Rural land cover surrounding a city has the potential to reduce the “urban heat island” (UHI) effect and cool the city centre by more than 0.5C, new research shows.
While heatwaves around the world are becoming more frequent and intense because of human-caused warming, they are made even more severe in cities by the UHI effect, which traps heat in urban areas and keeps them warmer than their rural surroundings.
The study, published in Nature Cities, analyses 20 years of data from 30 cities in China and finds that a ring of rural land around a city can bring the urban temperature down. A buffer ring that is at least half the city’s width can have the biggest cooling effect.
To optimise the land cover and reduce the UHI intensity, the authors recommend “joining up patches of rural land, planting more woodland around a city and having fewer, bigger lakes”.
Previous work on mitigating the UHI effect has mostly “focused on strategies that seek solutions within the city limits”, the study says.
However, a co-author tells Carbon Brief that as urban land is often limited, the findings show that making changes to land use “outside a city can make a big difference to temperatures downtown”.
Urban heat dome
Temperatures in cities are consistently higher than in the surrounding countryside due to the heat-trapping properties of urban infrastructure. Closely packed buildings, heat-absorbing surfaces, such as concrete, and human activity, such as driving cars, all contribute to the urban heat island effect (UHI).
The specific difference between the hotter city and cooler countryside is known as the UHI “intensity”. In London in summer, estimates suggest the temperature inside the city is an average of 5C more than surrounding rural areas at night and 3C more during the day.
In comparison, natural landscapes, such as trees or water bodies, can reduce surrounding temperatures through shade and water evaporation. Adding more green spaces inside a city can help to cool it down, but research shows the effects are generally limited without significant and well-distributed coverage.
Prof Shi-Jie Cao, director of the Center for Sustainable Built Environment at the School of Architecture, Southeast University in China and visiting professor at the University of Surrey’s Global Centre for Clean Air Research (GCARE), is a co-author on the new study. He tells Carbon Brief that “urban land is precious and limited” for heat mitigation strategies within cities. He continues:
“This study presents the first comprehensive quantification of how rural land cover mitigates the UHI and opens new avenues for addressing high-temperature urban catastrophes”.
Higher temperatures in cities lead to the formation of a “heat dome”, roughly twice the size of the city boundary, the study says.
The diagram below shows how hotter (red) and colder air (blue) circulate through the dome. Cooler breezes from the neighbouring rural areas around the city blow into the urban centre, exchanging heat within the dome.
UHIs also exacerbate the effect of heatwaves, which are becoming more likely and more severe due to climate change. This increases the vulnerability of the more than 4.5 billion people living in urban regions globally.
Dr Eunice Lo, a researcher of climate change, extreme weather and human health at the University of Bristol, explained in a 2020 Carbon Brief guest post:
“Urban inhabitants can be more susceptible to heat-related illnesses and deaths in hot summers because of the UHI effect.”
Cooling green ring
Vegetation is often sparse in cities, typically becoming more plentiful away from the city centre. The study investigates how the location and type of rural land cover affects the temperature within the city.
The researchers model the land inside the heat dome with concentric rings, investigating the relationships between land cover and temperature in different zones.
Using satellite images of 30 major cities in China, the authors categorise the rural land cover into four types represented by colours in the rural area below – woodland (green), cropland (yellow), and water body (blue) and impervious surface (brown).
By changing variables including the size, diversity and fragmentation of the different land cover types in computer simulations of the environment, the study evaluates which variables have the biggest effects on UHI intensity and by how much they can reduce the temperature.
The authors divide up the landscape into “patches” – areas of land that differ from their surroundings. The size and fragmentation of the patches are “pivotal factors”, each with the potential to individually lower city temperatures by 0.5C, the study finds, noting that larger, less fragmented rural land patches produce a greater cooling effect.
Cao tells Carbon Brief that, in theory, this result means that by optimising both factors, UHI could be reduced by as much as 1C. However, he says the analysis does not account for “slight overlaps in the heat island mitigation effects among different landscape parameters”.
The authors also analyse how land cover at different distances from the urban boundary affects UHI intensity. They find that the best cooling effects come from the rural ring “within a 10-15 km radius from the urban boundary”. This range sits inside the heat dome, meaning the air flow and exchange of heat is most effective at these distances.
