The “vast majority” of the UK government’s plans to prepare for climate hazards have made virtually no progress over the past two years, according to the Climate Change Committee (CCC).
In that time, the world has experienced the hottest year on record, while England has seen its wettest ever 18-month stretch between 2022 and 2024.
(Climate adaptation – outside of some issues such as defence – is mostly a devolved matter, with separate plans in place from the administrations for Scotland, Wales and Northern Ireland.)
The previous government introduced a new adaptation strategy for England in 2023, covering plans for rising temperatures and more extreme weather in the country.
However, in its latest analysis of the government’s progress, the CCC states that the current approach to adaptation in England is “not working” and requires “urgent strengthening”.
The government is failing to make “good” progress in adapting to climate change on any of the 46 outcomes measured by the committee, ranging from better healthcare during heatwaves to preparing financial institutions for climate risk.
The report marks the latest in a series of appraisals by the CCC that have repeatedly identified large gaps in the nation’s adaptation efforts.
This time, with a relatively new Labour government that has said it will act on adaptation, the committee says its report “must serve as the turning point”.
But the CCC also says it is “seriously concerned” that the government will cut funding for adaptation, ultimately leading to much higher future costs as temperatures continue to rise.
- Climate adaptation is ‘vital’
- What progress has been made?
- What does the CCC recommend?
- How prepared are different sectors for climate change?
Climate adaptation is ‘vital’
There is “unequivocal evidence” that climate change is already making extreme weather in the UK “more likely and more extreme”, the CCC says.
The report lays out major risks facing the country, noting that the number of properties at risk from flooding is set to increase from 6.3m today to 8m by 2050. Roads and railways at risk from flooding could increase from a third of the total length to half over the same timeframe.
At least 59% of top-quality farmland is already at risk from flooding, the report says, adding that this could also increase over the coming decades.
Meanwhile, annual heat-related deaths could increase “several times over” to pass 10,000 in an average year by 2050, the CCC says.
It also cites an Office for Budget Responsibility (OBR) report from 2024 that concludes the UK’s GDP could be around 3% lower by 2074, even under the Paris Agreement’s “below 2C” goal. It says this could increase to 5% in a “below 3C” scenario, according to the OBR.
High-quality climate adaptation is therefore “vital to ensure that these risks are managed most efficiently and at least cost”, according to the committee. Otherwise, government policy could “lock in” risks or even make them worse.
The CCC reports on adaptation progress in England every two years, as required under the 2008 Climate Change Act. These reports have consistently highlighted adaptation as an issue that has been “underfunded and ignored” by successive governments.
There have been a few major developments since the committee’s last report.
Notably, the previous Conservative government launched its third national adaptation programme (NAP3), which is the cornerstone of the nation’s adaptation policy, in summer 2023. (NAP3 covers adaptation policy in England, as well as non-devolved issues that affect the whole UK, such as defence.)
In a highly critical initial appraisal of the programme, the CCC concluded that it fell “far short of what is needed” and “must be strengthened”. NAP3 has also faced an ultimately unsuccessful legal challenge from activists, arguing that it breached people’s human rights.
Another big development since the committee’s last report is Labour winning the general election in 2024. The CCC acknowledges that the new government “inherited a NAP that fell short of the task”, but says it finds “little evidence of a change of course”.
What progress has been made?
The report looks at both the “policies and plans” underpinning climate adaptation, as well as the actual “delivery and implementation” of those plans. It states:
“Whilst there is some evidence of policies and plans improving [since 2023], it is clear that NAP3 has been ineffective in driving the critical shift towards effective delivery of adaptation.”
The CCC assesses the planning and delivery of 46 outcomes from adaptation policy across five overarching themes. It scores them using roughly the same monitoring framework used in its last report in 2023.
It notes that 11 policies and plans have improved over the past two years, including a new adaptation strategy from the Ministry of Justice and a green finance strategy.
Over the same period, it says four have gotten worse, among them investment in flood protection projects, as “plans no longer align with their stated objectives”.
The lack of significant improvement between 2023 and 2025, based on the CCC’s scoring system, can be seen in the chart below.
As for the government actually delivering on its plans, the CCC says the “vast majority of our outcomes have received the same score as in 2023, most at low levels”.
The small number of improvements mainly relate to the latest round of implementation of the “adaptation reporting power”, which allows the government to ask infrastructure providers to disclose how they deal with climate risks.
