On 22 April 2016, the leaders of 130 countries will meet at the United Nations in New York to sign the Paris climate agreement. But according to Chris Mooney at the Washington Post, these political leaders (not for the first time) have absolutely no idea what they are signing up to:
“The urgency of signing the agreement has been underscored by recent climate news and events, including devastating coral bleaching around the world, newly shattered temperature records and disturbing news about the vulnerability of Arctic permafrost and the Antarctic ice sheet.
“But there’s a problem: It is far from clear that, even if governments sign on to the Paris agreement and start implementing it rapidly, they actually know how to limit warming to 2 or 1.5 degrees Celsius.”
Mooney argues that there are three key problems. First, while the 2 degree limit is a good media device for encouraging efforts to decarbonise the economy, there is little agreement about what 2 degrees actually means:
“The problem is both that it will be hard to define where the actual threshold lies, and also hard to be sure when we’ve crossed it, given differing baselines and periods of analysis, and the fact that temperatures will always fluctuate up and down.”
Second, while there is a consensus that we need to reduce carbon emissions, there are broad disagreements about the amounts of carbon we can still safely burn. These are further complicated because of uncertainty about the impacts of other greenhouse gases like methane and nitrous oxide:
“These uncertainties mean that, from the year 2016 and on, for a 66 percent likelihood of staying under 2C, the carbon dioxide budget is about 850 billion tons, but that’s plus or minus 450 billion tons. That’s a pretty big uncertainty in a situation where we’re emitting well over 30 billion tons of carbon dioxide per year.”
Third and perhaps most worrying, the treaty is based on future technologies and policies that do not currently exist:
“The so-called ‘integrated assessment models’ that are employed to determine if and how we can actually stay under a given temperature threshold often include the assumption of new technologies that don’t exist yet, or new policies that aren’t in place, to help us get there. An example of the former would be massive carbon dioxide removal from the air — and an example of the latter would be setting a global price on carbon emissions.”
The trouble is that the artificial precision in the Paris thresholds and carbon budgets can very easily result in complacency when, in reality, we may need far more radical action immediately. As Moody notes, by pretending that we know where we are going, we risk rapidly arriving at a point where we realise that we have absolutely no idea how to get there.