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The Cleveland Steamer
12-06-2009, 05:07 PM
If America reduced its carbon emissions to zero, would there be a immediate measurable effect on global warming? How long would it take for the effect? What would be climate consequences be?

If the world reduced its carbon emissions to zero, would there be a immediate measurable effect on global warming? How long would it take for the effect? What would be climate consequences be?

How much will carbon emissions have to reduced to stop global warming? If global warming is stopped, how will the world climate be effected? Will glaciers return? Will ocean currents go back to their per-warming state? How long will it take for global warming to be reversed?

What effect will reduced carbon emissions have on the poor in developing countries?

Squink
12-06-2009, 05:40 PM
If America reduced its carbon emissions to zero...How many tons of carbon does the US emit each year?
What fraction of that is carbon dioxide and what's in the form of other greenhouse gases?

Could you possibly do some of the lifting for this OP yourself, or do you need our help?

Slypork
12-07-2009, 02:13 PM
How many tons of carbon does the US emit each year?
What fraction of that is carbon dioxide and what's in the form of other greenhouse gases?

Could you possibly do some of the lifting for this OP yourself, or do you need our help?
I think what the OP was trying to get at (and please correct me if Im wrong) was, If all Americans/all humans suddenly disappeared, how long would it take for the claimed AGW effects to reverse themselves? Sort of like that Discovery Channel series about the world after humans disappeared.

All of the current climate computer models presuppose continued manmade pollution production. What if the pollution production stopped? I dont mean tapered off or the growth slowed but starting on January 1, 2010 all factories shut down, all transportation was limited to bicycles, animal drawn vehicles or wind powered, and we basically went back to a pre-industrial society. Maybe wed have to go even further back because, after all, we have been burning coal and wood for millennia. How about we got back to Predynastic Egypt pollution production levels? How long before the AGW damage is fixed?

This might sound like Im being a smartass but Im serious when I ask if this had ever been modeled?

Chronos
12-07-2009, 05:29 PM
Knowing how science (and scientists) work, it probably has been modeled. Whenever you construct a model, you always try it out for the parameters on the boundary, just to see what happens and to gain a better qualitative understanding of the problem, even if those boundaries aren't very plausible. That said, though, I don't know what the results of those models have been.

Slypork
12-07-2009, 05:52 PM
Knowing how science (and scientists) work, it probably has been modeled. Whenever you construct a model, you always try it out for the parameters on the boundary, just to see what happens and to gain a better qualitative understanding of the problem, even if those boundaries aren't very plausible. That said, though, I don't know what the results of those models have been.That's what I figure as well but I was wondering if anyone had seen any results. Could GIGObuster or one of the resident AGW experts chime in?

Happy Fun Ball
12-07-2009, 07:28 PM
All of the current climate computer models presuppose continued manmade pollution production. What if the pollution production stopped? I dont mean tapered off or the growth slowed but starting on January 1, 2010 all factories shut down, all transportation was limited to bicycles, animal drawn vehicles or wind powered, and we basically went back to a pre-industrial society. Maybe wed have to go even further back because, after all, we have been burning coal and wood for millennia. How about we got back to Predynastic Egypt pollution production levels? How long before the AGW damage is fixed?The answer, if I understand the question correctly, is in here (http://www.pnas.org/content/106/6/1704.full?sid=9000324f-9333-42e9-9752-e4d863545755). Enjoy.




This was one of the reasons that I came to the conclusion that cap and trade, Kyoto, and Copenhagen are kinda stupid. See this thread (http://boards.straightdope.com/sdmb/showthread.php?t=509538) for more.

GIGObuster
12-07-2009, 09:45 PM
The answer, if I understand the question correctly, is in here (http://www.pnas.org/content/106/6/1704.full?sid=9000324f-9333-42e9-9752-e4d863545755). Enjoy.




This was one of the reasons that I came to the conclusion that cap and trade, Kyoto, and Copenhagen are kinda stupid. See this thread (http://boards.straightdope.com/sdmb/showthread.php?t=509538) for more.
I think he is referring to what the expected temperature will be if we stop now and at other times in the near future. The paper in your link concentrates on the very long picture.

The same writer of the cited article also published this in 2005 regarding the most probable effects that cutting emissions will do in a shorter time span:

http://www.pnas.org/content/102/31/10832.full
Fig. 3 shows the evolution of atmospheric CO2 calculated for each generation, showing that even a zero-emissions strategy leads to limited near-term reductions in atmospheric CO2; that is, Fig. 3 shows that there is prompt removal of a portion of the added CO2, but only a portion. As an example, if emissions were set to zero in 2000, atmospheric CO2 would be reduced by 20 ppm in the next 25 years and by 40 ppm by the end of the century. By 2100, the CO2 concentration would be about the same as that in 1975. That is to say, it would take approximately a century to remove the bulk of the anthropogenic CO2 injected in the atmosphere over the past 25 years. For the example shown above, extending this calculation beyond 2100 shows that the atmospheric CO2 would only drop by another 20 ppm over the 22nd century and by another 10 ppm over the 22002500 period. The long time-scale retention of CO2 in the atmosphere even after many centuries represents a commitment to future climate change that could include some very slow and uncertain aspects of the climate system, such as changes in the polar ice sheets that could affect sea level.

