Tag: Carbon Brief

Experts: The key ‘unknowns’ of overshooting the 1.5C global-warming limit
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Original article by Cecilia Keating and Robert McSweeney republished from Carbon Brief under a CC license.
Demonstrators from Extinction Rebellion push self-made cart in the shape of the 1.5C climate target in Berlin, Germany. Credit: dpa picture alliance / Alamy Stock Photo
Last week, around 180 scientists, researchers and legal experts gathered in Luxenburg, Austria to attend the first-ever international conference focused on the controversial topic of climate “overshoot”.
This hypothesised scenario would see global temperatures initially “overshoot” the Paris Agreement’s aspirational limit of 1.5C, before they are brought back down through techniques that would remove carbon dioxide from the atmosphere.
(For more on the key talking points, new research and discussions that emerged from the three-day conference, see Carbon Brief’s full write-up of the event.)
On the sidelines of the conference, Carbon Brief asked a range of delegates what they consider to be the key “unknowns” around overshoot.
Below are their responses, first as sample quotes, then, in full:
- Dr James Fletcher: “Yes, there will be overshoot, but at what point will that overshoot peak? Are we peaking at 1.6C, 1.7C, 2.1C?”
- Prof Shobha Maharaj: “There are lots of places in the world where adaptation plans have been made to a 1.5C ceiling. The fact is that these plans are going to need to be modified or probably redeveloped.”
- Sir Prof Jim Skea: “There are huge knowledge gaps around overshoot and carbon dioxide removal.”
- Prof Kristie Ebi: “If there is going to be a peak – and, of course, we don’t know what that peak is – then how do you start planning?”
- Prof Lavanya Rajamani: “To me, a key governance unknown is the extent to which our current legal and regulatory architecture…will actually be responsive to the needs of an overshoot world.”
- Prof Nebojsa Nakicenovic: “One of my major concerns has been for a long time…is whether, even after reaching net-zero, negative emissions can actually produce a temperature decline.”
- Prof Debra Roberts: “For me, the big unknown is how all of these areas of increased impact and risk actually intersect with one another and what that means in the real world.”
- Dr Oliver Geden: “[A key unknown] is whether countries are really willing to commit to net-negative trajectories.”
- Dr Carl-Friedrich Schleussner: “This is a bigger concern that I have – that we are pushing the habitability in our societies on this planet above that limit and towards maybe existential limits.”
- Dr Anna Pirani: “I think that tracking global mean surface temperature on an overshoot pathway will be an important unknown.”
- Prof Richard Betts: “One of the key unknowns is are we going to continue to get the land carbon sink that the models produce.”
- Prof Hannah Daly: “The biggest unknown is whether countries can translate these global [overshoot] pathways into sustained domestic action…that is politically and socially feasible.”
- Dr Andrew King: “[W]e still have a lot of uncertainty around other elements in the climate system that relate more to what people actually live through.”
Dr James Fletcher
Former minister for public service, sustainable development, energy, science and technology for Saint Lucia and negotiator at COP21 in Paris.
The key unknown is where we’re going to land. At what point will we peak [temperatures] before we start going down, and how long will we stay in that overshoot period? That is a scary thing. Yes, there will be overshoot, but at what point will that overshoot peak? Are we peaking at 1.6C, 1.7C, 2.1C? All of these are scary scenarios for small island developing states – anything above 1.5C is scary. Every fraction of a degree matters to us. Where we peak is very important and how long we stay in this overshoot period is equally important. That’s when you start getting into very serious, irreversible impacts and tipping points.
Prof Shobha Maharaj
Adjunct professor at the University of Fiji and a coordinating lead author for Working Group II of the IPCC’s seventh assessment
First of all, there is an assumption that we’re going to go back down from overshoot. Back down is not a given. And secondly, we are still in the phase where we are talking about uncertainty. Climate scientists don’t like uncertainty. We are not acknowledging that uncertainty is the new normal… But because we’re so bogged down in terms of uncertainties, we are not moving towards [the issue of] what we do about it. We know it’s coming. We know the temperatures are going to be high. But there is little talk about the action.
The focus seems to be more on how we can understand this or how we can model this, but not what we do on the ground. Especially when it comes to adaptation planning – [and around] how does this modify whatever the plans are? There are lots of places in the world where adaptation plans have been made to a 1.5C ceiling. The fact is that these plans are going to need to be modified or probably redeveloped. And no one is talking about this, especially in the areas that are least resourced in the world – which sets up a big, big problem.
Sir Prof Jim Skea
Chair of the Intergovernmental Panel on Climate Change (IPCC) and emeritus professor at Imperial College London’s Centre for Environmental Policy
There are huge knowledge gaps around overshoot and carbon dioxide removal. As it’s very clear from the themes of this conference, we don’t altogether understand how the Earth would react in taking carbon dioxide out of the atmosphere. We don’t understand the nature of the irreversibilities and we don’t understand the effectiveness of CDR techniques, which might themselves be influenced by the level of global warming, plus all the equity and sustainability issues surrounding using CDR techniques.
Prof Kristie Ebi
Professor of global health at the University of Washington‘s Center for Health and the Global Environment
There are all kinds of questions about adaptation and how to approach effective adaptation. At the moment, adaptation is primarily assuming a continual increase in global mean surface temperature. If there is going to be a peak – and of course, we don’t know what that peak is – then how do you start planning? Do you change your planning? There are places, for instance when thinking about hard infrastructure, [where overshoot] may result in a change in your plan – because as you come down the backside, maybe the need would be less. For example, when building a bridge taller. And when implementing early warning systems, how do you take into account that there will be a peak and ultimately a decline? There is almost no work in that. I would say that’s one of the critical unknowns.
Prof Lavanya Rajamani
Professor of international environmental law at the University of Oxford
I think there are several scientific unknowns, but I would like to focus on the governance unknowns with respect to overshoot. To me, a key governance unknown is the extent to which our current legal and regulatory architecture – across levels of governance, so domestic, regional and international – will actually be responsive to the needs of an overshoot world and the consequences of actually not having regulatory and governance architectures in place to address overshoot.
Prof Nebojsa Nakicenovic
Distinguished emeritus research scholar at the International Institute for Applied Systems Analysis and executive director of The World In 2050.
One of my major concerns has been for a long time – as it was clear that we are heading for an overshoot, as we are not reducing the emissions in time – is whether, even after reaching net-zero, negative emissions can actually produce a temperature decline…In other words, there might be asymmetry on the way down [in the global-temperature response to carbon removal] – it might not be symmetrical to the way up [as temperature rise in response to carbon emissions]. And this is really my major concern, that we are planning measures that are so uncertain that we don’t know whether they will reach the goal.
The last point I want to make is that I think that the scientific community should, under all conditions, make sure that the highest priority is on mitigation.
Prof Debra Roberts
Honorary professor at the University of KwaZulu-Natal, coordinating lead author on the IPCC’s forthcoming special report on climate change and cities, board chair of the Red Cross Red Crescent Climate Centre and co-chair of Working Group II for the IPCC’s sixth assessment
Well, I think coming from the policy and practitioner community, what I’m hearing a lot about are the potential impacts that come from the exceedance component of overshoot. What I’m not hearing a lot about is the responses to overshoot and their impacts – and how those impacts might interact with the impacts from temperature exceedance. So there’s quite a complex risk landscape emerging. It’s three dimensional in many ways, but we’re only talking about one dimension and, for policymakers, we need to understand that three dimensional element in order to understand what options remain on the table. For me, the big unknown is how all of these areas of increased impact and risk actually intersect with one another and what that means in the real world.
Dr Oliver Geden
Senior fellow and head of the climate policy and politics research cluster at the German Institute for International and Security Affairs and vice-chair of IPCC Working Group III
[A key unknown] is whether countries are really willing to commit to net-negative trajectories. We are assuming, in science, global pathways going net negative, with hardly any country saying they want to go there. So maybe it is just an academic thought experiment. So we don’t know yet if [overshoot] is even relevant. It is relevant in the sense that if we do, [the] 1.5C [target] stays on the table. But I think the next phase needs to be that countries – or the UNFCCC as a whole – needs to decide what they want to do.
Dr Carl-Friedrich Schleussner
Research group leader and senior research scholar at the International Institute for Applied Systems Analysis
I’m convinced that there’s an upper limit of overshoot that we can afford – and it might be not far outside the Paris range [1.5C-2C] – before human societies will be overwhelmed with the task of bringing temperatures back down again. This [societal limit] is lower than the geophysical limits or the CDR limit.
The impacts of climate change and the challenges that will come with it will undermine society’s abilities to cooperatively engage in what is required to achieve long-term temperature reversal. This is a bigger concern that I have – that we are pushing the habitability in our societies on this planet above that limit and towards maybe existential limits. We may not be able to walk back from it, even if we wanted to. That is a big unknown to me.
I’m convinced that there is an upper limit to how much overshoot we can afford, and it might be just about 2C or a bit above – it might not be much more than that. But we do not have good evidence for this. But I think these scenarios of going to 3C and then assuming we can go back down – I have doubts that future societies grappling with the impacts of climate change will be in the position to embark on such an endeavour.
Dr Anna Pirani
Senior research associate at the Euro-Mediterranean Center on Climate Change (CMCC) and former head of the Technical Support Unit for Working Group I of the IPCC
I think that tracking global mean surface temperature on an overshoot pathway will be an important unknown – how to take account of natural variability in that context, to inform where we are on an overshoot pathway and how well we’re doing on it. I think, methodologically, that would prove to be a challenge. The fact that it occurs over many, many years – many decades – and, yet, we sort of think about it as a nice curve. We see these graphs that say “by the 2050s, we will be here and we’ll start declining and so on”. I think that what that actually translates to in the evolution of global surface temperatures is going to be very difficult to measure and track. Even how we report on that, internationally, in the UNFCCC [UN Framework Convention on Climate Change] context and what the WMO [World Meteorological Organization] does in terms of reporting an overshoot trajectory, that would be quite a challenge.
Prof Richard Betts
Head of climate impacts research in the Met Office Hadley Centre and professor at the University of Exeter
One of the key unknowns is are we going to continue to get the land carbon sink that the models produce. We have got model simulations of returning from an overshoot.
If you are lowering temperatures, you have got to reduce emissions. The amount you reduce emissions depends on how much carbon is taken up naturally by the system – by forests, oceans and so on. The models will do this; they give you an answer. But we don’t know whether they are doing the right thing. They have never been tested in this kind of situation.
In my field of expertise, one of the key [unknowns] is how these carbon sinks are going to behave in the future. That is why we are trying to get real-world data into the models – including through the Amazon FACE project – so we can really try and narrow the uncertainties in future carbon sinks. If the carbon sinks are weaker than the models think, it is going to be even harder to reduce emissions and we will need to remove even more by carbon capture and removal.
Prof Hannah Daly
Professor of sustainable energy at University College Cork
We know ever more about the profound – and often irreversible – damages that will be felt as we overshoot 1.5C. Yet we seem no closer to understanding what will unlock the urgent decarbonisation that remains our only way to avoid the worst impacts of climate change.
Global models can show, on paper, what returning temperatures to safer levels after overshoot might look like. The biggest unknown is whether countries can translate these global pathways into sustained domestic action – over decades and without precedent in history – that is politically and socially feasible.
Dr Andrew King
Associate professor in climate science at the University of Melbourne
I think, firstly, can we actually achieve net-negative emissions to bring temperatures down past a peak? It’s a completely different world and, unfortunately, it’s likely to be challenging and we’re setting ourselves up to need to do it more. So I think that’s a huge unknown.
But then, beyond that, I think also, whilst we’ve built some understanding of how global temperature would respond to net-zero or net-negative emissions, we still have a lot of uncertainty around other elements in the climate system that relate more to what people actually live through. In our warming world, we’ve seen that global warming relates to local warming being experienced by everyone at different amounts. But, in an overshoot climate, we would see quite diverse changes for different people, different areas of the world, experiencing very different changes in our local climates. And also definitely worsening of some climate hazards and possibly reversibility in others, so a very different risk landscape as well, emerging post net-zero – and I think we still don’t know very much about that as well.
Original article by Cecilia Keating and Robert McSweeney republished from Carbon Brief under a CC license.
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21 October 2025

