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.
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.
The post Analysis: UK would need forest ‘twice size of London’ to offset new airport expansion appeared first on Carbon Brief.
Analysis: UK would need forest ‘twice size of London’ to offset new airport expansion
Fifty-six years after the first one rallied 20 million people across America, “we need to do things that make us feel more powerful.”
From our collaborating partner Living on Earth, public radio’s environmental news magazine, an interview by host Steve Curwood with environmental historian Adam Rome.
It was the second defeat for the Trump administration’s unusual litigation to stop states from acting on climate change.
In a setback to the Trump administration’s extraordinary legal campaign against state climate action, a federal judge threw out the Justice Department’s lawsuit seeking to prevent the state of Hawaii from suing oil companies for damages.
Judge Dismisses Trump Administration’s Bid to Block Hawaii Climate Lawsuit
Climate Change
DeBriefed 17 April 2026: Fossil-fuel power slumps | ‘Super’ El Niño warning | Afghanistan’s climate struggle
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Oil prices rebound
OIL UP AGAIN: Oil prices surged by more than 7% and back above $100 a barrel on Monday after US-Iran peace talks faltered and US president Donald Trump ordered the blockading of Iranian ports, reported BBC News. The jump came after prices fell last week in the wake of the announcement of a conditional two-week ceasefire, it said.
RESCUE PLANS: European countries unveiled plans to protect citizens and businesses from rising energy prices. Ireland announced a support package worth €505m, reported BBC News, while Germany agreed on measures worth €1.6bn, said Bloomberg. Meanwhile, Reuters reported on a draft EU proposal due to be unveiled next week that would see the bloc reduce electricity prices and roll out clean energy more quickly in response to the crisis.
UNSOLICITED ADVICE: Trump renewed his criticism of UK energy policy and called on the government to “drill, baby drill”, reported the Independent. Via social media, the president said: “Europe is desperate for energy, and yet the United Kingdom refuses to open North Sea oil, one of the greatest fields in the world. Tragic!!!” (See Carbon Brief’s recent factcheck of various false claims about the North Sea.)
Around the world
- C-WORD: Faced with pressure from the US, countries attending spring meetings of the International Monetary Fund and World Bank were urged to “not mention the climate”, reported the Guardian. It added that plans to agree a new “climate change action plan” for the World Bank “may be shelved, along with substantive discussion of the climate crisis”.
- NEW DIRECTION: Péter Magyar’s landslide victory over Victor Orbán in Hungary’s elections “presents new opportunities for the country to reduce emissions and invest in clean energy”, reported Time. Carbon Brief explored what it means for European climate action.
- ‘FURNACE’ SUMMER: There was widespread coverage – including in the Boston Globe, ABC News, CNN, Euro Weekly News, Guardian and New Scientist – of warnings from meteorologists of the development of a “super” El Niño phenomenon that could ramp up temperatures and drive extreme weather.
- ANTALYA COP: The Turkish government unveiled the dates and venues for the “leaders’ summit” segment of November’s COP31 conference, according to Climate Home News.
- PACIFIC PRE-COP: Meanwhile, the Guardian reported that Tuvalu will host a special meeting of world leaders before the climate summit in Antalya.
€10bn a year
The amount of state support that French prime minister Sébastien Lecornu has pledged for electrification through to 2030 in a bid to reduce the country’s dependence on fossil fuels. In a speech late on Friday 10 April, Lecornu noted the figure amounted to a “doubling” of existing support.
Latest climate research
- Over a four-month period of 2023, more than 70% of editorials discussing net-zero in four right-leaning UK newspapers included “at least one misleading statement” | Climate Policy
- Air pollution from global transport currently has a net cooling effect that offsets 80% of the warming impact of the sector’s CO2 emissions | npj Climate and Atmospheric Science
- The incorporation of “observational constraints” into climate-model projections suggests that the Atlantic Meridional Overturning Circulation could weaken by 50% by 2100 in a medium-emissions scenario | Science Advances
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
Analysis by the Centre for Research on Energy and Clean Air (CREA) found that global electricity generation from fossil fuels fell in the first month of the closure of the Strait of Hormuz. Across all countries with real-time electricity data outside of China, coal-fired power generation fell 3.5% and gas-fired power generation fell 4.0%, according to CREA. This was offset by a rise in solar power and wind generation, which increased by 14% and 8%, respectively. Hydropower generation also saw a small increase, the analysis showed, but this was “more than offset” by a drop in nuclear power generation.
Spotlight
How climate change affects Afghan lives
This week, Carbon Brief reports on the impact of climate change in Afghanistan, following deadly floods this year.
Earlier this month, heavy rains, flash floods and landslides struck large parts of Afghanistan, damaging thousands of homes, destroying crops, bridges and roads and taking nearly 100 lives.
The flooding – reported to have affected 74,000 people in 31 of 34 provinces – is the latest weather-related catastrophe to afflict the nation, whose communities have suffered the brunt of repeated flash floods, droughts and landslides in recent years.
