London’s environment affects people’s health, wellbeing and the city’s long‑term sustainability. Reducing emissions, improving air quality and ensuring access to green space are central to maintaining a high quality of life for Londoners. This chapter assesses progress across key environmental challenges facing the capital including carbon emissions, air quality, access to green spaces and climate change resilience.
Carbon emissions
Greenhouse gas emissions (GHG) in London are reported annually in the London Energy and Greenhouse Gas Inventory (LEGGI)1 . The latest report published in November 2025 shows data for 2023, the most recent year for which information is available.
In 2023, London’s GHG emissions were 28.6 million tonnes of carbon dioxide equivalent (MtCO₂e), down from 30.0 MtCO₂e in 2022. This represents a year-on-year fall of 4.7%. The decrease was mainly driven by lower emissions from domestic energy and industrial and commercial energy, while transport emissions remained broadly unchanged. Compared with 1990, London’s emissions have fallen by 37%. They are also 44% lower than their peak in 2000.
Domestic energy and industrial and commercial energy were responsible for 63% of total emissions, while transport accounted for 30%. Waste, industrial processes and product use, agriculture, forestry and other land use, and other stationary energy sources were responsible for the remainder.
Compared to the rest of the UK, London has the lowest per capita emissions of any region – partly a result of its extensive public transport system and lower levels of industrial activity than other regions. Between 1990 and 2023, average emissions (tCO2e) per person fell by 52% from 6.7 tonnes to 3.2 tonnes.
The historic emissions series was revised in LEGGI 2023 to reflect updates to several underlying datasets. This means the historic trajectory presented above is not directly aligned with previous LEGGI releases.
Improving the energy efficiency of the housing stock is vital for achieving London’s net zero ambitions because it reduces the overall demand for energy, which in turn lowers the amount of GHG emissions associated with energy production and consumption. An Energy Performance Certificate (EPC) indicates how energy efficient a building is, from A (most efficient) to G (least efficient).
EPCs are only required when properties are built, sold or let, at which point they are added to the Energy Performance of Buildings Register. As such, EPC-based statistics should not be interpreted as a complete representation of the entire building stock.
Across England, the share of domestic EPCs added to the register with a rating of A-C has trended upwards over the last decade. In London, the share increased from 36% in Q4 2014 to 70% in Q1 2026, consistently remaining above the national trend over this period. Overall, this indicates a gradual improvement in the share of A-C rated EPCs in both London and England, with London maintaining higher levels throughout the period.
Since 2014, renewable electricity generation in London has increased by around 65%. It reached 1,463 GWh in 2024, the highest level recorded over the period shown. This follows revised figures of 1,456 GWh in 2022 and 1,395 GWh in 2023, indicating that generation has remained above pre-2020 levels in recent years. Revisions to the 2022 and 2023 data reflect updates from suppliers and the incorporation of more up-to-date information, meaning the chart differs from last year’s report.
Total electricity consumption in London in 2023 was 34,642 GWh, the latest data available from LEGGI, meaning that local renewable electricity generation accounted for around 4% of London’s electricity consumption in that year.
Recycling helps reduce the greenhouse gas emissions associated with the entire product lifecycle, from extraction to disposal. By recycling more, London households help to reduce the need for raw materials, minimise landfill waste, and lower energy consumption associated with manufacturing new products.
The recycling rate in London has remained broadly unchanged over the last three years at 32.7%, with the latest data for 2024/25 showing a similar level at 32.6%. Since 2014/15, London’s household waste recycling rate has been consistently below that of England. Nationally, recycling rates increased slightly to 42.3% in 2023/24 before falling marginally to 42.0% in 2024/25, and remain below the peak of 43.8% observed in 2019/20.
Air Quality
There is strong evidence linking adverse health impacts to levels of nitrogen dioxide (NO2) and particulate matter (PM), especially the smaller-sized particulate matter (PM2.5). This section presents the latest data on air quality at the roadside and in the urban background.