The chart below, which compares the scores given to different adaptation outcomes between 2023 and 2025, demonstrates the lack of progress in the intervening years.
The CCC concludes that none of the outcomes could be classified as making “good” progress, in terms of delivery. Only four of them saw improvements over this period.
It highlights the water supply as an area where there has been backsliding over the past two years, noting that “continued slow rate of leakage reduction is now clearly inconsistent with meeting the sector’s targets”.
The CCC also points out that “tracking progress on adaptation remains challenging due to limited national-scale, up-to-date and relevant data”.
While there has been an improvement since 2023, nine of the 46 assessed outcomes for England still lacked enough evidence to assess progress, the report says.
These include important areas such as the impact of climate change on food supplies and the vulnerability of telecommunications and information and communication technology (ICT) assets.
In addition, ahead of NAP3, the CCC recommended – as part of its 2023 progress report – a list of 89 actions to close what it viewed as “policy gaps in government’s adaptation planning”.
It suggested that these could be dealt with either in NAP3 itself, or as part of other policy programmes.
However, only four of these recommendations have been achieved, with a further 14 seeing “partial progress”.
The report highlights food security, community preparedness and buildings as some of the areas where the government did not follow through on its recommendations.
What does the CCC recommend?
The CCC’s report echoes previous advice that, despite some improvements in NAP3 on previous efforts, the nation’s climate adaptation strategy needs an overhaul:
“The UK’s current approach to adaptation policy making is not working. Adaptation is not the cross-government priority that it needs to be, which is holding back delivery.”
NAP3 covers a five-year period from 2023 to 2028. With the latest report coming at a halfway point in this cycle, the committee says it “must serve as the turning point” for the government on climate adaptation.
As part of the “urgent strengthening” suggested in the report, the committee sets out key areas that it says should be improved.
“Adaptation” can mean different things in different contexts. The CCC stresses the need for a set of “specific and measurable sectoral targets” that can be used to guide progress, with clarity on how to monitor them and who is responsible.
The government has signalled its intention to strengthen adaptation objectives. The committee says that such objectives “must” be developed as a priority, no later than the end of 2025.
The CCC report highlights the “data gaps” that need to be closed, with “monitoring and evaluation…still not treated with sufficient urgency”. It says the government should direct relevant agencies to collect data on climate risks and the delivery of adaptation measures.
Adaptation is a topic that affects every area of government, from healthcare to education. Yet the CCC highlights that there is not enough coordination of activities between departments and says this should be improved.
In order to carry out adaptation policies, the CCC also stresses that the government “needs to ensure sufficient funding is available” as it undertakes its spending review. Baroness Brown, chair of the CCC’s adaptation committee, told journalists in a press briefing:
“We are seriously concerned that resilience and climate adaptation may be cut in the spending review. [The] government needs to recognise that this is not a future problem, this is today’s problem…I know the government is under a lot of pressure to make cuts, but this isn’t the easy one.”
Given the cost of future climate risk, the committee stresses that ignoring adaptation would not, ultimately, save money. In fact, acting early would “minimise the overall costs of tackling climate change”, it explains.
In the press briefing, CCC chief executive Emma Pinchbeck emphasised the “real need” for the government to think about the future when implementing key policies, such as home-building programmes and other major infrastructure developments.
“If you think about potential waste in terms of investment into the NHS, if we then have to retrofit hospitals to make them cooler,” she said, as an example.
How prepared are different sectors for climate change?
The CCC progress report looks at specific outcomes broken down across five broad sectors.
Within these, it highlights key problems and makes specific recommendations for each area.
Land, nature and food
The CCC highlights various “foundational” strategies covering farming and land that the Department for Environment, Food and Rural Affairs (Defra) is expected to publish in the coming months, including the land-use framework and the food strategy.
Delays in publishing such documents have “hampered” adaptation progress. However, the report highlights them as opportunities to set out clear objectives and responsibilities for the sector.
As it stands, important issues such as boosting climate-resilient farming and protecting food supply chains are rated “insufficient” for both government planning and implementation.
The CCC highlights the relatively new “environmental land management schemes” (Elms), which constitute England’s successor to the EU’s farm payments policy.
The report says these schemes lack guidance for climate adaptation, adding that the government should provide “certainty” about how much farmers will be paid for such measures.