Analysis: Clean energy just put China’s CO2 emissions into reverse for first time

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Original article by Lauri Myllyvirta republished from Carbon Brief under a CC license.

Workers install solar photovoltaic panels in Yinchuan, China. Credit: Cynthia Lee / Alamy Stock Photo

For the first time, the growth in China’s clean power generation has caused the nation’s carbon dioxide (CO2) emissions to fall despite rapid power demand growth.

The new analysis for Carbon Brief shows that China’s emissions were down 1.6% year-on-year in the first quarter of 2025 and by 1% in the latest 12 months.

Electricity supply from new wind, solar and nuclear capacity was enough to cut coal-power output even as demand surged, whereas previous falls were due to weak growth.

The analysis, based on official figures and commercial data, shows that China’s CO2 emissions have now been stable, or falling, for more than a year.

However, they remain only 1% below the latest peak, implying that any short-term jump could cause China’s CO2 emissions to rise to a new record.

Other key findings include:

Growth in clean power generation has now overtaken the current and long-term average growth in electricity demand, pushing down fossil fuel use.
Power-sector emissions fell 2% year-on-year in the 12 months to March 2025.
If this pattern is sustained, then it would herald a peak and sustained decline in China’s power-sector emissions.
The trade “war” initiated by US president Donald Trump has prompted renewed efforts to shift China’s economy towards domestic consumption, rather than exports.
A new pricing policy for renewables has caused a rush to install before it takes effect.
There is a growing gap that would need to be bridged if China is to meet the 2030 emissions targets it pledged under the Paris Agreement.

