Latest news with #coastalCities
Yahoo
6 days ago
- Politics
- Yahoo
Sea level rise will cause ‘catastrophic inland migration', scientists warn
Sea level rise will become unmanageable at just 1.5C of global heating and lead to 'catastrophic inland migration', the scientists behind a new study have warned. This scenario may unfold even if the average level of heating over the last decade of 1.2C continues into the future. The loss of ice from the giant Greenland and Antarctic ice sheets has quadrupled since the 1990s due to the climate crisis and is now the principal driver of sea level rise. The international target to keep global temperature rise below 1.5C is already almost out of reach. But the new analysis found that even if fossil fuel emissions were rapidly slashed to meet it, sea levels would be rising by 1cm a year by the end of the century, faster than the speed at which nations could build coastal defences. The world is on track for 2.5C-2.9C of global heating, which would almost certainly be beyond tipping points for the collapse of the Greenland and west Antarctic ice sheets. The melting of those ice sheets would lead to a 'really dire' 12 metres of sea level rise. Today, about 230 million people live within 1 metre above current sea level, and 1 billion live within 10 metres above sea level. Even just 20cm of sea level rise by 2050 would lead to global flood damages of at least $1tn a year for the world's 136 largest coastal cities and huge impacts on people's lives and livelihoods. However, the scientists emphasised that every fraction of a degree of global heating avoided by climate action still matters, because it slows sea level rise and gives more time to prepare, reducing human suffering. Related: The century of climate migration: why we need to plan for the great upheaval Sea level rise is the biggest long-term impact of the climate crisis, and research in recent years has shown it is occurring far faster than previously estimated. The 1.5C limit was seen as a way to avoid the worst consequences of global heating, but the new research shows this is not the case for sea level rise. The researchers said the 'safe limit' temperature for ice sheets was hard to estimate but was likely to be 1C or lower. Sea level rise of at least 1-2 metres was now inevitable, the scientists said. In the UK, just 1 metre of sea level rise would see large parts of the Fens and Humberside below sea level. 'What we mean by safe limit is one which allows some level of adaptation, rather than catastrophic inland migration and forced migration, and the safe limit is roughly 1cm a year of sea level rise,' said Prof Jonathan Bamber of the University of Bristol in the UK. 'If you get to that, then it becomes extremely challenging for any kind of adaptation, and you're going to see massive land migration on scales that we've never witnessed in modern civilisation.' Developing countries such as Bangladesh would fare far worse than rich ones with experience of holding back the waves, such as the Netherlands, he said. Durham University's Prof Chris Stokes, lead author of the study, said: 'We're starting to see some of the worst-case scenarios play out almost in front of us. At current warming of 1.2C, sea level rise is accelerating at rates that, if they continue, would become almost unmanageable before the end of this century, [which is] within the lifetime of our young people.' The average global temperature rise hit 1.5C for the first time in 2024. But the international target is measured as the average over 20 years, so is not considered to have been broken yet. Related: Greenland losing 30m tonnes of ice an hour, study reveals The new study, published in the journal Communications Earth and Environment, combined data from studies of warm periods up to 3m years ago; observations of ice melting and sea level rise in recent decades; and climate models. It concluded: 'Continued mass loss from ice sheets poses an existential threat to the world's coastal populations.' Prof Andrea Dutton of the University of Wisconsin-Madison, who was part of the study team, said: 'Evidence recovered from past warm periods suggests that several metres of sea level rise – or more – can be expected when global mean temperature reaches 1.5C or higher.' At the end of the last ice age, about 15,000 years ago, the sea level was rising at 10 times the rate today, driven by self-reinforcing feedbacks that may have been triggered by only a small increase in temperature. The last time CO2 levels in the atmosphere were as high as today, about 3m years ago, sea level rise was 10-20 metres higher. Even if humanity can bring the planet back to its preindustrial temperature by removing CO2 from the atmosphere, it will still take hundreds to thousands of years for the ice sheets to recover, the researchers said. That means land lost to sea level rise will remain lost for a long time, perhaps until the Earth enters the next ice age. Belize moved its capital inland in 1970 after a devastating hurricane, but its largest city is still on the coast and will be inundated with only 1 metre of sea level rise, Carlos Fuller, Belize's longtime climate negotiator, said: 'Findings such as these only sharpen the need to remain within the 1.5C Paris agreement limit, or as close as possible, so we can return to lower temperatures and protect our coastal cities.'
