Avoiding climate catastrophe will probably require going to near-zero net emissions of greenhouse gases this century. That is the conclusion of a new paper in Geophysical Research Letters (subs. req'd) co-authored by one of my favorite climate scientists, Ken Caldeira, whose papers always merit attention. Here is the abstract:
Current international climate mitigation efforts aim to stabilize levels of greenhouse gases in the atmosphere. However, human-induced climate warming will continue for many centuries, even after atmospheric CO2 levels are stabilized. In this paper, we assess the CO2 emissions requirements for global temperature stabilization within the next several centuries, using an Earth system model of intermediate complexity. We show first that a single pulse of carbon released into the atmosphere increases globally averaged surface temperature by an amount that remains approximately constant for several centuries, even in the absence of additional emissions. We then show that to hold climate constant at a given global temperature requires near-zero future carbon emissions. Our results suggest that future anthropogenic emissions would need to be eliminated in order to stabilize global-mean temperatures. As a consequence, any future anthropogenic emissions will commit the climate system to warming that is essentially irreversible on centennial timescales.
Since the rest of the article is behind a firewall, let me extract a couple of key findings:
... our results suggest that if emissions were eliminated entirely, radiative forcing from atmospheric CO2 would decrease at a rate closely matched by declining ocean heat uptake, with the result that while future warming commitment may be negligible, atmospheric temperatures may not decrease appreciably for at least 500 years.
In short, the time for dramatic action is upon us. The study concludes:
In the absence of human intervention to actively remove CO2 from the atmosphere, each unit of CO2 emissions must be viewed as leading to quantifiable and essentially permanent climate change on centennial timescales. We emphasize that a stable global climate is not synonymous with stable radiative forcing, but rather requires decreasing greenhouse gas levels in the atmosphere. We have shown here that stable global temperatures within the next several centuries can be achieved if CO2 emissions are reduced to nearly zero. This means that avoiding future human-induced climate warming may require policies that seek not only to decrease CO2 emissions, but to eliminate them entirely.
Bottom line: Stopping global warming is very hard -- easily the greatest challenge the human race has ever faced. The best we can hope for at this point is to limit warming to below the threshold where the carbon-cycle feedbacks kick into overdrive, bringing about catastrophe (80 feet of sea level rise, widespread desertification, greater than 50 percent species loss).
In all likelihood, we need to cut emissions deeply and quickly enough that we get to the point this century where we can actually have net negative emissions, by removing carbon dioxide from the atmosphere while emitting almost none.
This post was created for ClimateProgress.org, a project of the Center for American Progress Action Fund.
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Comments
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David Nicholson Posted 10:40 am
28 Feb 2008
What are some key markers that will bear out the theory/hypothesis you support regarding AGW or AGCC?
I would like to see some time capsule predictions that we can all review in 10 years.
My boyhood idol, Carl Sagan, cited "nuclear winter" science and claimed that if the Kuwaiti oil fields were set ablaze, the world's climate would be characterized by a "year without a summer" with devastating effects. He and the rest of the "nuclear winter" folks were wrong. Now the very same people call me a "denier" when I question there theory/hypothesis regarding AGW/AGCC?
* I use theory/hypothesis to avoid the navel gazing argument regarding the proper use of the terms. Pick the on that pleases you and I will stipulate that you are correct.
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LegumeSam Posted 11:13 am
28 Feb 2008
We are to compare the environmental effects of a number of localized oil fires in a desert region with the routine daily burning of 85 million barrels of oil across the globe, day in, day out?
http://www.dailykos.com/User/Cassiodorus
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Jon Rynn Posted 1:17 pm
28 Feb 2008
not even any plug-in hybrids, only electric vehicles powered from wind/solar/geothermal
A strict ban on any forest destruction, and massive replanting/soil reconstruction
No artificial fertilizers, as that means using natural gas, and maybe no pesticides, since that takes petroleum
No biofuels at all? Burning them emits carbon.
No hydropower in tropic areas that lead to methane release
No pools of cow and pig shit releasing ghg's
obviously, no coal, period. Storage, porridge, all energy has to be from electricity, and no electrical generation can emit carbon.
no big trucks, long-haul all from electric trains
all off-road vehicles have to be electric
A massive -- and I mean massive -- production of solar ovens and other measures to eliminate the need of most of the world's population to use biomass for heating and cooking
did I miss anything?
