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Guest post: How marine life provides climate benefits worth billions of dollars

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Original article by Dr Damien Couespel republished from Carbon Brief under a CC license.

Redtooth triggerfishes in the Indian Ocean, Maldives. Credit: Reinhard Dirscherl / Alamy Stock Photo

The ocean plays a vital role in regulating the climate, storing roughly 50 times more carbon dioxide (CO2) than the atmosphere.

Marine life plays a significant part in this process, as organisms transfer carbon from the ocean surface to the deep sea upon death or as they migrate.

Our new research, published in Nature Communications, suggests the contribution of ocean biology to climate regulation is more complex than previously thought.

To explore how ocean biology shapes the past, present and future climate, we explore an extreme scenario where all marine life has been wiped out. 

We find that – in a pre-industrial climate – CO2 levels would rise by 50% without marine life, leading to 1.6C of global warming.

In a separate study in Nature Climate Change, we estimate that ocean biology sequesters the equivalent of 10bn tonnes of CO2 each year. 

This is more than one quarter of annual fossil-fuel emissions from human activity.

We also calculate that the contribution of marine life to carbon storage is worth hundreds of billions of dollars each year.

Biological carbon pump

The ocean takes up and stores vast amounts of CO2 every year through two mechanisms known as “carbon pumps”.

The first is the “solubility pump”. This is the process by which dissolved CO2 in seawater is transported from the ocean’s surface to its depth through the sinking and upwelling of water mass.

The second is the “biological carbon pump”. This is the process where carbon is converted into organic materials by plankton and other marine organisms at the ocean’s surface and then transported to the deep sea when they die or migrate. 

Scientists have long known that the biological carbon pump played an essential role in maintaining low atmospheric CO2 levels before the industrial revolution.

However, the conventional view is that the solubility pump has been responsible for the ocean’s steady absorption of rising CO2 emissions caused by human activity.

Our findings challenge this view, by showing the biological carbon pump plays a crucial role in the modern ocean’s sequestration of atmospheric CO2.

We find that, without marine life, the ocean’s capacity to capture CO2 emissions would be significantly diminished.

Two scenarios 

To get an estimate of the contribution of the marine carbon pump in a stable pre-industrial climate, we simulate the planet’s climate as it was before the industrial era using a complex Earth system model.

(This is the second generation of the Norwegian Earth system model, which contributed to the sixth Coupled Model Intercomparison Project.)

We then explore what would happen to the Earth’s climate system under two scenarios:

  • A reference, “healthy ocean” scenario where ocean biology conditions were as realistic as possible.
  • An “abiotic” scenario where all marine life is removed. 

In a pre-industrial scenario with no marine life, we find that atmospheric CO2 levels would rise to 445 parts per million (ppm). This is an increase of more than 50% on the “healthy ocean” scenario, where CO2 levels are 282ppm.

(This suggests that the influence of marine life on global CO2 levels is greater than the sum of all human activity, which has – so far – raised atmospheric CO2 concentrations to around 425ppm).

The rise in CO2 levels caused by the absence of marine life would result in about 1.64C of global warming at the surface and a 1.15C increase in global sea surface temperature. 

This warming would have considerable impacts on the wider world, including declines in sea ice area at the Arctic and Antarctic of close to 25% and an Atlantic Meridional Overturning Circulation that was around 9% weaker.

The value of exploring such an extreme scenario is to investigate the role biological processes in the ocean play in carbon storage, as well as the implications of damage to marine life.

The role of terrestrial ecosystems

Our estimation that pre-industrial atmospheric CO2 would rise by 163ppm without ocean biology is on the lower end of the 150-240ppm range approximated by some previous studies.

However, previous estimates of the contribution of the biological carbon pump in a pre-industrial climate neglect the interactions between oceanic and terrestrial biospheres.

Our research reveals that terrestrial ecosystems – such as tropical forests and grasslands – play a crucial role in compensating for the increase in CO2 concentrations when ocean life declines. (This is due to the CO2 fertilisation effect, when higher CO2 concentrations speed up photosynthesis).  

We find that in the extreme pre-industrial scenario, approximately half the carbon lost from the ocean is absorbed by the land. 

The figure below illustrates the Earth’s carbon reservoirs in a pre-industrial climate with (left) and without (right) marine life. It shows how, if marine life is wiped out, carbon content decreases in the ocean and marine sediment, whereas more carbon accumulates in the atmosphere and on land.

