Slashdot Mirror
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.
Actually, what they're saying is that since we are finally getting pollution under control, the increased amount of sunlight will compound with the current greenhouse effect. At least that's how I read it
Don't you hate pants?
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!!!..
Got a question about UNIX ask it here : Unix/xBSD Forum
Finally, of course there's more to the story than just particles in the air, but do you really expect a thorough background in geothermal science which touches on all pertinent topics such as ocean currents when you're talking about this? That would be grounds for accusations of poor journalism.
"Waking up" to something simply means to take notice of it. Rejecting the obvious truth has nothing to do with it. It's impossible for scientists to keep track of all the minutiae that comprise the universe.
Secondly, I don't think the journalist came up with that conclusion. Scientists did, and the journalist is just reporting it, which incidentally is his job.
The media can be irresponsible at times, and does make mistakes. But reporting the findings of scientists, like this, is not one of them, even if the conclusions they have reached do not agree with yours. After all, if they didn't report it, and thus did not feed the "pop-sci crap" to the public, others would feel they're not doing their job. So relax.
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.
An Eye for an Eye will make the whole world blind - Gandhi
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?
This may be an interesting read for anyone concerned by scientific coverage in the media [cjr.org]. It basicly says unless you're a scientist it's very hard to determine what's a well thought out theory and what's not, and journalists try so hard to balance the coverage of the well known and unknown that they often will given too much exposure to a theory well understood in scientific circles to be junk.
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
Need a professional organizer?
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.
Fortunately, the models & supercomputers are just slightly more complex than your fallacious argument. Merits of the BBC presention nonwithstanding, the theory that is advanced is not inconsisent with the observations at all. (Any of those could might be wrong, but that's a different story.)
... errr... well, greenhouses and shading/clouds. They may may have opposite effect on temperature, but they are not matter & antimatter. The theory of global shading has two major implications:
Replace the common useage of' 'Global warming' as 'greenhouse effect', and then park GW for the time being. If you don't understand this, consider that a car with windows rolled up acts a like a greenhouse. Sit in the shade and you might get a little uncomfortable, but not seriously so. Move out of the shade and... toast. In both cases there was complete Car Warming, but you can easily see the two major and independent factors. The make of the car does *not* matter...
So, greenhouse effects and shading are as different as
1 - Our models are wrong. Shading deducts X amount of energy which means that our estimate for the strength of greenhouse-effect is probably off by X.
2 - Ironically, shading helps, in the sense that we get less total increase in temperature - but it isn't all good, and it isn't that simple. Most importantly, reducing shading by without reducing the greenhouse effect would is tantamount to raising the temperature - which is a big no-no.
Incidentally, the particles are doing exactly what you suggest, but the implication is not what you understand it to be. One of many observations was that during flight-less days post 9/11, it didn't just get "warmer", energy flow & flux (both ways!) increased. Warmer days, cooler nights.
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.
The Death Penalty: Killing people to show others that killing people is wrong.