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LPS Posted 1:20 pm
28 Feb 2008
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Jon Rynn Posted 1:31 pm
28 Feb 2008
no natural gas for heating, have to use geoexchange heat pumps, solar heating, etc.
no natural gas for industrial heating -- I guess large-scale electrical heating could replace it (from renewable sources, i suppose this would take large-scale storage).
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Pangolin Posted 3:53 pm
28 Feb 2008
The best we can hope for at this point is to limit warming to below the threshold where the carbon-cycle feedbacks kick into overdrive, bringing about catastrophe (80 feet of sea level rise, widespread desertification, greater than 50 percent species loss).
Well, it's becoming clear that we screwed the pooch on that standard because methane releases from former permafrost in Siberia and Canada are a given. Combined with projected rapid loss of ice in the Arctic Ocean and we have a lot more heat coming home and bringing their benzene sniffing boyfriends.
What does that really mean?
The mass hallucination that we call "the global economy" is toast. Most middlemen, paper-pushers, agents, reps, retailers and other parasites on actual work are simply fired as irrelevent.
Driving will be limited to electrical vehicles for the minority that can afford both the vehicle and the solar panels to feed it. Plug-in hybrids will be used for "official business only such as police and ambulances."
Conversion of second growth forests to carbon farms, carefully coppiced to maintain soil and shade canopies but yielding constant hand picked biomass for pyrolisis. The remaining bio-char would be used for Terra Preta nova in farmland and intensive food gardens. Old growth diverse forests will be maintained as genetic banks.
Closed loop farming. Minimal fertilizers and soil amendments will be restricted by transport and production costs. The Humanure handbook becomes a NY times bestseller.
Biofuels are a very scarce byproduct of pyrolisis. A tiny fraction of standard engine vehicles would be able to run.
Methane capture becomes a feature of reservoirs in the tropics as well as every landfill, dairy and pig yard.
A diaspora of farm animals from CAFO's as cows and pigs are needed as soil fertility builders on sterile croplands.
A desperate drawdown on coal production and burning combined with conservation measures exceeds the ramp-up of alternatives and creates regular blackouts worldwide.
Conversion of big rigs to electrical power and installation of trolly lines allows delivery of goods where railroads don't go.
Off-road vehicles come in feet, bike, horse and blimp. Nothing else. Air travel is limited to government officials and the super wealthy until airships are built and flight tested.
The massive conversion to solar power worldwide will be spotty and result in localized fuel shortages. The fuel shortages will lead to localized deforestation and then disease as environmental services are lost. "Lost" cities become more common.
A massive global education campaign ensures that every child over 6 knows better than to throw away so much as a twig or a brown leaf or a scrap of paper that can be converted to wood gas for cooking and char for soil improvement.
A universal education campaign ensures that every person with access to a radio understands Permaculture concepts and how depleted soils are rebuilt.
In essence the whole world will have to follow Cuba's economic model without the comfort of tourists to keep us sane.
Put the Carbon Back
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amazingdrx Posted 4:08 pm
28 Feb 2008
But with all these steps all around the globe, it could even be reversed. How much time do we have?
If it happened over 20 years with half in 10 years, that would do it. Waiting any longer is crazy. Those positive feedbacks like methane hydrate ice melt and exponential glacial and ice cap melting, that darkens the earth, absorbing more solar heat, are waiting to take off.
We have a mass delusion going around that fuel farming, clean coal, flex fuel gas guzzling, and nuclear power will be be positive steps. They aren't, in fact they all increase gHG and delay real solutions.
http://amazngdrx.blogharbor.com/blog
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stockypig Posted 10:16 pm
28 Feb 2008
Stop breathing
Stop eating
Stockypig
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ed34222 Posted 10:41 pm
28 Feb 2008
Ok, to start with experiments conducted to prove that CO2 is a Green House Gas have traditionally gone something like this: You take a container with 100% CO2 in it and the same size container with air in it, put them side by side, aim a light/heat source at them and see what happens. The result is fairly consistent: The CO2 container gets 20% warmer than the air.
