Tuesday, June 21, 2011

Global Dimming Global Warming

Original Post: Jun 4, '09 5:07 PM http://truemaskedwabbit.multiply.com/journal/item/30

In answer to Viccles questions


During the last American election debate I think we here in Canada all tuned in to the latest news on a daily basis and so one evening after suppertime I listened to the nightly news while enjoying a good fresh brewed cup of coffee when I overheard an interview with a news reporter and Sarah Palin. She was asked of her views on global warming, paraphrasing Ms Palin, she happily smiled and responded to the effect of there is no global warming it’s getting warmer because God is just holding us closer. That’s when I lost that one potential good swallow of java right then and there and my coffee made a quick exit through my nose. (a little side note…. I had mentioned in the previous post “The Sun” still today it can be noted that in many churches across the countries the rays of our sun are decorating the ceilings or distinctively shown behind the statues of some of our saints, holding a high revered place since the days of the Egyptian god Ra.) Some of course take it to another much higher level.


It was a fair question to Ms Palin since during that time Global Warming was still very much on the debating table and we all know of Al Gore’s demonstrations of the imminent global runaway greenhouse effect and the counter attacks of other scientists hired by Oil Companies, that we’re probably heading into an ice age.


It’s really not surprising that Ms Palin had no clue of the current events on Global Warming; politicians, it seems, never listen to scientists when it comes to the welfare of our planet. Case in point “Katrina” It seemed that Louisiana Officials had other pressing matters on their mind when Ivor van Heerden, a hurricane expert at Louisiana State University warned the government for years about the state of the levees. Van Heerden put a table exercise called the Pam Hurricane into effect for all the Louisiana Officials giving them his estimation of the catastrophe they would be facing in the event of a hurricane category 3. New Orleans, with the exception of the French quarters, would flood because the levees would have storm surges surging atop the levees due to the shrinking of the wetlands. Thousands would die, a million homes would be under water and millions would be homeless. Many officials took this warning serious and organized what to do in the event of a cat 3 hurricane hitting New Orleans, but some thought of van Heerden as a farce. Sadly Katrina a hurricane category 5, plus three levees breeching on the 17th street and London avenue, plus the two major levees breeching on the industrial side proved van Heerden right. Van Heerden had tears in his eyes witnessing the aftermath - some had not listened.


The debate on Global Warming has ended, so I won’t be humming on it with the exception to bring out some factors no one seems to mention excepting to show Polar Bears on a shrinking ice shelf, starving. Yes I agree, Polar Bears need the ice shelves to hunt, the harp seal, hooded seal and ringed seal need the ice to give birth and nurse their pups. Plus prepare a safety nursery for their pups under the ice. The Penguins need a vast area of ice to nest and raise their young. But it’s not all about the ice, the Arctic and Antarctic. Both poles are the scientist’s visual temperature gauges to show to the world as proof we are heading towards disaster, but there are other animals at risk with Global Warming and just to mention a few …erm.... “ALL OF THEM” globally. Including your loving pets. We turn on the air-conditioning when it gets too hot, animals cannot adjust to a rapid climate increase.


With every increase of our global temperature, consequences will show itself. Once the Amazon and the rainforests of the world are affected, because plants also cannot adjust to rapid climate increase, they will whither in the heat, dried out trees and bushes give rise to fire, fire gives rise to further increasing heat which gives rise to more fires and so on. Opening the gateways to hell itself. No vegetation for the herbivores, hence they’ll starve leaving the carnivores to die out also.


But, not to leave out the human factor, there would be mass migration from the already very hot countries to the bearable warm countries. Disease outbreak would be eminent; it always is whenever there are masses of people in a comparatively small area.

We are now in a plus 1°C of global warming. Ahhh but you might say ‘only 1°C+?’ Doesn’t sound like much does it, but that one degree Celsius (globally) is not calculated in ‘climate’ but rather the atmospheric warming. A different horse of a different colour or the difference between a hurricane 3 and a hurricane 5 at more frequent intervals. The difference of a few tornadoes per year and a few hundred per year, with more intensity. The difference that causes a puddle and a flood, and the difference that cause drought and increased fires. 

