Image for Doing the Climate Maths with Bill McKibben

Prominent American climate change activist and author Bill McKibben recently visited Australia on his ‘Do the Maths’ tour.

The ‘Do the Maths’ movement arose out of an article McKibben wrote for Rolling Stone magazine back in July last year called ‘Global Warming’s Terrifying New Math’.

That article became the most shared piece in Rolling Stone’s history, and I strongly suggest you read it: McKibben writes with more power and authority on the subject of climate change than just about anyone else around.

You can find the link below at (1). However for a quick overview of McKibben’s work, I’ll summarise his thesis here.

To do the maths with Bill McKibben you don’t have to be any kind of maths genius, you just have to understand three simple numbers:

The First Number: 2 Degrees Celsius

All the science, and the global agreement that almost every country in the world including Australia has signed on to, agrees that the absolute upper limit for ‘safe’ levels of global warming is 2 Degrees C.

Beyond this the science tells us we have an 80% chance of triggering climate change so severe it will bring to an end to the relatively stable climate of the 10,000 year Holocene epoch in which human civilization as we know it developed, resulting in destruction of ecosystems and death of species, including humans, on a mass scale(1).

It’s worth stating the obvious that it would therefore be in humanity’s utmost self-interest to limit global warming to below 2 Degrees C.

The Second Number: 565 Gigatons

565 gigatons is the calculated amount of CO2 we can ‘safely’ emit before we reach the 2 Degrees C limit. 

After decades of inaction on global warming, we’ve waited so long to do anything serious about carbon dioxide emissions that we now don’t have anything like a 2 Degrees C of temperature buffer to play with.

The world has warmed .8 Degrees C since humans first started burning fossil fuels, meaning we’ve used up nearly half of the allowable temperature rise already. And as McKibben says, since this .8 Degrees C rise has caused the Arctic to melt and the acidity of the ocean to increase by 30% (1), we’d be flat-out fools to find out what an additional 1.2 Degrees C will do.

However if we accept that 565 gigatons is the amount of CO2 that can be emitted before we overshoot the 2 Degrees C threshold , this figure gives us our carbon budget: the amount of CO2 we can expend into the atmosphere before we have an 80% likelihood of tipping the world into runaway climate change.

The Third Number : 2,795 Gigatons

2,795 gigatons is the amount of carbon dioxide that would be emitted if all the known fossil fuel reserves in the world were to be extracted and burnt.

Here is where the maths gets really important. Remember how anything over 565 gigatons we burn has an 80% chance of pushing the world into runaway climate change? Logically that means a full four-fifths, or 2230 gigatons, of CO2 must stay in the ground unused if humanity is to have any hope of avoiding climate catastrophe.

Let’s consider now the implications of this arithmetic. The fossil fuel industry has become the richest and most powerful industry in the world by giving humanity what it wants: cheap, abundant access to energy sources which have dramatically catapulted much of the global population into a standard of living that our ancestors could have only dreamed of.

But as is becoming increasingly apparent, this tidy back-scratching equation has now hit a roadblock. Not the usual pesky roadblocks of state and federal environmental laws holding up coal mining and fracking projects, or the fact that much of the world’s oil is located in politically unstable countries: as the industry has proved over the years, most of those problems can be solved by the application of money or force.

No, this roadblock is far more serious, because all the world’s billions and all the world’s armies cannot alter these basic laws of physics and chemistry: burning fossil fuels releases carbon dioxide into the atmosphere, the carbon dioxide molecules trap the sun’s heat, and the Earth warms as a result.

As the melting of the Arctic and the acidification of the oceans attests, the laws of physics and chemistry are irrefutable, immovable, and stubbornly immune to the spin of fossil fuel industry lobbyists and corporate PR hacks.

It’s not just a problem, it’s the death-knell for the fossil fuel industry, and they know it. You see, most of the book value of fossil fuel companies is tied to their assets, the fossil fuel reserves that these companies are in the business of finding and extracting.

If, as the maths tells us, four-fifths of those reserves must be kept safely in the ground to ensure the future of humanity and the planet, then by logical extension the value of those fossil fuel reserves will be written down. Instead of being able to extract all 2795 gigatons for immense profits, the fossil fuel companies can now only extract a fraction of that unless, to use McKibben’s phrase, we want to ‘run Genesis backwards’.

A big part of Mckibben’s ‘Do the Maths’ movement is the campaign urging investors to divest from fossil fuel stocks. He argues that not only is there an environmental and moral imperative to do so, but in a world that is rapidly moving towards renewables, fossil fuel stocks are simply a dud investment.

Not only is it ethically reprehensible to fry the planet our kids will inherit, it is also economically unviable to do so.

