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Filed under: — gavin @ 27 October 2009

I was quoted by Andrew Revkin in the New York Times on Sunday in a piece about the International Day of Climate Action (involving events in 181 countries). The relevant bit is:

Gavin A. Schmidt, a climate scientist who works with Dr. Hansen and manages a popular blog on climate science,, said those promoting 350 or debating the number might be missing the point.
“The situation is analogous to people trying to embark on a cross-country road trip to California but they’ve started off heading to Maine instead,” Dr. Schmidt said. “But instead of working out ways to turn around, they have decided to argue about where they are going to park when they get to L.A.”
“If you ask a scientist how much more CO2 do you think we should add to the atmosphere, the answer is going to be none.”

I’ve been told that some readers may have misinterpreted the quote as a criticism of the campaign itself. This was not the intent and in fact my metaphor wouldn’t have made sense in that context at all. Instead, it was a criticism of people who are expending effort arguing about whether 350 is precisely the right number for a long term target, or whether it should be somewhat higher or lower. Since we aren’t currently headed anywhere near 350 ppmv (in fact we are at 388 ppmv CO2 and increasing by about 2 ppmv/yr), we need to urgently think of ways the situation can turn around. Tapping into the creativity and enthusiasm shown by the campaigners will certainly be part of that process.

We discussed some of the thinking behind this ‘Target CO2‘ when Jim Hansen and colleagues’ paper first came out, where I think we made it clear that picking a specific CO2 target to avoid ‘dangerous’ climate change is an inexact science at best. The comments by Robert Brulle and Ray Pierrehumbert at DotEarth and James Hrynyshyn also highlight some of that complexity. And I think the suggestions by ‘Paulina‘ for how a tweaked article might have been clearer are very apropos.

However, as the final line in my NYT quote should make clear, personally I think the scientific case not increasing CO2 any further is very strong. Since the planet has not caught up with current levels of concentrations emissions (and thus will continue to change), picking an ultimate target that is less than today’s level is therefore wise. Of course, how we get there is much trickier than knowing where it is we should be going, but having a map of the destination is useful. As we discussed in the ‘trillionth ton‘ posting a couple of months back, how we get there also makes a difference.

In my original email to Andy Revkin, I had actually appended a line:

If you ask a scientist how much more CO2 do you think we should add to the atmosphere, the answer is going to be none.

All the rest is economics.

(and technology, and sociology, and psychology and politics etc.) but the point is that working out how we get there from here is the real challenge and the more people who are aware and involved in developing those solutions the better.

214 Responses to “350”

  1. 201
    Deep Climate says:

    #194, 197, 200

    The second version of JetStream was simply copied from the original SRH version as part of NOAA Year of Science education project. I’ve contacted the NOAA contact for this education program, and he has already replied to the effect that the problem will be rectified as soon as possible.

    Also, as noted at my website, I did receive an answer from NOAA SRH Deputy Head Steven Cooper, possibly because I mentioned that I was blogging about the matter. I’m sure there were too many emails to reply to each one. But the point is they did take action.

    The story so far:

    I’ll be updating my post with further news.

  2. 202
    Jim Galasyn says:

    Here’s a fun Google search on “If carbon dioxide had been the cause then the warmest years would have understandably been in the most recent years.”

    My favorite headline:

    NASA: No Evidence CO2 caused warming! – TheAmericanRight Web Forum

  3. 203

    BTW, the Environmental Education in Wisconsin Website removed the Fraser Institute link. :)

  4. 204
    Hank Roberts says:

    > someone elsewhere, then 198, 203
    > uvm
    is Vermont, as Scott noted earlier, not Wisconsin.

  5. 205

    Belated thanks to Dave Cook, Steve Fish and Mark for heating/cooling thoughts.

    We have been avid practitioners of heating/cooling moderation, eschewing AC for the most part (though we use our attic fan a good bit after about 7 PM to cool the house down from the day’s heat. In winter we keep the thermostat low-often about 60F. I’ll add a couple of layers & be just fine indoors during the day, even if engaged in something sedentary.