Asharq Al-Awsat
26-05-2025
- Science
- Asharq Al-Awsat
Sea Level Rise Expected to Accelerate
Rising seas will severely test humanity's resilience in the second half of the 21st century and beyond, even if nations defy the odds and cap global warming at the ambitious 1.5 degrees Celsius target, researchers said last week. The pace at which global oceans are rising has doubled in three decades, and on current trends will double again by 2100 to about one centimeter per year, they reported in a study. 'Limiting global warming to 1.5C would be a major achievement' and avoid many dire climate impacts, lead author Chris Stokes, a professor at Durham University in England, told AFP on Saturday. 'But even if this target is met,' he added, 'sea level rise is likely to accelerate to rates that are very difficult to adapt to.' Absent protective measures such as sea walls, an additional 20 centimeters (7.8 inches) of sea level rise—the width of a letter-size sheet of paper—by 2050 would cause some $1 trillion in flood damage annually in the world's 136 largest coastal cities, earlier research has shown. Some 230 million people live on land within one meter (3.2 feet) of sea level, and more than a billion reside within 10 meters. Sea level rise is driven in roughly equal measure by the disintegration of ice sheets and mountain glaciers, as well as the expansion of warming oceans, which absorb more than 90% of the excess heat due to climate change. Averaged across 20 years, Earth's surface temperature is currently 1.2C above pre-industrial levels, already enough to lift the ocean watermark by several meters over the coming centuries, Stokes and colleagues noted in the journal Communications Earth & Environment. The world is on track to see temperatures rise 2.7C above that benchmark by the end of the century. Tipping points In a review of scientific literature since the last major climate assessment by the UN-mandated Intergovernmental Panel on Climate Change (IPCC), Stokes and his team focused on the growing contribution of ice sheets to rising seas. In 2021, the IPCC projected 'likely' sea level rise of 40 to 80 centimeters by 2100, depending on how quickly humanity draws down greenhouse gas emissions, but left ice sheets out of their calculations due to uncertainty. The picture has become alarmingly more clear since then. 'We are probably heading for the higher numbers within that range, possibly higher,' said Stokes. Satellite data has revealed that ice sheets with enough frozen water to lift oceans some 65 meters are far more sensitive to climate change than previously suspected. The amount of ice melting or breaking off into the ocean from Greenland and West Antarctica, now averaging about 400 billion tons a year, has quadrupled over the last three decades, eclipsing runoff from mountain glaciers. 'We used to think that Greenland wouldn't do anything until the world warmed 3C,' said Stokes. 'Now the consensus for tipping points for Greenland and West Antarctica is about 1.5C.' 'If you want to slow sea level rise from ice sheets, you clearly have to cool back from present-day temperatures,' Stokes told AFP. 'To slow sea level rise from ice sheets to a manageable level requires a long-term temperature goal that is close to +1C, or possibly lower.'
CNA
20-05-2025
- Science
- CNA
Dire sea level rise likely even in a 1.5°C world: Study
PARIS: Rising seas will severely test humanity's resilience in the second half of the 21st century and beyond, even if nations defy the odds and cap global warming at the ambitious 1.5 degrees Celsius target, researchers said on Tuesday (May 20). The pace at which global oceans are rising has doubled in three decades, and on current trends will double again by 2100 to about one centimetre per year, they reported in a study. "Limiting global warming to 1.5°C would be a major achievement" and avoid many dire climate impacts, lead author Chris Stokes, a professor at Durham University in England, told AFP. "But even if this target is met," he added, "sea level rise is likely to accelerate to rates that are very difficult to adapt to." Absent protective measures such as sea walls, an additional 20cm of sea level rise - the width of a letter-size sheet of paper - by 2050 would cause some US$1 trillion in flood damage annually in the world's 136 largest coastal cities, earlier research has shown. Some 230 million people live on land within one metre of sea level, and more than a billion reside within 10m. Sea level rise is driven in roughly equal measure by the disintegration of ice sheets and mountain glaciers, as well as the expansion of warming oceans, which absorb more than 90 per cent of the excess heat due to climate change. Averaged across 20 years, Earth's surface temperature is currently 1.2°C above pre-industrial levels, already enough to lift the ocean watermark by several metres over the coming centuries, Stokes and colleagues noted in the journal Communications Earth & Environment. The world is on track to see temperatures rise 2.7°C above that benchmark by the end of the century. TIPPING POINTS In a review of scientific literature since the last major climate assessment by the UN-mandated Intergovernmental Panel on Climate Change (IPCC), Stokes and his team focused on the growing contribution of ice sheets to rising seas. In 2021, the IPCC projected "likely" sea level rise of 40 to 80 centimetres by 2100, depending on how how quickly humanity draws down greenhouse gas emissions, but left ice sheets out of their calculations due to uncertainty. The picture has become alarmingly more clear since then. "We are probably heading for the higher numbers within that range, possibly higher," said Stokes. The scientist and his team looked at three baskets of evidence, starting with what has been observed and measured to date. Satellite data has revealed that ice sheets with enough frozen water to lift oceans some 65m are far more sensitive to climate change than previously