Analysis: Government asks when UK should hit net-zero emissions

Update 15 October: The government has today written to the Committee on Climate Change (CCC) to ask when the UK should hit net-zero emissions.

The short letter asks when the UK should achieve net-zero greenhouse gas emissions “and/or” net-zero CO2, in order to contribute to the Paris Agreement. It asks “whether now is the right time for the UK to set such a target” in legislation. It also asks how far the UK should cut emissions in 2050, below 1990 levels, to be in line with the “well-below 2C” or 1.5C goals of Paris.

Finally, the letter asks for advice on how the UK could meet recommended targets and what the costs and benefits would be, including avoided damages, compared to meeting the current 80% by 2050 goal. However, the letter says the UK’s existing, legally binding carbon budgets up to 2032 are “out of scope” for this request.

The letter asks the CCC to respond by March 2019. The headline has been updated but the rest of this article has not.

The UK government has announced that it wants official advice on the “implications” of aligning its climate goals with the Paris Agreement.

Claire Perry, the UK’s energy and clean growth minister, confirmed the move earlier today during a speech at the meeting of Commonwealth leaders taking place in London this week.

The UK’s current aim is to cut greenhouse gas emissions “at least 80%” below 1990 levels by 2050, based on avoiding 2C of global warming above pre-industrial temperatures. The Paris deal set a higher ambition of staying “well below” 2C and striving for 1.5C. It also called for net-zero emissions in the second half of the century.

The government will ask what this higher ambition means for the UK’s long-term climate targets, after the the Intergovernmental Panel on Climate Change (IPCC) publishes a special report on 1.5C in early October.

Its official climate adviser, the Committee on Climate Change (CCC), has already said that a global 1.5C limit would mean a more ambitious 2050 goal for the UK, in the range of 86-96% below 1990 levels, as well as setting a net-zero target at some point, while the government has long accepted the need to set a net-zero goal “at an appropriate point in the future”. The UK may also need to tighten its legally binding five-yearly carbon budgets for the years before 2050.

Climate act

The UK’s Climate Change Act, passed into law a decade ago in 2008, sets a legally binding framework for cutting emissions. Its headline “at least 80%” by 2050 target was designed as the UK contribution to a 50-50 chance of limiting global warming to 2C above pre-industrial levels.

Beneath this long-term goal, the Act mandates five-yearly carbon budgets, set in advance in line with advice from the CCC. The most recently agreed fifth carbon budget calls for a 57% cut in emissions during 2028-2032. It’s worth adding that no government has yet gone against CCC advice on the level of carbon budgets – though the path to putting those budgets into law has not always been smooth.

The Act also allows for – but does not require – the long-term goal and budgets to be changed. This can only happen if there have been “significant developments in scientific knowledge about climate change, or European or international law or policy”. Together, the upcoming IPCC report on 1.5C and the Paris Agreement would clearly meet this test.

(A charity, Plan B Earth, is currently pursuing a legal case arguing the government must tighten UK carbon targets in light of the Paris Agreement. The case claims a failure to update the target would “frustrate” the legislative intent of the Climate Change Act, rather than directly breaching the terms of the Act.)

Speaking at the Commonwealth heads of government meeting in London, Perry said: “After the IPCC report later this year, we will be seeking the advice of the UK’s independent advisors, the Committee on Climate Change, on the implications of the Paris Agreement for the UK’s long-term emissions reduction targets.”

.@claireperrymp :"I am pleased to announce that after the IPCC report later this year, we will be seeking advice from the UK’s independent advisers, the Committee on Climate Change, on the implications of the Paris Agreement for the UK’s long-term emissions reduction targets." pic.twitter.com/WCXHsfEtwT

— Department for Science, Innovation and Technology (@SciTechgovuk) April 17, 2018

Perry’s words do not commit the UK to tighter goals in general, or a net-zero emissions target, in particular. Only a handful of countries – not including the G7 major economies – have set such a goal, including New Zealand’s plans to to reach net-zero by 2050 and Sweden’s 2045 target date. (Note that Sweden’s goal excludes international aviation and shipping.)

Perry’s announcement is nevertheless significant as it indicates the government might consider raising UK climate ambition to align with Paris. It also follows the advice of the CCC, which suggested that the government seek its views in this way.

However, Carbon Brief understands that there was resistance to Perry’s announcement being included in today’s speech, from Number 10 and the Treasury. Her comments on aligning UK goals with Paris do not appear in the government press release describing her speech.

In March 2016, then energy minister Andrea Leadsom said the government “believes we will need to” set a net-zero emissions goal in UK law.

In its Clean Growth Strategy, published last autumn, the government affirmed its commitment to legislate for a net-zero goal “at an appropriate point in the future” but said that more information was needed and that it was not the right time to make the change.

This strategy – which only covers the years to 2032 in detail – has this week been submitted to the UN climate convention as the UK’s long-term climate plan under the Paris Agreement. In a covering letter, the government reaffirms the need for a net-zero goal “at an appropriate point”.

Official advice

So far, the CCC has not called for higher UK targets in response to Paris, saying action to meet current targets was more urgent and that more evidence is needed before deciding when the UK should aim for net-zero emissions. However, it has also indicated that the UK goals are too weak.

The UK would need to cut emissions by “at least 90%” below 1990 levels, by 2050, to meet the Paris Agreement’s top ambition – and potentially raise targets before 2050 too…https://t.co/s5q7u1g379 pic.twitter.com/8XwnTU9M94

— Simon Evans (@DrSimEvans) April 17, 2018

With the arrival of the IPCC report on 1.5C later this year and the government’s Clean Growth Strategy – intended to meet the fourth and fifth carbon budgets – the stage is set for the CCC to advise on how far to raise UK ambition and when the country should reach net-zero.