As for the fishing industry, the report has downgraded its climate-adaptation plans, noting that they “no longer look credible”. It says the government’s marine strategy, published earlier this year, “does not include any specific or targeted adaptation actions”.
Infrastructure
According to the CCC, when the government publishes its 10-year infrastructure strategy, it should set out “clear resilience standards” for new infrastructure projects.
It also notes that major funding packages – for new roads and electricity networks, for example – should include incentives to fund climate adaptation.
Two out of the three adaptation policies that are scored as “good” are in the infrastructure sector, namely the plans for maintaining reliability in the road and rail networks.
Despite this, actual progress in improving transport resilience is largely “stagnant”, the committee says. It highlights increased flooding on railways and an increased number of roads deemed “susceptible” to flooding.
This is also the sector that has seen the most improvement in terms of delivery and implementation. The water, energy, telecommunications and transport sectors are all described as improving the identification and management of “interdependencies”.
This refers to better evidence of links between different sectors, which is being unveiled via adaptation reporting power. Notably, none of the sectors that have seen improvements are rated as “good”, indicating they still have work to do in this area.
Built environment and communities
Flooding is highlighted as the key risk facing many communities around England.
While the Environment Agency-led flood defence programme has been successful, “its budget in real terms is shrinking as risks are escalating, meaning delivery is falling short of targets and the condition of flood defence assets is declining”, according to the CCC.
The government’s investment programme needs “long-term” targets for cutting the risk posed by floods and coastal erosion, supported by sufficient funds, the report concludes.
It also recommends a “long-term cross-sector plan to manage future heat risk and drive joined-up action”.
The CCC is currently unable to track many of the important measures around heat risk, such as how many buildings are overheating, due to a lack of data.
Overall, none of the efforts to implement better protections for homes and communities have seen any positive change since 2023, despite this being a record period of heat and flooding.
Health and wellbeing
The CCC notes that there are only “limited” policies and plans in place to protect population health and healthcare delivery in the face of escalating climate hazards.
Extreme heat is the main risk identified in this context. As it stands, there are long-term, increasing trends of heat-associated deaths and overheating in hospital settings, the committee says.
In this context, the report recommends that the government develop an “improved climate and public health adaptation plan” that builds on the existing adverse weather and health plan.
Also, as part of the government’s decade-long plan to improve the NHS, the CCC says any upgrades must “make it more resilient to climate extremes today and in the future”.
Economy
The committee says that while businesses can take action to protect their own affairs from climate change, “barriers remain” and adaptation finance “remains nascent”.
It therefore highlights an important role for the government in removing these barriers, providing high-quality information and “correcting market failures”.
The report recommends setting up a portal for adaptation-related data that can be accessed by companies.
It also says the government should ensure that the UK’s sustainable disclosure requirements incorporate “adaptation-related disclosure”, to better prepare the private sector for climate risks.
The CCC also points out that an adaptation finance “deliverables and action plan”, promised for 2024, has not been produced. Among other things, this plan should lay out ways to “mobilise” private investment into adaptation projects, it adds.
The post CCC: England’s approach to climate adaptation is ‘not working’ appeared first on Carbon Brief.
CCC: England’s approach to climate adaptation is ‘not working’
The first study of microplastics in Texas coastal sediment was funded through a local environmental activist’s landmark legal victory over plastic pollution, one of many such research projects.
A recent study found surprisingly low levels of harmful microplastics in the sediments of Texas bays that are notorious for plastic pollution. This led researchers from the University of Texas at Austin to conclude the microplastics were being swept out to sea.
Microplastics from Texas Bays Are Washed Out to Sea, New Study Says
Climate Change
DeBriefed 16 May 2025: Has China’s CO2 peaked?; US bill ‘would kill IRA’; Poland’s coal collapse
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
US budget bill ‘would kill IRA’
WAYS AND MEANS: The future of Joe Biden’s signature climate policy, the Inflation Reduction Act (IRA), is in doubt after Republicans on two key Congressional committees passed budget proposals that “would effectively kill” it, reported Heatmap News. The proposals would end clean-energy tax credits and rebates for electric vehicle (EV) purchases, “claw back” climate grants and “slash” related spending, said Reuters.
