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The Paris Climate Agreement aims to keep the increase in global average temperature to below 2°C above pre-industrial levels. In an ideal world, the increase would not go beyond 1.5°C. We are, however, routinely told that the latter is a geophysical impossibility. Various reports based on climate models released just this year say we can continue to emit carbon at current rates for four years before our quota runs out – meaning that to keep temperature rises below 1.5°C, we would need to reduce emissions to zero after four years. Forever.
However, a report out today in Nature Geoscience contests this, arguing that what appear like small discrepancies in climate and Earth models actually make a significant difference to estimates. The team, led by University of Oxford post-doctoral research fellow Richard Millar, corrected these to produce its own timeline for the countries bound by the Paris agreement: we have 20 years at the rate of current emissions, or 40 years if we decline emissions in at a linear rate.
“1.5°C was thought of as an impossible goal,” says Millar. “Our study says it’s not quite a geophysical impossibility. It’s just very, very difficult.”
“Whether that makes things easier or not depends on how you look at it. In some ways it’s easier to say it’s not physically possible, we don’t even need to try to achieve it. We are saying it’s just about possible, physically. That’s a very big challenge for policymakers.”
Millar is optimistic, however, having seen a decrease in the price of renewables, and reductions in emissions in China in recent years. ”Hopefully that won’t rise after a pause, so it’s encouraging,” he says.
But reducing emissions to zero will require a strengthening of the Paris pledges for 2030. “In lots of cases, policymakers haven’t connected the dots in terms of what it means to truly reach zero emissions. There is a lack of focus in general in technologies that will reduce emissions.” This is where nations need to focus for the near and longterm, he argues. To get to zero emissions, we will need to look at technologies for transport, agriculture – every area. Some of these industries will be harder to tackle than others, so we need to be vigilant and proactive now, if there is a chance of abiding by the targets.
Read more: The 10 facts that prove we're in a climate emergency
Millar says the models he and his colleagues used were straightforward. They simply account for past “inevitable” discrepancies – “it’s a very hard task, building a comprehensive model of the whole Earth, and small discrepancies are expected”. Past models gave us “implausibly small carbon budgets,” says Millar. “They don’t stack up with the real world in terms of what we see today from human-induced climate change.”
As we near deadlines made in earlier studies, “things we previously thought of as having little effects start to matter,” he explains, “like what exactly is the warming today and what is considered pre-industrial”. “It’s only since the Paris Agreement that the community started to tackle these issues directly.”
The most high-profile case of the climate change battle being damaged, has been this year’s withdrawal from the Paris agreement by the US in June. This week the US appeared to, once again, flipflop on another major policy decision though, when Secretary of state Rex Tillerson and national security adviser HR McMaster told the press the US would be open to renegotiating the Paris terms. “We want to be productive. We want to be helpful,” Tillerson said.
Millar is not holding his breath on this one. “It’s hard to know what to make of a lot of what the administration in the US does, and whether this statement will be reversed in a few weeks’ time or not. What has been important though has been the reaction from the business community in the States, which have really taken on the task themselves quite strongly. Groups have been galvanised by the lack of direction that is going to come from a federal level. The economics of the situation are starting to kick in.”
It’s no secret that key elements of the US administration frequently do not agree with Trump’s policy u-turns. Defense Secretary James Mattis, for instance, has spoken of the threat of instability climate change brings, and the Pentagon is abiding by the results of the 2014 Climate Change Adaptation Roadmap, which details how to assess and mitigate the effects of climate change. It is achieving this simply by choosing its words carefully and not focussing on the causes of weather events (human-induced climate change).
This article was originally published by WIRED UK