Rural land within this range can “contribute up to a 30% reduction of UHI intensity”, with the most significant cooling felt at the very centre of the city, the study finds.
To achieve these levels of reduction, “synergistic regulation” that coordinates best practices for multiple land management factors is needed, Cao tells Carbon Brief. Explaining the paper’s recommendations on how to effectively manage the rural buffer zone, he said in a press release:
“We found that urban overheating was mitigated more by joining up patches of rural land, planting more woodland scattered around a city, and by having fewer, bigger lakes rather than lots of little bodies of water.”
Global relevance
The study focuses on cities in China that exceed 200 square kilometres and have a single centre, so they could be more easily categorised into concentric rings according to urban population density.
While most of the cities selected – including Shanghai, Wuhan and Chengdu – experience a subtropical monsoon climate zone, the paper suggests that “the majority of mitigation strategies identified in China are transferrable to different climate zones”.
Consequently, the researchers claim the findings have “relatively high generalisability and applicability in different cities”, but advise that future research should investigate cities of “different shapes, development levels, geographical locations and climatic conditions”.
Dr Chloe Brimicombe – a climate science and extreme heat researcher at the University of Graz in Austria and visiting fellow at LSE’s Grantham Research Institute, who is not affiliated with the research – says the study could be improved by “adjusting more carefully for the climate of each city”. She adds:
“Small differences in elevation or proximity to the coast can influence the UHI effect. In addition, cities have different designs; if such a study was reproduced for Europe this could also be taken into account.”
Temperatures are rising across the globe, with 2024 now very likely to be the hottest year on record. Study co-author Prof Prashant Kumar, founding director of the University of Surrey’s GCARE and co-director of Surrey’s Institute of Sustainability, adds in the press release:
“We hope planners and governments can use our findings to help urban communities become more resilient against rising global temperatures. Our findings show that if we want to cool our cities down, we need a joined-up approach between urban and rural planning.”
The post Rural ‘buffer ring’ can reduce urban heat island effect by more than 0.5C appeared first on Carbon Brief.
Rural ‘buffer ring’ can reduce urban heat island effect by more than 0.5C
Climate Change
New York Already Denied Permits to These Gas Pipelines. Under Trump, They Could Get Greenlit
The specter of a “gas-for-wind” compromise between the governor and the White House is drawing the ire of residents as a deadline looms.
Hundreds of New Yorkers rallied against new natural gas pipelines in their state as a deadline loomed for the public to comment on a revived proposal to expand the gas pipeline that supplies downstate New York.
New York Already Denied Permits to These Gas Pipelines. Under Trump, They Could Get Greenlit
A “critical assessment” report commissioned by the Trump administration to justify a rollback of US climate regulations contains at least 100 false or misleading statements, according to a Carbon Brief factcheck involving dozens of leading climate scientists.
The report – “A critical review of impacts of greenhouse gas emissions on the US climate” – was published by the US Department of Energy (DoE) on 23 July, just days before the government laid out plans to revoke a scientific finding used as the legal basis for emissions regulation.
The executive summary of the controversial report inaccurately claims that “CO2-induced warming might be less damaging economically than commonly believed”.
It also states misleadingly that “excessively aggressive [emissions] mitigation policies could prove more detrimental than beneficial”.
Compiled in just two months by five “independent” researchers hand-selected by the climate-sceptic US secretary of energy Chris Wright, the document has sparked fierce criticism from climate scientists, who have pointed to factual errors, misrepresentation of research, messy citations and the cherry-picking of data.
Experts have also noted the authors’ track record of promoting views at odds with the mainstream understanding of climate science.
Wright’s department claims the report – which is currently open to public comment as part of a 30-day review – underwent an “internal peer-review period amongst [the] DoE’s scientific research community”.
The report is designed to provide a scientific underpinning to one flank of the Trump administration’s plans to rescind a finding that serves as the legal prerequisite for federal emissions regulation. (The second flank is about legal authority to regulate emissions.)
