The Guardian’s “100 Months To Save The World”
By Paul Homewood
Eight years ago, the Guardian launched its “100 months to save the world” campaign, a series of monthly posts by Andrew Simms.
The basic message of that first article was that we were all doomed unless we transformed our economy to look something like Cuba’s.
It is worth emphasising that this was not 100 months to get some sort of climate agreement. In Simms’ own words:
Because in just 100 months’ time, if we are lucky, and based on a quite conservative estimate, we could reach a tipping point for the beginnings of runaway climate change. That said, among people working on global warming, there are countless models, scenarios, and different iterations of all those models and scenarios. So, let us be clear from the outset about exactly what we mean.
The concentration of carbon dioxide (CO2) in the atmosphere today, the most prevalent greenhouse gas, is the highest it has been for the past 650,000 years. In the space of just 250 years, as a result of the coal-fired Industrial Revolution, and changes to land use such as the growth of cities and the felling of forests, we have released, cumulatively, more than 1,800bn tonnes of CO2 into the atmosphere. Currently, approximately 1,000 tonnes of CO2 are released into the Earth’s atmosphere every second, due to human activity. Greenhouse gases trap incoming solar radiation, warming the atmosphere. When these gases accumulate beyond a certain level – often termed a "tipping point" – global warming will accelerate, potentially beyond control.
In other words, if we did not take action to immediately start cutting emissions, within eight years it could be too late to do anything about it.
The “100 month” figure was, apparently, not just plucked out of the air, as Simms goes on:
So, how exactly do we arrive at the ticking clock of 100 months? It’s possible to estimate the length of time it will take to reach a tipping point. To do so you combine current greenhouse gas concentrations with the best estimates for the rates at which emissions are growing, the maximum concentration of greenhouse gases allowable to forestall potentially irreversible changes to the climate system, and the effect of those environmental feedbacks. We followed the latest data and trends for carbon dioxide, then made allowances for all human interferences that influence temperatures, both those with warming and cooling effects. We followed the judgments of the mainstream climate science community, represented by the Intergovernmental Panel on Climate Change (IPCC), on what it will take to retain a good chance of not crossing the critical threshold of the Earth’s average surface temperature rising by 2C above pre-industrial levels. We were cautious in several ways, optimistic even, and perhaps too much so. A rise of 2C may mask big problems that begin at a lower level of warming. For example, collapse of the Greenland ice sheet is more than likely to be triggered by a local warming of 2.7C, which could correspond to a global mean temperature increase of 2C or less. The disintegration of the Greenland ice sheet could correspond to a sea-level rise of up to 7 metres.
In arriving at our timescale, we also used the lower end of threats in assessing the impact of vanishing ice cover and other carbon-cycle feedbacks (those wanting more can download a note on method from onehundredmonths.org). But the result is worrying enough.
We found that, given all of the above, 100 months from today we will reach a concentration of greenhouse gases at which it is no longer "likely" that we will stay below the 2C temperature rise threshold. "Likely" in this context refers to the definition of risk used by the IPCC. But, even just before that point, there is still a one third chance of crossing the line.
So, what has happened to emissions of CO2 since 2008? Simms recognised that the West had to lead the way:
Deflecting blame and responsibility is a great skill of officialdom. The most common strategies used by government recently have been wringing their hands and blaming China’s rising emissions, and telling individuals to, well, be a bit more careful. On the first get-out, it is delusory to think that countries such as China, India and Brazil will fundamentally change until wealthy countries such as Britain take a lead.
Well, since 2008 UK emissions have fallen by 22%. Unfortunately, though, the rest of the world’s emissions have risen 9%, utterly dwarfing our tiny little saving.
You could say that it is delusory to think that countries such as China, India and Brazil will fundamentally change, regardless of anything we do!
Plainly then, if Mr Simms is right, we should all be on the verge of climageddon by now .
Tomorrow, we’ll look at the state of the climate to see if he was right.