Reserves of carbon on land, in the atmosphere, ocean and marine sediment in a pre-industrial climate with (left) and without (right) marine life.
Reserves of carbon on land, in the atmosphere, ocean and marine sediment in a pre-industrial climate with (left) and without (right) marine life. Carbon content is measured in parts per million (ppm) and petagrams of carbon (PgC). Source: Tjiputra et al. (2025).

Ramifications for the future

Today, the ocean captures approximately 25% of human-caused CO2 emissions – which allows it to play a crucial role in slowing global warming. 

In order to estimate the overall importance of marine life to carbon sequestration in the ocean, we also conduct experiments for various future emission pathways – both with, and without, marine life. 

In all cases, we find that more CO2 emitted by human activities remains in the atmosphere when there is no marine life.

One might think that the ocean’s lower concentrations of carbon in the pre-industrial climate, relative to the atmosphere, might mean it would be able to absorb more additional carbon. 

However, we find the absence of marine life fundamentally alters the vertical distribution of carbon in the ocean. Although the total amount of carbon stored is lower, there is more carbon at the surface due to an absence of organisms. This, in turn, hinders additional CO2 from entering the ocean. 

Another surprising finding of the simulations was that the terrestrial biosphere’s capacity to absorb excess CO2 by increasing its vegetation mass diminishes over time, potentially due to limited nutrients. 

The figure below shows the distribution of human-caused CO2 in the Earth’s carbon reservoirs under two 2100 scenarios. The chart on the left shows a scenario with ocean life, and the chart on the right shows one without ocean biology.

It illustrates how, without marine life, more CO2 stays in the atmosphere and less goes into the land and the ocean. 

Projected distribution of the global carbon budget in 2100 in scenarios with (left) or without (right) marine life, with concentrations of carbon measured in parts per million (ppm).
Projected distribution of the global carbon budget in 2100 in scenarios with (left) or without (right) marine life, with concentrations of carbon measured in parts per million (ppm). The blue bars show the atmospheric CO2 concentration in 1850. Fossil fuel emissions added to the atmosphere between 1850-2100 are represented by a yellow bar. Land sinks and ocean sinks are represented in green and blue, and overall projected atmospheric CO2 levels shown in red. The pie charts depict fractions of fossil fuel emissions taken up by the land (green), ocean (blue) and atmosphere (red). Source: Tjiputra et al. (2025)

The study shows that in the absence of marine life, future warming would occur faster and more intensely. 

This acceleration in warming would potentially trigger other processes that could further amplify warming, such as greater ocean stratification, longer sea-ice free Arctic summers and greater loss of permafrost.

Economic benefits 

Damaging marine life is economically costly given the many and various benefits – or “ecosystem services” – provided by carbon sequestration.

We estimate that the sinking of organic matter sequesters approximately 2.8bn tonnes of carbon annually, locking it away from the atmosphere for at least 50 years. 

This carbon sequestration capacity is equivalent to 10bn tonnes of atmospheric CO2 – or roughly 27% of emissions generated by fossil fuels in 2024.  

We estimate – based on a carbon price of $90 per tonne of CO2 – that the carbon storage provided by the marine carbon pump is worth $545bn per year in international waters and $383bn per year within national waters. Its total value is projected to exceed $2.2tn by 2030. 

Carbon storage is valuable because it helps avoid climate impacts.

This economic value is important for developing countries, particularly small island developing states whose national waters are collectively responsible for 11% of biological carbon pump sequestration activity, in terms of carbon stored.

The top eight countries where the biological carbon pump value is highest in proportion to gross domestic product (GDP) are small island states. These are the Cook Islands, Kiribati, the Marshall Islands, Micronesia, Nauru, Niue, Palau and Tuvalu. Of these nations, just one – the Cook Islands – is classified by the World Bank as high income. 

These climate-impacted nations’ key role in preserving ocean health should be considered in discussions of international climate finance. 

The figure below shows the economic value of carbon sequestration of the biological carbon pump for each of these eight small island states, calculated on the basis of a carbon price of $90 per tonne of CO2. 

For example, it illustrates how Micronesia and Kiribati have an estimated biological carbon pump value of $4,620m and $8,525m each year, respectively.  