  6. 206
    Steve Fish says:

    Kevin McKinney (#205, November 2009 @ 2:56 PM):

    Kevin, for my part you are welcome. What I discovered a long time ago is that when it is cold out we have been very comfortable with the thermostat set quite low if there is a warm spot to back up to. I have always used a wood stove, but any small heater that has much less capacity than needed to heat a whole room, much less the the whole house, provides comfort. In some ways this strategy is much better than the dry, even, heat of a central heating system because it provides a warm place for the family to gather.


  7. 207

    #199 Kevin:

    It almost looks to me as though a good activity was then “balanced” with a discussion written by someone with an axe to grind.

    or there’s someone over there trying to get fired and hence claim martyrdom to the cause of the religion of carbon.

  8. 208
    Mark says:

    And Kevin, Steve’s #206 is rather more cozy because you are all together.

  9. 209
    Dorothy says:

    I am a strong supporter of the initiative for one simple reason. Bill McKibben has recognized that we must not only cease to emit carbon into our atmosphere, as this in itself will only delay disastrous climate change: we must also bring its atmospheric concentration down to a safe level, to 350 ppm or lower.
    It is my opinion that this level must be low enough to keep our planet well below the end-of-century two degrees Celsius of warming that is being talked about today.
    In their September 29 PNAS paper, “Constraining future greenhouse gas emissions by a cumulative target,” Matthew England et al state that “A global mean warming of 2 degrees C could still have devastating impacts on climate, ecosystems, human health, and infrastructure….Two degrees Celsius should thus not be seen as a mere aspirational target: it surely has to be the maximum stabilization target for global warming:
    However alarming this must sound, there is an even darker perspective, that of Australian professor Clive Hamilton, who has posted his October 21 lecture to the Royal Society of the Arts, “Is It Too Late to Prevent Catastrophic Climate Change?” He tells us, “It is clear that limiting warming to 2 degrees C is beyond us; the question now is whether we can limit warming to 4 degrees C. The conclusion that, even if we act promptly and resolutely, the world is on a path to reach 650 ppm and the associated warming of 4 degrees C is almost too frightening to accept.”
    I think most of us would agree that 4 C is not “almost,” but truly too frightening. And for the sake of humanity and our biosphere, we must not accept this fate. We should to all we can, on every level, to stop emitting any more carbon, and then use our brilliant minds to find a way to as soon as possible safely remove and neutralize all the excess atmospheric CO2 presently in our atmosphere.
    There is no other alternative.

  10. 210
    Lennart says:

    Also see the most recent presentation of Jim Hansen, at the Club of Rome in Amsterdam:

    And also The One Degree War Plan by Jorgen Randers (of the original Meadows of Rome-report Limits to Growth) and Paul Gilding:

  11. 211
    Jim Galasyn says:

    FYI, the other hacked NOAA page is still up. last Thursday, I received an email from Steven Cooper that said they would be removing it “as soon as they can get their IT folks involved.”

  12. 212
    Hank Roberts says:

    > the other hacked NOAA page
    Nothing there now. I wish they’d posted a correction and an explanation.

    Here’s the index page
    That still lists the one removed:
    10 It’s a Gas, Man – Discover if carbon dioxide has an effect on temperature.

    (they got the apostrophe right on the index page, perhaps another hint the page got hacked whether internally or externally)

    I’ll be curious to see what fills that “Its A Gas” spot.
    That line has disappeared from the sidebar lesson list you see when looking at any of the other pages in the set.

  13. 213

    Not sure if this is the topic originally posted to re biochar, but here’s a Science daily item on carbon in soil which tantalizes a bit (and is interesting in its own right.)

  14. 214

    Pretty good post. I just bumbled upon your blog and wanted to say that I have actually enjoyed reading your blog posts. Any way, I will be signing up to receive your feed and I hope you post again very soon.