If sustained, the drop in power-sector CO2 as a result of clean-energy growth could presage the sort of structural decline in emissions anticipated in previous analysis for Carbon Brief.

The trend of falling power-sector emissions is likely to continue in 2025.

However, the outlook beyond that depends strongly on the clean energy and emissions targets set in China’s next five-year plan, due to be published next year, as well as the economic policy response to the Trump administration’s hostile trade policy.

China’s emissions decline due to clean power

Over the past decade, China’s CO2 emissions from fossil fuels and cement have risen by nearly a fifth, but there have been ups and downs along the way.

The shallow decline in 2015 and 2016 was due to a slump that followed a round of stimulus measures, while zero-Covid controls caused a sharper fall in 2022. Overall, however, emissions have continued to increase, pausing only during periods of economic stress.

More recently, there have been signs that China’s CO2 emissions could be close to reaching a peak and plateau, or even a period of structural decline.

The latest data, for the first quarter of 2025, shows that China’s CO2 emissions have now been stable or falling for more than a year, as shown in the figure below.

However, with emissions remaining just 1% below the recent peak, it remains possible that they could jump once again to a new record high.

China's CO2 emissions drop due to clean energy for first time — China’s emissions from fossil fuels and cement, million tonnes of CO2, rolling 12-month totals. Source: Emissions are estimated from National Bureau of Statistics data on production of different fuels and cement, China Customs data on imports and exports and WIND Information data on changes in inventories, applying emissions factors from China’s latest national greenhouse gas emissions inventory and annual emissions factors per tonne of cement production until 2024. Sector breakdown of coal consumption is estimated using coal consumption data from WIND Information and electricity data from the National Energy Administration.

Therefore, the future path of China’s CO2 emissions hangs in the balance, depending on trends within each sector of its economy, as well as China’s response to Trump’s tariffs.

These sectoral trends are explored further in the sections below, along with signals on what could be coming next from Chinese policymakers as they consider the country’s international climate pledge for 2035 and the five-year plan for 2026-2030.

Power-sector emissions fall while other sectors rebound

The reduction in China’s first-quarter CO2 emissions in 2025 was due to a 5.8% drop in the power sector. While power demand grew by 2.5% overall, there was a 4.7% drop in thermal power generation – mainly coal and gas.

Increases in solar, wind and nuclear power generation, driven by investments in new generating capacity, more than covered the growth in demand. The increase in hydropower, which is more related to seasonal variation, helped push down fossil power generation.

Power-sector emissions fell by more than total generation from fossil fuels, as the share of biomass and gas increased, while average coal power plant efficiency improved.

Specifically, the average amount of coal needed to generate each unit of electricity at coal-fired power plants fell by 0.9% year-on-year.

The first-quarter reduction in CO2 emissions from coal use in the power sector is shown at the bottom of the figure below, below CO2 changes in other sectors.

Chart: Falling CO2 due to clean power outweighed rises elsewhere — Year-on-year change in China’s CO2 emissions from fossil fuels and cement, for the period January-March 2025, million tonnes of CO2. Source: Emissions are estimated from National Bureau of Statistics data on production of different fuels and cement, China Customs data on imports and exports and WIND Information data on changes in inventories, applying emissions factors from China’s latest national greenhouse gasemissions inventory and annual emissions factors per tonne of cement production until 2024. Sector breakdown of coal consumption is estimated using coal consumption data from WIND Information and electricity data from the National Energy Administration.

Outside of the power sector, emissions increased 3.5%, with the largest rises in the use of coal in the metals and chemicals industries.

The coal-to-chemicals industry is undergoing rapid expansion, driven by concerns about dependence on imported oil and gas. During the first quarter of 2025, it was also benefiting from more favourable economics due to lower coal prices and relatively high oil prices.

Crude steel production increased 0.6% year-on-year, metal products output by 6% and non-ferrous metals production by 2%. All of these increases were mainly due to a jump in March. Metals demand was boosted by the bump in exports ahead of the tariffs, but high output has continued well into April.

Real-estate construction “starts” fell by 24% and sales of new properties by 3%, indicating that the demand for cement, steel and glass from the construction sector continues to decline.

In contrast, economic output in vehicle and machinery production increased by 12% and 13%, respectively, signalling increased demand for metals.

Cement production fell by 1.4%, a slower rate of decrease than in previous years, likely due to an earlier start to weather-dependent construction activity thanks to warm weather.

Gas consumption increased by an estimated 6% in the power sector, due to a 14% increase in gas-fired power generation capacity, even as the average utilisation of the plants fell. However, gas consumption fell in other sectors, outweighing the increase for power.

Oil products consumption increased slightly, as shown by the bar at the top in the figure above. Warmer weather meant that weather-dependent construction and agricultural activity rose earlier in the year than usual.

However, structural factors, particularly vehicle electrification and the shift to liquified natural gas (LNG) in the freight sector, point to continued declines in oil demand.

Have China’s emissions peaked?

Following the 1.6% decline in the first quarter of 2025, China’s emissions have now been stable or falling for more than a year, starting from the beginning of March 2024.

However, emissions in the 12 months to the end of March 2025 were down only 1% from their recent peak, implying that any short-term jump could lead to a new record high.

After the sharp reduction in the first quarter, emissions from power generation are now down year-on-year for the most recent 12 months.

This has happened four times before over the past four decades – in 2009, 2012, 2015 and 2022. However, the current drop is the first time that the main driver is growth in clean power generation.

The falls in 2009 and 2012 were related to the global financial crisis and the Euro area crisis, while the drop in 2015 was driven by the construction and industrial sector slump that followed the 2008-12 stimulus program.

These economic shocks resulted in the sharp reduction in electricity demand shown in the figure below. The drop in 2022 was a combination of slow power demand growth due to strict “zero-Covid” measures and relatively strong clean-power additions.

Chart: For the first time, clean energy growth has cut China's fossil-fuel power in the face of surging electricity demand — Year-on-year change in electricity generation from fossil fuels and clean energy, terawatt hours, rolling 12-month totals. The total annual change in demand is shown by the solid line and the average annual increase is shown by the dotted line. Sources: China Electricity Council; Ember; analysis for Carbon Brief by Lauri Myllyvirta.

Importantly, the growth in clean power generation in the first quarter of 2025 was not only larger than the rise in demand overall, it was also higher than the average increase in demand over the past 15 years, marked by the dashed line in the figure above.

Moreover, hydropower has been stable year-on-year in the past six months, implying that the clean-energy growth has been driven by increases in solar, wind and nuclear power capacity, not year-to-year variation in hydropower output.

Looking beyond electricity generation, all sectors registered a fall in emissions over the most recent four months from December 2024 to March 2025, except for coal-to-chemicals.

In order for China’s emissions overall to peak and then start declining, CO2 cuts in declining sectors will need to outweigh continued growth elsewhere.