So, lets do some math (sorry but when you have numbers, math is just natural): 200 ppm difference in CO2, 1 degree of temp, 20% impact; so, thats 200/1,000,000 or 0.00002 * .20 * 1, or 0.0000040 = 40 millionths of that 1 degree being accounted for by the CO2 increase.
With wind causing convection effects (and/or using the more real numbers of less than .5 degrees and 150 ppm difference), the real number is even lower; but, the point is clear.
Scientific progress requires decent. Totalitarianism requires its absence.
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ed34222 Posted 10:58 pm
28 Feb 2008
.
.
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They are almost the same.
That implies that they would have the same AGW/AGCC effect; except that, O2 is 21% of air, and CO2 is only 0.0003%.
So it's really all that main made O2 causing it?
Not to fear, it's really all the di-hydrogen-monoxide in the air (#1 AGW/AGCC gas); so, lets ban that.
.
.
.
Just kidding: dy-hydrogen = H2, monoxide = O, H2O is water.
It (water vapor) really is the #1 AGW/AGCC gas though.
Scientific progress requires decent. Totalitarianism requires its absence.
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In the belly Posted 1:47 am
29 Feb 2008
Thank gawd for decent!
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SKenzie Posted 2:28 am
29 Feb 2008
I think you mean to say "dissent".
You're on your own with your math and chem problems.
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Delay And Deny Posted 2:48 am
29 Feb 2008
Guess we'll have to start emitting a lot more soon...
Evidence of Global Cooling
http://www.foxnews.com/story/0,2933,333328,00.html
Now there is word that all four major global temperature tracking outlets have released data showing that temperatures have dropped significantly over the last year. California meteorologist Anthony Watts says the amount of cooling ranges from 65-hundredths of a degree Centigrade to 75-hundreds of a degree.
That is said to be a value large enough to erase nearly all the global warming recorded over the past 100 years. It is reportedly the single fastest temperature change ever recorded -- up or down.
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amazingdrx Posted 2:51 am
29 Feb 2008
But first, hold your breath. Until this all makes sense.
http://amazngdrx.blogharbor.com/blog
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GonzoDon Posted 3:37 am
29 Feb 2008
Dude, why even bother to read it? That's like citing a press release from the Vatican regarding the merits of the birth control pill ...
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David Nicholson Posted 4:03 am
29 Feb 2008
We are to compare the scientific consensus of 1991 that predicted Nuclear Winter with the scientific consensus of today regarding AGW and the looming effects. If the very same people were dead wrong in 1991 isn't it fair to be skeptical about their latest claims?
The data was indisputable. Every reputable scientist agreed. Deniers were impugned and ridiculed on 60 Minutes.
But my main point is to establish a criteria we can agree upon. In ten years, what would the data from the next decade have to look like for you to agree that AGW is not anything to worry about?
If your kids can't take care of an ant farm, don't buy them a pet elephant. You make an excellent point.
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Sam Wells Posted 4:28 am
29 Feb 2008
After reading that article I came across all these nice goals that we just stop all CO2 emissions at once and thought "gee, dream on teenage queen." It reminded me of a ozone dispersion model of Houston that showed if all ozone precursors were zero, no cars or industry, ozone would still occur.
Telling the public things like this - that warming and ozone will still happen even if all emissions were stopped - isn't very smart PR, is it?
Onward through the fog
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Jon Rynn Posted 4:51 am
29 Feb 2008
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infp Posted 5:47 am
29 Feb 2008
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Jon Rynn Posted 5:54 am
29 Feb 2008
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Sam Wells Posted 6:01 am
29 Feb 2008
What is happening is truly horrific but no, it doesn't make for good PR either ... but I wish the word would get out that unless we do something, our coasts will be nothing but a barren wasteland, and no swimming either. /sam
Onward through the fog
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bookerly Posted 8:28 pm
29 Feb 2008
Perhaps one of the reasons for all the deniers is that they can't stand (psychologically) to face the truth. So, they cling to whatever falsehoods they can find. See, it won't be so bad.
You can see this whenever there is a crisis ("Don't worry, baby, we won't hit the iceberg, and if we do, everything will be okay, I'm sure!).
One of the weaknesses of the American electoral system is that it tends candidates towards the center, towards feel good promises. Most candidates in order to reach the highest office have had to mold themselves into whatever they think will comfort people.
