The proposition that global warming driven by greenhouse gas (GHG) emissions is a risk that needs to be dealt with has achieved a large measure of agreement among policymakers. The proposition that it has to be dealt with right now and at great cost has no such consensus.
One point to note is that the passion and intensity of the climate emergency movement has not been matched by an equivalent breakthrough in the underlying science and policy arguments. The main thrust of last year’s Intergovernmental Panel on Climate Change (IPCC) report was the greater likelihood of harm from given temperature increases.
It also appears to be generating stronger and more co-ordinated pushback than before. Read the letter from 500 climate scientists and professionals telling the UN Secretary-General there is no emergency. The sceptical consensus seems to have coalesced around the so-called ‘lukewarming’ thesis. (Here a slightly dated but very easy to read guide from a former science editor of The Economist.)
If you are wondering how this could play out, there are three issues worth keeping an on.
First, what happens to global temperature measures?
The case for rapid climate action derives much of its force from the calculation of a particular trend of temperature increase. The Economist (with a different science editor) says:
“The [IPCC] estimates that mean surface temperature is now 1°C above what it was in the pre-industrial world, and rising by about 0.2°C a decade.”
The thrust of the lukewarmer challenge is an argument that global temperatures have probably been increasing more gently (by 0.13°C per decade over the last 40 years using satellite, rather than surface, measurements). Climate modelling has typically predicted a rate twice as high as this, mainly because of the assumption that GHG emissions have a strong ‘forcing effect’ on temperature. The lukewarmers are not convinced by the explanations for why the forcing effect has not kicked in on the predicted scale.
On these measurement differences (and the modelling built on them) rests the efficacy of trillions of dollars of policy proposals – real money that could be spent on all sorts of useful things from new houses to eliminating malaria.
The next few years of temperature data and research look crucial. Without a decisive upward break in temperature measures, extreme climate change model projections, and calls for emergency action, become harder to sustain.
Secondly, what are the consequences of rising temperatures?
Calls for urgency put a lot of weight on feedback loops and accelerating levels of harm as we move into uncharted levels of atmospheric GHG levels. The Economist, again:
“… there must be thresholds and tipping points in a warming world …. For the most part the harm warming will do—making extreme weather events more frequent and/or more intense, changing patterns of rainfall and drought, disrupting ecosystems, driving up sea levels—simply gets greater the more warming there is.”
Lukewarmers believe that warming is likely to be less harmful and more within our capability to adapt. Indeed, some are a bit more aggressive. A paper for the Copenhagen Consensus argued that warming to date has been beneficial (because of improved greening and higher agricultural yields) and that this trend could continue until around 2070 (at which point net costs from things like increased water stress would become greater).
Don’t expect this debate to be resolved soon. A looming tipping point is more-or-less impossible to refute. But the political climate around it may change. Every year that the world sees growth in agricultural output and avoids a climate disaster probably reduces the intensity for urgent climate action.
Thirdly, what’s the rest of the world doing?
Two factors are at work here. Energy use is increasingly decoupled from economic growth in rich countries and the trend is getting stronger. US energy use has dropped 2% since its 2008 peak but the economy has grown 15%. At the same time, poorer countries are growing so fast that they are using a lot more energy and emitting more GHGs. China tripled its output of carbon dioxide in just 15 years.
Combine the two and you get a dramatic shift in the sources of global GHG emissions over time. By 2017, the share of GHG emissions from the US (15%) and EU (9%) had fallen behind China (28%).
A continuation of these trends would push rich Western countries’ share of global GHG output down from the current level of about 30%. For example, if India (currently 6% of global GHG output) were to emulate China, it would be like adding another EU’s-worth of emissions to the annual total.
This would put a greater premium on effective global collective action, and potentially reduce the emphasis on trying to persuade rich country voters to pay up-front for expensive decarbonisation.
So what are the options for rich country governments?
These trends play out in the medium term, while governments must operate in the short term. And in the short term, there seem to be two options.
One is to stay ahead of climate action demands. Britain’s government is trying to do this but the costs of a ‘climate emergency,’ might prove too much. When former PM Theresa May wanted to go for zero carbon by 2050, the Treasury had to remind her that – even with heroic assumptions about new technology – this would mean banning gas and oil central heating, limiting indoor temperatures to 19 degrees, scrapping the internal combustion powered vehicle fleet, a 20% reduction in beef, sheep and dairy consumption and less air travel – at a cumulative cost for the UK of £1 trillion.
Other governments seem more inclined to wait-and-see. The government of Singapore also says all the right things about international commitments in its public pronouncements. But go to the fine print and you find a story of carefully targeted and more cost-effective measures (eg, switching to natural gas for power, restricting car numbers, energy efficiency etc) coupled with a more achievable goal of “… [stabilising] greenhouse gas emissions with the aim of peaking around 2030”.
Climate emergency activism highlights more starkly the difference between these two approaches. Governments will have to decide. Recent experience from France, the US and Australia suggests that the median voter might be becoming less tolerant of more cost.