The “endangerment finding” – enacted by the Obama administration in 2009 – states that six greenhouse gases are contributing to the net-negative impacts of climate change and, thus, put the public in danger.
In a press release on 29 July, the US Environmental Protection Agency said “updated studies and information” set out in the new report would “challenge the assumptions” of the 2009 finding.
Carbon Brief asked a wide range of climate scientists, including those cited in the “critical review” itself, to factcheck the report’s various claims and statements.
The post Factcheck: Trump’s climate report includes more than 100 false or misleading claims appeared first on Carbon Brief.
https://www.carbonbrief.org/factcheck-trumps-climate-report-includes-more-than-100-false-or-misleading-claims/
Climate Change
Cropped 13 August 2025: Fossil-fuelled bird decline; ‘Deadly’ wildfires; Empty nature fund
We handpick and explain the most important stories at the intersection of climate, land, food and nature over the past fortnight.
This is an online version of Carbon Brief’s fortnightly Cropped email newsletter. Subscribe for free here.
Key developments
‘Deadly’ wildfires
WINE BRAKE: France experienced its “largest wildfire in decades”, which scorched more than 16,000 hectares in the country’s southern Aude region, the Associated Press said. “Gusting winds” fanned the flames, Reuters reported, but local winemakers and mayors also “blam[ed] the loss of vineyards”, which can act as a “natural, moisture-filled brake against wildfires”, for the fire’s rapid spread. It added that thousands of hectares of vineyards were removed in Aude over the past year. Meanwhile, thousands of people were evacuated from “deadly” wildfires in Spain, the Guardian said, with blazes ongoing in other parts of Europe.
MAJOR FIRES: Canada is experiencing its second-worst wildfire season on record, CBC News reported. More than 7.3m hectares burned in 2025, “more than double the 10-year average for this time of year”, the broadcaster said. The past three fire seasons were “among the 10 worst on record”, CBC News added. Dr Mike Flannigan from Thompson Rivers University told the Guardian: “This is our new reality…The warmer it gets, the more fires we see.” Elsewhere, the UK is experiencing a record year for wildfires, with more than 40,000 hectares of land burned so far in 2025, according to Carbon Brief.
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WESTERN US: The US state of Colorado has recorded one of its largest wildfires in history in recent days, the Guardian said. The fire “charred” more than 43,300 hectares of land and led to the temporary evacuation of 179 inmates from a prison, the newspaper said. In California, a fire broke out “during a heatwave” and burned more than 2,000 hectares before it was contained, the Los Angeles Times reported. BBC News noted: “Wildfires have become more frequent in California, with experts citing climate change as a key factor. Hotter, drier conditions have made fire seasons longer and more destructive.”
FIRE FUNDING: “Worsening fires” in the Brazilian Amazon threaten new rainforest funding proposals due to be announced at the COP30 climate summit later this year, experts told Climate Home News. The new initiatives include the Tropical Forests Forever Facility, which the outlet said “aims to generate a flow of international investment to pay countries annually in proportion to their preserved tropical forests”. The outlet added: “If fires in the Amazon continue to worsen in the years to come, eligibility for funding could be jeopardised, Brazil’s environment ministry acknowledged.”
Farming impacts
OUT OF ORBIT: US president Donald Trump moved to “shut down” two space missions which monitor carbon dioxide and plant health, the Associated Press reported. Ending these NASA missions would “potentially shu[t] off an important source of data for scientists, policymakers and farmers”, the outlet said. Dr David Crisp, a retired NASA scientist, said the missions can detect the “glow” of plant growth, which the outlet noted “helps monitor drought and predict food shortages that can lead to civil unrest and famine”.
FARM EXTREMES: Elsewhere, Reuters said that some farmers are considering “abandoning” a “drought-hit” agricultural area in Hungary as “climate change cuts crop yields and reduces groundwater levels”. Scientists warned that rising temperatures and low rainfall threaten the region’s “agricultural viability”, the newswire added. Meanwhile, the Premium Times in Nigeria said that some farmers are “harvest[ing] crops prematurely” due to flooding fears. A community in the south-eastern state of Imo “has endured recurrent floods, which wash away crops and incomes alike” over the past decade, the newspaper noted.
