Wednesday, September 05, 2007

Global Dimming and the World's Future


Listen up, guys. This is important. In fact, it may be the most important news story you hear this year. It’s about the relationship between “Global Warming” and “Global Dimming” — which I’d never heard of until last night.

NOVA broadcast a TV show about it that everyone – repeat, EVERYONE — needs to see. Since you probably won’t see it, I took notes, which I’ll present herewith.

You may already know that the has increased by .6 to .8 degrees Celsius. Well, that’s only part of the story, which NOVA recounted by beginning with September 12, 2001, when a climate scientist named David Travis noticed that the Wisconsin sky was unusually clear. This meant something special to him, since he had been studying airplane ““ for several years. After 9/11, almost all airplanes in the US were grounded, so there were no contrails, though the atmospheric conditions were ideal for creating them.

Next we go to Israel, where 40 years ago another scientist, , had begun measuring the intensity of the sun in various parts of Israel so as to determine how much water was needed for plants. In the 1980s, Stanhill had updated his measurements and was astonished to find a reduction in the sunlight by about 22 percent. Though he published these findings, other scientists ignored them.

But in Germany, was studying the solar levels in the Bavarian Alps, and she too found remarkable reductions. Both Liepert and Stanhill independently began searching records around the world and found declines everywhere – in some places as little as 9 percent, in other places as much as 30%. Overall, the worldwide amount of sunshine had declined by 2-4 percent. This was puzzling. If there is , the world should be cooling, but in fact it is heating up.

Next NOVA took us to Australia, where climatologists Roderick and Farquhar had been recording the “.” This term refers to the process of measurement that had been followed worldwide for about 100 years. Scientists pour sufficient water into an outdoor pan each day to bring the level up to that of the previous day. The difference is the amount that had evaporated. The Australian researchers found that evaporation is decreasing. Why, when the earth’s temperature is increasing? Because heat is not the main determining factor; sunlight is. It’s the impact of photons hitting the surface of the water. By accident they discovered an article in Nature magazine titled “Evaporation is Losing its Strength.” Measurements in Russia, Eastern Europe, and the United States matched the findings of Liepert and Stanhill; sunshine is declining everywhere.

Onward, to the Maldive Islands in the Indian Ocean. These islands run from north to south, with the northern ones receiving polluted air blown from India, and the southern islands receiving pristine air blown from Antarctica. The climatologist Veerabhadren undertook a major international study to document and explain these differences. The difference between the amount of sunshine reaching land in the northern and southern Maldives indicates the extent of the “.” It turned out to be more than ten percent. Ramanathan had expected it to be between half a degree and one degree Celsius, so these results were ten times the predicted amount.

What is “global dimming”? It is the amount of sunlight filtered out or reflected back into space by the visible pollution in the air—soot, or sea salt, say, or the clouds produced from contrails.

What causes it? Particles of pollution. Water droplets collect on particles, then often bump into and merge with other particles that hold water, getting larger and larger until they may fall as rain. There were up to ten times as many man-made particles in the northern Maldives as in the south. Numerous small droplets reflect more light than fewer big ones, so the polluted clouds were reflecting more light back into space, preventing the heat of the sun from getting through. This is the same thing that goes on all around the world – especially today in India and China.

These more reflective clouds can alter the world’s rainfall, with tragic consequences. For 20 years in the 1970s and 1980s, the belt of clouds around the equator failed to move northward, as they do ordinarily. As a result, the in Africa received no monsoon rains – the source of water on which they depend. Drought followed, causing suffering and death of 50 million people, notably in Ethiopia.

But why had the rainbelt failed to move upward? According to Leon Rothstein, pollution from North America and Europe had been blown across the ocean as usual. But when Rothstein took account of the Maldives findings, he could recognize that the polluted clouds had stopped the heat that would have drawn the raincloud belt northward. Others had supposed until then that the explanation must have had something to do with global warming, but in this case, it was the cooling effect instead – global dimming.

