Global warming maths – we’re down to our last 500 gigatonnes

mckibben

Global warming can be confronting, it can be scary, and it has become politically divisive. But what if we stripped it back to a question of maths?

Climate change, after all, is basically a big maths problem, involving the quantity of carbon we wish to burn and the capacity of the atmosphere to contain it. The question is, how much more can we burn before we’re in trouble?

Australians may be forgiven for having a similar opinion—after all, the slightly-less-than-1-degree we’ve already raised the global average temperature allowed your ‘angry summer’. Averages hide extremes: all over the world we’re seeing government weather services having to add new colors to their charts. I’m not going to

cite all the endless records that have fallen across your continent in recent times, because I imagine you’re tired of hearing about them. Record rainfalls inundate some spot on the globe almost every week (because warm air holds more water vapor than cold, loading the dice for greater downpours). There’s only 20 percent as much ice in the summer Arctic as there was 40 years ago. That bears deeper consideration: we’ve taken one of the biggest physical features on earth, one of the things you can see about our planet from a great distance, and we’ve broken it. If that’s what one degree of warming will do, it’s actually quite daring to find out what two degrees will bring, using ‘daring’ in the sense of ‘stupid.’

But environmentalists and scientists lost that fight, and the world settled on the two-degree target—it’s essentially the only thing about climate change the world has settled on.

The next stage of our maths lesson requires finding out how much more carbon we could pour into the atmosphere and stay below two degrees. Here the answer is easier: a wide variety of computer models have converged on the figure of about 500 gigatons more. A rough number. And it comes with no guarantee that it will keep us below two degrees, just about an 80 percent chance. So, worse than Russian roulette, but it’s only our planet.

500 gigatons is a lot, but we’re producing more than 30 gigatons a year as a planet, and that number has been growing about 3 percent a year. Which gives us, oh, about 15 years before we go soaring past the two-degree threshold. If we are to avoid doing that, computer modeling shows that the world’s carbon emissions have to peak in 2015 and then come hurtling down.

Now let’s complicate matters. Let’s add in the new coal mines your carbon baro

ns, supported by government ministers Labor and Liberal, are planning on developing. In fact, let’s just take one set of mines, in the Galilee Valley. Those mines contain enough carbon to fill up 6 percent of the space between us and two degrees. One valley! There are plenty of other coal mines planned for Australia, not even mentioning shale oil and coal seam gas.

I want to be very clear – it’s very important that Australia has put a price on carbon, and very important that it not be overturned as a result of the next election. It’s a modest start that has had good effects in opening up the debate around the world, reduced domestic energy use and spurred development of renewable energy. Credit to Prime Minister Gillard, and more credit to the Greens’ Christine Milne who forced her hand. But, in mathematical terms, it’s even more important to rein in the huge expansion of Australia’s coal mines.

The maths doesn’t work from individual changes alone. It demands structural shifts on a massive scale. That’s why, in the USA, we’ve built a vast campaign on college campuses and in city governments demanding divestment from fossil fuel stocks. Because, if it’s wrong

Monthly-June-cover-web

asking you to consider taking your own money out of funds (your bank or your superannuation) which invest in fossil fuels. We’ll also be asking governments to stop putting your money into helping build more coal mine

s, coal trains and coal ports.

We’re already deep in a hole. And the first rule of holes is, when you’re in one stop digging. In this case, stop digging new coal mines.

This is an edited extract from Bill McKibben’s essay in The Monthly magazine of June 3, False Profits: doing the maths on Australia’s coal exports. McKibben is founder of 350.org

Comments

13 responses to “Global warming maths – we’re down to our last 500 gigatonnes”

  1. Sid Abma Avatar
    Sid Abma

    We need to use more natural gas ~ Efficiently ~ to near 100% Efficiency, venting Cool exhaust instead of hot, until the solar and the wind and the tidal and the other renewables have enough in place to cover for what we need natural gas to supply today.
    Increased natural gas energy efficiency = Reduced utility bills = Profit
    Increased natural gas energy efficiency = Reduced global warming
    Increased natural gas energy efficiency = Reduced CO2 emissions
    Increased natural gas energy efficiency = Water conservation

    Green Jobs
    How many chimneys are there poking out of the roofs of commercial buildings and industry?
    How many jobs can be created assessing all these locations?
    How many engineers will be required to design the most effective ways of utilizing all this recovered heat energy?
    How many mechanical contractors will be required to install all these Condensing flue gas heat recovery systems?