DEFENCE DOUBTS: While a “small subset” of House Republicans have been trying to defend the IRA, it is unclear if they would block passage of the wider budget bill to get their way, according to E&E News. In the Senate, Politico said “some” Republicans are “pushing back” on the current proposals. A New York Times feature said Republican districts “have the most to lose” if all of the IRA tax credits are repealed. Semafor reported Republicans were “wrestling with possible failure” of the bill, in the face of opposition from Democrats and their own ranks. (Law firm Grant Thornton said policymakers were hoping to pass the bill by 4 July.)
SOCIAL COST: Meanwhile, a new White House memo directed US government agencies to disregard economic damages from climate change, reported E&E News. Under a headline asking, “What’s the cost of pollution? Trump says zero”, the New York Times explained that the “social cost of carbon” had been used for more than two decades to help weigh the costs and benefits of federal policies and regulations. It said the move could face legal challenges.
Around the world
- DOWNPOUR DEATHS: More than 100 people were killed by floods in the Democratic Republic of the Congo, Agence-France Presse reported. Extreme rainfall also killed at least seven people in Somalia, the Associated Press said.
- PARIS PERIL: A UK opposition minister falsely attacked climate science and said his party could exit the Paris Agreement if elected, the Guardian said. The Guardian also reported on how Australia’s new opposition leader “could abandon net-zero”.
- GERMAN GAS: New economy minister Katharina Reiche wants more gas-fired power plants, according to Die Zeit. The country’s climate council warned the new government’s plans could breach climate goals, said Clean Energy Wire.
- DENGUE DANGER: Colombia’s El Espectador reported on rising climate-driven risks from dengue fever in Brazil, Costa Rica, Ecuador, Mexico and Panama.
- COP30 CREW: The Brazilian COP30 presidency has appointed 30 envoys, including “key liaisons” for strategic regions such as China’s Xie Zhenhua, Jonathan Pershing from the US and former UNFCCC chief Patricia Espinosa, Climate Home News said.
60%
The yearly rise in EV sales in emerging markets in Asia and Latin America in 2024, according to new data from the International Energy Agency.
Latest climate research
- Even passing 1.5C of global warming temporarily would trigger a “significant” risk of Amazon forest “dieback”, said research covered by Carbon Brief.
- Rapidly rising emissions from China’s agricultural machinery could “hinder” the country’s push towards net-zero, according to a study covered by Carbon Brief.
- Findings in Environmental Research Letters found that the benefits of CO2 “fertilisation” on forests are likely to be constrained by warming.
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
For the first time on record, China’s CO2 emissions have fallen as a result of clean energy expansion rather than weak growth in electricity demand, according to new analysis for Carbon Brief. The analysis, which has been covered by outlets including AFP, Semafor and the New York Times, found that China’s emissions from fossil fuels and cement fell 1.6% in the first quarter of 2025 and are now 1% below the peak reached in March 2024. The months ahead will be critical for what comes next, as Beijing is working to finalise its next international climate pledge for 2035 and its five-year plan for 2026-2030.
Spotlight
How Poland started speeding away from coal power
This week, Carbon Brief reports on coal falling to barely half of Poland’s power supplies.
The first round of Poland’s presidential election is on Sunday and Rafał Trzaskowski, from prime minister Donald Tusk’s centre-right party Civic Platform, is favoured to win.
Long seen as one of the world’s most coal-reliant countries, Poland’s electricity system is in the midst of dramatic and increasingly rapid change.
When Poland joined the EU in 2004, coal-fired power stations supplied 93% of the country’s electricity. Coal accounted for more than three-quarters of the total as recently as 2018, the year the country hosted COP24 in Katowice.
Since then, a gradual shuffle away from coal has turned to a sprint.
In 2024, coal generated little more than half of Poland’s electricity, according to data from thinktank Ember – and a coal power phaseout by 2035 is now seen as a realistic prospect.
While the topic has not played a big role in the election campaign, there is now broad public acceptance that “coal is over in Poland”, said Joanna Maćkowiak-Pandera, president of Polish thinktank Forum Energii. She told Carbon Brief:
“The extreme rightwing tries to claim that coal is the future and there is coal for [another] 400 years…[But] even the coal-mining sector does not believe it.”
As of 2024, coal contributed just 53.5% of electricity generation in Poland, with wind and solar making up 23.5%, gas power 12.1% and other renewables another 6.3%.
