The future of the global marine ecosystem is on a knife-edge, scientists studying the impact of rising temperatures on plankton – the “lifeblood of the oceans” – have warned, after new findings suggest we could be feeling the “devastating effects” of global warming within the next 70 years.

Research led by the University of Bristol and published last week in Nature has compared, for the first time, how tiny ocean organisms called plankton responded when the world last warmed significantly in ancient history with what they predict will happen under similar conditions by the end of our century. 

Finding that the plankton were simply unable to keep pace with the current speed of temperature rises, scientists have expressed concern over what impact this will have upon the “huge swathes” of marine life that depend on them as a food source.

“The results are alarming as even with the more conservative climate projections of a 2°C increase, it’s clear plankton cannot adjust quickly enough to match the much faster rate of warming which we’re experiencing now and looks set to continue,” said the paper’s lead author, Dr Rui Ying, who led the project as part of his PhD in marine ecology at the University of Bristol.

“Plankton are the lifeblood of the oceans, supporting the marine food web and carbon storage. If their existence is endangered, it will present an unprecedented threat that will disrupt the whole marine ecosystem with devastating, wide-reaching consequences for marine life and also human food supplies.”

To reach this conclusion, the researchers developed a new model which allowed analysis of how plankton behaved some 21,000 years ago during the last Ice Age to be analysed alongside how they might act under future climate projections. The modelling focused on a specific group of plankton which has existed throughout the ages.

“The past is often considered key to understanding what the world could look like in future,” said Dr Ying. “Geological records showed that plankton previously relocated away from the warmer oceans to survive.

“But using the same model of ecology and climate, projection showed the current and future rate of warming was too great for this to be possible again, potentially wiping out the precious organisms.”

Under the Paris Agreement, 196 nations agreed to limit the increase in the global average temperature to well below 2°C above pre-industrial levels and strive to limit the increase to 1.5°C. However, a United Nations report, last month, warned the world now faces as much as 3.1°C warming if governments do not take action to rescue carbon emissions. 

World leaders are currently convened in Baku, Azerbaijan to discuss the next crucial steps in limiting global warming at the climate change conference, COP29. Despite the urgency to act fast to not miss the window of diminishing opportunity to mitigate the worst impacts of climate change, COP29 has been mired in controversy, including that its host nations, Azerbaijan had been using the platform to pitch for new gas and oil deals, despite recognition of urgency to move away from fossil fuels.

This is all set, too, upon a landscape of uncertainty since the re-election of climate change-denier Donald Trump as President of the United States.

Despite this, the feeling from the scientific community, however, remains resolute that changes need to be made, fast if we are to avert a collapse of current ecosystems, such as that underpinned by the fate of plankton in this new paper. 

Daniela Schmidt, professor of Earth Sciences at the University of Bristol and a world renowned marine ecologist who has led multiple Intergovernmental Panel on Climate Change reports, is also a co-author on this latest research.

“This work emphasises the great risks posed by the dramatically fast climate and environmental changes the world is now facing,” she said. “With these worrying trends set to worsen, there will be very real consequences for our ecosystems and people’s livelihoods, including fishing communities.

“The message is clear – all nations must collectively and individually step up efforts and measures to keep global warming to a minimum.”