As Ramanathan points out, there are billions of people in Asia whose lives are at stake. We have to cut down on air pollution, if not indeed eliminate it altogether. In the rich countries this is happening because of such inventions as catalytic converters on cars, smokestack scrubbers, and the like. That is probably why the monsoons have returned to the Sahel. But the growing economies in Asia also are suffering from pollution, with huge numbers of . Those countries will probably reduce their too, since it is much easier to achieve than the reduction of CO2. But now we see that pollution, for all its horrible qualities, has been protecting us from an even greater threat: accelerated global warming.

It was Travis who showed us a world without global dimming. He had been studying contrails for fifteen years. Water droplets produce clouds that can blanket the sky. In the southwest US, there are photos showing them covering half the sky. But to determine how large their effect was, Travis needed to find a period when the conditions were right for contrails to form but when there were no flights. There had been no such period until the three days following September 11, 2001. And suddenly Travis could collect data from all over the US, comparing it to other measurements taken over the past thirty years. His particular interest was in the temperature range – the differential between the highest and lowest temperature within a 24-hour period. This turned out to be much greater than expected. However, Travis knew that contrails are only a minor contributor to global dimming. If they could have this much effect, then the total amount of global dimming caused by all factors together must be huge.

Now shifts to a British climatologist, Peter Cox, who is formulating models to depict these phenomena. He explains that there has been a tug of war between two factors influencing global temperature: greenhouse gases, which produce warming effects, and pollution, which produces cooling effects. Which is stronger?

We are pumping out greenhouse gases now with enough energy to light a 100 watt bulb ever six square meters over the entire globe. That means, we’re producing 2.6 – 3 watts per square meter.

How much effect is global dimming having? In 2002 NASA launched the aqua satellite with instruments capable of measuring pollution. It seems that there’s a minus 1.5 watt effect per square mater – i.e. a cooling effect of one degree Celsius. So while greenhouse gases have been adding 2.6 watts per square meter, global dimming has subtracted 1.5 watts – more than half the effect of the greenhouse gas emissions, thus masking the gases’ emissions. Without this masking, we would have noticed the warming earlier and would have had more time to respond.

If we keep bringing particle pollution down, this will greatly benefit human health, but if we keep on pumping out greenhouse gases, we could worsen the effect on global temperature. This would soon cause a heating by more than 1 degree Celsius – which is more than we have seen already. And by continuing, the temperature could rise by 2-3 degrees Celsius or 5 degrees by mid-century. An increase of two degrees guarantees disaster.

We have already seen the shield melting. (Today’s Globe and Mail, page A3, has this heading: “Dramatic collapse of ice cap stuns experts: Area almost twice as big as Britain disappears in the last week alone as levels of sea ice in Arctic reach record low.” Once this starts, it is out of our control

Earth was three degrees warmer some three million years ago when there was a natural increase in gases in the atmosphere. This raised 25 METERS higher than today. At the rate we are going, most of New York City, Washington, DC, Florida, and Louisiana will be under water. The Amazon will dry and burn, releasing more CO2 and accelerating global warming.

Most current models do not take account of global dimming. Even the scientists have been misled by it. Cox says we may be underestimating the heating effect of future global warming , and that by 2100, the temperature could rise by 10 degrees Celsius. Many plant species would die. In the far north, would melt. Some or all of the 10,000 billion tonnes of methane would be released. That is a greenhouse gas eight times stronger than carbon dioxide. When this last happened 50 million years ago, the temperature was increased by 13 degrees Fahrenheit.

Within less than a decade we will pass the point of no return. To achieve less than 1 degrees Celsius, we’d have to make greenhouse gases decline by mid-century. As it is, we are experiencing increases of over 2 percent per year.

In other words, what we are facing is probably the greatest emergency in human history. NOVA does not tell us exactly what we should be doing about it. Nobody knows. However, I have an opinion. I believe it is too late to turn this around by any conservation measures that have any chance of political acceptance in a free society. I’m not saying that we shouldn’t take radical steps ourselves, beginning by holding meetings with our friends, co-workers, and neighbors. But I think that high-tech inventions MAY make a essential difference, if we support them quickly and with big money.