Coal ‘death spiral’
The “death spiral” for coal power is due to the high cost of coal mining in Poland, the old age of coal power plants, pressure from climate policies such as the EU emissions trading system (EUETS) and a loss of market share to renewables, said Maćkowiak-Pandera:
“You can be pro-coal, but you will not change the economics, physics, geology and the reality of the financial market.”
Until 2023, the right-wing Law and Justice party (PiS) had held the reins of government, having won the 2015 election after promising to protect the coal industry.
Following power cuts that summer, however, PiS increasingly accepted that renewbles – particularly solar power – could support energy security, explained Maćkowiak-Pandera.
(Renewables enjoy broad public support and are associated with energy security, she said.)
With backing from government policy, Poland’s solar capacity leapt from just 200 megawatts in 2015 to more than 20 gigawatts in 2024 – a 100-fold increase.
Still, PiS strongly resisted calls to phase out coal. In 2020, it struck a deal with unions to subsidise the Polish coal-mining industry until 2049. The subsidies remain in place.
After winning parliamentary elections in 2023, Tusk promised a “much faster energy transition” based on renewables and nuclear power, said Maćkowiak-Pandera.
While utility firms would “really love” to phase out coal plants within as little as three to five years, there is a growing consensus around 2035 as a more achievable end date, she said:
“It’s really not controversial any more…I speak with politicians, with utilities, with [electricity] transmission system operators, even with miners. Everybody is aware of the situation.”
Instead, there is a practical conversation around how best to replace coal at the lowest cost, explained Maćkowiak-Pandera.
This will mean more renewables, but also the flexible capacity needed to manage the grid – including some new gas-fired power plants – as well as energy storage and market reforms, she said.
Poland’s rapid transition may not have made many headlines, but other major coal-burning countries are starting to pay attention.
Maćkowiak-Pandera has welcomed delegations from China, South Africa, Mexico and Brazil, eager to learn about Poland’s experience. She added:
“For Chinese partners, it’s interesting because they like [our] pragmatic approach…they like that Poland [is] sometimes not mentioning climate, [but] is doing it anyhow.”
Watch, read, listen
CHINESE CROWING: A widely shared blog post on nationalist media outlet Guancha said China was taking climate action to “win the future energy revolution” and, among other things, to “save at least $600bn” on imported oil by shifting to EVs.
‘RUNNING BLIND’: For the Bulletin of Atomic Scientists, climate scientist Peter Gleick said the Trump administration’s “purges” of climate research were “threats to national security”.
‘REALISM’ REJECTED: The Wicked Problems podcast discussed the “defeatism” behind a recent initiative calling for “climate realism”, as well as the “abundance agenda”.
Coming up
- 18 May: Poland presidential election
- 19 May: EU-UK summit, London
- 19-23 May: First UN climate week 2025, Panama City, Panama
- 19-27 May: World Health Assembly 2025, Geneva, Switzerland
Pick of the jobs
- European Commission, programme manager (climate change and sustainable energy) | Salary: Unknown. Location: Brussels, Belgium
- Dialogue Earth, southeast Asia editor | Salary: £43,370. Location: London
- Royal Botanic Gardens Kew, postdoctoral research associate in genomics and climate change | Salary: £43,751. 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 16 May 2025: Has China’s CO2 peaked?; US bill ‘would kill IRA’; Poland’s coal collapse appeared first on Carbon Brief.
DeBriefed 16 May 2025: Has China’s CO2 peaked?; US bill ‘would kill IRA’; Poland’s coal collapse
Even passing 1.5C of global warming temporarily would trigger a “significant” risk of Amazon forest “dieback”, says a new study.
Dieback would see large numbers of trees die, shifting the lush rainforest into a dry savannah.
The research, published in Nature Climate Change, assesses the impact of “overshooting” the aspirational goal of the Paris Agreement on the Amazon and Siberian forests.
Overshoot would see warming surpass 1.5C above pre-industrial levels in the coming decades, before being brought back down before 2100 through large-scale carbon dioxide removal.
Using hundreds of climate-model simulations, the authors assess the influence of the “sensitivity” of the climate – a measure of the planet’s temperature response to a given increase in atmospheric CO2.
Across all simulations where global warming in 2100 surpasses 1.5C, 37% show “some amount of dieback”, the study says.
However, the risk increases further in the long term, with “55% of simulations exhibiting dieback by 2300”.
