A reasonable goal at this point in time is to stabilize CO2 concentrations around 600-650 ppm. Given the the current CO2 concentrations (~390 ppm) and the political challenges reaching a deal, an extremely ambitious goal of 350 or 450 is simply not realistic. The most important thing is that the global community agrees to take some type of action now. Setting a goal of around 650 ppm entails national policies that countries might actually be willing to agree to and, most importantly, is still aggressive enough to avoid/significantly reduce the worst risks of climate change. Most of the effort of our plan is supported by developed countries, but developing countries are still required to reduce their emissions relative to BAU.NOTE In comments L Carey clarifies: your post is not clear that the text is from a grad student submission and not an "official" MIT document - in light of the heated nature of the topic, I'd suggest that you might want to clarify that and forestall the likely "green doom-monger" comments.
Is 650 ppmv as a goal tantamount to doom? I mean, given how quickly we have slipped from 450 to 650, this is pretty scary. I hope we get some sort of a grip before even that goal slips out of reach. I think we can survive it, but not without tragic loss. We are committing our future selves and our descendants to a much diminihsed natural world, at very best.
But in any case, it makes it more urgent than ever to cut back on ancillary greenhouse gases, a goal that perhaps can achieve more support. (After all, the saturation argument, however wrongheaded, doesn't even apply to the trace GHGs.)
To that end, I will take up Alex Viets of INECE's suggestion to draw your attention to a recent New York Times article on expanding the Montreal protocol to limit HFC emissions.
In any case, the possibility of avoiding unprecedented climate change is likely out of reach. So it's biosphere management time for us. We just smashed the autopilot. Time to start thinking about steering.
17 comments:
My understanding is that a sustained period above ~420 ppm presents a high probability of triggering major methane release from permafrost and perhaps clathrates. If so, that would pretty much remove any steering wheel we thought we had, by putting the ultimate level of CO2 increase out of our control. Last I checked, 650 > 420. (Word verification is "loseu".)
Michael, I took a look at the Climate Colab page, and note that the material cited in your post is a submission in a contest for graduate students to put forward competing international climate frameworks. This particular scenario is one of 4 student proposals, put together by 4 grad students. Accordingly, I would hope that it does not represent an authoritative projection. Regards.
We are quite doomed.
In Bulgaria, where this time the average temperature should be around 7-8°C, there are more than 200 wildfires (!) and winds gusting up to hurricane intensity and temperatures up to 27 °C!!
http://www.sofiaecho.com/2010/11/11/991498_more-than-200-wildfires-raging-in-bulgaria
here is Bulgaria climatology:
http://www.climatetemp.info/bulgaria/
In the absence of any political momentum towards carbon pricing, I don't see how setting any threshold makes much sense.
You can move it higher, and thus in theory have the time to do what it takes to stop the increase by then (because even with a hyper-BAU, 650 is decades away). But without policies that could slow the growth, all it is is theory.
L Carey, your point is taken, but on the other hand, it does seem realistic that a 450 ppmv peak is no longer in reach.
This in turn means that we reach a point where economic growth is no longer possible in the global aggregate, which means that the surplus effort to address the problem will be less available.
Michael, I fully agree that we may well be past a 450ppm peak, and that the likely consequences would be dire. I also agree that it's of concern that the grad student authors could arrive at the conclusion that 650 is the best we can do. However, your post is not clear that the text is from a grad student submission and not an "official" MIT document - in light of the heated nature of the topic, I'd suggest that you might want to clarify that and forestall the likely "green doom-monger" comments (and also save some folks from the elevated blood pressure I probably experienced on first reading). Regards.
Seems to me entirely appropriate to -- under the CFC protocol --- deal with the climate problems that turn out to have been caused by the first attempt to replace CFCs.
Unintended consequences are part of the deal and have to be addressed -- otherwise people just say "well, I fixed it, I'm not responsible for the problems my fix caused, am I?
Yes, unintended consequences -- which otherwise are externalized costs inflicted on others -- are part of the deal.
Dealing with them under the Montreal Protocol is a responsibility, not a misuse of the Protocol.
http://www.schlockmercenary.com/uploads/2010/11/Megamind-Poster.jpg
The degree of overshoot has nothing to do with the safe level we need to return to, other than to drive it down somewhat as the overshoot grows larger. 650 is depressing but not out of the realm of possibility, and if we get that high I agree with Michael that there will be increasingly few resources available for any hope of a transition that doesn't involve the deaths of hundreds of millions if not billions. All we can do in the present is emphasize the necessity of returning to the safe level ASAP (which very probably is more on the order of 320 ppm rather than 350).