I’ll only mention three approaches, though there are several important high-tech projects being explored. First, there’s the possibility of creating “artificial trees” to remove carbon from the ambient atmosphere, then hide it underground. This approach is being developed by Professor at Columbia University. He says that to make it economically viable, we’d have to introduce a carbon tax or ration carbon emissions. I personally would like to work on promoting a . It wouldn’t add to our total tax burden, for it would reduce income taxes while making us pay more for anything that emits greenhouse gases. If you Google Lackner you will find several sources explaining what he is doing. Or you can listen to his Q and A on NPR at: http://www.npr.org/templates/story/story.php?storyId=10621219

Lackner himself says that only solar can suffice in the long term as an alternative to fossil fuels, which are emitting greenhouse gases. There are some solar innovations that will shortly multiply by four or five the efficiency of solar panels. I cannot describe them to you now but you will have more this fall.

Finally, there is a lot of interest in . There’s one fellow in Florida who can burn salt water in fields, but it is controversial whether there’s any payoff. (See the preceding blog about that.) And there are inventions that would possibly make hydrogen more accessible. See: http://www.npr.org/templates/story/story.php?storyId=10621219

All I intend to say here is that we cannot go on living as we have done before. We are stewards of this planet and must protect it with all the force of our intellect and physical capacities. I hereby sign up for the task. Do you?

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10 Comments:

Anonymous Manuel Rozental said...

Thankyou very much for this.

I was reading Vicente Barros, an Argentinian who has been part of the IPCC International Panel on Climate Change) and who explains in very simple terms the effects of aerosols and dimming, in a book published by Desde Abajo in spanish in 2006. Your note provides much more information and bibliography. I would love to watch and share the video.

I would suggest that you read George Monbiot's HEAT (maybe you have already), where he does a fantastic job at addressing the "what needs to be done". I believe you would find solid documentation on the tremendous limitations of the proposals you put forward (as well as their relative benefit). The main point is that there is no "quick fix" and that no technique will do it, yet it needs to be done and soon or else, mother earth is dead. Given the emergency of this reality, what global warming is demanding is precisely that humanity develops the capacity, very quickly and effectively, to understand the risks, the causes and the required collective actions to be taken in a way that we have never been able to act up until now. We need massive awareness, collective planning and effective acctions that require another world and another relationship between peoples and with mother earth and all living beings. We need what has not been possible. We need social justice, harmanoy and balance with nature and Life as an end and not anymore as an economic variable. Can we achieve this? Apparently not!, yet, we have to. That's where dimming and warming puts us. That's what the very real upcoming massive destruction of life demands. No less.

But who is "US". Who are the subjects of these actions?: Having read Monbiot and trying to know what to do, I have to say that in terms of climate change and risk to survival, what we mean by "WE" has to be very specific. It is suicide not to address carefully, thoroughly and systematically who we mean by "we" when discussing and acting on environmental crimes and catastrophes. By that I mean that "WE", as a generalization is a nothing other than a mechanism to hide the responsibility of polluters (who profit from it) and hence those who's actions and interests must be made accountable and transformed by the actions of a conscious humanity in order to achieve solid impact and save life. The "melting pot" of a collective "WE" is misleading and leaves the criminals free to blame and manipulate. While we all have to do "something" and are guilty or accomplices of the strutural plan, getting to those who are doing the most damage is imperative and an utmost priority. Methane and the Montreal protocol have proven this to be a fact. Methane has been the onlygreenhouse gas to diminish as a result of "an agreement at the top" to regulate the emission of this gas. Those in power should be left with no choice but to reduce emissions. That would be, right now, the most effective measure. How to do it, comes after becoming aware of this fact: NOT INSTEAD OF DOING IT.