SECURITY RISKS: Food supply chains in the UK face “escalating threats from climate impacts and the migration they are triggering”, according to a report covered by Business Green. The outlet said that £3bn worth of UK food imports originated from the 20 countries “with the highest numbers of climate-driven displacements” in 2024, based on analysis from the Energy and Climate Intelligence Unit. The analysis highlighted that “climate impacts on food imports pose a threat to UK food security”. Elsewhere, an opinion piece in Dialogue Earth explored how the “role of gender equity in food security remains critically unaddressed”.
Spotlight
Fossil-fuelled bird decline
This week, Carbon Brief covers a new study tracing the impact of fossil-fuelled climate change on tropical birds.
Over the past few years, biologists have recorded sharp declines in bird numbers across tropical rainforests – even in areas untouched by humans – with the cause remaining a mystery.
A new study published this week in Nature Ecology and Evolution could help to shed light on this alarming phenomenon.
The research combined ecological and climate attribution techniques for the first time to trace the fingerprint of fossil-fuelled climate change on declining bird populations.
It found that an increase in heat extremes driven by climate change has caused tropical bird populations to decline by 25-38% in the period 1950-2020, when compared to a world without warming.
In their paper, the authors noted that birds in the tropics could be living close to their “thermal limits”.
Study lead author Dr Maximilian Kotz, a climate scientist at the Barcelona Supercomputing Center in Spain, explained to Carbon Brief:
“High temperature extremes can induce direct mortality in bird populations due to hyperthermia and dehydration. Even when they don’t [kill birds immediately], there’s evidence that this can then affect body condition which, in turn, affects breeding behaviour and success.”
Conservation implications
The findings have “potential ramifications” for commonly proposed conservation strategies, such as increasing the amount of land in the tropics that is protected for nature, the authors said. In their paper, they continued:
“While we do not disagree that these strategies are necessary for abating tropical habitat loss…our research shows there is now an additional urgent need to investigate strategies that can allow for the persistence of tropical species that are vulnerable to heat extremes.”
In some parts of the world, scientists and conservationists are looking into how to protect wildlife from more intense and frequent climate extremes, Kotz said.
He referenced one project in Australia which is working to protect threatened wildlife following periods of extreme heat, drought and bushfires.
Prof Alex Pigot, a biodiversity scientist at University College London (UCL), who was not involved in the research, said the findings reinforced the need to systematically monitor the impact of extreme weather on wildlife. He told Carbon Brief:
“We urgently need to develop early warning systems to be able to anticipate in advance where and when extreme heatwaves and droughts are likely to impact populations – and also rapidly scale up our monitoring of species and ecosystems so that we can reliably detect these effects.”
There is further coverage of this research on Carbon Brief’s website.
News and views
EMPTY CALI FUND: A major voluntary fund for biodiversity remains empty more than five months after its launch, Carbon Brief revealed. The Cali Fund, agreed at the COP16 biodiversity negotiations last year, was set up for companies who rely on nature’s resources to share some of their earnings with the countries where many of these resources originate. Big pharmaceutical companies did not take up on opportunities to commit to contributing to the fund or be involved in its launch in February 2025, emails released to Carbon Brief showed. Just one US biotechnology firm has pledged to contribute to the fund in the future.
LOSING HOPE: Western Australia’s Ningaloo reef – long considered a “hope spot” among the country’s coral reefs for evading major bleaching events – is facing its “worst-ever coral bleaching”, Australia’s ABC News reported. The ocean around Ningaloo has been “abnormally” warm since December, resulting in “unprecedented” bleaching and mortality, a research scientist told the outlet. According to marine ecologist Dr Damian Thomson, “up to 50% of the examined coral was dead in May”, the Sydney Morning Herald said. Thomson told the newspaper: “You realise your children are probably never going to see Ningaloo the way you saw it.”
‘DEVASTATION BILL’: Brazil’s president, Luiz Inácio Lula da Silva, signed a “contentious” environmental bill into law, but “partially vetoed” some of the widely criticised elements, the Financial Times reported. Critics, who dubbed it the “devastation bill”, said it “risked fuelling deforestation and would harm Brazil’s ecological credentials” just months before hosting the COP30 climate summit. The newspaper said: “The leftist leader struck down or altered 63 of 400 provisions in the legislation, which was designed to speed up and modernise environmental licensing for new business and infrastructure developments.” The vetoes need to be approved by congress, “where Lula lacks a majority”, the newspaper noted.