suspected. The amount of ice melting or breaking off into the ocean from Greenland and West Antarctica, now averaging about 400 billion tonnes a year, has quadrupled over the last three decades, eclipsing runoff from mountain glaciers. Estimates of how much global warming it would take to push dwindling ice sheets past a point of no return, known as tipping points, have also shifted. "We used to think that Greenland wouldn't do anything until the world warmed 3°C," said Stokes. "Now the consensus for tipping points for Greenland and West Antarctica is about 1.5°C." The 2015 Paris climate treaty calls for capping global warming at "well below" 2°C, and 1.5°C if possible. The scientists also looked at fresh evidence from the three most recent periods in Earth's history with comparable temperatures and atmospheric levels of CO2, the main driver of global warming. About 125,000 years ago during the previous "interglacial" between ice ages, sea levels were two to nine metres higher than today despite a slightly lower average global temperature and significantly less CO2 in the air - 287 parts per million, compared to 424 ppm today. A slightly warmer period 400,000 ago with CO2 concentrations at about 286 ppm saw oceans 6-to-13 metres higher. And if we go back to the last moment in Earth's history with CO2 levels like today, some three million years ago, sea levels were 10-to-20 metres higher. Finally, scientists reviewed recent projections of how ice sheets will behave in the future. "If you want to slow sea level rise from ice sheets, you clearly have to cool back from present-day temperatures," Stokes told AFP.
News.com.au
20-05-2025
- Science
- News.com.au
Dire sea level rise likely even in a 1.5C world: study
Rising seas will severely test humanity's resilience in the second half of the 21st century and beyond, even if nations defy the odds and cap global warming at the ambitious 1.5 degrees Celsius target, researchers said Tuesday. The pace at which global oceans are rising has doubled in three decades, and on current trends will double again by 2100 to about one centimetre per year, they reported in a study. "Limiting global warming to 1.5C would be a major achievement" and avoid many dire climate impacts, lead author Chris Stokes, a professor at Durham University in England, told AFP. "But even if this target is met," he added, "sea level rise is likely to accelerate to rates that are very difficult to adapt to." Absent protective measures such as sea walls, an additional 20 centimetres (7.8 inches) of sea level rise -- the width of a letter-size sheet of paper -- by 2050 would cause some $1 trillion in flood damage annually in the world's 136 largest coastal cities, earlier research has shown. Some 230 million people live on land within one metre (3.2 feet) of sea level, and more than a billion reside within 10 metres. Sea level rise is driven in roughly equal measure by the disintegration of ice sheets and mountain glaciers, as well as the expansion of warming oceans, which absorb more than 90 percent of the excess heat due to climate change. Averaged across 20 years, Earth's surface temperature is currently 1.2C above pre-industrial levels, already enough to lift the ocean watermark by several metres over the coming centuries, Stokes and colleagues noted in the journal Communications Earth & Environment. The world is on track to see temperatures rise 2.7C above that benchmark by the end of the century. - Tipping points - In a review of scientific literature since the last major climate assessment by the UN-mandated Intergovernmental Panel on Climate Change (IPCC), Stokes and his team focused on the growing contribution of ice sheets to rising seas. In 2021, the IPCC projected "likely" sea level rise of 40 to 80 centimetres by 2100, depending on how how quickly humanity draws down greenhouse gas emissions, but left ice sheets out of their calculations due to uncertainty. The picture has become alarmingly more clear since then. "We are probably heading for the higher numbers within that range, possibly higher," said Stokes. The scientist and his team looked at three baskets of evidence, starting with what has been observed and measured to date. Satellite data has revealed that ice sheets with enough frozen water to lift oceans some 65 metres are far more sensitive to climate change than previously suspected. The amount of ice melting or breaking off into the ocean from Greenland and West Antarctica, now averaging about 400 billion tonnes a year, has quadrupled over the last three decades, eclipsing runoff from mountain glaciers. Estimates of how much global warming it would take to push dwindling ice sheets past a point of no return, known as tipping points, have also shifted. "We used to think that Greenland wouldn't do anything until the world warmed 3C," said Stokes. "Now the consensus for tipping points for Greenland and West Antarctica is about 1.5C." The 2015 Paris climate treaty calls for capping global warming at "well below" 2C, and 1.5C if possible. The scientists also looked at fresh evidence from the three most recent periods in Earth's history with comparable temperatures and atmospheric levels of CO2, the main driver of global warming. About 125,000 years ago during the previous "interglacial" between ice ages, sea levels were two to nine metres higher than today despite a slightly lower average global temperature and significantly less CO2 in the air -- 287 parts per million, compared to 424 ppm today. A slightly warmer period 400,000 ago with CO2 concentrations at about 286 ppm saw oceans 6-to-13 metres higher. And if we go back to the last moment in Earth's history with CO2 levels like today, some three million years ago, sea levels were 10-to-20 metres higher. Finally, scientists reviewed recent projections of how ice sheets will behave in the future. "If you want to slow sea level rise from ice sheets, you clearly have to cool back from present-day temperatures," Stokes told AFP.
