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  (Source: Civilianism)
But reducing soot will lower the Arctic climate more quickly than CO2

Stanford researcher has proven that reducing soot emissions rather than carbon emissions will slow the melting of Arctic sea ice faster. 

Stanford researcher Mark Z. Jacobson developed a special computer model of air pollution, weather and global climate that has atmospheric processes that do not appear in other models. With this, he observed the effects of soot from both fossil fuels like gasoline, coal and diesel, and from solid biofuels like dung, wood and manure. According to his findings, both types of soot combined together is the "second-leading cause of global warming after carbon dioxide."

Climate models previous to Jacobson's have misread the effects of soot in the atmosphere, hence, it has been ignored when it comes to national and international global warming policy legislation. Soot is now second place in the global warming contribution ranks, putting itself above methane. Soot also "prematurely" claims the lives of more than 1.5 million people each year, and causes respiratory illnesses in millions more worldwide. 

While decreasing carbon emissions is important and at the top of the list, reducing soot emissions from fossil fuels and solid biofuels could slow the progression of global warming almost instantly. Jacobson came to this conclusion because soot only lingers in the atmosphere for a few weeks, and then it is washed out. Contrarily, carbon emissions stay in the atmosphere up to a century, which is a large gap of time before visible results of emission cuts are available. 

"Controlling soot may be the only method of significantly slowing Arctic warming within the next two decades," said Jacobson. "We have to start taking its effects into account in planning our mitigation efforts and the sooner we start making changes, the better."

During the last century, the Arctic's net warming has been at 2.5 degrees Celsius, and will only get warmer if no action is taken. By reducing soot emissions, warming above the Arctic Circle will decrease over the next 15 years by as much as 1.7 degrees Celsius. 

While these two types of soots combined are largely contributing to global warming, the soots individually are just as dangerous. Soot caused by the burning of fossil fuels is more of a contributor to global warming while soot caused by the burning of solid biofuels is more dangerous to humans. Solid biofuel soot causes eight times more deaths as fossil fuel soot. 

The difference between the two types of soot is black carbon, which is found in the fossil fuel soot and has a significant effect on warming over the Arctic. Black carbon absorbs solar radiation, converts sunlight to heat and radiates it back to its surroundings (air). It is able to absorb light reflecting away from the Earth's surface as well. This is particularly threatening to the Arctic because the black carbon is in the air over ice or snow, sunlight hits the black carbon both while coming toward Earth and when it reflects off the ice and back into space. 

"There is big concern that if the Arctic melts, it will be a tipping point for the Earth's climate because the reflective sea ice will be replaced by a much darker heat-absorbing ocean below," said Jacobson. "Once the sea ice is gone, it is really hard to regenerate because there is not an efficient mechanism to cool the ocean down in the short term."

Researchers have found that the best way to reduce soot emissions is to attach particle traps, which filter soot particles from exhaust, to vehicles like buses and diesel trucks. This is a cheap, effective and fast way of taking care of the issue. Another way to eliminate soot would be the use of electric vehicles, but automakers are just now releasing these cars onto the market, and it will take some time to push gasoline-powered vehicles completely out of the picture. 



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RE: Wrong
By wookie1 on 7/30/2010 2:49:15 PM , Rating: 2
Like water vapor, CO2 concentration is a slave to temperature. Also, there is widespread disagreement about the length of time CO2 stays in the atmosphere. I think that the climate models depend on something like 1000 years, but some scientists believe that it is in the tens of years.

Also, water vapor is both a positive and negative feedback. Which one depends on the types of clouds it produces, and similar factors.


RE: Wrong
By Solandri on 7/30/2010 6:25:45 PM , Rating: 2
What OP is referring to is the vapor pressure of water vapor. It's entirely dependent on temperature (and pressure, but it's a safe assumption that the pressure at sea level is 1 atmosphere).
http://en.wikipedia.org/wiki/Partial_pressure

The way it works is, say humans built huge factories which did nothing but evaporate water and release it into the atmosphere. At first glance you'd think that this would cause the amount of water vapor in the atmosphere to rise. But that's not how it works. At a given temperature, there is a certain partial pressure of water vapor which is stable. If the concentration of water vapor in the atmosphere rises above that point, it simply condenses and falls as rain until it's back to that stable level. If the concentration of water vapor falls below that point, more simply evaporates from the oceans and lakes until it's back to that stable level (this can take a while if the air is over a place with no water, such as a desert). So the amount of water vapor in the atmosphere is dependent almost entirely on the temperature, with a moderating time of days, if not hours or minutes.

CO2 doesn't have a similar moderating mechanism since at ambient temperature and pressure, it only exists in gaseous form. So the amount in the atmosphere is how much gets produced by animals and burning fossil fuels, minus how much is absorbed by plants, breaks down naturally, or escapes into space.


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