The Reality Gap in the Push to Close the Global Warming ‘Emissions Gap’ in Paris

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Year by year, the great transition away from the world’s risky carbon-based path to progress is said to be just around the corner. This year’s Emissions Gap report from the United Nations Environment Program, aiming to energize Paris climate talks next month, was released today with this headline:

Unprecedented Momentum for Climate Agreement in Paris, But Achieving 2 Degree Objective Contingent upon Enhanced Ambition in Future Years

The message? You’re doing great, world, but raise your ambition some more and we’ll really get on track toward a safe climate.

You’ll be hearing the phrase “emissions gap” a lot in coming weeks. This is the difference between countries’ pledged commitments to reduce emissions of heat-trapping greenhouse gases after 2020 and scientifically calculated trajectories giving good odds of keeping global warming below the threshold for danger countries pledged to try to avoid in climate talks in 2010 (to “hold the increase in global average temperature below 2°C above pre-industrial levels”).

Under the climate treaty process, these commitments have become known as “Intended Nationally Determined Contributions” (the shorthand is INDCs; the World Resources Institute has a great set of related resources.)

The problem is that year-by-year evaluation of tweaks in such short-term plans completely misses the monumentally harder challenge that can be seen when you look at curves out through the rest of the century. Most such pledges don’t go beyond 2030, and those from developing countries are mostly “conditional” — they’ll proceed if wealthy countries pay the cost or otherwise help.

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A portion of a graphic in a United Nations Environment Program report shows the gap between commitments for cuts in greenhouse gas emissions filed with the United Nations by the world's nations (the orange band) and a track (blue) deemed safe. The gray area reflects projections with no policy. Yellow is existing policies. Credit UNEP.org

This portion of a graph in the U.N.E.P. gap report shows the short stretch of time and emissions rates it focuses on in the context of the grander challenge. Click here to see the full graphic and here for a nice Carbon Brief discussion.

Lots of U.N. officials and climate campaigners are pressing for Paris to produce a ratchet-style mechanism that boosts the scope of such pledges every five years or the like. But there’s a lot of magical thinking in all of this when you zoom out from this myopic way of defining progress.

There are enormous assumptions in most calculations, including the assumption that “carbon negative” technologies, like capturing CO2 from power plants burning biomass, can be done at a scale remotely relevant to the climate problem (to be relevant one needs to be talking in gigatons of avoided CO2 emissions per year — each a billion tons).

I’ll be writing soon about ways some scientists have proposed (here and here) to integrate commitments for boosting basic research, development and demonstration on next-generation energy options into the treaty process. In the meantime, here are a few sobering, but valuable reactions to the latest emissions gap news:

Here’s Guido Schmidt-Traub, a leader of the Deep Decarbonization Pathways Project assessing how countries might contribute to the grander task of avoiding dangerous warming:

It puzzles me how people can conclude that needed technologies exist today when they only look at emission reductions through to 2030. The really hard part starts thereafter. Since every new power plant built today will still be in operation in 2050 the structural transformation of energy systems must start very soon. To understand how energy systems must be transformed over the next ten years we need a longer-term view through to 2050. If one looks at such pathways the technology challenges become very clear indeed – you just need to compare required mid-term technology penetration rates with the IEA roadmaps. If, however, we do not worry about post-2030 then UNEP might well be right.

As an example of what the Deep Decarbonization project does, you can read the 2014 pathways report for the United States through 2050 here and here’s the 2015 synthesis report summarizing similar studies in 16 countries.

Oliver Geden at the German Institute for International and Security Affairs sent this reaction:

The message is the same as every year: There’s a large emissions gap that has to be closed to keep warming within 2 degrees. But if the world starts to act now, we can still make it.

It’s remarkable that the message stayed just the same since 2010, although emissions have increased continuously. As already anticipated in my Nature article in May 2015, this conclusion can only be reached by shifting the reference year and taking “negative emissions” into account.

Originally, the gap had been calculated for 2020, and it hasn’t decreased over the years. In the meantime, scientific advisers should have reached a point where they tell climate policymakers that it isn’t possible to reach the 2C target anymore (since the 2020 gap can’t be closed). Instead, they shift the reference year to 2025/2030. And while the first four Emission Gap reports (2010-2013) made it very clear that the global emissions peak would have to be reached before 2020, the report downplays this aspect now.

It’s only possible to keep the 2C target alive with a growing share of “negative emissions” being integrated into the models, primarily the combination of bioenergy and carbon capture and storage.

As the U.N. Framework Convention on Climate Change has showed in its INDC assessment last week, by 2030 almost 75 percent of the remaining carbon budget will already be consumed, the total budget by around 2036-37. “Negative emissions“ simply work like a “carbon debt” mechanism, but it’s somewhat dubious to count on “payback” starting in 2050.

In these ways, the emissions gap report gives the questionable impression that despite increasing emissions there’s always a way to reach the 2C target, it’s always “five minutes to midnight.”

Brad Plumer looked into these issues for Vox after other assessments of the global emissions gap were released last month.