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The amount of UK electricity generated from fossil fuels fell 22% year-on-year in 2023 to the lowest level since 1957, Carbon Brief analysis reveals.

The 104 terawatt hours (TWh) generated from fossil fuels in 2023 is the lowest level in 66 years. Back then, Harold Macmillan was the UK prime minister and the Beatles’ John Lennon and Paul McCartney had just met for the first time.

Electricity from fossil fuels has now fallen by two-thirds (199TWh) since peaking in 2008. Within that total, coal has dropped by 115TWh (97%) and gas by 80TWh (45%).

These declines have been caused by the rapid expansion of renewable energy (up six-fold since 2008, some 113TWh) and by lower electricity demand (down 21% since 2008, some 83TWh).

As a result, fossil fuels made up just 33% of UK electricity supplies in 2023 – their lowest ever share – of which gas was 31%, coal just over 1% and oil just below 1%.

Low-carbon sources made up 56% of the total, of which renewables were 43% and nuclear 13%. The remainder is from imports (7%) and other sources (3%), such as waste incineration.

Overall, the electricity generated in the UK in 2023 had the lowest-ever carbon intensity, with an average of 162g of carbon dioxide per kilowatt hour (gCO2/kWh).

This remains a long way from the government’s ambition for 95% low-carbon electricity by 2030 – just seven years from now – and a fully decarbonised grid by 2035.

Fossil falls

Historically, fossil-fuel generation rose steadily as the size of the UK’s economy expanded – and, relatedly, as demand for electricity grew.

The rise in demand for electricity paused during the late 1970s and 1980s, as the country’s economic situation and industrial relations worsened. Yet the upwards march soon resumed.

Electricity demand then started to “decouple” from economic growth in the early 2000s, leading to a peak in 2005. Since then, demand has dropped precipitously, falling from 396TWh in 2008 to 313TWh in 2023, as shown by the dark blue line in the figure below.

This reduction in demand of 83TWh (21%) is equivalent to more than three times the expected output of the Hinkley Point C nuclear power plant, which is currently being built in Somerset.

Demand reductions are the result of a poorly understood combination of more efficient appliances and lighting, high prices driven by expensive gas and changes in the structure of the UK as it shifts to an ever more service-led rather than manufacturing-heavy economy.

(In the medium- to long-term, electricity demand is expected to rise as transport and heating are increasingly electrified using electric vehicles and heat pumps.)

While electricity demand was falling, the UK was also starting to rapidly scale its renewable energy capacity, primarily from wind, but also from solar and bioenergy.

As a result, renewable electricity output climbed six-fold from 23TWh in 2008 to 135TWh in 2023, shown by the red line in the chart below.

The combined impact of falling demand (-83TWh) and rising renewables (+113TWh) has acted as a pincer on electricity generation from fossil fuels, squeezing it from two directions.

Having peaked at 303TWh in 2008, the UK got just 104TWh of electricity from fossil fuels in 2023 – as shown by the steep black line in the figure below – a two-thirds reduction in 15 years. This takes fossil-fuel generation to its lowest level since 1957.

UK electricity from fossil fuels drops to lowest level since 1957
Annual UK electricity generation from fossil fuels (black) and renewables (red), TWh, as well as overall demand (dark blue). Source: DESNZ, BM Reports and Carbon Brief analysis.

In 1957, the Conservative party’s Harold Macmillan was elected UK prime minister in January following Anthony Eden’s resignation due to ill health.

That same year, the Central Electricity Generating Board was established ‘to keep the lights on’. It was responsible for electricity generation, transmission and bulk sales in England and Wales up until the electricity sector was privatised in the 1990s. 

The world’s first commercial nuclear power station, at Calder Hall in Cumbria, had just opened its second unit, yet fossil fuels still supplied 97% of the UK’s electricity.

Also that year, the Suez canal was reopened, “Sputnik 1” – the first artificial satellite to orbit Earth – was launched by the Soviet Union and the UK government unveiled plans to allow women to join the House of Lords for the first time.

