The climate change talks to be held in Paris this December (COP 21 in UN lingo) are all about how much risk to the livability of our planet we’re willing to accept.
And the dirty little secret is, we’re accepting a hell of a lot right now, and we’re imposing even more on our children and future generations.
- The agreed upon target, 2 degrees C, is dangerously high and the pre-agreements going into Paris assure we won’t even meet that;
- The best case assumptions built into the IPCC’s carbon budgets designed to stay below 2C assume a 34% probability of failure;
- Most of the IPCC carbon budgets require our progeny to invent and build a massively expensive technology to clean up the carbon we’re releasing. The effort would dominate the economic activity of their entire society, choking off other economic activity; and
- Even if we manage to hold temperatures to 2 C, the carbon budgets will assure that we’ll acidify our oceans and usher in irreversible sea-level rise.
Let’s look at the facts.
2 degrees C is too high, and COP 21 isn’t on target to meet it in any case: The press accounts are referring to the 2 C limit as the “maximum safe level.” Scientists are more careful, referring to it as a “speed limit” or “guardrail,” and even this phrasing implies a level of protection that the 2C limit simply doesn’t afford.
Doubt that? So far, human actions have increased the temperature by .85 degrees C over pre-industrial levels, and look what that’s done. We’re experiencing record-setting droughts; widespread desertification, an explosion in the number and frequency of forest fires; increases in extreme weather events; mass extinctions; irreversible melting of the polar ice caps, Greenland and large parts of Antarctica, and the centuries of rising seas and costal inundation this will inevitably cause; and we’re seeing the bow wave of a massive migration of environmental refugees. Finally, we’re acidifying the oceans, turning them into giant jellyfish incubators in which edible seafood can’t survive.
If that’s what .85 C has done, imagine what 2C would do. Or, better yet, don’t imagine, look to the geologic record. As James Hansen and 16 co-authors note in their paper, "Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling and modern observations that 2C global warming is highly dangerous."
Worse, the agreements countries have announced in preparation for the Conference (called “intended nationally determined contributions” or INDCs) clearly show that the Paris COP will fall far short of what’s needed to prevent us from exceeding even a 2 C temperature increase.
The IPCC’s Carbon Budgets --Playing Craps with the Planet: Settling on 2C as an acceptable limit is bad enough, but the way we are using carbon budgets borders on criminal negligence.
Carbon budgets are established to determine the amount of GHG we can emit, and for how long. The greater the probability of staying below 2C, the lower the carbon budget and the sooner we have to get off it. Similarly, if we wanted to limit warming to 1.5 C – something most scientists agree poses less danger to people, the planet and the oceans – then we’d have a lower carbon budget and we’d have to get off carbon sooner.
So, higher odds of success require lower carbon budgets, lower odds of success allow more carbon to be released.
The IPCC uses three scenarios based on the probability of staying below 2C. That’s appropriate, given the uncertainties inherent in forecasting a system as complex as the climate. But the probabilities it is using are a 66% chance of succeeding, a 50% chance and a 30% chance.
So, for example, if we wanted to have a 66% probability of staying below 1.5C, our total carbon budget would be 2250 tonnes of carbon dioxide. By the end of 2015, and the conclusion of the Paris talks, we will have burned through all but 200 billion tonnes of that budget. Since we are emitting about 40 billion tonnes per year (about 44 US tons), we will blow through the budget by 2020, the year in which the Paris agreements are to start being implemented. In other words, that ship will have sailed before any action is taken.
Contrast this with the carbon budget based on a 66% probability of staying below 2C, or 2900 billion tonnes of carbon dioxide (GtCO2e). By the end of 2015, we would have nearly 850 GtCO2 left, or twenty years worth.
Obviously, a better margin of safety would make sense; playing craps with the planet we live on is – to say the least -- irresponsible.
But the option to be prudent no longer exists.Here’s the sad truth: we’ve already blown past the carbon budgets required to have a 90% probability of staying below 2 C – let alone 1.5C.
Negative Emissions – or après moi, le deluge: There’s one other way of expanding carbon budgets: Pass the problem on to our children and their children, so we can burn more fossil fuels now and still appear to stay within our carbon budget. And that’s precisely what the IPCC carbon budgets do. They only work if we require our offspring to create extraordinarily expensive new technologies that will take massive quantities of carbon dioxide out of the air and safely sequester it.
No one knows how to do this, and the scale of this activity is so large it will leave little room for more productive economic activity.
To get an idea of just how crazy our current approach is, imagine you are about to board an airplane, when the engineer responsible for designing it tells you it has a 34% probability of malfunctioning. Would you proceed? Of course not.
A core precept of risk analysis and risk management is that dangers which are irreversible and consequential demand very high safety margins. People intuitively understand this, and that’s why the airplane example is so obvious. We’re genetically hard-wired to recognize risks that are proximate in time and place. We understand that when the alarms start sounding at 35,000 feet, we can’t simply exit the plane and grab another that’s flying by.
Yet, the same is true of our planet. If we screw it up, we can’t hop off and wait for another. But the scale of this danger is so large, and the time-frame sufficiently long (exceeding a single life-span) that we don’t experience this threat in the same way. Responding to this danger will require us to exercise wisdom, not simply rely on the genes we’ve been given by natural selection.
But when it comes to climate change, wisdom is obviously in short supply.
It's the physics, stupid: If we want a reasonable margin of safety for the world, we have to get off fossil fuels as soon as possible, preferably within the next five or six years.
Impractical? No more impractical than pretending it makes sense to adopt a carbon budget that risks global catastrophe simply because we failed take the action we needed to take in the past.
The amount of GHG we can emit without ushering in Armageddon is determined by physics, not politics. And as I said back in July, the approach we’re adopting in COP 21, poses an existential threat to humanity and the global ecosystem because "... in a clash between physics and politics, physics always wins."
The thing is, we have everything we need to get off fossil fuels within the next five to six years, except the wisdom and the political will.
 I have used figures for tons of carbon dioxide, whereas many of the IPCC’s numbers are expressed in tons of carbon. The IPCC also includes GHGs other than carbon, but other don't so you might see a variety of carbon budget numbers being used. The key is to always compare apples to apples. For those who wish, the conversion factor is: 1 ton of carbon is equivalent to 3.67 tons of carbon dioxide.
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John Atcheson is author of the novel, A Being Darkly Wise, an eco-thriller and Book One of a Trilogy centered on global warming. His writing has appeared in The New York Times, the Washington Post, the Baltimore Sun, the San Jose Mercury News and other major newspapers. Atcheson’s book reviews are featured on Climateprogess.org.