The monthly average roadside and urban background concentration of NO₂ in January 2026 was 28 µg/ m³ and 21 µg/ m³ respectively, compared with 26 µg/ m³ and 17 µg/ m³ in January 2025. Urban background NO₂ concentrations are generally lower than roadside concentrations due to the distance from the main pollutant source, that is vehicular traffic on roads. The averages were calculated from air quality monitoring sites in Central, Inner and Outer London.
For both site types, concentrations have followed a broad downward trend since 2015, despite some monthly variation. The January 2026 values remain well below the UK legal annual limit of 40 µg/ m³, but above the World Health Organisation (WHO) Air Quality Guideline target of 10 µg/ m³. This means that, although NO₂ levels in London are much lower than at the start of the series, they remain above the level recommended by the WHO.
The annual mean roadside concentration of PM₂.₅in 2026 was 11 µg/ m³, unchanged from 2025 at 11 µg/ m³. The annual mean urban background concentration of PM₂.₅in 2026 was 9 µg/ m³, down from 10 µg/ m³ in 2025. As is the case for NO₂, PM₂.₅ concentrations in the urban background are also lower than those in roadside areas, albeit marginally and the difference has reduced over time.
The averages were calculated from air quality monitoring sites in Central, Inner and Outer London. For both site types, the averages remain well below the requirements of UK legislation, which state that the annual average concentration must not exceed 20 µg/ m³, but remain above the WHO Air Quality Guideline target of 5 µg/ m³.
Green and wild spaces
Parks, woodlands, nature reserves, riversides and other open spaces play a vital role in Londoners’ health and wellbeing, offering places for recreation, relaxation and contact with nature. This section presents indicators on people’s connection to nature, access to open spaces, biodiversity and green cover across London.
The People and Nature Survey by Natural England collects information on adults’ and children’s experiences and views about the natural environment, and its contribution to health and wellbeing. The question on whether people feel part of nature provides an indication of whether they are able to access and enjoy green and wild spaces.
The latest available London figure shows that 62.8% of adult Londoners reported feeling part of nature in 2024/25, compared with 59.3% in 2020/21. Due to low sample sizes in the survey, the indicator has not been updated for this edition but will be in due course when a more robust estimate becomes available.
For Londoners to enjoy green and wild space and its multiple benefits, it is important that all Londoners have access to public open space. The London Plan defines seven categories of public open space, based on the size of the sites and the facilities they offer, including acceptable distances from home.
Greenspace Information for Greater London CIC (GiGL), the capital’s environment records centre, has developed an approach to estimate Londoners’ access to public open space based on walking distances along roads and paths. Areas within acceptable distances to public open space are calculated using network analysis, while areas outside these calculated spaces are classified as Areas of Deficiency in Access to Public Open Space (AODPOS). As of 2026, 38% of residential addresses in London fell within an AODPOS, down slightly from 38.85% in 2025.
The Department for Environment, Food & Rural Affairs (Defra) also publishes statistics on access to green and blue space in England2 . These provide a useful wider benchmark but are not directly comparable with GiGL’s AODPOS measure because they use different datasets, definitions and access standards.
London’s most valuable sites for wildlife are recognised as Sites of Importance for Nature Conservation (SINCs). This is a non-statutory designation, but SINCs are still afforded a high level of protection within the planning system. Development that negatively impacts on a SINC will only be permitted in exceptional circumstances and where mitigation can be proven from the beginning. The amount of area covered by SINCs in London provides an indication of the extent of wild spaces across London.
As of 2026, data compiled by GiGL finds that the total area designated as SINC in London is 31,815 hectares, up slightly from 31,676 hectares in 20253 . GiGL’s data indicates that between 2012 and 2026 there was an increase of 1,697 hectares in land designated as SINC, increasing the coverage of London from 19.2% to 20.2%.
The GLA’s Green Cover Map4 provides estimates of how much of London is green, specifically tree canopy cover and green cover. The latest update published in 2024 was generated via computer modelling techniques, using aerial imagery primarily from 2022. London’s tree canopy cover is estimated at 19.6% (with a ±0.3% margin of error) and its green cover at 51.7% (±1.11%). Previously, London’s canopy cover was estimated at 21.06% (± 0.2%) and green cover estimated at 47.6% to 50.7% (in both instances, underlying aerial imagery was from 2016).