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Shifting shares

For most of the past century, fossil fuels generated almost all of the UK’s electricity, as shown by the black line in the figure below. Fossil fuels – predominantly coal – made up 97% of the total in 1957, a figure that had barely changed for decades.

The rise of nuclear power (dark blue line) from the late 1950s onwards – after Calder Hall opened in 1956 – pushed the fossil fuel share downwards.

Yet electricity demand continued to grow and the earliest nuclear reactors were starting to shut down by the early 2000s, with only Sizewell B in Suffolk, in 1995, having replaced them.

With renewables still in their infancy, this meant that, in 2008, the UK was still getting 76% of its electricity from fossil fuels. Of this, 45% was from gas and 30% from coal.

Since then, fossil fuels’ share has dropped to a record-low 33% in 2023, being overtaken by renewables in the process (red line).

Renewables’ share reached a record high of 43% in 2023, with nuclear (13%, light blue line), imports (7%) and other sources (3%) making up the remainder.

Fossil fuels met a record-low 33% of UK electricity needs in 2023
Share of electricity generation from fossil fuels (black), renewables (red) and nuclear (light blue), %. Source: DESNZ, BM Reports and Carbon Brief analysis.

The total share from low-carbon sources – renewables and nuclear – was 56% in 2023. This was down one point from the record 57% share in 2022, as a result of a drop in nuclear output.

The current government’s ambition is to get 95% of the country’s electricity from low-carbon sources by 2030, which would mean an increase of 39 percentage points in seven years.

To date, the fastest rate of increase has been 25 percentage points in seven years, achieved between 2010 (23% low-carbon) and 2017 (48%).

The aim is then to fully decarbonise the grid by 2035. The opposition Labour Party’s aim is even more ambitious, hoping to fully decarbonise the electricity grid already by 2030. This would be a 44 percentage point increase in seven years.

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Renewable rise

The rise of renewables since 2008 has been nearly as steep as the fall for fossil fuels, as shown by the red line in the figure below.

Notably, however, since reaching 134TWh in 2020, renewables have effectively stood still, with output of 135TWh in 2023, matching the record 135TWh set in 2022.

This reflects the balance between continued increases in wind and solar capacity, variations in average weather conditions and reduced output in the past two years from bioenergy.

The 135TWh of renewable electricity in 2023 was made up of:

  • 82TWh from wind (up 2TWh year-on-year, a 2% increase);
  • 35TWh from bioenergy (down 5TWh and 13% from 2021 levels);
  • 14TWh from solar (up 2% year-on-year);
  • 5TWh from hydro (down 1TWh year-on-year, a 9% drop).

At the same time, coal has nearly disappeared from the UK electricity system, falling from 119TWh in 2008 to 4TWh in 2023 (down 115TWh, 97%), shown by the black line below.

Gas, meanwhile, is now down to levels rarely seen since the mid-1990s (grey line), falling from 178TWh in 2008 to just 98TWh in 2023 (down 80TWh, 45%).

Nuclear also continues to decline, reaching 41TWh in 2023, a 7TWh reduction year-on-year (15%) from already low levels, after Hinkley Point B in Somerset closed down and the remaining five stations were temporarily offline for planned maintenance outages.

Renewables are the largest contributor to UK electricity needs
Top: Annual UK electricity generation by source, TWh. Bottom: Share of electricity generation by source, %. The jump in generation in 1951 reflects a change in the scope of the data, which only included “major” power producers prior to that date. The spikes in 1984 reflect the substitution of coal with oil as part of the government’s strategy against the miners’ strikes. Source: DESNZ, BM Reports and Carbon Brief analysis.

Capacity for both onshore and offshore wind projects rose in 2023, by 0.6GW and 1.1GW, respectively.

Average wind speeds in the first 11 months of 2023 were well below the long-term average however, according to government figures, whereas 2022 had only been marginally below average. This muted overall generation growth over the last year somewhat. 