For example, process emissions from cement production peaked in 2021 and have declined by 27% since then, as shown in the top left chart in the figure below.

Six line charts of China's sectoral emissions: CO2 emissions have fallen in most sectors this year — Sectoral emissions from fossil fuels and cement, million tonnes of CO2, rolling 12-month totals. Source: Emissions are estimated from National Bureau of Statistics data on production of different fuels and cement, China Customs data on imports and exports and WIND Information data on changes in inventories, applying emissions factors from China’s latest national greenhouse gas emissions inventory and annual emissions factors per tonne of cement production until 2024. Sector breakdown of coal consumption is estimated using coal consumption data from WIND Information and electricity data from the National Energy Administration.

Coal use outside the power and chemicals sectors peaked at the same time as cement, but has been rebounding since then and is now close to previous peak levels.

The China Coal Association expects coal use in the steel and building materials industries to fall, while coal consumption in the chemical industry is projected to continue growing.

Hopes of future growth in demand for coal are pinned on the chemical sector, described as a shift from using coal primarily as a fuel to a role as both a fuel and a raw material.

The association also believes that coal-fired power generation will resume growth – at least in the short term – but it recently revised down its projections for 2025 compared with the outlook at the end of 2024.

The tariff “war” may have affected expectations. One analysis suggests a 0.5 to 1 percentage point reduction in China’s GDP growth rate due to the tariffs could result in a similar reduction in demand for thermal coal – mainly used at power stations.

Oil product consumption has been declining since the post-Covid rebound ended in March 2024, falling 2% from its peak. The long-term trend is expected to be downwards, due to the electrification of transportation, despite rising demand for chemicals and aviation.

Gas use has been falling for a few months, but the trend is likely still increasing.

The table below lists the 12-month periods with the highest emissions for each sector, as well as the reduction since the latest peak in each case.

Sector	Date of highest emissions	Reduction since peak
Cement	April 2021	-28.2%
Coal and gas: Power	November 2024	-1.7%
Coal-to-chemicals	March 2025	Still increasing
Coal: Other sectors	April 2021	-3.0%
Gas: Other sectors	December 2024	-0.8%
Oil products	April 2024	-1.0%
Total CO2	February 2024	-0.8%

For all of the sectors other than cement production, it is too early to declare a definitive peak in emissions. Still, there are signs that other sectoral peaks could be past their peak, too.

Indeed, for oil products consumption and steel production, industry projections indicate that the future trend is likely to be falling.

For the power sector, clean-energy additions at or above current levels would likely lead to a structural peak, as clean-energy growth would more than cover electricity demand growth.

Together, these sectors cover more than 80% of China’s total emissions. If all of them enter a structural decline, then total emissions are very likely to do so too.

China pushes domestic demand in response to US tariffs

The economic and emissions outlook for this year and beyond will be affected by the Trump administration’s unprecedented trade tariffs – and China’s counter-measures.

The initial impact was a drop in emissions due to lower factory output in export-oriented coastal provinces and possible knock-on impacts on investment and consumer spending.

Conversely, the temporary easing of tariffs for 90 days will lead to a rush of orders from the US to make up for the short-lived slowdown in trade and to stockpile goods before the relief ends.

China’s reactions to the tariffs focused on counteracting the economic impacts with stimulus.

An anonymous comment piece in People’s Daily, the main Communist party affiliated newspaper, says the country should “strive to make consumption the main driving force and ballast stone of economic growth”, leveraging China’s large domestic market.

(The piece has the byline “People’s Daily commentator”, which implies that it is written by someone with authority.)

The article says that this will involve increasing consumer income, while easing financial and social burdens to boost purchasing power and willingness to consume.

While the temporary easing of tariffs will reduce the urgency of these measures, the US tariff rate on China, at 40%, remains much higher than it was before Trump’s presidency – and China’s leaders will likely want to prepare against the risk of renewed tariff hikes.

The focus will be creating domestic markets for the products China exports to the US. The long-held aim of rebalancing China’s economy towards consumption could finally become reality as a result. A successful rebalancing could mean less energy-intensive growth.

China’s response also includes redoubling its focus on “new quality productive forces”, a concept that emphasises new technology.

The concept includes the clean-energy industry, which has become such an important economic driver in China that it would be hard to leave out of stimulus plans.

A new list of low-carbon demonstration projects, published by the National Development and Reform Commission, provides a look at China’s priorities for clean-energy investment. Green hydrogen, energy storage, “virtual power plants” and industrial decarbonisation based on hydrogen are new growth areas.

In terms of the emissions implications of China’s response to Trump’s tariffs, the big question is whether stimulus focused at these favoured sectors – including the new low-carbon focus areas and other clean-energy industries – is deemed sufficient.

Some traditional recipients of stimulus spending, such as shipbuilding and public infrastructure, have already posted strong growth in the first quarter of this year as a result of stimulus measures announced in 2024.

New wind and solar pricing policy increases uncertainty

An additional source of uncertainty for China’s emissions comes in the form of its new electricity pricing policy for renewable energy, which enters into force in June.

The new policy removes price guarantees pegged to coal-power prices, with new wind and solar projects supposed to secure direct contracts with electricity buyers. This is likely to lead to lower prices being paid to new wind and solar projects.

However, it offers more favourable pricing – via “contracts for difference” – to the amount of new capacity needed to meet central government energy targets.

The immediate effect of the policy will likely be a rush of projects rushing to complete installation before the June deadline, so as to secure guaranteed prices.

This rush was already apparent in the latest data: 23 gigawatts (GW) of solar and 13GW of wind was added in March alone, up 80% and 110% from previous records for the month.

Furthermore, this year’s installations are likely to be very strong, even topping last year’s record, as a lot of centralised solar power and wind-power projects are racing to complete before the end of the 14th five-year plan period.

The China Wind Energy Association expects a new record of 105-115GW installed this year across onshore and offshore wind projects – up from the record-breaking 80GW last year – based on very active bidding last year. It also expects volumes to stay at that level even in 2026 and to then grow further towards 2030.

The China Electricity Council predicts an even larger wind-power capacity addition of 120GW in 2025. Another analyst projects a 20% drop in wind-power capacity additions in 2026, but after an even steeper increase in 2025 to 120-130GW of capacity added. So he also expects 2026 installations to be far above the current record year of 2024.

For solar, the China Photovoltaic Industry Association forecasts a drop in installations of 8-23% this year, from the staggering record of 278GW last year. Even the low end of this projection would see installations stay at 2023 levels in 2025 and then recover from there. The China Electricity Council’s projection for solar additions in 2025 matches the low end of the industry association’s forecast.

The figure below, based on these various projections, shows that additional electricity generation from new clean power capacity is expected to remain above last year’s record-breaking levels in both 2025 and 2026.