But now scientists are scratching their head and wondering just by how much their world climate reading is actually off?


Global Dimming


Scientists have uncovered a new factor that may be masking the full impact of global warming. Called global dimming, it's powerful enough to alter temperatures in a matter of days. It may have contributed to the world's deadliest drought, and it could mean that the Earth's climate is about to start heating up as fast as the direst predictions.

The trail that would lead to this extraordinary discovery of global dimming began 40 years ago, in Israel, with the work of Gerry Stanhill, a young English immigrant. Trained as a biologist, Gerry got a job helping to design irrigation systems. His task was to measure how strongly the sun shone over Israel. For a year, Gerry collected data from a network of light meters. The results were much as expected and were used to help design the national irrigation system. But, 20 years later, in the 1980s, Gerry decided to update his measurements. What he found stunned him. What he had found was since the 1950’s there was a staggering 22 percent drop in the sunlight.


A 22 percent drop in solar energy was simply massive. The figures were hard for other scientists to take seriously, so when Gerry published, his results were ignored. But Gerry was not the only scientist who had noticed a decline in sunlight. In Germany, a young graduate student, Beate Liepert found that the same thing seemed to be happening over the Bavarian Alps, as well. Other scientists working independently began searching through journals and meteorological records from around the world. And everywhere they looked, they found the same story.


Between the 1950s and the early 1990s, the level of solar energy reaching the Earth's surface had dropped: nine percent in Antarctica, 10 percent in areas of the U.S.A., by almost 30 percent in one region of Russia, and by 16 percent in parts of the British Isles. This seemed to be a global phenomenon, so Gerry gave it a suitable name: "global dimming."


Gerry claimed that, on average, the solar energy reaching Earth had fallen by two percent to four percent. That should be making the world significantly cooler, (to give you an idea of cooling percentage, if global dimming would be at a 6% cooling without the global warming factor, we’d be sitting in a global mini ice age) yet scientists knew the Earth was getting hotter. Of course there was good reason for the scepticism, less energy from the sun should be making the world cooler yet scientists knew the Earth was getting hotter as the carbon dioxide and other greenhouse gases we emit trap ever more heat in the Earth’s atmosphere and cause global warming. So Liepert and Stanhill's work was widely dismissed. But global dimming was not the only phenomenon that didn't seem to fit with global warming. In Australia, two other biologists, Michael Roderick and Graham Farquhar, were intrigued by another paradoxical result, the worldwide decline in something called the "pan evaporation rate." It's called pan evaporation rate because it's evaporation rate from a pan. Every day, all over the world, people come out in the morning and see how much water they've got to add to a pan to bring it back to the level it was the same time the morning before. It's that simple. The long-term measurements of pan evaporation are what gives it its real value. In the 1990s, scientists spotted something very strange; the rate of evaporation was falling. There is a paradox here about the fact that the pan evaporation rate's going down but the global temperature's going up. Most scientists thought that as the temperature warms up the water in the pan should evaporate, but it was realized that is not the heat of the climate but the energy of the photons of the sun itself that cause the water to evaporate. It is the photons that kick the water out of the pan and into the atmosphere. With the evaporation pan’s readings declining in evaporation meant the sun’s photons were going down.


To better understand how the sun’s energy of the photons (heat) would not able to come through because of pollution lets take a look at the clouds at a microscopic point. Clouds are made of droplets of water, these are formed when droplets of water in the atmosphere starts to condense on naturally airborne particles such as pollen or sea salt. As they grow the water droplets eventually become so heavy they fall down as rain. But the polluted air holds far more particles than the unpolluted air. Such as millions of particles of ash, soot and sulphur dioxide where the water droplets form. So polluted clouds contain many more water droplets, each one far smaller than it would be naturally. Many small droplets reflect more light than fewer big ones. So the polluted clouds are reflecting more light back into space preventing the heat of the sun getting through. This is the cause of global dimming. Pollution is turning our clouds into giant mirrors.


 Further facts of global dimming came to the fore when Michael Roderick searched through the white papers (reports scientists send into the library of science papers) and found an article called, "Evaporation Losing Its Strength," which reported a decline in pan evaporation over Russia, the United States and Eastern Europe.


