Supporters of 350, understand what you are proposing

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The 350 movement is a group concerned about climate change that has adopted an upper limit of 350 parts per million (ppm) of carbon dioxide equivalent in the atmosphere as their target. The target is a good and extremely ambitious one, and the group is doing well in the media. That said, I worry that some of the 350 proponents don’t understand what they are arguing for.

The carbon cycle

To understand climate change, you need to understand the carbon cycle. In a normal situation, this refers to carbon in sugars being released as CO2 when animals, bacteria, and fungi metabolize them. This adds CO2 to the atmosphere. In turn, green plants use sunlight to make sugars out of CO2, releasing oxygen. These processes happen in a balanced way, with more CO2 emission in the winter (when plants are inactive) and more CO2 absorption in the summer.

Alongside the biological processes are geological ones. Two are key. Volcanoes emit greenhouse gases, and the erosion of certain kinds of rock locks up CO2 underground. The latter process happens very slowly. It is very important to understand that this is the only long-term phenomenon that keeps on drawing CO2 out of the atmosphere. The oceans will suck it up when CO2 accumulates in the air, but only until the seas become more acidic and come into balance. CO2 likewise accumulates in the biomass of living things, but there can only be so many forests and so much plankton on Earth.

When we burn fossil fuels, we add to the concentration of greenhouse gases in the atmosphere. Before the Industrial Revolution, it was around 280 ppm. Now, it is about 383 ppm and rising by 2 ppm per year.

What 350 means

It isn’t impossible to get back to 350 ppm. This is because the oceans haven’t caught up with the atmosphere yet. If we suddenly stopped burning coal, oil, and gas the quantity of CO2 in the atmosphere would start to fall as more of it went into the sea. That being said, if we keep burning these fuels in the way we are now, getting back to 350 ppm will become impossible.

When you argue to cap the atmospheric concentration at 350, you are arguing to cut the net human emissions of the entire planet to zero – and to do so before we cross the point where the oceans can’t draw us back under the number. The same is true if you argue for stabilizing at a higher level, such as 450 ppm or 550 ppm; those scenarios just give us more time to keep emitting before we reach zero net emissions. When you support 350 ppm, you are committing to keeping the great majority of the carbon bound up in remaining fossil fuels underground and unused by human beings. ‘Net’ human emissions means everything that goes up into the air from burning fossil fuels, minus the trickle of CO2 into rocks (as described above) and possibly minus whatever CO2 we can suck out of the air and bury (a costly and energy-intensive procedure).

Cutting net human emissions to zero is a laudable aim. Indeed, it is the only way concentrations (and global temperatures) can ever be kept stable in perpetuity. I just hope that more 350 supporters will come to understand and accept that, and realize that achieving that ambition requires massive societal change, not just marches and savvy media campaigns.

P.S. If all that isn’t enough of a challenge, remember that there are also positive feedback effects within the climate system where, once we kick off a bit of warming, CO2 concentrations rise on their own in response. These feedbacks include melting permafrost and burning rainforests. Keeping below 350 ppm requires cutting net human emissions to zero before these positive feedbacks commit us to crossing the threshold.

Why Bury Coal? explains this in more detail.

See also:

[Update: 24 March 2011] Some of what I just added to the bottom of my Earth Hour post is also relevant here, in that symbolic acts can help environmental groups achieve attention, even if the acts capturing the attention are dubious in some ways. should be commended for attracting so much general public attention.

Author: Milan

In the spring of 2005, I graduated from the University of British Columbia with a degree in International Relations and a general focus in the area of environmental politics. In the fall of 2005, I began reading for an M.Phil in IR at Wadham College, Oxford. Outside school, I am very interested in photography, writing, and the outdoors. I am writing this blog to keep in touch with friends and family around the world, provide a more personal view of graduate student life in Oxford, and pass on some lessons I've learned here.

23 thoughts on “Supporters of 350, understand what you are proposing”

  1. What do you think that China can do to reduce carbon emissions as they rely so much on coal and have a large supply of it? The poor people there live extremely modestly, but it gets very cold in many parts of China. Hydroelectric power from the Three Gorges Dam has also caused huge environmental problems. Should they turn to more nuclear power?

  2. I haven’t studied China specifically, but my guess is that there are significant opportunities to save money and reduce emissions by improving efficiency. Things like tightening building efficiency codes will save money in the long run, while cutting GHG emissions.