Bar chart: Newly added clean generation is set to remain above the record levels set in 2024 — Annual electricity generation from clean power capacity newly added each year, terawatt hours by source. Two alternative projections for 2025 are taken from a range of different organisations, while the 2026 projection is a combined total from the wind and solar industry associations. Power generation from new capacity is projected using average capacity factors for each technology over 2015–2024. Sources: Historical data from China Electricity Council; projections from China Wind Energy Association, China Photovoltaic Industry Association and China Electricity Council; analysis for Carbon Brief by Lauri Myllyvirta.

The projections shown in the figure above illustrate that the energy industry expects to be able to navigate the new renewable pricing policy and to maintain a high level of wind and solar additions over the next two years.

The policy has, however, created a lot more uncertainty. The stop-go cycle of a flood of installations in the first half of this year and then a slowdown in the second half – likely especially in the distributed solar segment – is likely to be a tough time for the industry.

The uncertainty relates above all to two things. First is the local implementation of the policy, as provincial governments have a lot of leeway here. Given the economic significance of clean energy for many provinces, they can be expected to seek to implement the policy in a way that minimises disruptions to the industry.

The other source of uncertainty is central government targets. The pricing policy ties the availability of more favorable pricing to central government energy targets, after clean-energy growth outpaced those targets by a wide margin in the past few years.

This emphasises the importance of the targets set for the next five year plan. The National Energy Administration (NEA) is targeting “more than 200GW” per year of clean-energy capacity added, which is far lower than the 360GW added last year.

The effect of the pricing policy also depends on market conditions, of course, with a risk of oversupply of coal-fired power due to the ongoing rapid addition of new coal-fired power plants.

China’s nuclear construction also keeps accelerating, with another 10GW of reactor projects approved in April, on top of 10GW approved in each of the previous two years. These projects will contribute to clean power supply towards 2030 as they are completed.

China faces widening gap to Paris pledge

The uncertainty around wind and solar expansion also has implications for China’s international climate pledges under the Paris Agreement.

After exceptionally slow progress in 2020-23, China is significantly off track for its 2030 commitment to reduce carbon intensity – the emissions per unit of economic output. It is almost certain to miss its 2025 target. Carbon intensity fell by 3.4% in 2024, falling short of the rate of improvement needed to meet the 2025 and 2030 targets.

The government work plan for 2025 did not set a carbon intensity target. It only included a target for reducing the intensity per unit of GDP for energy supply from fossil fuels by 3%, excluding use for raw materials.

This provides an indirect indication of the targeted improvement in carbon intensity. In 2024, carbon intensity fell by 3.4%, while fossil energy intensity fell by 3.8%. If the ratio is similar in 2025, then carbon intensity would need to fall by around 2.5% at a minimum, allowing CO2 emissions to increase by more than 2%, if the target for 5% GDP growth is also met.

The absence of a carbon intensity target and the lack of emphasis on reducing carbon intensity also signals that meeting the target is not seen as a priority at the moment.

The government work plan emphasised the “dual-carbon” goals of peaking CO2 emissions before 2030 and achieving carbon neutrality before 2060.

However, these goals allow CO2 emissions to continue to increase until the end of the decade, implying the potential for a significant absolute emission increase from 2024 levels by 2030. The “dual-carbon” goals, even if met, therefore do not guarantee the delivery of China’s current key international climate commitment, the 2030 carbon-intensity target.

Even if emissions fell this year, improvements to carbon intensity would need to accelerate sharply in the next five years to meet China’s 2030 Paris commitment.

If China remains committed to its 2030 pledge, then this acceleration would need to be reflected in the targets set in the country’s next five-year plan.

Outlook for 2025 and beyond

The past 12 months mark a potentially significant turning point for China’s CO2 emissions, with clean-energy growth for the first time outpacing demand growth and displacing fossil fuel use in the power sector.

Record-breaking clean energy additions expected in 2025, despite new pricing policy uncertainties, suggest that the trend will continue this year.

The longer-term trajectory depends heavily on the targets set in the upcoming five-year plan and on the economic policy response to US tariffs and other economic headwinds.

In the short term, the US tariffs will dampen energy demand growth and emissions. Economic policy designed to offset the impacts of Trump’s tariffs will likely boost the clean-energy sector further and might lead to a shift towards domestic consumption as an economic driver, implying lower energy consumption growth relative to GDP.

On the other hand, previous rounds of economic stimulus in China have led to sharp increases in emissions. If China is to deliver stimulus that targets consumption and new technology, rather than emissions-intensive construction and heavy industry, then it will require a significant break with earlier patterns.

Whether power-sector emissions have peaked will be determined by a race between growth in clean energy supply and total power demand growth.

The new renewable electricity pricing policy, which ties the volume of “contracts for difference” given out to new solar and wind projects to national clean energy targets, further increases the importance of target-setting in China’s upcoming 2035 climate targets under the Paris Agreement and in the next 15th five-year plan, covering 2026-2030.

Sector-by-sector analysis suggests that, in addition to the power sector, emissions have likely also peaked in the building materials and steel sectors, as well as oil products consumption.

These sectors together represent over 80% of China’s fossil fuel-related CO2 emissions. However, there are uncertainties and potential for short-term rebound in all of these sectors.

The sector with remaining potential for substantial emissions growth is coal-to-chemicals. The drop in oil prices after US tariff announcements will undermine the profitability of this sector and likely lead to lower utilisation of plants, even as more capacity is added. China’s counter-tariffs on imports of petrochemical products from the US could have benefited the industry – but these have reportedly been waived.

All of this suggests that there is potential for China’s emissions to continue to fall and for the country to achieve substantial absolute emissions reductions over the next five years.

However, policy choices working in the opposite direction could just as easily see emissions increase further towards 2030.

About the data

Data for the analysis was compiled from the National Bureau of Statistics of China, National Energy Administration of China, China Electricity Council and China Customs official data releases, and from WIND Information, an industry data provider.

Wind and solar output, and thermal power breakdown by fuel, was calculated by multiplying power generating capacity at the end of each month by monthly utilisation, using data reported by China Electricity Council through Wind Financial Terminal.

Total generation from thermal power and generation from hydropower and nuclear power was taken from National Bureau of Statistics monthly releases.

Monthly utilisation data was not available for biomass, so the annual average of 52% for 2023 was applied. Power sector coal consumption was estimated based on power generation from coal and the average heat rate of coal-fired power plants during each month, to avoid the issue with official coal consumption numbers affecting recent data.

When data was available from multiple sources, different sources were cross-referenced and official sources used when possible, adjusting total consumption to match the consumption growth and changes in the energy mix reported by the National Bureau of Statistics.

CO2 emissions estimates are based on National Bureau of Statistics default calorific values of fuels and emissions factors from China’s latest national greenhouse gas emissions inventory, for the year 2018. Cement CO2 emissions factor is based on annual estimates up to 2024.

For oil consumption, apparent consumption is calculated from refinery throughput, with net exports of oil products subtracted.

Original article by Lauri Myllyvirta republished from Carbon Brief under a CC license.