The Maldives, consist of a thousand tiny islands in the middle of the Indian Ocean, so recently battered by the tsunami: it was here that Veerabhadran Ramanathan, one of the world's leading climate scientists, began to unravel the mystery of what's causing global dimming. He had first noticed declining sunlight over large areas of the Pacific Ocean in the mid-1990s. Ramanathan was certain of one thing, the big drop in sunlight reaching the ground had to be something to do with changes in the Earth's atmosphere. There was one obvious suspect. Burning fuel doesn't just result in the invisible greenhouse gases which cause global warming; it also produces visible pollution of particles themselves shielding the ocean from the sunlight, on the other hand, making the clouds brighter. So this insidious soup, consisting of soot, sulphates, nitrates, ash and what have you, is having a double whammy on the global dimming. When Ramanathan looked at satellite images, he found the same thing was happening all over the world: over India; over China, and extending into the Pacific; over Western Europe extending into Africa; over the British Isles. But it was when scientists started to investigate the effects of global dimming that they made the most disturbing discovery of all. Those more reflective clouds could alter the pattern of the world's rainfall, with tragic consequences. Global Dimming was a killer. Responsible for famine and death on a biblical scale and global dimming is poised to strike again.


Sahel, Hell on Earth


The 1984 Ethiopian famine shocked the world. It was partly caused by a decades-long drought right across sub-Saharan Africa, a region known as the Sahel. For year after year, the summer rains failed. There were many factors at work, but now there's evidence that among them was global dimming. The Sahel's lifeblood has always been a seasonal monsoon. For most of the year it is completely dry, but every summer, the heat of the sun warms the oceans north of the Equator. This draws the rain belt that forms over the Equator northward, bringing rain to the Sahel.


But for 20 years, in the 1970s and 80s, the tropical rain belt consistently failed to shift northward, and the African monsoon failed. For climate scientists like Leon Rotstayn, the disappearance of the rains had long been a puzzle. He could see that pollution from Europe and North America blew right across the Atlantic, but all the climate models suggested it should have little effect on the monsoon.


But then Rotstayn decided to take the Maldive findings about the impact of pollution on clouds into account.

In Rotstayn's calculations, polluted clouds kept the heat of the Sun from getting through, the heat that was needed to draw the tropical rains northward. So the life-giving rain belt never made it to the Sahel. Other models suggest that global warming was also a factor in the Sahel disaster. But Rotstayn's work shows the potential for air pollution to have far reaching effects on rainfall, perhaps even contributing to a terrible drought that blighted the lives of over 50,000,000 people. And this could be just of taste of what global dimming has in store.


The Sahel is just one example of the monsoon system. Let me take you to anther part of the world, Asia, where the same monsoon brings rainfall to 3.6 billion people, roughly half the world's population. Veerabhadran Ramanathan main concern is this air pollution and the global dimming will also have a detrimental impact on this Asian monsoon. We are not talking about few millions of people; we are talking about few billions of people.


The Double Edged Sword


In Europe and North America, air pollution is already in decline. Scrubbers in power stations, catalytic converters in cars, and low sulphur fuels, though they do nothing to reduce greenhouse gases, have already led to a marked reduction in visible air pollution.

Coincidence or not, this should be good news for the Sahel, and in recent years the droughts have not been nearly so bad. But there is a terrible catch because while global dimming itself a major threat to humanity, it now appears global dimming is protecting us from an even greater threat, the full impact of global warming. As we have reduced the effects of global dimming we may find ourselves facing even something worse. A double-edged sword.