The economic value of biological carbon pump carbon sequestration in the eight countries where biological carbon pump sequestration value represents the largest proportion of GDP.
The economic value of biological carbon pump carbon sequestration in the eight countries where biological carbon pump sequestration value represents the largest proportion of GDP. Value is displayed in million US dollars per year (M US$/year) and the 50-year sequestration rate in million tons of carbon per year (MtC/year). Income groups are determined by the Work Bank. Source: Berzaghi et al. (2025).

A healthy ocean buys the world time in the battle against global warming, but the window to protect it is closing rapidly. 

Marine ecosystems remain vulnerable to a raft of human activities, including industrial fishing, pollution, shipping and deep-sea mining. Stronger conservation policies, enhanced financial incentives for lower income countries and increased international cooperation are essential to protect the services provided by ecosystems. 

These are important steps towards not only protecting 30% of the global ocean as agreed under the new Global Biodiversity Framework – but it will help to reach the Paris Agreement’s climate target.

There are a number of tools at governments disposal to protect the valuable services provided by marine ecosystems. This includes promoting sustainable fishing and ecotourism, establishing marine protected areas and undertaking robust environmental impact assessments. 

Nations can also support protection of the biological heat pump within international waters by ratifying the High Seas Treaty, which recognises the importance of protecting biogeochemical cycles.

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Tjiputra, J.F. et al. (2025): Marine ecosystem role in setting up preindustrial and future climate, Nature Communications, doi:10.1038/s41467-025-57371

Berzaghi, F. et al. (2025): Global distribution, quantification and valuation of the biological carbon pump, Nature Climate Change, doi:10.1038/s41558-025-02295-0

Original article by Dr Damien Couespel republished from Carbon Brief under a CC license.

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Continue ReadingGuest post: How marine life provides climate benefits worth billions of dollars

World leaders to gather in France to tackle global emergency in the oceans

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https://morningstaronline.co.uk/article/world-leaders-gather-france-tackle-global-emergency-oceans

 A star fish near a beach [Pic: Jakob Owens]

THE world’s nations will gather in France next month to tackle what the United Nations says is a global emergency facing global oceans.

Conference secretary-general Li Junhua told reporters on Tuesday that he hopes the third UN Ocean Conference would not be another routine meeting but “the pivotal opportunity” to accelerate action and mobilise people in all sectors and across the world.

The conference aims to unite governments, scientists, businesses and civil society to take action and raise money to address these and other crises facing the oceans and the people who rely on them for their survival.

…

French UN ambassador Jerome Bonnafont said his country’s priorities for the conference included obtaining 60 ratifications of the treaty to protect biodiversity in the high seas, which was adopted in March 2023, so that it comes into force. 

The treaty’s mission is to ensure sustainable fishing, mobilise support to protect and conserve at least 30 per cent of the oceans’ waters, fight plastic pollution, “accelerate decarbonisation” of maritime transport and mobilise financing.

…

Article continues at https://morningstaronline.co.uk/article/world-leaders-gather-france-tackle-global-emergency-oceans

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Earth is heading for 2.7°C warming this century. We may avoid the worst climate scenarios – but the outlook is still dire

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Aliraza Khatri’s Photography/Getty

Sven Teske, University of Technology Sydney

Is climate action a lost cause? The United States is withdrawing from the Paris Agreement for the second time, while heat records over land and sea have toppled and extreme weather events have multiplied.

In late 2015, nations agreed through the Paris Agreement to try to hold warming well under 2°C and ideally to 1.5°C. Almost ten years later, cutting emissions to the point of meeting the 1.5°C goal looks very difficult.

But humanity has shifted track enough to avert the worst climate future. Renewables, energy efficiency and other measures have shifted the dial. The worst case scenario of expanded coal use, soaring emissions and a much hotter world is vanishingly unlikely.

Instead, Earth is tracking towards around 2.7°C average warming by 2100. That level of warming would represent “unprecedented peril” for life on this planet. But it shows progress is being made.

How did we get here?

Global greenhouse gas emissions have risen since industrialisation began around 1850. Carbon dioxide (CO₂) is far and away the most common greenhouse gas we emit, while methane and nitrous oxide also play a role. These gases trap the sun’s heat in the atmosphere, preventing it from radiating back out to space.

In 2023, 41% of the world’s energy-related CO₂ emissions came from coal, mainly for electricity generation. Some 32% came from burning oil in road vehicles, and 21% from natural gas used for heating buildings and industrial processes.