The Guardian
20-05-2025
- Science
- The Guardian
Sea level rise will cause ‘catastrophic inland migration', scientists warn
Sea level rise will become unmanageable at just 1.5C of global heating and lead to 'catastrophic inland migration', the scientists behind a new study have warned. This scenario may unfold even if the average level of heating over the last decade of 1.2C continues into the future. The loss of ice from the giant Greenland and Antarctic ice sheets has quadrupled since the 1990s due to the climate crisis and is now the principal driver of sea level rise. The international target to keep global temperature rise below 1.5C is already almost out of reach. But the new analysis found that even if fossil fuel emissions were rapidly slashed to meet it, sea levels would be rising by 1cm a year by the end of the century, faster than the speed at which nations could build coastal defences. The world is on track for 2.5C-2.9C of global heating, which would almost certainly be beyond tipping points for the collapse of the Greenland and west Antarctic ice sheets. The melting of those ice sheets would lead to a 'really dire' 12 metres of sea level rise. Today, about 230 million people live 1 metre above current sea level, and 1 billion live 10 metres above sea level. Even just 20cm of sea level rise by 2050 would lead to global flood damages of at least $1tn a year for the world's 136 largest coastal cities and huge impacts on people's lives and livelihoods. However, the scientists emphasised that every fraction of a degree of global heating avoided by climate action still matters, because it slows sea level rise and gives more time to prepare, reducing human suffering. Sea level rise is the biggest long-term impact of the climate crisis, and research in recent years has shown it is occurring far faster than previously estimated. The 1.5C limit was seen as way to avoid the worst consequences of global heating, but the new research shows this is not the case for sea level rise. The researchers said the 'safe limit' temperature for ice sheets was hard to estimate but was likely to be 1C or lower. Sea level rise of at least 1-2 metres was now inevitable, the scientists said. In the UK, just 1 metre of sea level rise would see large parts of the Fens and Humberside below sea level. 'What we mean by safe limit is one which allows some level of adaptation, rather than catastrophic inland migration and forced migration, and the safe limit is roughly 1cm a year of sea level rise,' said Prof Jonathan Bamber of the University of Bristol in the UK. 'If you get to that, then it becomes extremely challenging for any kind of adaptation, and you're going to see massive land migration on scales that we've never witnessed in modern civilisation.' Developing countries such as Bangladesh would fare far worse than rich ones with experience of holding back the waves, such as the Netherlands, he said. Durham University's Prof Chris Stokes, lead author of the study, said: 'We're starting to see some of the worst-case scenarios play out almost in front of us. At current warming of 1.2C, sea level rise is accelerating at rates that, if they continue, would become almost unmanageable before the end of this century, [which is] within the lifetime of our young people.' The average global temperature hit 1.5C for the first time in 2024. But the international target is measured as the average over 20 years, so is not considered to have been broken yet. Sign up to Down to Earth The planet's most important stories. Get all the week's environment news - the good, the bad and the essential after newsletter promotion The new study, published in the journal Communications Earth and Environment, combined data from studies of warm periods up to 3m years ago; observations of ice melting and sea level rise in recent decades; and climate models. It concluded: 'Continued mass loss from ice sheets poses an existential threat to the world's coastal populations.' Prof Andrea Dutton of the University of Wisconsin-Madison, who was part of the study team, said: 'Evidence recovered from past warm periods suggests that several metres of sea level rise – or more – can be expected when global mean temperature reaches 1.5C or higher.' At the end of the last ice age, about 15,000 years ago, sea level was rising at 10 times the rate today, driven by self-reinforcing feedbacks that may have been triggered by only a small increase in temperature. The last time CO2 levels in the atmosphere were as high as today, about 3m years ago, sea level rise was 10-20 metres higher. Even if humanity can bring the planet back to its preindustrial temperature by removing CO2 from the atmosphere, it will still take hundreds to thousands of years for the ice sheets to recover, the researchers said. That means land lost to sea level rise will remain lost for a long time, perhaps until the Earth enters the next ice age. Belize moved its capital inland in 1970 after a devastating hurricane, but its largest city is still on the coast and will be inundated with only 1 metre of sea level rise, Carlos Fuller, Belize's longtime climate negotiator, said: 'Findings such as these only sharpen the need to remain within the 1.5C Paris agreement limit, or as close as possible, so we can return to lower temperatures and protect our coastal cities.'