It was David Travis who first caught a glimpse of what the world could be like without global dimming. It happened in those chaotic days following the tragedy of 9/11. For 15 years, Travis had been studying the vapour trails, or contrails, left behind by high-flying aircraft. As a jet passes through the air, the pollution particles it emits can trigger the condensation of water droplets. These manmade clouds seem small, but when they all spread out, they can blanket the sky. During the three-day grounding of planes throughout America, the nights had gotten colder and the days, warmer. Averaged over the whole continental U.S., the temperature difference between day and night had suddenly increased by over a degree Celsius. Manmade clouds from aircraft are a minor contributor to global dimming. If removing them had such a dramatic effect, what would happen if air pollution were to be reduced all over the world? The world would get dramatically hotter. This is the real sting in the tail and not just a theory it may be already happening. In Western Europe the steps we had taken in removing particle pollution had started to bear fruit in a noticeable improvement in the air quality and even a slight reduction in global dimming over the last few years. Yet at the same time European temperature have started to rapidly rise, cumulating in the savaged summer of 2003. Forest fires devastated Portugal, glaciers melted in the Alps. And in France people died by the thousand.

Climate change, to the current date, appears to have been a tug of war, really, between two manmade pollutants. On the one side, we've got greenhouse gases that are pulling the system towards a warmer state, on the other hand, we've got particles from pollution that are cooling it down. And there's a kind of tug of war going on between the two, in which the middle of the rope, if you like, determines where the climate system is going in terms of warming or cooling. Because greenhouse gases trap heat, when we add to them we increase the heat energy trapped in the atmosphere. Today, the extra energy trapped by manmade greenhouse gases would be enough to run a 100-watt light bulb, placed every six meters over the entire surface of the globe, an extra 2.6 to three watts of energy for every square meter. It's this extra energy that's driving global temperatures ever higher. In 2002, NASA launched the Aqua satellite. Onboard was a suite of instruments designed to measure the effect of dimming pollutants on the energy budget of the Earth. The observations from Aqua have enabled climate scientists to make a rough estimate of global dimming's total cooling effect on our planet. It was estimated for the particle forcing is minus-one-and-a-half-watts- per-meter-squared. So that would imply a cooling of more than one degree Celsius. In other words, while the human greenhouse effect has produced 2.6 to three watts of extra energy for every square meter of the Earth, global dimming has subtracted about 1.5 watts, so, more than half the warming effect of our greenhouse emissions has been masked by the cooling effect of particle pollution.


Perhaps this is why, despite a large rise in the concentration of greenhouse gases, until recently, the temperature rise has been hard for most of us to notice.

Ironically, if we keep bringing particle pollutants down—with great benefits to health—but continue pumping greenhouse gases into the atmosphere, scientists believe we could be creating the worst possible combination for global temperatures. If we continue as we are, combining reduced air pollution with an increase in greenhouse gases, temperatures could rise by a further two or even three degrees Celsius.


Most models do not yet take full account of the impact of global dimming and predict warming between two and five degrees Celsius, by the end of the century. But just as global dimming may have lulled the public and politicians into a false sense of security about climate change, has it misled climate scientists about the real power of the greenhouse effect to change global temperatures?


While today's models foresee a maximum warming of five degrees Celsius by the end of the century, Cox thinks that it is not beyond the realms of possibility that by 2100, temperatures could rise by as much as 10 degrees Celsius.

Many plant species could not survive such rapid climate change. In his scenario, trees would die all over the planet; the world's best agricultural land would be struck by drought and soil erosion; famine would not be far behind. And in the far north, there would be a risk of releasing a vast natural store of greenhouse gas bigger than all the oil and coal reserves of the planet.


Methane Hydrates


We will be in danger of destabilizing these things called "methane hydrates," which store a lot of methane at the bottom of the ocean, in a kind of frozen form—ten thousand billion tons of this stuff—and they're known to be destabilized by warming.

If this were to happen, some or all of the ten thousand billion tons of methane, a greenhouse gas eight times stronger than carbon dioxide, would be released into the atmosphere. When this last happened 50,000,000 years ago, when the Earth was already warmer than it is today, the average temperature rocketed by 13 degrees Fahrenheit, making the Earth 25 degrees hotter than today, and life struggled to survive.

Some scientists consider this model extreme, but all climate models contain important unknowns and ranges of possibility. Our new understanding of global dimming has complicated the task of forecasting the future but has also brought the probability of dangerous climate change much closer.


Today, there's a strong scientific consensus that without urgent action to reduce our burning of coal, oil and gas, we risk creating a world very different from the one which has been so hospitable to humanity.

Global Dimming Global Warming

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