If the current (20002025) generation emits carbon dioxide at the same rate as the previous generation and cuts emissions abruptly to zero in 2025, the calculated atmospheric CO2 in 2025 reaches 437 ppm and only drops to 382 (approximately the current level in 2005) by 2100. It is worth recalling that constant emissions will lead to a linear increase in atmospheric CO2, not to stabilization. Atmospheric CO2 stabilization can be reached only with an emission scenario that eventually drops to zero.

These simple calculations highlight the time lag between reduction of emissions and reduction of atmospheric CO2 concentrations.

If a zero-emissions scenario had been adopted after each of the six successive past generations, the atmospheric CO2 levels reached in 2000 would be ≈287, 291, 297, 306, 328, and 383 ppm, respectively (Table 1), which indicates the contribution each generation has made to the present-day CO2 increase. The 19752000 generation alone increased atmospheric CO2 by ≈45 ppm, more than half of the total increase over the industrial era.

Because of the time response of the carbon cycle shown above along with the response times of the climate system (particularly linked to the lags between oceanic and atmospheric temperature), if emissions were set to zero by 2000, temperature would still keep increasing by another several tenths of a degree Celsius for another ≈30 years (Fig. 4), although atmospheric CO2 would display some decrease (Fig. 3). Thus, the comparison between Figs. 3 and 4, particularly the shapes of the curves after cessation of emissions in the two cases, illustrates the character and duration of the warming commitment. Different climate models suggest quantitative differences in the magnitude and duration of the existing warming commitment, believed to be linked largely to differences in representations of ocean/atmosphere interactions, but the general behavior shown in Fig. 4 is robust across models (e.g., see refs. 27 and 28).

Stated differently, Fig. 4 underscores the character of the warming commitment: today's observed climate change represents a portion rather than the total of what is expected to occur in the future even if emissions of CO2 are reduced dramatically. Although the warming commitment implies that near-term actions do not have an immediate effect on CO2-induced climate change, Fig. 4 shows that they do have an affect within a few decades (i.e., on the time scale of the next assumed generation). This change occurs because CO2 removal is characterized by multiple time scales, i.e., a portion of the emitted CO2 is removed on time scales of decades. Thus, the difference between cutting emissions to zero in 2025 and continuing constant emissions is ≈0.5C of added warming by approximately 2050. Because of additional removal of CO2 on longer time scales, the difference reaches 1.6C by 2100. That is, cutting the emissions of CO2 to zero in 2025 leads to a total warming of 1.3C by 2100, with a peak value of 1.4C around 2050, whereas capping emissions at their 2025 level leads to a warming of ≈1.9C by 2050 and 2.9C by 2100. Thus, the actions of each generation influence the climate passed on to their children and later generations, but each inherits much of their own climate. Fig. 4 illustrates how this also applied for the last generation. Constant emissions after 2000 lead to a warming of 1.7C higher than with zero emissions by 2100.

Blake
12-07-2009, 10:56 PM
If America reduced its carbon emissions to zero, would there be a immediate measurable effect on global warming? How long would it take for the effect? What would be climate consequences be?

In the real world: no, forever and none at all.

In the real world the productivity, and hence the emmissions, would simply be taken up by somewhere else. This is one of the biggest problems facing the Copenhagen conference. If the US, or indeed the entire developed world, reduce emmissions without either drastically reducing their standard of living or ensuring a concommitant reduction in the developing world, the only result will be that the developing world wil take up the slack and increase emmissions to the same degree.

The fact is that people will want aluminium foil as long as they can afford it. The only way to make them not afford it is to reduce the standard of living which is political suicide. So the alternative is for the US not to produce aluminium. At which stage, because the demand is still there, production will increase in the developing world to take up the slack. There's no advantage to this, and in fact it is counter productive, because developing economies tend t produce more greenhouse gases per unit of product.

The US unilaterally switching to zero emmissions mode won't do a damn thing unfortunately.


What effect will reduced carbon emissions have on the poor in developing countries?

Depends.

If we follow some of the suggestions on the table ATM, developing countries are expected to reduce their emissions by much less, or actually allowed to increase emissions, in addition to which they will be compensated for any emissions reductions they do achieve over business as usual. Under that scenarios more industry will move to developing countries and the poor in those countries will be much better off.


If you mean under a scenario where everybody reduces emissions, that's highly debatable. Reducing emissions means making everything more expensive. IOW everybody becomes poorer, but people in the developed world are hit relatively harder. That means fewer taxes, less charity donations, more people in poverty at home, less purchasing of foreign goods and an inevetible decline in both foreign aid and foreign spending. That ain't gonna be good for a factory worker in Delhi of Beijing.