Could Sunak's green review threaten UK net zero?

The Prime Minister has said he wants to be honest about the "costs and trade offs" of tackling climate change.

In a statement yesterday Rishi Sunak said he was proud that "Britain is leading the world on climate change" and will stick by the agreements the UK has made internationally.

But he is considering watering down some of the government's biggest green commitments.

So, is the UK really a world leader on emissions cuts, and how would the kind of changes the PM is considering affect its efforts?

Importantly Mr Sunak says the government is still committed to the 2050 net zero target his predecessor, Theresa May, made law back in 2019.

Net zero means a country does not add any additional greenhouse gases like carbon dioxide to the atmosphere.

It is true the UK has been successful in cutting emissions compared to other countries.

Since 1990, emissions within the UK have fallen by 48.7% up to the end of 2022 - excluding international aviation and shipping - according to government data.

These cuts are greater than other countries in the G7 (Group of Seven), an organisation of the world's seven largest so-called "advanced" economies - although Germany has reduced its emissions at a faster rate compared with the UK since 2015.

But the cuts the UK has made so far are - arguably - the easiest ones.

They have largely been achieved by switching away from fossil fuels - coal, oil and gas - for electricity.

The biggest gains have been in electricity generation where emissions have fallen by around three-quarters since 1990.

Meanwhile the proportion of electricity generated by renewables - like wind and solar - has grown to around 40% in the last few years, up from just over 10% a decade ago.

The government has bold plans to continue this decarbonisation process.

It has pledged that all of the UK's electricity will come from low carbon sources (renewables and nuclear) by 2035.

It plans to increase offshore wind capacity five-fold by 2030, increase solar power capacity five-fold by 2035, and approve up to eight new nuclear reactors.

There was no mention of whether it intends to stick to these goals in the statement the Prime Minister made yesterday.

But achieving net zero means cutting emissions across all sectors of the economy.

That is why we have targets for phasing out petrol and diesel vehicles and switching from gas boilers to heat pumps or other low carbon alternatives to heat our homes.

And, despite the UK's achievements on climate, there have been a number of warnings that progress is beginning to falter.

The Climate Change Committee (CCC), the government's independent advisors on cutting carbon emissions, has told the BBC it was not consulted by the government about its plans to water down its climate commitments.

"We have not been approached formally or informally about what is being proposed", a spokesperson said.

But earlier this year the CCC warned that the UK's efforts to meet its net zero commitments were already "worryingly slow" and that it was "markedly less confident" than a year earlier that it would meet its targets in the 2030s.

It joined the National Audit office and a cross party group of MPs in raising concerns that the UK risked missing its targets for tackling climate change without clearer planning and much faster action.

It's difficult to quantify the exact carbon costs of the rumoured shifts in policy, because it would rely on many assumptions - for example how our consumption patterns might change.

But inevitably, it would make the current targets harder to achieve - as any extra carbon costs would have to be balanced by extra savings in other areas. And how much carbon the UK can use in coming years has already been set down in carbon budgets.

The Chief Executive of the CCC, Chris Stark, has said that any change to the planned trajectory of UK emissions would be a "genuine surprise" because the "legal carbon budgets [how much can be emitted in five-year periods] determine that path".

The CCC has estimated that meeting the legally binding 2050 goal will require an extra £50bn of investment every year by 2030.

It said once the savings from reduced use of fossil fuels are factored in, the overall resource cost is less than 1% of GDP and that by 2044 it should become cost-saving, as newer cleaner technologies are more efficient than those they are replacing.