Michael my understanding is that total co2 is more important than any stabilization scenario because there is no going back without some method of removing co2 from the atmosphere...From my article of a year ago with an interview with Myles Allen:
The climate negotiators heading to Copenhagen in December must accept the fact that the world’s carbon emissions must eventually stop – and stop completely. There is no sustainable per capita carbon emission level because it is the total amount of carbon emitted that counts, explains Myles Allen of the Climate Dynamics group at University of Oxford’s Atmospheric, Oceanic and Planetary Physics Department.
Carbon dioxide remains in the atmosphere for many centuries, which makes it the most important greenhouse gas to reduce and eliminate. The current focus on CO2 concentrations like 450 ppm or 350 ppm is the not the right approach since it is the total cumulative emissions that determine how warm the planet will get, Allen told the conference.
If climate negotiators only look at slowing rates of carbon emissions, then natural gas will be substituted for coal because it has half of the carbon – but the total amount of carbon in the atmosphere will continue to increase.
“We didn’t save the ozone layer by rationing deodorants,” said Allen.
http://stephenleahy.net/2009/11/08/four-degrees-of-devastation/
I admit to being a bit fuzzy on all this having spent the last three weeks covering the big biodiversity summit in Japan
http://stephenleahy.net/
Stephen, honored to make your acquaintance. I commend your nerve in doing what I keep telling myself I ought to be doing.
Agree that emissions must be driven to or BELOW zero. Anyone wearing a "350" cap implicitly supports carbon sequestration whether they are aware of it or not.
Total emissions to first order is a good way to think about it. If one neglects sequestration both natural and artificial (natural sequestration being very slow as you say) the peak concentration and the total emissions come down approximately to two different ways of expressing the same quantity.
Earth has just gotten to 390 ppmv of CO2. We do not know what life on Earth at 390 would be like once all the feedbacks kick in. The feedback effects from lower levels of CO2 that have not yet been felt, and still we have lost sea ice, had great heat waves, record rain, ocean acidification, and a rise in sea level. Granted that these effects are sporadic and minimal, but it has only been a short time since CO2 was at 350, and not all of the feedbacks have kicked in yet.
http://www.esrl.noaa.gov/gmd/webdata/ccgg/iadv/graph/zep/zep_ch4_ts_surface_00475.pdf tells me that under current conditions, the Arctic is starting to out gas CH4. That is, feedbacks for current levels of AGG may be starting to kick in. If CH4 is starting to outgas, then what is the next stable level of CO2 in the atmosphere?
We should not be too sanguine about surviving the impacts of 450 ppm, until we understand the full equilibrium impacts of 390 ppmv.
Wow, cheery topic you got here, Michael.
I've had several conversations with people studying this issue in considerable depth, some scientists (in the formal sense), some not. A surprisingly high percentage of them talk about a net loss of billions of human beings before 2100, solely from things like drought and famine triggered by climate change. (Basically the Lovelock view.) I've had a very hard time believing we were already in that much trouble; perhaps I'm just another denier.
I noticed that recent methane levels have spiked pretty conspicuously: http://www.grinzo.com/energy/index.php/2010/11/11/methane-update-2/ I don't think this is the permafrost/hydrates bomb going off, etc.; my blatant guess is it's merely methane from the bog fires in Russia this year. Or that could be yet another sign of my denial.
As for CO2, I consider its atmospheric lifetime to be the most inconvenient of all truths, and a subtle point that lay people simply don't get. Literally every one of them I've talked with about this topic is under the impression that if we cut CO2 emissions the atmospheric level will drop by the same percentage within a year or two. Nothing I tell lay people scares them more than this one fact about CO2: Love is fleeting, but CO2 is forever.
Agree Michael, (and good to meet) but I don't think that going to "zero and below" is well understood. 'Stabilization' for most means no net increase in emissions.
Aaron I think your point is reflected in this piece citing two renowned permafrost experts, who remark that emissions must peak by 2015 and decline otherwise:
“In a matter of decades we could lose much of the permafrost,” Shuur told IPS.
http://stephenleahy.net/2010/09/23/arctic-ice-in-death-spiral-risks-climate-catastrophe/#more-3705
Steve Bloom --- I agree that 350 ppm isn't safe in the long term, but neither is 320 ppm. As best as I can make out 300 ppm CO2e is the upper limit and due to orbital parameter changes may still be too high.
What do you think of geo-engineering, using synthetic trees to remove CO2?
It is probably more expensive than not emitting CO2 in the first place.
In any case, that cost should be surcharged on CO2 emissions starting as soon as possible.
But removing CO2 is the next best thing to not emitting it, and is far preferable to other sorts of geoengineering schemes in my opinion.
Post a Comment