    What can this do for Australia’s economy?
    What will this do for Australia’s environment?

  2. Rob Avatar
    Rob

    It is a question of maths and so far none of it matches up very well. and Carbon taxes or theft of cash will not do a thing to help the environment. The answer is to absolutely ban the use of anything that is burned, anything that causes residual heat to be released into the atmosphere, and anything that exhales CO2 if you are sticking with it being a pollutant. That means humanity must go by the math. Otherwise it is just a power and money grab

    1. thin_king Avatar
      thin_king

      err “Rob”, I think i need to see that maths laid out in order to be convinced that your not speaking absolute troll bollocks. Nature doesn’t have to pull it’s head in – we do.

      1. Rob Avatar
        Rob

        Tell me it didn’t just eat all that response.

        1. thin_king Avatar
          thin_king

          After all this time, I’m not sure whether you, Rob, or anyone else will read this. Nonetheless, just stumbled across your reply to my reply, so here goes…

          Firstly, since you made an effort to follow up and to produce some sort of a line of reasoning, the first part of my initial statement of “troll bollocks” obviously was mistaken – I get now that you’re not just trolling. Your obviously passionate about this debate and prepared to put effort into discussion. So I withdraw the troll part and apologise if it caused any offence.

          But to be honest, the mathematics of your last post makes absolutely no sense. You jump between the CO2 exhalation of humanity, the pounds of food per acre of food production and the temperature differences between cities and surrounding rural areas with no discernible connection between the figures. I’m aware that you had explained it in a longer post that just crashed on you. You may have spelt it out clearer in that lost post, but I really can’t see how you can possibly build a coherent, logical argument out of that hodgepodge. I am definitely not saying this to be nasty, or to belittle you; it is just my observation. Logical/mathematic arguments require that a logical connection be shown at every step. You can’t just leap around like a drunk monkey from tree to tree and go “you see, there’s all these trees, therefore the forest is a plantation”

          But, just to turn your first “tree” – you say that humans exhale 500kg of CO2 per year.
          In contrast, the average car in the US produces 5.1 metric tonnes per year
          (http://www.epa.gov/otaq/climate/documents/420f11041.pdf)
          That’s the equivalent of 10.2 extra people breathing each year for every car

          The average coal power station produces 3.5million tonnes per year (http://www.ucsusa.org/clean_energy/coalvswind/c02c.html)
          That’s the equivalent of 7 million extra people exhaling every year for every coal power-plant.

          By your mathematics, we could convince seven million people not to breathe or we could just shut down one coal power plant and have the same impact on reducing emissions.

          No, governments are, somewhat sluggishly and half-heartedly going after the actual source of excessive levels of CO2 in our atmosphere – the burning of fossil fuels. The reasoning, if it isn’t clear, is as follows;-

          The vast majority of scientists educated in at least some of the relevant scientific fields are absolutely convinced that the data shows that human activity is tipping the climate into a warmth and instability that will cause, and already is causing, grave problems for every nations society and economy. They have shared this data transparently and openly and it has been extensively reviewed.

          The same evidence that points to an excess of greenhouse gases as as a driver of climate change also points to the idea that this calamity can be avoided or at least reduced by deliberately transitioning the global economy (energy supply, transport etc) from one powered by fossil fuels to one that combines low/zero emissions technology with improved energy efficiency. (The good news here being that this transition represents a real economic and business opportunity.)

          The majority of economists have argued that the cheapest ethical and least invasive way to achieve this transition is to put a price on industrially produced CO2 emissions either via emissions trading schemes or a direct price on CO2 via taxes. It simply becomes something to factor into business calculations and each business works out for themselves how they can reduce their costs (by reducing emissions) and increase their benefits (lower emission technologies become economic winners)

          There’s no conspiracy. Just a real problem and governments trying to use the best advice they have to find practical ways to solve that problem.