The world is certainly feeling the effects. The World Meteorological Organization confirmed 2024 was the hottest year on record, temporarily hitting 1.5°C over the pre-industrial era. In turn, the world suffered lethal heatwaves, devastating floods and intense cyclones.

flooded houses, climate change.
Extreme weather hit hard in 2024. Pictured: Flooded houses after Cyclone Debby hit Florida. Bilanol/Shutterstock

How are we tracking?

In 2014, the world’s peak body for assessing climate science – the Intergovernmental Panel on Climate Change – began using four scenarios called Representative Concentration Pathways (RCPs). These four big picture climate scenarios are based on what actions humanity does or doesn’t take. They comprise:

  • rapid climate action, low emissions (RCP 2.6)
  • two scenarios of some action and medium emissions (RCP 4.5 and 6.0)
  • no action, high emissions (RCP 8.5).

The numbers refer to how many more watts of heat strike each square metre of the planet.

Of these four, only the RCP 2.6 scenario is compatible with the Paris Agreement’s goal of holding climate change well under 2˚C.

But Earth is tracking towards somewhere between RCP 2.6 and 4.5, which would translate to about 2.7°C of warming by 2100.

IPCC experts also developed five pathways of possible social, economic and political futures to complement the four scenarios.

Of these pathways, we are tracking closest to a middle of the road scenario where development remains uneven, the intensity of resource and energy use declines, and population growth levels off.

While effective, these scenarios are now more than a decade old and need to be updated. In response, my colleagues and I produced the One Earth Climate Model to outline rapid pathways to decarbonise. We set an ambitious carbon budget of 450 gigatonnes of CO₂ before reaching net zero – a pathway even more ambitious than the RCP 2.6.

The US, European Union and China together represent about 28% of the global population, but are responsible for 56% of historic emissions (926 gigatonnes) . The pathways compatible with 1.5°C give them a remaining carbon budget of 243 Gt CO₂. China would require the largest carbon budget to reach decarbonisation.

For this to happen, by 2050, the world would have to be 100% powered by clean sources and phase out fossil fuel use. This would limit global warming to around 1.5°C, with a certainty of just over 50%. We would also have to end deforestation within the same timeframe.

Emissions peak – are we there yet?

Emissions of carbon dioxide and other greenhouse gases have still not plateaued, despite sharply increasing renewable electricity generation, battery storage and lower-cost electric vehicles.

But there has been real progress. The EU says its emissions fell by 8.3% in 2023 compared to 2022. Europe’s net emissions are now 37% below 1990 levels, while the region’s GDP grew 68% over the same period. The EU remains on track to reach its goal of reducing emissions by at least 55% by 2030.

Australia’s emissions fell by 0.6% last year. The country is now 28.2% below June 2005 levels, which is the baseline set for its Paris Agreement goal of a 43% reduction by 2030.

In the US, emissions are still below pre-pandemic levels and remain about 20% below 2005 levels. Since peaking in 2004, US emissions have trended downward.

The world’s largest emitter, China, is finally cutting its emissions. Huge growth in renewables has now led to the first emissions drop on record, despite surging demand for power. This is good news. For years, China’s domestic emissions remained high despite its leading role in solar, wind, EVs and battery technology.

China produces almost one-third (31%) of the world’s energy-related carbon emissions – not least because it is the workshop of the world. Every cut China makes will have a major global effect.

According to the IPCC, limiting warming to around 1.5°C requires global emissions to peak before 2025 at the latest. It now looks like the peak may occur this year.

Despite daily negative news, the decarbonisation train has left the station. In 2024, renewables accounted for more than 90% of growth in electricity production globally. Electric vehicles became cost competitive, while heat pumps are developing fast and solar is on a winning streak.

So, is it too late to save the climate? No. The technologies we need are finally cheap enough. The sooner we stop climate change from worsening, the more disasters, famine and death we avert. We might not manage 1.5°C or even 2°C, but every tenth of a degree counts. The faster we make the shift, the better our climate future.

Sven Teske, Research Director, Institute for Sustainable Futures, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Continue ReadingEarth is heading for 2.7°C warming this century. We may avoid the worst climate scenarios – but the outlook is still dire

Record January heat suggests La Niña may be losing its ability to keep global warming in check

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The eastern Pacific is cooling, but the world keeps warming. Harvepino / NASA / Shutterstock

Richard P. Allan, University of Reading

January 2025 was the hottest on record – a whole 1.7°C above pre-industrial levels. If many climate-watchers expected the world to cool slightly this year thanks to the natural “La Niña” phenomena, the climate itself didn’t seem to get the memo. In fact, January 2025’s record heat highlights how human-driven ocean warming is increasingly overwhelming these natural climate patterns.