Orcas comment on killer apes destroying the planet by continuing to burn fossil fuels.

7 June 2025

Children born in 2020 will face ‘unprecedented exposure’ to climate extremes
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Original article republished from Carbon Brief under a CC license.
Children drink water from a pipeline in the village of Afraaga, Somaliland. Credit: Joe Giddens / Alamy Stock Photo
Children born in 2020 will face “unprecedented exposure” to extreme weather events, including heatwaves, droughts and wildfires, even if warming is limited to 1.5C above pre-industrial temperatures.
That is according to a new study, published in Nature, which calculates the number of unprecedented extreme events that people born in different decades and countries might live through.
Using a case study focused on Brussels, the researchers find that people born in 2020 will experience an “unprecedented” 11 heatwaves in their lifetime – even if global warming is limited to 1.5C by the end of the century.
In contrast, in a pre-industrial climate, a person living in the Belgian capital would likely experience just three such heatwaves, according to the study.
More than half of children born in 2020 – around 62 million people – will experience “unprecedented lifetime exposure” to heatwaves, even if warming is limited to 1.5C, the study finds.
However, this number nearly doubles to 111 million under a scenario where warming hits 3.5C.
The study also analyses crop failures, river floods, tropical cyclones, wildfires and droughts.
The research “helps the climate community build new narratives that better clarify the impacts [of climate change] on younger generations and vulnerable populations”, one expert who was not involved in the study tells Carbon Brief.
Intergenerational justice
As the planet warms, extreme weather events such as heatwaves, floods and droughts are becoming more intense, more frequent and lasting longer.
A popular 2021 study found that children born in the 21st century will be exposed to more extreme weather events in their lifetimes than their parents and grandparents.
The paper found that in a scenario of 3C of warming above pre-industrial levels, a child who turns six in 2020 will experience twice as many wildfires and tropical cyclones, three times more river floods, four times more crop failures, five times more droughts and 36 times more heatwaves over their lifetime than a six-year-old living in a pre-industrial climate.
The authors also found a “particularly strong increase” in children’s future exposure to extremes in the Middle East and North Africa.
The lead author of the study – Prof Wim Thiery from Vrije Universiteit Brussel – told Carbon Brief at the time that today’s youth will live “an unprecedented life”, in which they will “face conditions which older generations have never experienced”.
Four years later, Dr Luke Grant – a researcher in Thiery’s team – has led a new study building on the ideas of the 2021 paper.
Grant tells Carbon Brief that rather than counting the number of extreme events that an individual might experience, his new study counts the number of people that reach an “unprecedented state” of exposure to extremes.
Prof Kaveh Madani is the director of the UN University Institute for Water, Environment and Health and was not involved in the study. He tells Carbon Brief that the paper “helps the climate community build new narratives that better clarify the impacts [of climate change] on younger generations and vulnerable populations”.
The authors define “exposure” as the number of extreme events that a person experiences in their lifetime, relative to the number they would have experienced in a pre-industrial climate.
“Unprecedented lifetime exposure” is defined as exposure so high that it has only a one-in-10,000 chance of happening in a world without any greenhouse gas emissions.
‘Unprecedented lifetime exposure’
The authors present a case study of extreme heat in Brussels, Belgium, to explain their method.
They define a heatwave as a three-day extreme heat event, which reaches average temperatures that would be expected once per century in a pre-industrial climate.
Using models from the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), the authors calculate heatwave frequency in a world without climate change. They also assess scenarios in which warming is limited to 1.5C, 2.5C and 3.5C by the end of the century.
They combine this data with demographic information, including how many people are born in the country each year and their average life expectancy, using data from sources including the ISIMIP database and UN population estimates and projections.
In a world without climate change, the study finds that a person born in 1960 in Brussels would have a one-in-10,000 chance of experiencing six of the pre-defined heatwaves in their lifetime. Any member of this “birth cohort” who experiences more than six heatwaves in their lifetime has therefore faced “unprecedented lifetime exposure” to extreme heat, according to the study.
The authors find that a person born in Brussels in 1960 is likely to experience three heatwaves on average during their lives under all of the three future warming pathways– meaning that they are unlikely to face “unprecedented lifetime exposure” to heat.
By contrast, the researchers find that many younger age cohorts will experience unprecedented heatwave exposure. For many younger age cohorts, lifetime exposure to heatwaves is greater for higher warming pathways.
For example, people born in Brussels in 2020 will experience 11 heatwaves in their lifetime if global warming is limited to 1.5C by the end of the century. If warming rises to 2.5C or 3.5C, they could experience 18 or 26 heatwaves, respectively.
The graphic below shows heat exposure since birth in Brussels for three “birth cohorts” of 1960 (bottom row), 1990 (middle row) and 2020 (top row). It presents three future scenarios, in which warming is limited to 1.5C (blue), 2.5C (yellow) and 3.5C (red) by 2100. The dotted line shows the threshold for an “unprecedented” lifetime exposure to extreme heat.
Lifetime exposure to unprecedented heat for people born in Brussels in 1960 (bottom row), 1990 (middle row) and 2020 (top row), under scenarios that limit warming to 1.5C (blue), 2.5C (yellow) and 3.5C (red) by the year 2100. The dotted line shows the threshold for an “unprecedented” lifetime exposure to extreme heat. Source: Grant et al (2025).
Heat exposure
The authors repeat their analysis across the Earth’s entire land surface, by dividing it into grid cells and using location-specific temperature and demographic data.
Of the 81 million people born in 1960, they find that 13 million are likely to face unprecedented exposure to heatwaves in their lifetimes. They add that for this age cohort, lifetime exposure to unprecedented extremes does not vary depending on the warming scenario.
However, 21st century warming has a significant effect on exposure for younger generations. Under a 1.5C warming pathway, 52% of people born in 2020 will face unprecedented exposure to heatwaves. This rises to 92% under a 3.5C warming scenario.
The study adds:
“This implies that 111 million children born in 2020 will live an unprecedented life in terms of heatwave exposure in a world that warms to 3.5C versus 62 million in a 1.5C pathway.”
The charity Save the Children has published a report which unpacks the findings of the study. The graphic below, from the report, shows the percentage of people from different countries born in 2020 who will face unprecedented lifetime exposure to heatwaves under the 1.5C (top), 2.5C (middle) and 3.5C (bottom) warming scenarios.
Each circle shows a country, indicated by its three-letter countries code. The size of the circle indicates the number of people in the country. Darker circles indicate higher-income countries.
Circles on the right hand side of the graphic indicate that more than half of the country’s 2020 cohort will be exposed to unprecedented heatwaves in their lifetime.
The percentage of people born in 2020 who will face unprecedented lifetime exposure to heatwaves under the 1.5C (top), 2.5C (middle) and 3.5C (bottom) warming scenarios. Each circle indicates a country, indicated by its three-letter countries code. The size of the circle indicates the number of people in the country. Darker circles indicate higher-income countries. Source: Save the Children
