Climate 2016: the curate’s Easter egg

How are we doing? American readers in particular could use a little perspective. Trump is not the USA, the USA is not the world. So: good in parts. I will leave out the record temperatures, droughts, floods here and there, and melting Arctic ice. You know all that and it’s bad, bad. But we are maybe not doomed – yet.

1. To start with the good news. Global industrial carbon emissions are about flat. The IEA says they are exactly flat at 32.1 gigatonnes of CO2 a year.

That’s 8.5 GT of carbon. I propose to use carbon rather than CO2 (1 unit carbon = 3.67 units CO2, by the molecular formula). Nobody can imagine a tonne of a gas. A tonne of carbon corresponds to about 1.3 tonnes of typical US hard coal, 1.2 tonnes of crude oil (with some variation).

The Tyndall Centre and the Global Carbon Project estimate global emissions including the hard-to-measure land-use changes and methane leaks. They find a slight rise: +0.7% in 2014, approximately constant in 2015, and up again by 0.2% in 2016 (provisional data excluding Q4). See here and Le Quéré et al here.  Global GDP growth was about 3%. We have decoupled GDP growth from industrial carbon emissions. There is still a little growth from land-use changes like deforestation.

2. A plateau isn’t enough. Emissions have to go down. Carbon Brief  has estimated the world’s remaining carbon budget at 222 GT for a 66% chance of staying within the 2 degree C target; 56 GT for the more demanding and prudent 1.5 degree target. I set up a few scenarios to show what these imply.

Sources and my calculations in a spreadsheet here.

The straight-line reduction paths are not realistic. An S-shaped logistic curve would be more likely for a technological transformation, but I don’t know how to model this. However, it’s good enough to show the scale of the effort needed. For 2 degrees, we have to cut emissions by 2% linear or 170 MT a year starting now, 2.17% or 190MT if we delay for 5 years. Should be doable. For 1.5%, it’s a staggering 730 MT a year or 8.35% linear, for a mere 11 years. Ouch. Delay makes it flatly impossible.

I infer that 2 degrees is plausibly attainable with effort, even with a fairly leisurely glide-path to zero in 2065. 1.5 degrees is impossible by mitigation alone.

3. Why are we stuck on an emissions plateau? You would expect the forces that produced the slowdown and decoupling from growth to keep working at the peak and start an actual reduction. The explanation seems to be this. The flatlining reflects a balance between the now clearly declining trend in coal and continued growth in oil and gas. Here’s the chart from the Global Carbon Project (slide 16).

The numbers:
Changes in consumption from previous year (source BP).
Year      2013       2014       2015
Coal  +2.0%    +0.5%    -1.8%
Oil     +0.2%    +1.0%    +1.9%
Gas    +1.9%     +0.6%   +1.7%

There aren’t full data for 2016, but the coal decline accelerated in China (-4.7%). In the USA it fell even more spectacularly, -17% over 2015. Growth in India did not make up for the slide in the two giants, and is itself slowing.

The death of coal is now a pretty sure thing. In several US states (Texas, Colorado) old coal plants are now more expensive generators than new renewables. A brand-new coal generating plant in Rotterdam has had half of its €1.7 bn construction cost written off already.

The growth in oil use reflects that in internal-combustion vehicles and in aviation. Electric cars are growing fast, but are still only 0.86% of annual new car sales, and an even lower proportion of the fleet. There is no immediate prospect of these uses slowing. The growth rate of EVs is so high (42% last year) that we can expect them to start having a real impact on gasoline use early in the 2020s. Three more doublings, taking 6 years at current rates, and the share will be 7%, five doublings (10 years) 27%. Electric buses are ahead of cars and already hold 20% of the Chinese market. Policy initiatives by cities like London may lead to another rapid switch in light commercial vehicles. The energy transition in land transport is a strong likelihood, but it will be delayed. Aviation? Commuter electric aircraft are being developed, but need a breakthrough in battery density. We may be stuck with expensive biofuels.

The real joker is gas. A good part of the decline in coal generation in the USA and the UK has come from substitution by gas. This is cheap for now, and allows either more efficient large baseload plants or cheaper peaker ones. Renewables have helped dig coal’s grave. But they are now competitive with gas on the unsubsidised LCOE of new build. Once built, their top place in the merit order cuts into gas usage as well as coal. This is only partly compensated by the greater use of gas peakers to backup wind and solar when they aren’t producing: a function which is itself coming under threat from cheaper grid batteries and cleverer demand management. It’s a complex and murky picture.

This pattern explains the political stance of the oil companies. They have abandoned coal: the faster coal shrinks, the more room for their gas. They will even accept a carbon tax to speed the euthanasia of coal, which has higher unit emissions than gas. They also work behind the scenes to hamper renewables, as with solar in Arizona and wind in Ohio and England. Exxon wants the USA to stay in the Paris Agreement, going to all the meetings and throwing sand in the gears of the transition.

The oil companies will not have an easy pass here. The economic advantages to utilities of wind and solar are now enormous, and the banks and investment funds are now on their side too. The Trump administration (the Goldman Sachs crowd) has for instance dropped opposition to offshore wind. You can’t seriously imagine a policy that would force utilities to burn gas against their interests.

4. Where does this leave our prospects?
Of my emissions scenarios for the 2 degrees warming target, the “five more years flat and then cut” looks by far the most feasible, even though it’s more expensive and riskier than starting now. It depends on the following realistic assumptions:

• continued decline in coal generation (sure thing)
• continued rapid growth in wind and solar (sure thing)
• continued rapid growth in electric vehicles (pretty sure thing, requiring overcoming obstacles to better batteries, but  with major impact delayed +/- five years)
• significant substitution of gas for generation by renewables and storage (more likely than not).

5. What if we go for the 1.5 degree warming target? We are already seeing significant climate disruption from the 1 degree warming we have already caused. I expect the next IPCC report to conclude that safety requires going firm on the 1.5 degrees. But this target is already out of reach by mitigation alone. So it will have to involve truly massive sequestration to mop up the overshoot. A crash research programme is needed, starting now.

Oh, and BTW, whatever fix is chosen will require a pretty uniform global carbon tax – not all of it rebated to the taxpayers, the sequestration is the first charge. A slice of socialist world government, more or less. Well, the Kochs and Exxon and all of us in our shiny freedom! cars have asked for it.

Salvation may be offered cheap, to the customer at any rate. But it’s never free. It does call for rather more cojones than the curate showed.