A windy December helped boost overall generation figures for the year, with a new wind generation provisionally set on 21 December according to National Grid ESO. Wind generation hit 21.8GW between 8:00 and 8:30 on 21 December, providing 56% of the generation mix.

Notably, only one offshore windfarm was completed in 2023 – the 1GW Seagreen development off the east coast of Scotland – whereas three projects totalling 3GW were commissioned in 2022.

In October 2023, Dogger Bank off the coast of Yorkshire sent power to the national grid for the first time. It will be the world’s largest offshore windfarm, at 3.6GW, when it is completed in 2026.

Nevertheless, the government’s ambition for 50GW of offshore wind by 2030 is in doubt after the latest auction for new renewable capacity failed to secure any additional projects.

For bioenergy, the 35TWh in 2023 was similar to the level delivered in 2022, but down from 40TWh in 2020 and 2021. Plant biomass – mainly woodchips – is around two-thirds of these annual totals.

The four wood-burning former coal units at the Drax plant in Yorkshire account for around one-third of power from bioenergy on their own. However, their output has been subdued in 2022 and 2023, with some reporting having raised questions about the incentives at play.

Meanwhile, electricity generation from solar power only increased by 2% in 2023, despite a surge in new capacity being connected to the grid.

The number of hours of sunshine during 2023 was roughly in line with the long-term average, government figures show, whereas 2022 had been unusually sunny.

According to figures from consultancy Rystad Energy cited by Drax Electric Insights, the UK’s solar capacity was expected to rise from 15GW at the start of 2023 to 18GW by the end of the year.

Recent growth in solar installations comes after an extended period of stagnation, with installed capacity having reached 13GW in 2018 and only climbing to 14GW in 2022.

Rystad Energy expects UK solar capacity to continue accelerating, topping 25GW in 2025.

The latest reduction in coal generation, down another 33% in 2023, came as three of the UK’s four remaining coal-fired power stations shut down.

Dr Simon Evans on X: Not sure if you noticed, but as of yesterday, the UK only had one coal-fired power station remaining
Dr Simon Evans on X: Not sure if you noticed, but as of yesterday, the UK only had one coal-fired power station remaining

West Burton in Nottinghamshire closed in March, then Drax in Yorkshire closed in April, followed by Kilroot in Northern Ireland at the end of September.

Only Ratcliffe in Nottinghamshire, operated by utility firm Uniper, remains operational. It plans to close in September 2024, ahead of the government’s ambition to end coal power by October 2024.

While the UK saw a major coal-to-gas transition in the 1990s “dash for gas”, recent reductions in coal use have been driven by renewables and reduced demand. These same forces have also been driving gas out of the mix.

The large drop in gas generation in 2023 of 27TWh (21%) reflects a combination of this longer-term trend with a one-off flip in the UK’s electricity imports.

The dip in the dark blue line for “oil, imports and other” in 2022 is due to the UK becoming a net electricity exporter that year for the first time ever.

Every year since the opening of the first “interconnector” linking the grids of the UK and France in 1986, the UK has been a net electricity importer – apart from 2022.

The switch in 2022 was due to widespread outages in the French nuclear fleet, with neighbouring countries including the UK picking up the slack.

In 2023, the UK reverted to being a net importer, buying 23TWh of electricity from countries including France, the Netherlands, Belgium and Norway. This was similar to 2021 (25TWh).

The switch from being a net exporter of 5TWh in 2022 to net imports of 23TWh in 2023 combined with steady output from renewables and falling demand to push down the need for fossil fuels.

The UK now has 8.4 gigawatts (GW) of interconnector capacity to link its electricity system with that of neighbouring countries. Some 4.4GW of this has been added in the past five years.

In addition, the 1.4GW Viking Link interconnector between the UK and Denmark was completed in late 2023 and was due to have started operating in late December.

Another 4.7GW has regulatory approval, with further projects totalling 5.6GW also planned.

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Cleanest power

With fossil fuels reaching a record-low 33% share and coal down to 1% of the total, the UK saw its lowest-carbon electricity mix ever in 2023.