Those within global transnational capital who pollute the most for profit must be controlled and restricted in their power to kill life (we can make a list easily just by follwing backwars greenhouse gases and their sources). That is the MOST EFFECTIVE MEASURE. In order to achieve this, we must all understand who is most responsible for global warming (and dimming) and knowing that, how global warming occurs so that we don't get distracted by thinking that if we ride a bike or consume differently, or engage in a limited impact campaign or activism, we are stopping the ones who profit from massive pollution and even further from depriving the last remaining forests and agricultural lands and food sources for people with the argument of producing bio-fuels (food for cars, rather than food for people!). No argument against any specific actions or inventions or campaigns. All I am saying is that the priority to make these effective is to go for the head of the monster, or "we" (the real collective all encompassing one) will dye. Monbiot gives fantastic data and solid analysis on ususally superficially presented ideas. What he does not do enough of is provide a context and a political-economic analysis so that conscioussness and action become ecologically and economically effective (and urgent). Little things here and there that we can do, will not do what we MUST. That is the problem as I have began to understand it. Initiatives, campaigns and inventions are, given what is happening, good means to raise awarenes through smal actions. But until and unless they lead to a profound change of social relationships and the paradigm that uses life for profit, nothing will work.

This is a rushed note to contribute to the debate and a way to express my gratitude for the great piece you published.

2:37 PM  
Anonymous Gary Boyd said...

Yes that is the challenge-as for good solutions:- global educational technology and the kind of systemic social science agenda set out by Mario Bunge in his (1998) Social Science under debate. book Uof Toronto Press,
which is neither Opportunistic market individualism =tragedy of the commons, nor magic Holism =totalitarian collectivism (Nazisim Maoism)- SHOULD work.

3:21 PM  
Blogger Metta Spencer said...

Thanks for two very thoughtful comments. I will go looking for Mario Bunge's book, which I have not read yet. However, I did read Monbiot's book quite a while back and with immense gratitude, for he has done more than anyone else to spell out the radical changes that we have to undertake. Unfortunately, I don't think there is any chance that individuals will take such steps voluntarily. I cannot talk anyone out of flying to other continents for their holidays, or giving up eating meat from ruminants, or keeping a second home, such as a cottage. Monbiot does not explore the more radical and macro-level changes that are being proposed now. I am going to write a blog about some of them, which I have already mentioned. He does not, to my knowledge, reveal their limitations; he just doesn't look at them -- though one should not expect him to do everything.

Anyhow, thanks for your thoughts on these matters.

3:12 PM  
Anonymous Anonymous said...

Unfortunately the NOVA broadcast was produced before some of the most-recent research. So it turns out, although part of the global dimming is due to soot, soot causes a net HEATING effect because it traps more heat in the atmosphere than it shades on the ground. see my blog: http://www.scientificblogging.com/the_soot_files

10:41 AM  
Anonymous richarde said...

I was reading your very interlectual debate about global warming and dimming, and was very suprised. I was very touched and moved. I actually cried. Of boredom that was. I couldn't sit through the whole thing. I only read the 1st paragraph and burst into tears. Can you actually physically die of boredom? If so, please come to my funeral tomorrow. My family would be very happy to hear the cause of my death.

9:45 AM  
Anonymous ya mum is a homo said...

i love you

8:21 AM  
Blogger Metta Spencer said...

This blog entry has attracted the strangest possible combination of comments! Thanks to all of you -- including the ones I don't understand at all.

As you can find in the list of my blog entries, I wrote a different one later, taking into account the comments about how the knowledge of global dimming has altered since the NOVA show was produced. However, the particular details are still obscure to me. I did ask Richard Peltier at a conference on climate change a week ago whether global dimming is a reality and he said not. It has been "debunked" completely. But that doesn't tell me enough about what IS the reality. Nor does it square with what we knew about particulates -- e.g. Mt. Pinatubo, which cooled the planet's temperature significantly. So I am wrong in this blog but in what respects I cannot say.

Anyhow, thanks to the person who loves me. I love you back.
Metta

8:42 AM  
Anonymous landscaping trees said...

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4:21 AM  
Anonymous Calvin said...

Actually, what are differences between global warming and global dimming? I haven’t got the point of this article. Which one is more dangerous? What things to do for solving all problems related to global warming and dimming?

1:37 AM  
Blogger Metta Spencer said...

Calvin, I'm now almost as uncertain as you are. I have been told that we don't need to worry about global dimming, but certainly we need to eliminate pollution. Apparently there is a need for more research, as one of my preceding comments indicates.

11:34 AM  

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