The push for net zero

The UK has some of the most ambitious environmental targets in the world, thanks to legislation passed by Theresa May's government in 2019, which committed the nation to reducing carbon emissions by 100% by 2050. Britain was the first of the G7 industrialised countries to do so.

That doesn't mean it is committed to eradicating all emissions; but by that date, any produced must be offset by capturing carbon from the atmosphere, or by planting trees and the like. Net zero is fundamental to the UN's Paris climate change agreement, which committed the world's nations to keeping temperature rises to no more than 2°C above the pre-industrial average, and ideally no more than 1.5°C, in order to avert catastrophic climate change (we have already passed 1°C).

Today, more than 140 countries (and 90% of the world economy) have net-zero targets, though fewer than 30 have enshrined them in law.

What would moving to net zero entail?

The Government aims not only to decarbonise our electricity supply by 2035, but to expand it vastly to power cars, heat pumps and the like. Progress on decarbonising electricity has been rapid since 1990: in 2023, 51% of the UK's electricity was zero-carbon, but the rest – notably the 32% coming from gas – will have to be replaced, probably with nuclear, wind and solar. Wind and solar, being intermittent, will also need new and unproven energy storage systems.

The Government's climate adviser, the Climate Change Committee (CCC), estimates that electricity supply will need to double by 2050. It has been projected that this will require 286,000 miles of new onshore electricity cables. The challenge is "mind-boggling", said Sir John Armitt, chair of the UK's National Infrastructure Commission.

How much will this cost?

Trying to estimate the costs of a policy goal that will take the best part of three decades to realise is very difficult; but the sums are likely to be vast. In 2020, the CCC estimated that reaching net zero will require investments of £50 billion a year by the end of the 2020s, and a total of £1.4 trillion by 2050 (roughly the equivalent of £1,700 a year for every household).

Other projections are even higher. The McKinsey Global Institute estimates that an annual average of 7.5% of national economic output, or GDP, must be spent on physical assets to hit net zero by 2050. However, these figures may be more affordable than they sound.

How are they affordable?

Boilers, cars and power plants are continually being replaced anyway, so incremental increases to replace them with greener alternatives are not prohibitively expensive: McKinsey Global Institute estimates that it will increase spending by only 2.8% of GDP. Besides, upfront costs – to industry, consumers and the taxpayer – will be offset, in time, by some savings. Consumers who insulate their homes will see their bills come down. A driver who spends £1,000 a year on petrol could spend as little as £300 charging their electric car.

And there may be unexpected savings, too. The price of solar, for instance, became 88% cheaper during the 2010s. We are still, though, talking about very big sums, most of which will fall on the Government and, ultimately, the taxpayer. The cost of a new air-source heat pump, for instance, is around £10,000, compared with perhaps £3,000 for a new boiler – affordable only because a £7,500 grant is available in England.

Is net zero worth it?

Critics of the UK's net-zero targets argue that they were passed with too little scrutiny of the costs and sacrifices involved. They point out that the UK alone (which accounts for about 1% of global emissions) will have little impact on climate change so long as the likes of the US and China (which together account for some 45% of emissions) keep polluting.

On the other hand, Britain is among the top 20 emitting countries, with a high per capita rate, and a large share of cumulative historical emissions. There will, of course, be no global progress without swift national action. And if the rich world invests in green tech, it can be spread to the developing world too. Besides, China and the US now also have net-zero targets (albeit not enshrined in law).

Will we get there?

It's difficult to say. "Although the economics of decarbonisation are manageable, it is the politics that are hard," said The Economist. The most recent YouGov poll, from 2023, suggests a clear majority, over 70%, in the UK support the net-zero target in principle. But even very modest environmental policies tend to attract criticism if they affect people's finances.

Backbench Conservative MPs have set up a Net Zero Scrutiny Group to fight on the issue, and last year Rishi Sunak delayed a ban on new petrol and diesel cars from 2030 to 2035. There is a growing sense that net zero may become a "wedge issue" in British politics between the Tories and Labour. This may delay progress along the way.

Britain's report card

The Government likes to boast that Britain is a "world leader" in the quest to reach net zero by 2050, "far ahead of every other country in the world". In some ways, it is: UK greenhouse gas emissions have fallen the fastest of any G7 country since 1990 (they're down almost 50%, compared with 24% in France, and no reduction at all in the US).

But the UK was more carbon intensive to start with: France, for instance, has long relied heavily on nuclear for its power generation, meaning its per capita emissions were lower than Britain's in 1990 – and still are today. Critics say that Britain has had success so far by picking off lowhanging fruit – eliminating coal-fired power stations, for example. And at a time when we need to reduce emissions by half again in the next 14 years if we're to hit interim net-zero targets, there are signs that progress is slowing.

A CCC report in June found that fewer homes were insulated last year than in 2021; that homes still being built will need to be retrofitted with low-carbon heating and efficiency measures, because building standards haven't been revised; and that decisions to approve a new coal mine in Cumbria and oil and gas fields in the North Sea would undermine efforts to hit the 2050 target. Its verdict? Must do better.