While the latest data might suggest a decrease in tree canopy cover, given the margins of error in the modelling there is no statistically significant change in canopy cover across London within the timeframe (2016 to 2022), and improvements to the methodology are also likely to have contributed to the change in figure. Please see the green cover map methodology report for more information about the accuracy and limitations of the modelling approach, via the London Datastore green cover page5 , and canopy cover page6 .
Climate change resilience
The London Climate Resilience Review7 published in June 2024 was an independent report, commissioned by the Mayor of London, to take stock of London’s preparations for climate impacts including recommended actions. The three most urgent climate risks facing London are: 1) extreme heat; 2) drought; and 3) surface water flooding. Indicators for each are provided below. These risks and resulting negative impacts are likely to increase even with significant investment in adaptation measures.
The change in global climate is causing an increase in frequency, duration, and magnitude of extreme heat events, including heatwaves. High temperatures in cities affect infrastructure, worker productivity and have significant effects on health and wellbeing, particularly for vulnerable populations.
The Health Security Agency (UKHSA) defines heat episodes as at least one day with an amber Heat-Health alert in at least one region and/or a mean Central England Temperature of at least 20°C. UKHSA reports the number of all-cause excess heat deaths that occur during heat episodes across the summer period. Although the actual number of heat-associated deaths is likely to be higher, this measure reflects population vulnerability and exposure, with projections indicating an increase without further heat adaptation8 .
Data from UKHSA show that in 2025, London experienced five heat episodes, resulting in an estimated 317 excess heat-associated deaths. This represents an increase on the previous year, although it remains below the peak levels seen in 2018 and 2020. Since 2016, the number of excess deaths in London has varied year on year, broadly in line with the trend for England.
These statistics were calculated using death registration data, comparing daily deaths during heat episodes with baseline daily deaths. Definitions and methods for the calculation are consistent from 2020 onwards. Previous reports were published by Public Health England and only statistically significant values are included.
During prolonged dry periods, water companies put in place different measures to protect water supply. There are four levels of drought plan measures used in England; level 3 and above are defined as emergency measures to protect supply and involve non-essential water use bans. Measures must be timely and proportionate to the drought risk to avoid the need for even more severe level 4 restrictions.
In 2025, there were zero days in which emergency drought measures (level 3 and above) were implemented in London, indicating that no severe drought conditions triggered this level of response.9 This continues the recent trend of no emergency measures being reported in the preceding two years, with the last occurrence in London recorded in 2022.
While the absence of emergency drought measures in recent years is positive, it should be interpreted with caution. Evidence from the Environment Agency indicates that, despite no formal escalation to emergency measures, there can still be underlying pressures on water supply during dry periods10 .
Surface water is the biggest flood risk facing London and monitoring the number of properties flooded assesses the real-world impact on Londoners. London’s Surface Water Strategy11 published in May 2025 estimates that there are almost 320,000 properties at high risk of flooding in London.
Data on flooded properties is collected by Environment Agency Flood Resilience Teams and is based on reported incidents. As such, it is likely to underestimate the true number of properties affected, as not all flooding incidents are reported.
In 2024, around 18 properties in South London and 121 properties in North London were reported to have flooded12 . Most of these incidents occurred in September 2024, a period during which London faced surface water flooding resulting from heavy rainfall13 .
In 2025, reported incidents were more limited. Following a thunderstorm on 19 July 2025, there were reports of two internally flooded properties (one confirmed and one unconfirmed) and one externally flooded property in the Colindale area, along the Silkstream (a tributary of the River Brent). No property flooding was reported in South London from fluvial, tidal or surface water sources during this period.
These figures should be treated as indicative only, given known limitations in reporting. Improvements to flood incident reporting are expected over time following the publication of new national flood investigation guidance14 by Defra in April 2025, which aims to support Lead Local Flood Authorities and standardise reporting across England.