The carbon intensity of electricity – in other words, the amount of CO2 associated with each unit of electricity – fell to a record-low 162gCO2/kWh in 2023, a reduction of 18% year-on-year.

This continues a longer-term trend, shown in the figure below. In the early years of the series, the reductions in carbon intensity reflect a shift towards more efficient power plants.

The expansion of nuclear power in the 1970s and 1980s was followed by the “dash for gas”, which is lower-carbon than coal. From around 2008, the decline is due to the rise of renewables.

Electricity generated in 2023 was the cleanest ever
Carbon intensity of UK electricity supplies, gCO/kWh. Source: DESNZ, BM Reports and Carbon Brief analysis.

The government had earlier set a goal of reducing the carbon intensity of electricity generation to below 100gCO2/kWh by 2030. Since then, the UK’s 2050 climate target has been strengthened from an 80% cut in emissions to a 100% cut – reaching net-zero by that date.

If the government reaches its aim of 95% low-carbon electricity by 2030 then the carbon intensity of generation would fall to well-below 100gCO2/kWh. Just how far below would depend on the contribution from bioenergy and whether CO2 associated with imported electricity is counted.

The figure above counts bioenergy lifecycle emissions and imports towards the total.

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Methodology

The figures in the article are from Carbon Brief analysis of data from DESNZ Energy Trends chapter 5 and chapter 6, as well as from BM Reports. The figures from BM Reports are for electricity supplied to the grid in Great Britain only and are adjusted to include Northern Ireland.

In Carbon Brief’s analysis, the BM Reports numbers are also adjusted to account for electricity used by power plants on site and for generation by plants not connected to the high-voltage national grid. This includes many onshore windfarms, as well as industrial gas combined heat and power plants and those burning landfill gas, waste or sewage gas.

The analysis of carbon intensity is based on the methodology published by National Grid ESO, but also takes account of fuel use efficiency for earlier years.

DESNZ historical electricity data, including years before 2009, is adjusted in line with other figures and combined with data on imports from a separate DESNZ dataset. Note that the data prior to 1951 only includes “major” power producers.

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What Is the Economic Impact of Data Centers? It’s a Secret.

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N.C. Gov. Josh Stein wants state lawmakers to rethink tax breaks for data centers. The industry’s opacity makes it difficult to evaluate costs and benefits.

Tax breaks for data centers in North Carolina keep as much as $57 million each year into from state and local government coffers, state figures show, an amount that could balloon to billions of dollars if all the proposed projects are built.

What Is the Economic Impact of Data Centers? It’s a Secret.

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GEF raises $3.9bn ahead of funding deadline, $1bn below previous budget

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The Global Environment Facility (GEF), a multilateral fund that provides climate and nature finance to developing countries, has raised $3.9 billion from donor governments in its last pledging session ahead of a key fundraising deadline at the end of May.

The amount, which is meant to cover the fund’s activities for the next four years (July 2026-June 2030), falls significantly short of the previous four-year cycle for which the GEF managed to raise $5.3bn from governments. Since then, military and other political priorities have squeezed rich nations’ budgets for climate and development aid.

The facility said in a statement that it expects more pledges ahead of the final replenishment package, which is set for approval at the next GEF Council meeting from May 31 to June 3.

Claude Gascon, interim CEO of the GEF, said that “donor countries have risen to the challenge and made bold commitments towards a more positive future for the planet”. He added that the pledges send a message that “the world is not giving up on nature even in a time of competing priorities”.

    Donors under pressure

    But Brian O’Donnell, director of the environmental non-profit Campaign for Nature, said the announcement shows “an alarming trend” of donor governments cutting public finance for climate and nature.

    “Wealthy nations pledged to increase international nature finance, and yet we are seeing cuts and lower contributions. Investing in nature prevents extinctions and supports livelihoods, security, health, food, clean water and climate,” he said. “Failing to safeguard nature now will result in much larger costs later.”