RAINFOREST DRILLING: The EU has advised the Democratic Republic of the Congo (DRC) against allowing oil drilling in a vast stretch of rainforest and peatland that was jointly designated a “green corridor” earlier this year, Climate Home News reported. In May, the DRC announced that it planned to open the conservation area for drilling, the publication said. A spokesperson for the European Commission told Climate Home News that the bloc “fully acknowledges and respects the DRC’s sovereign right to utilise its diverse resources for economic development”, but that it “highlights the fact that green alternatives have facilitated the protection of certain areas”.
NEW PLAN FOR WETLANDS: During the 15th meeting of the Ramsar Convention on Wetlands, held in Zimbabwe from 23 to 31 July, countries agreed on the adoption of a new 10-year strategic plan for conserving and sustainably using the world’s wetlands. Down to Earth reported that 13 resolutions were adopted, including “enhancing monitoring and reporting, capacity building and mobilisation of resources”. During the talks, Zimbabwe’s environment minister announced plans to restore 250,000 hectares of degraded wetlands by 2030 and Saudi Arabia entered the Convention on Wetlands. Panamá will host the next COP on wetlands in July 2028.
MEAT MADNESS: DeSmog covered the details of a 2021 public relations document that revealed how the meat industry is trying to “make beef seem climate-friendly”. The industry “may have enlisted environmental groups to persuade people to ‘feel better’ about eating beef”, the outlet said, based on this document. The strategy was created by a communications agency, MHP Group, and addressed to the Global Roundtable for Sustainable Beef. One of the key messages of the plan was to communicate the “growing momentum in the beef industry to protect and nurture the Earth’s natural resources”. MHP Group did not respond to a request for comment, according to DeSmog.
Watch, read, listen
MAKING WAVES: A livestream of deep-sea “crustaceans, sponges and sea cucumbers” has “captivated” people in Argentina, the New York Times outlined.
BAFFLING BIRDS: The Times explored the backstory to the tens of thousands of “exotic-looking” parakeets found in parks across Britain.
PLANT-BASED POWER: In the Conversation, Prof Paul Behrens outlined how switching to a plant-based diet could help the UK meet its climate and health targets.
MARINE DISCRIMINATION: Nature spoke to a US-based graduate student who co-founded Minorities in Shark Science about her experiences of racism and sexism in the research field.
New science
- Applying biochar – a type of charcoal – to soils each year over a long period of time can have “sustained benefits for crop yield and greenhouse gas mitigation”, according to a Proceedings of the National Academy of Sciences study.
- New research, published in PLOS Climate, found that nearly one-third of highly migratory fish species in the US waters of the Atlantic Ocean have “high” or “very high” vulnerability to climate change, but the majority of species have “some level of resilience and adaptability”.
- A study in Communications Earth & Environment found a “notable greening trend” in China’s wetlands over 2000-23, with an increasing amount of carbon being stored in the plants growing there.
In the diary
- 18-29 August: Second meeting of the preparatory commission for the Agreement on Marine Biological Diversity of Areas beyond National Jurisdiction | New York
- 24-28 August: World Water Week | Online and Stockholm, Sweden
- 26-29 August: Sixth forum of ministers and environment authorities of Asia Pacific | Nadi, Fiji
Cropped is researched and written by Dr Giuliana Viglione, Aruna Chandrasekhar, Daisy Dunne, Orla Dwyer and Yanine Quiroz. Please send tips and feedback to cropped@carbonbrief.org
The post Cropped 13 August 2025: Fossil-fuelled bird decline; ‘Deadly’ wildfires; Empty nature fund appeared first on Carbon Brief.
Cropped 13 August 2025: Fossil-fuelled bird decline; ‘Deadly’ wildfires; Empty nature fund
New York Already Denied Permits to These Gas Pipelines. Under Trump, They Could Get Greenlit
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