One author tells Carbon Brief that the study highlights that overshooting 1.5C leaves forest ecosystems “exposed to more risk than [they] need to be”.
The findings show that “we can’t afford complacency”, he warns.
Warming pathways
As the planet warms, there is an increasing risk that parts of the Earth system will cross “tipping points” – critical thresholds that, if exceeded, could push a system into an entirely new state.
For example, a seminal 2022 study warned that five tipping elements – including the collapse of the West Antarctic ice sheet and abrupt permafrost thaw – are already within reach, while others are becoming increasingly more likely as temperatures rise.
One way to limit warming to 1.5C by the end of the century involves initially overshooting the threshold. However, research published last year warns that the longer the 1.5C threshold is breached – and the higher the peak temperature – the greater the risk of crossing tipping points.
The new study uses modelling to investigate the risks of overshoot for the Amazon and Siberian forests.
The paper considers three illustrative mitigation pathways taken from the Intergovernmental Panel on Climate Change’s (IPCC) mitigation report from its sixth assessment cycle, which was published in 2022.
Gregory Munday is an applied scientist at the UK Met Office Hadley Centre and lead author on the study. He tells Carbon brief that the authors selected “optimistic” pathways that “each have different relationships to the Paris Agreement goals”.
For each scenario, the authors assess a range of different climate sensitivities – a measure of the planet’s temperature response to a given increase in atmospheric CO2. The average outcome of each pathway is:
- The “renewables” scenario shows a future with reduced emissions and a heavy reliance on renewable energy, which keeps warming below 1.5C by 2100.
- The “negative emissions” pathway shows a world in which warming initially overshoots the 1.5C threshold, but extensive use of carbon removal sees warming drop back below 1.5C before 2100.
- The “gradual strengthening” pathway illustrates a strengthening of climate policies implemented in 2020, with rapid reductions mid-century and a reliance on net-negative emissions by the end of this century. This pathway sees global average temperatures reach 1.8C by 2100.
The authors run the emissions pathways through a simple climate “emulator” model, which calculates the global temperatures associated with each emission pathway.
The charts below show cumulative CO2 emissions (left), atmospheric CO2 concentration (middle) and changes in global average surface temperature compared to the pre-industrial level (right), for the renewables (green), negative emissions (purple) and gradual strengthening (yellow) pathways until the year 2300.
The authors then use a different modelling framework to project the impacts of each emissions scenario.
Study author Dr Chris Jones leads the UK Met Office Hadley Centre’s research into vegetation and carbon cycle modelling and their interactions with climate. He tells Carbon Brief that the new study is the first application of this modelling framework, which he describes as a “rapid response tool”.
He says the tool was developed to “rapidly look at a range of climate outcomes, both global and local, for new scenarios”, adding that it provides a “pretty good approximation” of what traditional global climate models would do.
Munday adds that the framework is able to produce results within days or weeks, rather than taking “months and months”.
Finally, the authors use land surface model JULES to assess forest health under the different scenarios. Overall, the authors produce 918 simulations each of Amazon and Siberian forest health.
Forest health
The authors assess forest health using two metrics. The first is the forest growth metric “net primary productivity”, a measure of the rate that energy is stored as biomass by plants, which can indicate forest productivity. The second metric, forest cover, is a way of measuring the forest’s long-term response.
The models show that rising CO2 levels causes net primary productivity to increase, due to the CO2 fertilisation effect, driving more rapid forest growth. Conversely, many of the impacts of climate change, such as increased heat and changes to rainfall patterns, can be detrimental to forests, damaging or killing trees.
To identify the impacts of overshooting 1.5C on the Amazon and Siberian forests, the authors compare the “renewables” and “negative emissions” pathways. Both of these scenarios reach a similar global average temperature by the year 2100, but the former does so without overshoot, while the latter overshoots 1.5C before temperatures come back down.
The maps below show the difference in net primary productivity in the Amazon (left) and Siberian forests (right) between the two scenarios in the year 2100. Brown shading indicates that net primary productivity was higher in the non-overshoot scenario, while blue indicates that it was higher in the overshoot scenario.
The maps show that “large areas of both Amazonian and Siberian forest show reduced net primary productivity” by 2100 due to overshoot, compared to a scenario with no overshoot, the paper says.
‘High-risk zones’
From the three pathways, the authors generate 918 simulations of future climate and corresponding Amazon forest health.
