforting it is to take such a position, because otherwise you'd actually have to be worried about this issue.
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So, you read the "article" and because the "article" was "crap," you decided the science must be as well? One of the problems with modern science is precisely this. So-called scientists "familiarize" themselves with research by reading some typically untrained, largely ignorant, possibly near-illerate, probably politically motivated journalist's rendition of the research and then call it bogus science. Courses in logic typically identify this kind of argumentation as "straw man" because nothing in the ensuing debate has anything to do with a reasoned critique of a real argument and instead substitute the straw man (the "article" in this case) for the actual research. Possibly you should look into a career as a demagogue. There is room at the top on both sides of the political fence for this kind of reasoning.