La Niña is a part of the El Niño southern oscillation, a climate fluctuation that slowly sloshes vast bodies of water and heat between different ocean basins and disrupts weather patterns around the world. El Niño was first identified and christened by Peruvian fishermen who noticed a dismal drop in their catch of sardines that coincided with much warmer than usual coastal waters.

El Niño is now well known to be part of a grander climate reorganisation that also has a reverse cool phase, La Niña. As vast swathes of the eastern Pacific cool down during La Niña, this has knock on effects for atmospheric weather patterns, shifting the most vigorous storms from the central Pacific to the west and disrupting the prevailing winds across the globe.

This atmospheric reaction also helps to amplify the sea surface temperature changes. Typically, La Niña will lower the global temperature by a couple of tenths of a degree Celsius.

In 2024 the Pacific swung from moderate El Niño conditions to a weak La Niña. However, this time around, it’s apparently not enough to stop the world warming – even temporarily. So what’s different this time?

Each La Niña cycle is unique

Scientists aren’t entirely surprised. Each El Niño and La Niña cycle is unique. Following a surprisingly lengthy “triple dip” La Niña starting in 2020, the El Niño that developed in 2023 was also unusual, struggling to stand out against globally warm seas. The switch to a weak La Niña has only slightly cooled a narrow band along the equatorial Pacific, while surrounding waters have remained unusually hot.

Recent research shows human caused warming of the ocean is accelerating – so a year on year rise in temperature is itself getting bigger – and this is dominating to an ever greater extent over El Niño and other natural oscillations in the climate. This means that even during La Niña – when equatorial eastern Pacific waters are cooler than normal – the rest of the world’s oceans have remained remarkably warm.

More carbon, less reflection

There is also a sense of inevitability as greenhouse gas levels continue to grow, even despite the demise of El Niño. During El Niño years, the land tends to absorb less carbon from the atmosphere as large continental areas, such as parts of South America, temporarily dry out causing less plant growth and more carbon-emitting plant decay.

La Niña tends to have the opposite effect. In the strong La Niña of 2011, so much extra rain fell on the normally dry lands of Australia and parts of South America and southeast Asia that sea levels dropped as the land held on to this excess moisture borrowed temporarily from the ocean. This meant more carbon was taken from the atmosphere to feed extra plant growth. But despite the switch to La Niña, the rate of rise in atmospheric carbon in 2024 and January 2025 remains above the already high levels of previous years.

To this we can also add the diminishing effects of particle pollution from industry, big ships and other sources of “aerosols”, which in some regions had added a reflective haze in the atmosphere meaning the world absorbed less sunlight. Clean air policies introduced over time have made the world less smoggy, but they also seem to have caused clouds to reflect less sunlight back to space, adding to global heating.

As industrial activity continues to spew greenhouse gases into the air, while air cleansed of particle pollution causes more sunlight to reach the ground, this growing heating effect is beginning to drown out natural fluctuations, tipping the balance toward record warmth and worsening hot, dry and wet extremes.

The long-term trend is clear

But, just as one swallow doesn’t make a summer, a single month is not reflective of the overall trajectory of climate change. Changing weather patterns from week to week can rapidly shift temperatures especially over big landmasses, which warm up and cool down more quickly than the oceans (it takes a long time to boil up water for your vegetables but not long to super heat an empty pan).

Large areas of Europe, Canada and Siberia experienced much less cold weather than is normal for January (by up to about 7°C). Parts of South America, Africa, Australia and Antarctica also experienced above average temperatures. Along with the balmy oceans, this all contributed to an unexpectedly warm start to 2025.

While this particular warm January isn’t necessarily cause for immediate alarm, it suggests natural cooling phases may become less effective at temporarily offsetting the impact of rising greenhouse gas levels on global temperatures. And to limit the scale of the inevitable, ensuing climate change, there is a clear, urgent need to rapidly and massively cut greenhouse gas emissions and to properly account for the true cost of our lifestyles on societies and the ecosystems that underpin them.

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Richard P. Allan, Professor of Climate Science, University of Reading

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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What a 120-year-old research station is telling us about the warming of the sea around the UK

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Tim Smyth, Plymouth Marine Laboratory

A marine heatwave has been building in the ocean surrounding the UK during an exceptionally warm and dry spring. In other words, the sea surface temperature has been within the top 10% of records for each day of the year since at least the beginning of 2025.