The authors use these results to identify which future temperature and rainfall conditions result in net forest “dieback”. This is when large numbers of trees die, shifting the rainforest into a dry savannah.
The plots below show which simulations result in Amazon dieback by the year 2100 (left) and 2300 (right), for different amounts of rainfall and temperature levels in the year 2100. Each graph is divided into four sections – hot and wet (top right), hot and dry (bottom right), cold and wet (top right) and cold and dry (bottom right). These sections are based on average regional temperature and rainfall in the year 2100.
Coloured dots indicate scenarios that see forest dieback. These are coloured by pathway, for renewables (green), negative emissions (purple) and gradual strengthening (yellow). Grey dots indicate scenarios without Amazon dieback. The red lines indicate “high-risk climatic zones”, above which there is “a significant risk of dieback”.
The study finds that most Amazon dieback scenarios happen in hot, dry conditions, the authors note.
Across all simulations where warming in 2100 is above 1.5C, 37% show “some amount of dieback” the study says. However, in these model runs, the risk increases further in the long term, the study notes, with “55% of simulations exhibiting dieback by 2300”.
Prof Nico Wunderling is a professor of computational Earth system science at the Potsdam Institute for Climate Impact Research and was not involved in the new research. He tells Carbon Brief it is significant that, according to this study, the Amazon will face impacts from climate change below the tipping point threshold of 2-6C, as assessed in the landmark 2022 tipping points paper.
The authors also carry out this analysis for Siberian forests. Instead of a drop in tree cover, they find a change in the composition of trees. Munday tells Carbon Brief that the vegetation shifts “from grassy surface types to lots more trees and shrubs” in a process called “woody encroachment”.
Woody encroachment can have significant negative impacts on terrestrial carbon sequestration, the hydrological cycle and local biodiversity.
“The Siberian forest is probably committed to a long-term, and possibly substantial, expansion of tree cover,” the authors write.
High-risk scenarios
The greatest uncertainty in this study comes from the spread of climate sensitivities, Munday tells Carbon Brief.
He elaborates:
“This means that although we simulate the impacts from extremely optimistic mitigation scenarios, there is a chance that the Earth’s climate sensitivity is much higher than we expect, and so, small but significant risks of short- and long-term forest ecosystem impacts exist in spite of the choice of these strong-mitigation scenarios.”
In other words, if climate sensitivity is higher than expected, forests could face harmful impacts even under low emissions scenarios.
Dr David McKay – a lecturer in geography, climate change and society at the University of Sussex – is the lead author of the 2022 study. He tells Carbon Brief that the new paper “shows the value in focusing not just on model averages, but also exploring a wide range of possible futures to capture potential ‘low probability, high impact’ outcomes”. He adds:
“[The study shows] how negative emissions to reduce warming might help restabilise these forests in future if we do overshoot 1.5C, but as such large-scale CO2 removal remains hypothetical, we shouldn’t assume we can rely on this in practice.”
However, McKay also notes some uncertainties in the models used. Mckay tells Carbon Brief that the vegetation model used in this study doesn’t include fire and “has some limitations around soil moisture stress and vegetation in the tundra”. These are “likely important for resolving potential tipping points in these biomes”.
Therefore, he adds, the study “doesn’t show how regional tipping points could potentially further amplify and lock-in these future forest shifts, even with negative emissions”.
Dr David Lapola is researcher at the University of Campinas in Brazil and was not involved in the study. He also warns that vegetation models provide a “poor representation of how CO2 may affect these forests directly”. Lapola argues that scientists must “collect field data to make any new advancement with models”.
Nevertheless, Lapola tells Carbon Brief that studies such as this will be “extremely useful” for the IPCC’s upcoming seventh assessment cycle, which will include a dedicated chapter on tipping points and other “low-likelihood high impact events” for the first time.
Study author Jones tells Carbon Brief that overshooting 1.5C leaves forest ecosystems “exposed to more risk than [they] need to be”. The findings show that “we can’t afford complacency”, he warns.
The post ‘Significant’ risk of Amazon forest dieback if global warming overshoots 1.5C appeared first on Carbon Brief.
‘Significant’ risk of Amazon forest dieback if global warming overshoots 1.5C
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Climate Change2 years ago
Spanish-language misinformation on renewable energy spreads online, report shows
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