“The evidence is now inescapable that heatwaves impact every community around the world,” Dr Luke Harrington, a senior lecturer in environmental science at the University of Waikato, who was not involved in the study, tells Carbon Brief. He adds:
“This paper offers the clearest view that climate change is verifiably unfair: those who have done the least to contribute to rising global temperatures will experience the most extreme impacts.”
From floods to fires
The authors apply the same method to five other climate extremes – crop failure, wildfires, droughts, floods and tropical cyclones.
The graphic below shows the key findings. The coloured portion of the bar shows the number of people born in 2020 who will face unprecedented exposure to each extreme under a 1.5C warming pathway. The dark green and light green bars show the additional exposure under 2.7C and 3.5C warming.
Number of people born in 2020 who will face “unprecedented lifetime exposure” to heatwaves, crop failures, river floods, tropical cyclones, wildfires and droughts under 1.5C 2.7C and 3.5C warming. Source: Save the Children
The authors find that unprecedented lifetime exposure to heatwaves will affect the most people, with 62 million people born in 2020 likely to face unprecedented exposure to heat in their lifetimes if warming is limited to 1.5C.
This is followed by crop failures and river floods, which will impact 23 million and 10 million people from the 2020 birth cohort under the 1.5C warming pathway, respectively.
Lead author Grant tells Carbon Brief that he is “most confident” about his heatwave findings because temperature is a “basic” metric for climate models to “get right”.
Meanwhile, extremes such as crop failure depend on a range of factors including soil moisture, land-atmosphere interactions and rainfall, which can make it harder for the models to accurately capture changes, Grant explains.
Vulnerability
The authors also assess how “socioeconomic vulnerability” affects their findings using a global deprivation index – a tool which measures the level of disadvantage and hardship experienced by individuals or communities in a particular geographic area.
The authors use the index to identify the 20% most and least vulnerable people in each age cohort. They find that the most vulnerable groups are overwhelmingly from African countries.
The authors also conclude that “socioeconomically vulnerable people have a consistently higher chance of facing unprecedented lifetime heatwave exposure compared to the least vulnerable members of their generation”.
The graph below, taken from a news and views article about the study, shows the percentage of high vulnerability (red) and low vulnerability (pink) people in each age cohort who would be exposed to unprecedented heat, under a 2.7C warming scenario.
The percentage of high vulnerability (red) and low vulnerability (pink) people in each age cohort who would be exposed to unprecedented heat, under a 2.7C warming scenario. Source: Gualdi and Muttarak (2025).
Dr Marina Romanello, a research fellow at the University College London and research director of the Lancet Countdown on Health and Climate Change who was not involved in the study, tells Carbon Brief that the paper “is an important addition to the scientific literature, showing how our delays in tackling climate change are putting the future of our children at risk”.
She adds:
“The authors have used well-established models to project future health threats, framing them around what matters the most: the wellbeing, health and survival of present and future generations.”
Grant, L. et al. (2025) Global emergence of unprecedented lifetime exposure to climate extremes, Nature, doi:10.1038/s41586-025-08907-1
Original article republished from Carbon Brief under a CC license.
8 May 2025
Reeves’s Heathrow third runway report was commissioned by London airport
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https://www.theguardian.com/environment/2025/feb/01/reevess-heathrow-third-runway-report-was-commissioned-by-london-airport
The chancellor is under fire after a study cited as evidence for expanding the terminal to boost the UK’s economic growth was ordered by Heathrow itself
Rachel Reeves was facing criticism on Saturday night as it was confirmed that a report she cited as evidence that a third runway at Heathrow would boost the UK economy was commissioned by the airport itself.
Experts and green groups also challenged Reeves’s view that advances in the production of sustainable aviation fuel (SAF) had been a “gamechanger” that would substantially limit the environmental damage of flying, saying the claims were overblown and did not stand up to scrutiny.
…
Alex Chapman, senior economist at the NEF, said: “It is very concerning that the chancellor appears to be basing her support for Heathrow expansion on a figure from a report commissioned by Heathrow airport.
“Even more worrying is the fact that the methodology they have applied is one that the Department for Transport has previously decided is not fit for purpose, and that the report uses forecast data supplied by the airport itself.
“Heathrow expansion represents a major threat to the UK’s climate goals and flies in the face of scientific advice. To ensure that the claimed economic benefits are concrete, assessments should be carried out by independent government economists following best-practice methodology.
“NEF’s analysis has identified a wide range of weaknesses in the economic case, which have emerged since it was last fully appraised in 2015. Not least, the decline of business air travel, the surge in outbound leisure travel and the negative impacts on wider regions of the UK – all of which erode the potential growth benefit.”
Analysis by climate crisis website Carbon Brief suggests that, using the government’s own figures, SAF will barely cut emissions by 2040, and any reduction will be wiped out by rising flight numbers.
…
https://www.theguardian.com/environment/2025/feb/01/reevess-heathrow-third-runway-report-was-commissioned-by-london-airport
2 February 2025
Analysis: UK would need forest ‘twice size of London’ to offset new airport expansion
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Original article by Josh Gabbatiss Verner Viisainen republished from Carbon Brief.
Planes queuing for takeoff at Heathrow airport in Britain. Credit: david pearson / Alamy Stock Photo
A forest twice the size of Greater London would need to be planted in the UK to cancel out the extra emissions from the expansion of Heathrow, Gatwick and Luton airports, Carbon Brief analysis reveals.
New runaways at these airports surrounding London would result in cumulative emissions of around 92m tonnes of extra carbon dioxide equivalent (CO2e) by 2050, if the number of flights increases in line with their operating company targets.
If the UK is to remain on track for net-zero, it would need to cut emissions further in other sectors of the economy or remove an equivalent amount from the atmosphere.
For example, offsetting these emissions would require more than 300,000 hectares of trees to be planted within just a few years. This equates to all the trees planted in the UK since 2000.
The Labour government is set to back all three airport expansions, according to media reporting ahead of a speech by chancellor Rachel Reeves this week.
This is in spite of opposition from within the Labour party and the government’s climate advisors recommending against airport expansion.
Reeves has stressed that “sustainable aviation fuels” (SAFs) and electric planes could help to offset these emissions.
However, such technologies are still in the early stages of deployment and previous Carbon Brief analysis suggests the role of SAFs in achieving net-zero may be limited.
Two Londons
Reeves is expected to reveal plans for a third runway at Heathrow in a speech on Wednesday.
This, alongside suggestions she will also announce her support for the expansion of Gatwick and Luton airports, has prompted days of political debate over the friction between the government’s climate and economic plans.
Reeves sees the expansion of airports as a key part of the government’s “growth strategy”. However, senior Labour politicians, notably energy secretary Ed Miliband, have previously opposed such expansions on environmental grounds.