A few factors are likely to influence this advice. One is that the UK will miss its fourth and fifth budgets, despite the new government strategy, according to the CCC. The government has argued it can use “flexibilities” built into the Climate Change Act to carry forward over-achievement against earlier budgets, whereas the CCC says any extra savings should go towards raising ambition.

This means that the CCC advice is likely to reduce the political wiggle room for meeting the fourth and fifth budgets, even if it does not recommend raising them. It also means the CCC could recommend greater ambition for 2050 be met, in part, with those same flexibilities.

Carbon budgets

Another factor likely to weigh on the CCC advice is recent science on the carbon budget for 1.5C. This suggests previous IPCC estimates may have been too low and that there may be a little more space to play with than previously thought.

Recent studies show large disagreements on the allowable 'carbon budget' remaining to keep warming below 1.5C. We take a look @carbonbrief at why they differ and how they might be reconciled: https://t.co/DsJe5n7v2C pic.twitter.com/dJHRO4Gqxw

— Zeke Hausfather (@hausfath) April 9, 2018

Nevertheless, a likely (66%) chance of meeting the 1.5C target means global CO2 emissions will need to fall to zero some time between 2040 and 2060, before turning net-negative as CO2 is drawn from the atmosphere. A separate study suggests the UK would have to reach net-zero CO2 between 2045 and 2070, for the well-below 2C limit of Paris.

The CCC will have to decide what years are appropriate as a net-zero target, if the UK is to aim for the 1.5C Paris ambition or the firmer “well below 2C” limit. It will also have to judge what likelihood of reaching those targets is acceptable and what is a fair share for the UK’s contribution to the global effort.

The CCC was criticised for targeting a 50/50 chance of 2C in advising on the 80% by 2050 target, as well as for its approach to global equity. Its choices in relation to a Paris-compliant UK goal are likely to face similar scrutiny.

Meanwhile, the CCC has already indicated that the 1.5C Paris goal would require a UK target of 86-96% reductions by 2050.

To align with the 1.5C Paris target, the UK will prob have to cut emissions 86-96% by 2050, below 1990 levels – and that’s only allowing for a 50/50 chance of limiting warming to 1.5C. Other approaches to global equity imply a larger cut.https://t.co/Z7pkMAZQfQ pic.twitter.com/G0QovRDhUW
— Simon Evans (@DrSimEvans) April 17, 2018

This could change in light of the findings of the IPCC report and other recent scientific research. Other points of contentions will include the treatment of international aviation and shipping, as well as accounting for emissions embedded in imports of products and biomass.

Allowances for aviation and shipping were set aside within the 80% by 2050 goal in a way that – for example – did not allow for rising emissions from a third runway at Heathrow. On the other hand, both shipping and aviation have recently agreed international climate goals, which could give cover to a decision to continue holding them outside the UK’s targets.

Negative emissions

Once it has decided on the appropriate range for a Paris-compliant UK climate goal, one final key question for the CCC will be how to meet this target, in practical terms. As a matter of its legislated remit, the CCC must consider not only the science, but also the costs of benefits of action.

It remains unclear how, exactly, the UK could meet a net-zero emissions goal, with existing pathways relying on negative emissions to offset continued emissions from hard-to-tackle sectors, including agriculture and industry.

Net-negative emissions could come from bioenergy with carbon capture and storage (BECCS), though this is controversial and untested at scale, leading some researchers to investigate alternative pathways to 1.5C. The CCC has previously said the UK would need negative emissions to reach net-zero overall.

To align with Paris, the UK will need to aim for net zero emissions *at some point* and meeting that aim *will require CO2 removal* via afforestation, BECCS or other negative emissions optionshttps://t.co/s5q7u1g379 pic.twitter.com/hNjxcMVlEu

— Simon Evans (@DrSimEvans) April 17, 2018

The UK government is already funding the world’s first research project on negative emissions. This £9m scheme is looking at everything from how feasible negative emissions technologies will be, to what might happen if we try to use them, as well as the “moral hazard” of assuming such options will become available instead of cutting emissions faster now.

Another unofficial consideration for the CCC is the political context at the time it is giving each piece of official advice. Indeed, this is why the committee has so far avoided calling for UK carbon targets to be tightened, considering it more important to secure early action to meet existing goals.

In this respect, it is worth considering new polling that shows a majority of the wider public supports a net-zero goal for the UK, as does a majority of Conservative voters.

New analysis by @WeAreBrightBlue shows a compelling political case for today's net zero announcement by @claireperrymp, with clear majorities of the public, including Conservative voters, in favour of a net zero target https://t.co/y7wPluOZid pic.twitter.com/UQoirIbvLT

— Sam Hall (@samuelhall0) April 17, 2018

Assuming the CCC recommends a more ambitious UK target for 2050 and a net-zero target year or years, it will then be up to the government to change or add to the UK’s existing legally-binding goals, subject to parliamentary time and – given the government’s slim majority in parliament – the support of other parties.

The Climate Change Act itself was passed with near-unanimity, with only a handful of parliamentarians voting against.

It is not yet clear what status the CCC’s advice will have. This will depend on the terms of reference it is given by government.

The government has the power to amend the UK’s 2050 target under Section 2 of the Climate Change Act, while Section 3, reproduced below, sets out the process for making such a change. This includes seeking, and taking into account, the advice of the CCC.

If the government seeks the CCC views on the UK’s long-term goals under this part of the Act, it could still choose to go against the advice but would have to explain why.

Update 18/4/18: We updated the article with additional information.