    At COP29 in Baku, developed countries pledged to mobilise $300bn a year in public climate finance by 2035, while at UN biodiversity talks they have also pledged to raise $30bn per year by 2030. Yet several wealthy governments have announced cuts to green finance to increase defense spending, among them most recently the UK.

    As for the US, despite Trump’s cuts to international climate finance, Congress approved a $150 million increase in its contribution to the GEF after what was described as the organisation’s “refocus on non-climate priorities like biodiversity, plastics and ocean ecosystems, per US Treasury guidance”.

    The facility will only reveal how much each country has pledged when its assembly of 186 member countries meets in early June. The last period’s largest donors were Germany ($575 million), Japan ($451 million), and the US ($425 million).

    The GEF has also gone through a change in leadership halfway through its fundraising cycle. Last December, the GEF Council asked former CEO Carlos Manuel Rodriguez to step down effective immediately and appointed Gascon as interim CEO.

    Santa Marta conference: fossil fuel transition in an unstable world

    New guidelines

    As part of the upcoming funding cycle, the GEF has approved a set of guidelines for spending the $3.9bn raised so far, which include allocating 35% of resources for least developed countries and small island states, as well as 20% of the money going to Indigenous people and communities.

    Its programs will help countries shift five key systems – nature, food, urban, energy and health – from models that drive degradation to alternatives that protect the planet and support human well-being by integrating the value of nature into production and consumption systems.

    The new priorities also include a target to allocate 25% of the GEF’s budget for mobilising private funds through blended finance. This aligns with efforts by wealthy countries to increase contributions from the private sector to international climate finance.

    Niels Annen, Germany’s State Secretary for Economic Cooperation and Development, said in a statement that the country’s priorities are “very well reflected” in the GEF’s new spending guidelines, including on “innovative finance for nature and people, better cooperation with the private sector, and stable resources for the most vulnerable countries”.

    Aliou Mustafa, of the GEF Indigenous Peoples Advisory Group (IPAG), also welcomed the announcement, adding that “the GEF is strengthening trust and meaningful partnerships with Indigenous Peoples and local communities” by placing them at the “centre of decision-making”.

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    Marine heatwaves ‘nearly double’ the economic damage caused by tropical cyclones

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    Tropical cyclones that rapidly intensify when passing over marine heatwaves can become “supercharged”, increasing the likelihood of high economic losses, a new study finds.

    Such storms also have higher rates of rainfall and higher maximum windspeeds, according to the research.

    The study, published in Science Advances, looks at the economic damages caused by nearly 800 tropical cyclones that occurred around the world between 1981 and 2023.

    It finds that rapidly intensifying tropical cyclones that pass near abnormally warm parts of the ocean produce nearly double – 93% – the economic damages as storms that do not, even when levels of coastal development are taken into account.

    One researcher, who was not involved in the study, tells Carbon Brief that the new analysis is a “step forward in understanding how we can better refine our predictions of what might happen in the future” in an increasingly warm world.

    As marine heatwaves are projected to become more frequent under future climate change, the authors say that the interactions between storms and these heatwaves “should be given greater consideration in future strategies for climate adaptation and climate preparedness”.

    ‘Rapid intensification’

    Tropical cyclones are rapidly rotating storm systems that form over warm ocean waters, characterised by low pressure at their cores and sustained winds that can reach more than 120 kilometres per hour.

    The term “tropical cyclones” encompasses hurricanes, cyclones and typhoons, which are named as such depending on which ocean basin they occur in.

    When they make landfall, these storms can cause major damage. They accounted for six of the top 10 disasters between 1900 and 2024 in terms of economic loss, according to the insurance company Aon’s 2025 climate catastrophe insight report.

    These economic losses are largely caused by high wind speeds, large amounts of rainfall and damaging storm surges.

    Storms can become particularly dangerous through a process called “rapid intensification”.

    Rapid intensification is when a storm strengthens considerably in a short period of time. It is defined as an increase in sustained wind speed of at least 30 knots (around 55 kilometres per hour) in a 24-hour period.