For her part, the chancellor told BBC News that she thought “sustainable aviation and economic growth go hand in hand”.
Carbon Brief has used estimates of passenger numbers from the airports’ planning applications, combined with assumptions used by UK government advisors the Climate Change Committee (CCC), to calculate emissions from the three expansions.
As the chart below shows, the CCC assumes aviation emissions fall in the coming years due to technological and efficiency improvements.
However, the expansion of Heathrow, Gatwick and Luton would drive an uptick in emissions around 2040 as the projects are completed, if the expected number of extra flights take off and if there are no additional improvements in aircraft efficiency.
This would amount to an additional 92MtCO2e being emitted cumulatively by 2050.
In order to remain on track for the UK’s net-zero target, these emissions would need to be avoided by additional technological innovations in the aviation sector, balanced by faster cuts in other parts of the economy – or removed from the atmosphere after being emitted.
Annual UK aviation emissions, MtCO2e. The blue line indicates the trajectory for emissions set out by the CCC. The three red lines indicate the additional emissions that would result from the expansion of Heathrow, Gatwick and Luton airports, plus the resulting flights. The airport expansions are assumed to follow approximate timelines based on their respective planning applications, with some dates assumed based on the views of AEF. The Heathrow expansion is assumed to be in operation in 2035 and at full capacity by 2040. The Gatwick expansion is assumed to be operational in 2028 and at full capacity by 2038. The Luton expansion is assumed to be operational in 2033 and at full capacity by 2043. Sources: DESNZ, CCC, AEF, airport planning documents.
Aviation is generally viewed as a difficult sector to decarbonise, due to the lack of cheap and effective technologies to cut emissions from planes.
This is why campaigners and researchers frequently stress demand reduction as the most effective way to cut aviation emissions.
The UK’s net-zero plans already allow for aviation to be one of the final sectors producing sizable volumes of emissions in 2050, when most of the economy has decarbonised.
One strategy to remove the excess emissions from the additional Heathrow, Gatwick and Luton flights would be to plant more trees. However, this would be a significant undertaking, as Carbon Brief analysis shows.
It would require planting around 301,000 hectares of new forest by around 2028 so that the trees are large enough by the middle of the century to absorb significant amounts of CO2.
This is equivalent to around twice the size of Greater London, which covers 157,000 hectares. It is 10 times higher than the UK’s most recent annual tree-planting target and equates to all of the trees planted in the past 24 years across the country.
More passengers
Government advisors at the CCC have recommended that there should be no more than a 25% growth in the number of air passengers from 2018 levels, in order to meet the UK’s net-zero goal by 2050.
This amounts to an increase from 292 million passengers to 365 million by 2050. The number of UK flights collapsed during Covid-19 lockdowns and has been slow to recover to pre-pandemic levels, but the number of air passengers in 2023 reached 273 million.
The CCC has consistently stressed that there should be “no net increase” in airport capacity if the UK is to reach net-zero by the middle of the century, meaning any expansion is “balanced by reductions in capacity elsewhere”. It has also stated there should be no airport expansion without a UK-wide framework for managing capacity.
The committee criticised the previous Conservative government for setting “no plans” to limit growth in passenger numbers in its “jet-zero” strategy, which envisaged demand for flying increasing by 70% out to 2050.
Airport expansion at Heathrow, Gatwick and Luton would help bring the total number of passengers at these three sites up to 243 million in 2050, according to the airports’ own planning applications, compiled by the Aviation Environment Federation (AEF).
This amounts to an additional 100m passengers passing through these airports, compared to 2018 levels. This would bring the total number of UK passengers to 392 million – equivalent to a 34% increase in UK airport traffic – meaning that growth at Heathrow, Gatwick and Luton alone would be enough to breach the CCC’s guidance.
(In reality, more than 20 UK airports have plans for more capacity and some already have unused capacity, so it is unlikely that expansion would be limited to three airports around London.)
SAF concerns
The CCC leaves some flexibility in its advice to the government, allowing for future capacity growth, if “the carbon intensity of aviation is outperforming the government’s emissions reduction pathway”.
Essentially, if clean technologies slash aviation emissions faster than expected, then there will be space for more flights within a pathway to net-zero by 2050.
This has been alluded to by Reeves in recent days. She has stated that a “lot has changed in terms of aviation” and reportedly based an internal proposal to expand Heathrow on the use of “sustainable aviation fuels” (SAFs).
In reality, there has been very limited progress in developing SAFs or any other technologies to decarbonise planes in the UK. In 2023, the CCC chastised the Conservative government for “rel[ying] heavily on nascent technologies”.
Government modelling has shown SAFs will have a limited impact on cutting UK aviation emissions. Experts have pointed to the issues with the supply of materials for making SAFs and noted that none of the five SAF plants originally pegged to start construction in the UK this year are being built yet.
Methodology
This analysis is based on the CCC’s sixth carbon budget “balanced pathway” for the aviation sector, combined with data obtained from AEF on the expected increase in passenger numbers from the expansion of Heathrow, Gatwick and Luton airports.
The CCC pathway assumes that the emissions per passenger fall from 0.14 tCO2 in 2020 to 0.06tCO2 in 2050, accounting for the rollout of SAF and more efficient aircraft. It also assumes that no net expansion of airport capacity occurs.
Therefore, in this analysis, the three airport expansions are considered additional to the emissions included within the CCC pathway.
To calculate the additional emissions from the expansion of the three airports, the additional passenger numbers this would facilitate are multiplied by the emissions intensity per passenger in each year of the CCC pathway.
The additional passenger numbers from each airport are added to a Department for Transport pathway that assumes no further expansion. Each airport expansion is assumed to ramp up linearly from the year of operation to the year of operation at full additional capacity.
Based on the airport planning applications and AEF, it is assumed that:
- The Heathrow expansion will be operational by 2035 and operating at full capacity by 2040.
- The Gatwick expansion will be operational by 2028 and operating at full capacity by 2038.
- The Luton expansion will be operational by 2033 and operating at full capacity by 2043.
The calculated CO2 removals from planting trees are based on assumptions used by the CCC’s sixth carbon budget “balanced pathway”, in which there is a 2:1 ratio of conifers to broadleaves planted across the country.
The CO2 removals per hectare for conifers and broadleaves are taken from the UK Centre for Ecology and Hydrology (CEH), whose numbers are also used by the CCC.
Based on these numbers, the cumulative emissions removed per hectare of forest after 22 years – from the start of airport expansion in 2028 to 2050 – is 304tCO2. Dividing this value by the total additional cumulative emissions from the airport expansion (92 MtCO2), gives a total area required of 301,000ha. Given that Greater London is 157,200ha, this corresponds to approximately two (1.91) times the area of Greater London.
Historical UK aviation emissions are taken from the Department of Energy Security and Net Zero (DESNZ) up to 2022. For 2023 and 2024, the emissions are estimated based on percentage annual changes in UK jet fuel use, which are then applied to the emissions from 2022.
Original article by Josh Gabbatiss Verner Viisainen republished from Carbon Brief.
28 January 2025