    Other sensible moves include carbon pricing, encouraging the development of renewable energy, integrating energy grids, fuel switching from coal to less emissions intensive fuels, developing energy storage capacity to use at times of peak demand, employing variable electricity pricing, tightening vehicle standards, protecting forests, and employing lower carbon forms of agriculture.

    Nuclear will probably also play a role, though it is probably more worrisome in a Chinese context than in states that have better industrial safety records.

  3. What does the number 350 mean?

    Is 350 scientifically possible?

    Right now, mostly because we’ve burned so much fossil fuel, the atmospheric concentration of co2 is 390 ppm—that’s way too high, and it’s why ice is melting, drought is spreading, forests are dying. To bring that number down, the first task is to stop putting more carbon into the atmosphere. That means a very fast transition to sun and wind and other renewable forms of power. If we can stop pouring more carbon into the atmosphere, then forests and oceans will slowly suck some of it out of the air and return us to safe levels.

    Is 350 politically possible?

    It’s very hard. It means switching off fossil fuel much more quickly than governments and corporations have been planning. Our best chance to speed up that process will come in December in Copenhagen, when the world’s nations meet to agree on a new climate treaty. Right now, they’re not planning to do enough. But we can change that—if we mobilize the world to swift and bold climate action, which is what we’re planning to do on October 24th.”

  4. It means switching off fossil fuel much more quickly than governments and corporations have been planning.

    This is quite the understatement. How many governments and corporations have expressed the reality that we need to give up fossil fuels entirely – before they run out – because burning them all would change the climate enough to threaten our survival?

  5. Sometimes, it is better not to understand the scale of the problem you are facing. If you do, it might drive you to give up. Whereas if you carry on in ignorance – thinking that you are just walking up a little hill – you might eventually turn around to see that you’ve gone up a mountain.

  6. Sometimes, it is better not to understand the scale of the problem you are facing. If you do, it might drive you to give up.

    This may be true, but I also think that in order to keep pushing for something that seems impossible – you need to be able to maintain a fiction for yourself. The fiction being: no matter how it looks now, you know that you can make change for the better. Whether this is religious faith, or just plain old bitter determination, I think it’s necessary to employ some imagination.

  7. “you need to be able to maintain a fiction for yourself. ”

    Interestingly, Kant also argued this. He calls these fictions “postulates of pure reason” – things reason can’t prove but must believe in order to be the moral being which reason requires you to be. They are not strictly fictions though – they are just unknowables: God exists (so you can imagine that nature and rational will could not contradict each other), Your soul is forever (because you can’t live up to the law, you have to believe that you can continuously slowly improve, and over a permanent time span, reach the law), and Freedom (a kind of freedom which does not contradict rationally knowable orderliness of the world – thus one in principle un observable).

  8. I think it is better to at least understand what stabilizing at 350 means, and then to ignore how hard it is and do what you can, than it is to just assume that stabilizing below 350 can be done.

  9. This graphic helps put things in perspective:

    (Image: CO2 concentration data from Vostok ice core)

    Note that 675 ppm by 2100 is far from a worst-case projection. Business-as-usual growth in emissions could produce concentrations of 800 to 1000 ppm by 2100.

  10. CLIMATE CHANGE: 350 PPM Too Ambitious, Say Lawmakers

    Faced with Fankhauser’s proposal, the chair of the GLOBE forum, British MP Barry Gardiner, asked the 120 legislators present whether they believed limiting CO2 concentration to 350 ppm by 2050 was practicable.

    Only two legislators said yes. Reacting to such a display of pessimism, Gardiner told the meeting: ”We should be terrified.”

    ”If you of all people do not believe that an ambitious goal is realistic, then we are lost,” he said.

    This is more emphatically so, given that GLOBE leaders said the forum was organised ”to decide on key guiding principles to enact climate change legislation” in the participating countries, in order to ”make a significant step towards limiting global temperature rise to two degrees Celsius, to avoid devastating runaway climate change.”

  11. Reducing carbon dioxide levels to 350 would mean reversing the trend of the past couple of centuries. Carbon dioxide stays in the atmosphere for as long as 100 years. And the emissions cuts currently being pledged by developed countries, including the United States and European nations, are aimed at having CO2 levels peak at around 450, not 350, in coming decades.

    And even that may not be possible. Some economists say the world should plan to stop at 550.

    Economist Henry Jacoby, co-director of MIT’s Joint Program on the Science and Policy of Global Change, has said that even 450 is “totally impossible, there’s no way we can do that.”