    There are several factors that can lead to rapid intensification, including warm ocean temperatures, high humidity and low vertical “wind shear” – meaning that the wind speeds higher up in the atmosphere are very similar to the wind speeds near the surface.

    Rapid intensification has become more common since the 1980s and is projected to become even more frequent in the future with continued warming. (Although there is uncertainty as to how climate change will impact the frequency of tropical cyclones, the increase in strength and intensification is more clear.)

    Marine heatwaves are another type of extreme event that are becoming more frequent due to recent warming. Like their atmospheric counterparts, marine heatwaves are periods of abnormally high ocean temperatures.

    Previous research has shown that these marine heatwaves can contribute to a cyclone undergoing rapid intensification. This is because the warm ocean water acts as a “fuel” for a storm, says Dr Hamed Moftakhari, an associate professor of civil engineering at the University of Alabama who was one of the authors of the new study. He explains:

    “The entire strength of the tropical cyclone [depends on] how hot the [ocean] surface is. Marine heatwave means we have an abundance of hot water that is like a gas [petrol] station. As you move over that, it’s going to supercharge you.”

    However, the authors say, there is no global assessment of how rapid intensification and marine heatwaves interact – or how they contribute to economic damages.

    Using the International Best Track Archive for Climate Stewardship (IBTrACS) – a database of tropical cyclone paths and intensities – the researchers identify 1,600 storms that made landfall during the 1981-2023 period, out of a total of 3,464 events.

    Of these 1,600 storms, they were able to match 789 individual, land-falling cyclones with economic loss data from the Emergency Events Database (EM-DAT) and other official sources.

    Then, using the IBTrACS storm data and ocean-temperature data from the European Centre for Medium-Range Weather Forecasts, the researchers classify each cyclone by whether or not it underwent rapid intensification and if it passed near a recent marine heatwave event before making landfall.

    The researchers find that there is a “modest” rise in the number of marine heatwave-influenced tropical cyclones globally since 1981, but with significant regional variations. In particular, they say, there are “clear” upward trends in the north Atlantic Ocean, the north Indian Ocean and the northern hemisphere basin of the eastern Pacific Ocean.

    ‘Storm characteristics’

    The researchers find substantial differences in the characteristics of tropical cyclones that experience rapid intensification and those that do not, as well as between rapidly intensifying storms that occur with marine heatwaves and those that occur without them.

    For example, tropical cyclones that do not experience rapid intensification have, on average, maximum wind speeds of around 40 knots (74km/hr), whereas storms that rapidly intensify have an average maximum wind speed of nearly 80 knots (148km/hr).

    Of the rapidly intensifying storms, those that are influenced by marine heatwaves maintain higher wind speeds during the days leading up to landfall.

    Although the wind speeds are very similar between the two groups once the storms make landfall, the pre-landfall difference still has an impact on a storm’s destructiveness, says Dr Soheil Radfar, a hurricane-hazard modeller at Princeton University. Radfar, who is the lead author of the new study, tells Carbon Brief:

    “Hurricane damage starts days before the landfall…Four or five days before a hurricane making landfall, we expect to have high wind speeds and, because of that high wind speed, we expect to have storm surges that impact coastal communities.”

    They also find that rapidly intensifying storms have higher peak rainfall than non-rapidly intensifying storms, with marine heatwave-influenced, rapidly intensifying storms exhibiting the highest average rainfall at landfall.

    The charts below show the mean sustained wind speed in knots (top) and the mean rainfall in millimetres per hour (bottom) for the tropical cyclones analysed in the study in the five days leading up to and two days following a storm making landfall.

    The four lines show storms that: rapidly intensified with the influence of marine heatwaves (red); those that rapidly intensified without marine heatwaves (purple); those that experienced marine heatwaves, but did not rapidly intensify (orange); and those that neither rapidly intensified nor experienced a marine heatwave (blue).