What is needed is not a comforter but a scourge.
patrick in Beijing
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LegumeSam Posted 10:20 pm
29 Feb 2008
I'd be interested in what the article had to say. "Education" about climate change usually limits itself to depictions of the problem. The solution, of course, is to burn less carbon; the problem is that privileged world-society (and to a much MUCH lesser extent that 40% of the human race that lives on less than $2 per day) is locked into CAPITALIST world-society. To that privileged stratum of capitalist world-society, energy, specifically fossil-fuel energy, is power, economic and political power. Its individual members compete for that power when they compete for good jobs, when they compete for power within those jobs, and so on.
To consume less energy means, in practical terms, dropping out, and (ultimately) joining the 40% with no stake in the system. But doing such a thing is the complete opposite of what most students desire when they sign up with educational systems to take courses of study. People go to educational systems so that they may acquire privileges and power within the capitalist system. Employers, conversely, hire people to well-paying jobs based upon their having received academic degrees.
The problem of abrupt climate change will NEVER be solved unless world-society can make some sort of commitment to getting off of the capitalist track. Think that's impossible? Kill yourselves NOW -- avoid the mass rush that will occur when your self-fulfilling prophesy becomes true, and capitalist "development" DOES destroy the Earth's ecosystems to breaking.
To the eco-capitalists: good luck with your alternative path of saying "pretty please" to the representatives of the rich and powerful. In fact, if you believed your own words you wouldn't be wasting time talking with the likes of us.
The post continues:
After reading that article I came across all these nice goals that we just stop all CO2 emissions at once and thought "gee, dream on teenage queen."
Indeed, world-society will not stop all CO2 emissions at once; but this is because world-society is not organized collectively to do that, or to do anything but to compete for status, money, power. The abrupt climate change literature is shot through with fatuous assumptions that the problem of collective organization will just solve itself.
http://www.dailykos.com/User/Cassiodorus
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LegumeSam Posted 10:24 pm
29 Feb 2008
The truth about climate change does indeed defy the task which PR sets for itself. PR, of course, is what corporations buy to foster the public impression that "we are all powerful and you should like that." Abrupt climate change, on the other hand, is a problem no for-profit corporation can solve.
http://www.dailykos.com/User/Cassiodorus
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Billhook Posted 12:23 pm
01 Mar 2008
First, there is an assumption that, for all we have a great deal more committed warming coming down the pike, plus at the least another three decades worth of intensifying climate destabilization, the various accelerating interactive feedback loops will (far from offsetting our GHG cuts) somehow cease their diverse outputs as we cut GHG emissions to zero.
Second, there is a parallel assumption that the various GHG sinks will be maintained during the period of our emissions reduction, despite the present indications of increasing instability in oceans' capacity, in soils' capacity and in forests' capacity.
Under these two assumptions, a third is supposedly justified, namely that airborne CO2eq ppmv and thus global temperature could be "stabilized" by cutting GHG outputs to zero by 2100.
I wonder if you're able to justify these three assumptions ?
In reality, I think we are lagging in the race to recover sufficient airborne GHGs and cut further emissions to the extent of lowering global temperature sufficiently to decelerate the feedback loops and stabilize the declining carbon sinks, before these phenomena develop to the point of global warming becoming self-fuelling.
(For reference, the DOC feedback [Dissolved Organic Carbon] from peat-bogs' global decay due to elevated CO2, was already active in 1960 with airborne CO2 at around 320ppmv).
That we can recover airborne GHGs in relevant quantities per year - via global reforestation, plus terra preta, plus short-rotation grazing - is not in question. Nor is there any real question over the potential scale of usable sustainable energy supplies if geothermal, forest biomass and offshore wave are included (though the feasible rate of their scaling up seems unlikely to power conventional measures of economic growth for a period).
So I wonder if you'd agree that the core of the problem is essentially ideological - that powerful national & corporate interests are unable to face relinquishing their centralized controls on energy supply in favour of its globally decentralized production ?
Meaning that only a globally equitable treaty could address the issue ?
And that no amount of unilateral effort for sustainable energy, for energy efficiency and for carbon sequestration will make a significant difference until that Treaty of the Atmospheric Commons is in operation ?
Regards,
Billhook
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frankbi Posted 2:06 pm
10 Mar 2008
Source?
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