    To get down to 350, civilization has to remove massive amounts of carbon dioxide from the skies, something talked about but not yet achieved. Trees and oceans suck CO2 from the atmosphere, but that process is overwhelmed by emissions from burning coal and oil. McKibben said it would probably take 40 years to get down to 350 even if emissions stopped today.

    “It may be on the edge of impossible,” he said Sunday. “We could do it. At the moment, there’s no sign that we are going to do it.”

    MIT management professor John Sterman said scientifically 350 makes sense, even if economically it seem unreachable.

    “We ought to have a goal of 350 and realize we’re already above that,” Sterman said.”

  12. “Today we are faced with the need to achieve rapid reductions in global fossil fuel emissions and to nearly phase out fossil fuel emissions by the middle of the century. Most governments are saying that they recognize these imperatives. And they say that they will meet these objectives with a Kyoto-like approach. Ladies and gentleman, your governments are lying through their teeth. You may wish to use softer language, but the truth is that they know that their planned approach will not come anywhere near achieving the intended global objectives. Moreover, they are now taking actions that, if we do not stop them, will lock in guaranteed failure to achieve the targets that they have nominally accepted.

    Figure 26 shows that if coal emissions are phased out entirely and unconventional fossil fuels are prohibited, fossil fuel emissions in 2050 will be somewhere between 20 and 40 percent of emissions in 2008. In other words, the reserves of conventional oil and gas are already enough to take emissions up to the maximum lebels that governments have agreed on. The IPCC estimate, in which we exploit only the most readily available oil and gas, allows the possibility of getting emissions levels back to 350 ppm this century.”

    Hansen, James. Storms of My Grandchildren. p. 184-5 hardcover

  13. Maybe it isn’t necessary for the rank-and-file of the 350 movement to understand the carbon cycle, or the long-term objectives of the movement to address climate change.

    Just by being a large and active movement 350 attracts political attention. A big crowd will draw the gaze of vote-hungry politicians a lot better than a few eggheads who really understand the problem but do not have a movement behind them.

  14. Hey Milan, Thanks for sharing your 350 reflections from last year — you have an excellent handle on the science! And we’re with you, and are campaigning hard this year to keep fossil fuels in the ground, where they belong. And we could sure use your help. Have you checked out our community inspired & empowered plans for 2010?

    We’re literally getting to work in our communities — to sear a vision within the eyes the world and its leaders of a world that’s powered by clean, renewable energy (not fossil fuels.) Building on the success of last year’s actions (112 countries endorsed the 350 target — hopefully knowing fully what it meant!), we’re going to try once again to tip the balance, this time leading by example.

    Your voice as a scientific messenger is beyond welcome. And we’d love to engage with you as an organizer to really make the change you write about into a reality. Check out these ideas for inspiration: — and please keep us posted on your personal twist! Thanks again, friend!

  15. Thanks for the gracious response, people. I am definitely keen to do what I can to help stabilize GHG concentrations at as low a level as possible.

    I am not saying that 350 is the wrong target. Rather, I am saying that the media coverage of 350 stunts doesn’t usually convey the reality of what is necessary to meet that target.

    Building enthusiasm and momentum is necessary, but it’s also key to appreciate exactly what the movement is trying to do, and what the implications from that are.

  16. This point is also a good one.

    That said, actually understanding the nature of the climate change problem does seem vitally important. This post was originally kicked off when I spoke with a young woman who was volunteering at a event, but who also believed that it was impossible for humanity not to burn all the remaining fossil fuels.

    People don’t need to understand all the intricacies of the carbon cycle – I certainly do not – but they do need to understand that dealing with climate change ultimately requires reaching a position of global carbon neutrality.

  17. Pingback: What’s possible?
  18. But perhaps the most dangerous misconception about the climate crisis is that we have to “lower” our emissions. Because that is far from enough. Our emissions have to stop if we are to stay below 1.5-2C of warming. The “lowering of emissions” is of course necessary but it is only the beginning of a fast process that must lead to a stop within a couple of decades, or less. And by “stop” I mean net zero – and then quickly on to negative figures. That rules out most of today’s politics.

    The fact that we are speaking of “lowering” instead of “stopping” emissions is perhaps the greatest force behind the continuing business as usual. The UK’s active current support of new exploitation of fossil fuels – for example, the UK shale gas fracking industry, the expansion of its North Sea oil and gas fields, the expansion of airports as well as the planning permission for a brand new coal mine – is beyond absurd.

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