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Carbon budgets

In November last year, the independent Committee on Climate Change delivered its advice to the Westminster parliament on setting the fifth carbon budget, covering the period 2028-2032. This week, the Commons Select Committee on Energy and Climate Change has recommended acceptance of the budget, to no-one’s great surprise. It has also gone further and proposed a ‘carbon intensity target’ for the power sector of 100g/CO2 per kWh. Under the terms of the Climate Change Act, the government is now obliged to give this budget legal force before the end of June.

The country is already committed to meeting certain emissions targets taking us up to 2028. This fourth carbon budget was judged by many observers to be tight but achievable. Whether the following one will prove to be is a moot point. And, if the budget is not met, then technically a law has been broken. What can be done to punish an elected government making and implementing policy on behalf of the whole country is another matter.

It is ironic to see once again that the UK, the most sceptical of member states about membership of the EU, was the first not just to support the bloc’s agreed emissions reduction plans, but to gild the lily by passing the Climate Change Act in 2008. Only five MPs, all Conservative, voted against the Bill, which brought the Committee on Climate Change into being and committed the government to reducing the country’s net emissions of greenhouse gases in 2050 by at least 80% relative to 1990.

Not only was the UK the first country to place itself under a legal obligation to reduce emissions by a certain amount, but the final legislation went considerably further than the target of 60% originally recommended by the Royal Commission on Environmental Pollution. An important part of this proposal was the restriction of emissions counting to terrestrial sources, ie not including shipping or aviation, as some had called for.

The advice from the Royal Commission was based on the IPCC Second Assessment Report, which suggested that the target of limiting the rise in average temperatures to 2°C could be achieved by keeping atmospheric carbon dioxide levels to a maximum of 550ppm. However, there was a pivotal conference held in Exeter in 2005 (Avoiding Dangerous Climate Change), which concluded that even stabilising atmospheric CO2 at 450ppm would give only a 50:50 chance of meeting the temperature target.

Faced with a campaign to make the Bill even more ambitious, the Act that was finally passed set the current target of an 80% reduction in emissions, with an intention to include shipping and aviation in the total once an appropriate accounting system could be agreed upon.

This, of course, is based on the understanding that the assumptions made by the IPCC on the contribution of atmospheric CO2 to average temperatures are correct. As has been quite clearly established, the evolution of temperatures since the end of last century has singularly failed to follow the projections that currently form the received wisdom on this critical issue.

More recently, the Paris climate change agreement resulted in a commitment to keep temperature rises to below 1.5°. This is a barely credible figure given that many people already called into question the viability of the 2° target some years ago. Unless, of course, we are being prepared for the real possibility that 1.5° turns out to be closer to the truth than the official line because the hypothesised positive feedback mechanism on which the edifice of the dangerous anthropogenic global warming argument is base is incorrect.

In this case, we can imagine the next generation of politicians and climate change still congratulating themselves for mitigating climate change despite a (highly likely) failure to achieve global emissions targets.

In the meantime, the fifth carbon budget, which the government is expected to agree to, would see a reduction in emissions of 57% (against the 1990 baseline) by 2030, equivalent to an annual 1% decrease. In the words of the Select Committee “Should the Government deviate from the Committee on Climate Change’s advice for the fifth carbon budget, we will be looking carefully for a robust evidence-base on any alternative level proposed.”

There are two crucial questions which we should ask: is this budget achievable and what difference will it make? In the first case, achieving a 57% reduction will be very difficult. By far the easiest sector to ‘decarbonise’ is electricity generation, but this comprises only about 20% of total energy use. Transport, meanwhile, is nearly double that, and domestic and commercial heating account for most of the remainder. Some of the reduction will come about via increased energy efficiency, which will benefit everyone, but this cannot be the whole answer.

Although electricity generation is the easiest sector to tackle, it should be becoming obvious by now that radical decarbonisation is not possible without heavy investment in nuclear. Even then – with or without renewables – there will be a significant need for gas turbines to balance supply and demand. In other sectors, the problems are much greater: for example, car and lorry engines continue to become more efficient, but current electric cars can only make a fairly modest contribution to total miles driven.

In the case of domestic heating, the CCC envisages about 2.5 million heat pumps being installed in new houses and in those without access to mains gas by 2030.  The Energy Savings Trust puts the cost of an air source heat pump installation at £7,000 to £11,000, rising to £13,000 to £20,000 for a ground source system. Assuming an average cost of £10,000 over the next 15 years, that’s a total cost of £25 billion or about the likely total cost of the planned Hinkley C nuclear station, if it ever gets built. The cost would clearly be met mainly by taxpayers, since few householders would decide to invest that much in a heating system. Is this really likely?

But perhaps more important is the effect on global warming. Even if we assume that the current extended pause in any upward trend soon ends and temperatures rise at something close to the rate projected from the IPCC array of climate models, net global emissions are still likely to be rising by 2030. China’s energy intensity is certainly declining, and its current lower rate of economic growth has led to predictions of the country’s emissions peaking by 2025. But in practice there are many millions of Chinese who will continue to increase their energy consumption for many years to come. And India, which we hear less about, will overtake China as the world’s most populous country before too long and has no intention of restraining economic growth by reining back on power generation.

Where does this leave the UK and other developed countries determined to set an example? Almost certainly out on a limb, making their economies increasingly uncompetitive while much of the nominal emissions reduction is simply exported to less constrained economies. Sooner or later, the crunch will come and a Westminster government will find it politically impossible to agree to a proposed carbon budget. The question is, when?