    Average maximum sustained wind speed (top) and rate of rainfall (bottom) for tropical cyclones in the period leading up to and following landfall. Storms are categorised as: rapidly intensifying with marine heatwaves (red); rapidly intensifying without marine heatwaves (purple); not rapidly intensifying with marine heatwaves (orange); and not rapidly intensifying, without marine heatwaves (blue). Source: Radfar et al. (2026)
    Average maximum sustained wind speed (top) and rate of rainfall (bottom) for tropical cyclones in the period leading up to and following landfall. Storms are categorised as: rapidly intensifying with marine heatwaves (red); rapidly intensifying without marine heatwaves (purple); not rapidly intensifying with marine heatwaves (orange); and not rapidly intensifying, without marine heatwaves (blue). Source: Radfar et al. (2026)

    Dr Daneeja Mawren, an ocean and climate consultant at the Mauritius-based Mascarene Environmental Consulting who was not involved in the study, tells Carbon Brief that the new study “helps clarify how marine heatwaves amplify storm characteristics”, such as stronger winds and heavier rainfall. She notes that this “has not been done on a global scale before”.

    However, Mawren adds that other factors not considered in the analysis can “make a huge difference” in the rapid intensification of tropical cyclones, including subsurface marine heatwaves and eddies – circular, spinning ocean currents that can trap warm water.

    Dr Jonathan Lin, an atmospheric scientist at Cornell University who was also not involved in the study, tells Carbon Brief that, while the intensification found by the study “makes physical sense”, it is inherently limited by the relatively small number of storms that occur. He adds:

    “There’s not that many storms, to tease out the physical mechanisms and observational data. So being able to reproduce this kind of work in a physical model would be really important.”

    Economic costs

    Storm intensity is not the only factor that determines how destructive a given cyclone can be – the economic damages also depend strongly on the population density and the amount of infrastructure development where a storm hits. The study explains:

    “A high storm surge in a sparsely populated area may cause less economic damage than a smaller surge in a densely populated, economically important region.”

    To account for the differences in development, the researchers use a type of data called “built-up volume”, from the Global Human Settlement Layer. Built-up volume is a quantity derived from satellite data and other high-resolution imagery that combines measurements of building area and average building height in a given area. This can be used as a proxy for the level of development, the authors explain.

    By comparing different cyclones that impacted areas with similar built-up volumes, the researchers can analyse how rapid intensification and marine heatwaves contribute to the overall economic damages of a storm.

    They find that, even when controlling for levels of coastal development, storms that pass through a marine heatwave during their rapid intensification cause 93% higher economic damages than storms that do not.

    They identify 71 marine heatwave-influenced storms that cause more than $1bn (inflation-adjusted across the dataset) in damages, compared to 45 storms that cause those levels of damage without the influence of marine heatwaves.

    This quantification of the cyclones’ economic impact is one of the study’s most “important contributions”, says Mawren.

    The authors also note that the continued development in coastal regions may increase the likelihood of tropical cyclone damages over time.

    Towards forecasting

    The study notes that the increased damages caused by marine heatwave-influenced tropical cyclones, along with the projected increases in marine heatwaves, means such storms “should be given greater consideration” in planning for future climate change.

    For Radfar and Moftakhari, the new study emphasises the importance of understanding the interactions between extreme events, such as tropical cyclones and marine heatwaves.

    Moftakhari notes that extreme events in the future are expected to become both more intense and more complex. This becomes a problem for climate resilience because “we basically design in the future based on what we’ve observed in the past”, he says. This may lead to underestimating potential hazards, he adds.

    Mawren agrees, telling Carbon Brief that, in order to “fully capture the intensification potential”, future forecasts and risk assessments must account for marine heatwaves and other ocean phenomena, such as subsurface heat.

    Lin adds that the actions needed to reduce storm damages “take on the order of decades to do right”. He tells Carbon Brief:

    “All these [planning] decisions have to come by understanding the future uncertainty and so this research is a step forward in understanding how we can better refine our predictions of what might happen in the future.”

    The post Marine heatwaves ‘nearly double’ the economic damage caused by tropical cyclones appeared first on Carbon Brief.

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