          Feel free to reply to this if you want Rob, but I’m unlikely to be entering into further dialogue, simply because it’s a bit of a time sink. One thing I would like to acknowledge is that although we have very different perspectives on the issue, we both are passionate about the implications of government policy in this area on peoples lives and we both have made some attempt to apply our reason to understanding the issues involved . Thanks for taking time to share your perspective.

  3. Pelton Sequira Avatar
    Pelton Sequira

    The main reason for Global Warming is the burning of fossil fuels (coal, oil, gas) and the conversion of forest-lands to other uses (80% of the original forest cover on Earth has been cleared, fragmented or degraded). Offsetting your carbon footprint by planting trees is an effective direct method to contribute toward reversing climate change.

    1. Brian Avatar
      Brian

      What you meant to say is plant a tree, thats a good thing. However, the main reason for global warming or cooling is the sun, as is being demonstrated right now. CRU (land/SST) is showing .1C drop in temps since 05, which coincides with an abnormally weak solar cycle 24. We are only half way through 24, how much more will temps dip before the peak of 25? What if 25 is equal in magnitude to 24, how much further will temps drop? The solar output in conjunction with a weaker PDO, will show just how uncoupled CO2 is to temps…. I do agree though, plant trees and reinvigorate the earths ability to naturally remove CO2.

      1. MorinMoss Avatar
        MorinMoss

        Deniers have been saying for a long time that Earth is carbon starved and plant life would respond positively to increased levels of CO2 so why is it necessary to plant trees?

        And the correlation between solar activity and global temp is not as strong as you’d think, especially over the last 40 yrs.

  4. Brian Avatar
    Brian

    Bill Mckibbon never stretches the truth, no never! Anyway, these models he has, are saying they predict 500 gigatons is a tipping point, forgot or possibly better put were ill equipped to predict the current 17 year hiatus of warming globally. Now do not take a skeptics word on it, the Under Secretary of Alarmism Gavin Schmidt just tweeted friday that our current models have erroneous assumptions. I would hate to assume, although in this case I will, those erroneous assumptions are in our climates sensitivity to CO2. I think the world will be shocked when the IPCC publishes AR5 and the ‘new’ sensitivity to a doubling of CO2 will be about 40% lower than AR4, although from what I am reading, they have let upper bounded uncertainty go wild…. Meaning they want to tell the truth, demonstrating what real sensitivity will be but they also what to leave the door open for alarmist to scream the ‘sky is falling’.

    It is time for this cherade to be up, yes CO2 causes warming, no it is not causing all the warming at the end of the last century. Most of it was natural variability and we will see that as temps begin to drop a little over the next decade and a half.

    Australia, if you want to handcuff your economy, sorry that is your choice, as for America, you may have invaded the liberal institutions, that easy liberals are morons. You will never get your carbon tax, as if paying more for energy would ever help a warming climate. Having plentiful cheap energy would be the best hope for combating man-made climate change, if it was actually true.

  5. agsb Avatar
    agsb

    Humanity produces 500 gegatons of CO2 and yet the centration of CO2 in the atmosphere is still 0.04%. It took 300 years to go from 0.03% to 0.04% and 1 in 30 molecules of CO2 is manmade meaning 29 our of 30 molecules of CO2 comes from natural sources. Add to this is the scientific fact that CO2 is a poor greenhouse gas with emphasis on “poor”. The author sure is science illerate.

    1. thin_king Avatar
      thin_king

      .003% to .004% increase is, proportionally, a 33% increase. And to have this happen in the mere geological eye-blink of 300 years – an unprecedentedly rapid rise, at least over the last 800, 000 years, would surely suggest to any rational person that this is at least worthy of taking a serious look at. Check out this video to visualise what this actually means – http://www.youtube.com/watch?v=SXHDwdd7Tf8

      I’m not sure you’re in a position to accuse the author of being “science illiterate” (sic)

    2. agsb Avatar
      agsb

      Look I have a degree in Chemistry and wrote my senior thesis at the University on Global Warming. If you do the math and know Organic Chemistry as well as InOrganic Chemistry, know about molecular orbitals then you will realize that CO2 is a very, very weak greenhouse gas. If you also study the Krebs Cycle in Biology you will see all living things on Earth expel CO2 to live.

  6. ectogamit Avatar
    ectogamit

    The biggest myth about global warming is man made global warming.

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