Hameed Hakimi, non-resident senior fellow at the Atlantic Council’s South Asia Center, told Carbon Brief the recent floods would hurt livelihoods and food security, noting reports of destroyed wheat and rice crops in the most affected eastern parts of the country. He said:
“This is common. For at least a decade now, [we have seen] these flash floodings and the damage that happens to rural life, farming, the disruption to crops…Flash flooding physically eats up the land. So, it not only damages where people live, but also people’s livelihoods, based on what they grow.”
The damage to crops will be felt acutely, he explained, given that food security in the landlocked nation is already strained by the blockage of its main transit trade artery through Pakistan and international sanctions that have frozen long-term development aid.
Speaking to Carbon Brief, Abdulhadi Achakzai, founding CEO of the Environmental Protection Trainings and Development Organization (EPTDO), an Afghan NGO, described flooding in Afghanistan as a “chronic situation”.
Achakzai, whose organisation runs projects that help urban and rural communities adapt to climate impacts, says climate change hurts the country in four key ways: extreme drought; extreme temperature; “natural hazards”, including landslides and dust storms; and, finally, flash flooding. He said:
“Climate change is a serious matter in Afghanistan. Every nation and every corner within this country is severely affected.”
Ranked 176 of 187 on the University of Notre Dame “global adaptation index”, Afghanistan is among the countries most vulnerable to climate change.
Average temperature across the country has increased from 12.2C in 1960 to 14.2C in 2024, according to the World Bank’s climate change knowledge portal. Drought is widespread, severe and persistent – harming food and water security in a nation of subsistence farmers.
Meanwhile, extreme weather events are the leading driver of internal displacement in the country. More than three-quarters of the 710,000 people who relocated within Afghanistan in 2024 did so driven by “environmental hazards”, such as drought and flood, according to a recent climate vulnerability assessment from the International Organization for Migration.
Finance struggles
Despite feeling the impacts of extreme weather, Afghanistan has been barred from UN climate negotiations and had limited access to climate finance since 2021. (The government attended COP29 in Baku as guests of the Azerbaijan hosts, but did not take part in formal negotiations.)
This is because the international community does not recognise the Taliban government, which resumed power in 2021, due to its record on human rights and its repression of women and girls in particular.
Almost all financing from key climate funds has been suspended, with the exception of a few projects where UN agencies and NGOs act simultaneously as a “requesting” and “implementation” partner.
Aid from UN climate funds fell from $5.9m annually over 2014-20 to $3.9m annually over 2021-24, according to recent analysis by the Berghof Foundation. Multilateral development banks provided a further $337m of funds badged as “climate finance” over 2021-23, it said.
By comparison, Afghanistan’s national climate plan, submitted to the UN Framework Convention on Climate Change (UNFCCC) in 2016, requested $17.4bn in climate finance over 2020-30. An updated national climate plan seen by Carbon Brief – completed in 2021 and later endorsed by the Taliban government, but not accepted by member governments of the UNFCCC – called for $20.6bn through to 2030.
Achakzai, whose organisation attends the COP climate summit each year in an observer capacity, has in the past been the sole delegate from Afghanistan to the conference.
He is calling on the UNFCCC to accept the country’s latest climate plan – and to find an “alternative solution” that would give the people of the country a voice in negotiations. He said:
“Every year we are losing hundreds, thousands of people because of climate change-related matters. Every year we are losing hundreds, thousands of hectares of crops. We are affected by [the decisions of] other countries. Why are we not part of this process?”
Watch, read, listen
BLOSSOM WATCHER: The Guardian reported on the successful search to find a researcher to continue Japan’s 1,200-year cherry blossom record.
COP OUT: Deutsche Welle spoke to experts to understand why India walked away from its bid to host COP33 in 2028.
‘BOMBS AND PORN’: The New Republic looked at who is set to benefit from the rapid build-out of energy-intensive AI datacentres.
Coming up
- 20-24 April: Intergovernmental Panel on Climate Change (IPCC) working group one report author meeting, Santiago, Chile
- 22 April: Earth day
- 22 April: Launch of third edition of the Lancet Countdown’s Europe report
- 24-29 April: First conference on transitioning away from fossil fuels, Santa Marta, Colombia
Pick of the jobs
- International Organization for Migration, senior thematic associate (climate action) | Salary: UN G-6 salary grade | Location: Dakar, Senegal
- Climate Action Network UK, several board member roles | Salary: Unknown. Location: Unknown
- UK Department for Energy, Food and Rural Affairs, G7 science lead | Salary: £56,375. Location: Bristol, London, Newcastle-upon-Tyne or York, UK
- Save the Children UK, senior climate change advisor | Salary: £62,000-£65,000. Location: London
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.
The post DeBriefed 17 April 2026: Fossil-fuel power slumps | ‘Super’ El Niño warning | Afghanistan’s climate struggle appeared first on Carbon Brief.
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