The growing carbon bubble, and its implications for investment in the fossil fuel and renewable industries respectively, is well described in Paul Gilding’s article ‘What’s Driving Climate Action? It’s the Market, Stupid’ (2). As Gilding points out, the key feature of market bubbles everywhere is their denial of obvious risks. To continue to bet investment dollars on the fossil fuel industry is to bet that in coming years the global community will do nothing to act on climate change, and accept without protest the business as usual scenario of a 4-6 degree celsius temperature rise this century with all that portends for the fate of our children, our grandchildren, and all life on Earth.

I may be wrong, but I just don’t think that’s a bet many rational people will be willing to make when the true consequences of the fossil fuel industry’s current trajectory become apparent.

Unsurprisingly, as the writing on the wall becomes increasingly clear, the fossil fuel industry is becoming more desperate in its attempts to continue what it sees as its rightful business of supplying carbon intensive fuels to world markets, regardless of the outcome for the planet.

You can see this clearly in the case of the coal industry, which, as the supplier of the world’s dirtiest and most polluting source of carbon, is the industry which McKibben has most firmly set in his divestment campaign sights. In an extraordinary speech (3) to the Sydney Institute last week, Australian Coal Association CEO Nikki Williams described anti-coal activists like McKibben as professional and well-resourced ‘eco-warriors’ who use tactics akin to ‘guerilla insurgencies’:

‘The war against coal and fossil fuels in the name of climate should be exposed , should really be exposed for what it is – an attempt to snooker development by stealth.  It’s often an affront to democratic values while posing as legitimate people power. Anti-development activists are attempting to bludgeon society with a singular value set that has the capacity to transform our world in ways that most of us would not endorse…I do question the motives of people and of movements whose objectives are not aligned with the broader interests of the society in which we live.’

Ms Williams, like many fossil fuel representatives, is trying to paint McKibben and other coal activists as fringe radicals, impeding the work of the good honest citizens of the fossil fuel industry by advocating a shift in the world’s energy supply that she asserts ‘most of us would not endorse’.

If ‘most of us’ means members of the fossil fuel companies then Ms Williams is probably correct.

However if we take ‘most of us’ to mean the inhabitants of a planet that is rapidly heading towards dangerous climate change, due in large part to the burning of coal, then Ms William’s argument is on shakier ground.

It’s becoming obvious that, as more and more people ‘do the maths’ on what carbon emissions are really doing to our climate, a great shift in the energy economy away from fossil fuels and towards renewable energy sources is not only necessary environmentally and morally, it’s also the only path that makes sense economically.

As for climate activists being radicals, as McKibben points out in his speech to the National Press Club (4), the real radicals these days work at coal companies:

‘If you’re willing to fund your desire for replica Titanics by altering the chemical composition of the atmosphere, then you’re a radical on a scale that would make any 60s hippie blush.’

All over the world, everyday citizens like you and me are doing the maths and coming up with the answer that urgent and widespread action on climate change is needed now.

The fossil fuel industry, with the support of right wing political factions and privately owned media outlets, have managed to obscure, deny, and suppress the facts about climate change for decades, but their time is drawing to an end.

Reality is quickly overtaking them, and they know they can’t keep doing what they do for much longer. On their side they have trillions of dollars of wealth and a pathological disregard for the balance of life on Earth in favour of the balance of their bank accounts.

As ordinary people, we can’t fight them with money, but the good news is we don’t have to.

We just need to do the maths, all of us, then demand a shift to an economy that’s based on clean renewable energy instead of dirty fossil fuels.

Be assured, the fossil fuel companies don’t want you to do the maths. For the sake of this planet, and all the life on it, make sure that you do.


1) Bill McKibben, Rolling Stone article 19 July 2012 ‘Global Warming’s Terrifying New Math’: You can also watch the ‘Do the Math’ movie on YouTube:
2) Paul Gilding, Renew Economy article 4 April 2013 ‘What’s Driving Climate Action? It’s the Market, Stupid’ :
3) Nikki Williams, speech to the Sydney Institute 22 May 2013 ‘Politics and the Australian Coal Industry – What’s Next?’ :
4) Bill McKibben, speech to Canberra Press Club 6 June 2013 ‘To my Foreigner’s Eye’:

Pic: Rolling Stone

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Miriam Moriarty is a Tasmanian writer with a focus on the environment and society.

• Peter Boyer, in Comments: Thank you Miriam, for bringing our attention to McKibben’s unarguable case for getting out of fossil fuels. But like the voters who’ve stopped listening to Gillard, the people who need to read and heed this remain disengaged. We need that critical mass of minds sufficiently outraged to make a noise that can’t be ignored. We have managed a lot of outrage in Tasmania in defence of our forests. Now it’s time to lift our eyes and expand our horizons. May others join you in a rising chorus against fossil energy and its hugely powerful friends who would have us ignore the maths and delude ourselves that doing nothing is an option.

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