The COP-27 meeting at Sharm-el-Sheikh has once again disappointed climate activists, who expect breakthroughs which never come from these monster get-togethers.

After a brief dip through the COVID-19 lockdowns in 2020, greenhouse gas emissions rose again in 2021 as economies rebounded. Renewables output is growing worldwide but not quickly enough to offset rising demand for energy in the developing world and the resort to coal in place of Russian gas in European power stations.

Emissions are back on a trajectory which will not keep the mean temperature increase below 1.5°C, the target agreed at the last COP. Many climate scientists believe even a 2°C warming is now unavoidable.

These gross emissions need to halve, relative to the year 2000 figure, if climate stability is to be attained over the next few decades. Since every nation represented at the regular COP meetings accepts targets along these lines as a worldwide policy objective, their reluctance to agree measures that bring down emissions needs to be explained.

The simple explanation is that, while it is in the interests of all that emissions be cut, it is best to leave the hard work to others. The planet has one atmosphere, damaged equally by emissions from all countries and all sources, but has 200 sovereign states. Each state gains if climate disaster is averted but cutting emissions is costly and each state has an incentive to pass the buck. The system agreed at the Paris COP meeting in 2015 requires that states adhere to the voluntary targets solemnly enunciated on that occasion. This is a system of self-policed national emissions targets. The measurement of national emissions is controversial but the system would be flawed even if the measurement problems could be fixed.

Everyone’s problem

While the excess of emissions worldwide is everyone’s problem, the costs of emission reduction is national and they differ enormously. Some countries should reduce emissions by a lot, because it is not too costly to do so, but they are unwilling to shoulder costs when the benefit accrues mainly to others. It would be simpler if universal levies and charges were imposed on the consumption of goods and services which entail emissions, letting output take place in the best locations, but the benefits would be unequally distributed and there is no alignment of interests.

This issue emerged again at Sharm-el-Sheikh in familiar form. Less developed countries argued that the effort required of them is unfair, not least because they played no great role in the industrial revolution and are responsible for only a small portion of the stock of greenhouse gases already in the atmosphere. Some of these countries could cut emissions at lower cost than rich countries but demand compensation for doing so. Compensation at adequate scale has proven impossible to agree. It would all be so much simpler if each country was a planet, fully incentivised to look after its own unique atmosphere.

Mitigation

Mitigation is the chosen course of climate policy, which means cutting emissions to whatever the climate scientists feel is a safe level. The alternative is adaptation, which means accepting further global warming and doing the best possible to ameliorate the negative effects. Adaptation is not favoured in the policy community because the costs are likely to be high and are uncertain.

Reliance on coal in less developed countries will not fall unless rich countries meet some of the costs, which is in their interests

Nobody knows for sure what happens if there is 4°C or 5°C of warming, and unconstrained growth in emissions could, according to some model-builders, see temperatures rise by even larger figures over the next century. That means loss of coastal cities and damage to food production capability, all difficult to predict but likely to cost far more than mitigation.

The system of national targets is essentially voluntary and requires a degree of international cohesion not much in evidence outside Europe. It will not be met unless technological solutions, including the next generation of nuclear power production and the electrification of transport and space heating, are accelerated. Reliance on coal in less developed countries will not fall unless rich countries meet some of the costs, which is in their interests. It would also help if countries with high incomes and cheap fossil fuels would mimic European policies. Next year’s COP will be held in the United Arab Emirates, where petrol costs 86c/l, less than half the typical figure in EU countries.