How can we know the temperature of the sea surface over such a large area? Throughout April and May 2025, scientists have been able to map and monitor the seas surrounding the UK via satellites, buoys and other floating devices, plus computer models that simulate the ocean’s physical and chemical properties.

Infrared detectors mounted on pole-orbiting satellites can infer the temperature of the top layer of the ocean and have been doing so continuously since the late 1970s. These sensors cannot “see” through clouds, which is why other sources of data are essential.

These datasets are now 45 years old, which is long enough to create a baseline assessment of the climate during that time. This is important to properly contextualise any departures from the long-term average. Without it, scientists would not know how severe and widespread a marine heatwave truly is.

Thanks to a research station that has been collecting ocean temperatures in the western English Channel for over a century, we know that this part of the sea south of Devon is 2.7°C warmer than the 120-year average, which makes it a category II (“strong”) marine heatwave within the four-category scheme.

The importance of long-term monitoring

Marine heatwaves are different to what we expect in a meteorological heatwave. Since 2023, the waters around the UK have been regularly experiencing marine heatwave conditions, because the data shows that the sea temperature has been in the top 10% of records: but most of us would admit that a sea temperature of 10°C in early March doesn’t exactly conjure up the impression of a heatwave.

The search for better definitions of a marine heatwave continues among scientists, particularly as long-term baseline temperatures continue to warm and the top 10% of warm temperatures shifts upwards. Datasets gathered over several decades in the same place are valuable to this effort.

For example, the Plymouth Marine Laboratory and the Marine Biological Association have been monitoring conditions in the western English Channel for over a century. One of the longest running surveys in the world is situated 20 miles south of Plymouth.

Station E1 was originally founded by the International Council for the Exploration of the Seas in 1902, as part of the English (hence the “E”) effort in ocean observation.

What sets E1 apart is the near continuous nature of its recording since then, the frequency of its data collection (monthly in winter, fortnightly in summer) and its sampling throughout the entire water column (80 metres deep), not just at the surface. This enables scientists to observe the seasonal progression of water mixing and layer formation in that location.

The 123-year old dataset shows that sea surface temperatures have increased markedly within the past 40 years, at a rate of around 0.6°C a decade. Warm anomalies have been increasingly common, and cold anomalies increasingly rare.

Marine heatwave conditions have become increasingly frequent, particularly since 2010. The data also shows that at a depth of 50 metres – well below the top layer of the ocean – temperatures have also increased markedly. The ongoing marine heatwave is not just a surface phenomenon.

Octopus in a fish market stall.
Fishers are catching octopus in large numbers off Devon and Cornwall due to the warm sea temperatures. Captured by Aixa/Shutterstock

What caused this heatwave?

The marine heatwave of spring 2025 has resulted from a combination of factors. It boils down to the fact that more energy is being put into the ocean during the day than is being lost at night.

March 2025 was the sunniest March on record (since 1910), with UK Met Office statistics showing there were around 185 hours of sunshine. April set new records for UK solar power generation, with a peak of 12.2 gigawatts (GW) being produced on April 1 out of a possible solar generating capacity of 18 GW.

May continued that trend, with long periods of clear skies under areas of the atmosphere with persistent high pressure. High-pressure areas are also associated with relatively low winds, which restricts the mixing of the warm surface with cooler deep water.

During the spring, rapidly lengthening days mean the time for energy in (day) outweighs energy out (night). It has also been notable that the spring phytoplankton bloom was very early this year (during early March). This is when tiny plant cells at the seawater surface burst into life, like plants on land. The bloom finished relatively early and the surface waters cleared earlier.

The conditions during May at E1 resembled those we would ordinarily associate with midsummer, with the phytoplankton bloom sitting deeper in the water. The clearer water at the surface allowed sunlight to penetrate deeper.

It is evident from our century-plus of measurements that marine heatwaves are happening more frequently and that there appears to be an almost continuous marine heatwave state emerging around the UK.

The intensity of a marine heatwave is generally tied to persistent high-pressure areas remaining static over the UK, but it is still unclear whether or not this is an emerging climate pattern, or just an episode within the general patterns of change within UK seas.

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Tim Smyth, Head of Group: Marine Processes and Observations, Plymouth Marine Laboratory

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Continue ReadingWhat a 120-year-old research station is telling us about the warming of the sea around the UK