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.'
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
The Guardian
3 hours ago
- The Guardian
Politicians seem reluctant to take necessary action over sea level rise
There seems to be an inability among politicians to take in what scientists are telling us about the consequences of the climate crisis. Perhaps the most glaring example relates to the Guardian's latest report on sea level rise, which said that whatever we do now, the rise will have devastating consequences for coastal communities, causing millions of people to migrate to higher ground. Greenland and the west Antarctic ice caps are doomed to melt. Even in countries that do take cutting carbon emissions seriously, such as the UK, governments do not seem to have accepted that the prediction about sea level rise means policies must adapt to damage that has already been done. The coastline of the North Sea is a classic example. Stretches of England's east coast both in and south of Yorkshire are eroding, and large areas are close to or at sea level already. A storm surge coinciding with a high tide, like the one that killed hundreds in 1953, may be a rarity, but each year a similar event becomes more likely to overwhelm the existing sea defences. And yet the government is still talking about building nuclear power stations with a 150-year lifespan on this coast, notably Sizewell C, and small modular reactors on other sites. Future generations may wonder why scientists' warnings were so easily ignored.
Daily Mail
11 hours ago
- Daily Mail
Doctors make breakthrough in HIV cure search: 'We've never seen anything close to as good'
Experts may have moved one step closer to curing HIV for good. Researchers in Australia have developed a new treatment that forces hidden fragments of the virus — normally concealed within human cells — to emerge and expose themselves to the immune system. The breakthrough could enable the body, aided by antiviral drugs, to detect and destroy these lingering viral reservoirs. HIV has remained incurable because the virus can integrate itself into a cell's DNA, lying dormant and undetectable to both medication and immune defenses. But the scientists say they have created a nanoparticle capable of delivering genetic instructions to infected cells, prompting them to produce a signal that reveals the virus's presence. Dr Paula Cevaal, research fellow at the Doherty Institute and co-author of the study, told the Guardian that this feat was 'previously thought impossible'. 'In the field of biomedicine, many things eventually don't make it into the clinic,' she said, 'that is the unfortunate truth; I don't want to paint a prettier picture than what is the reality'. 'But in terms of specifically the field of HIV cure, we have never seen anything close to as good as what we are seeing, in terms of how well we are able to reveal this virus. 'So, from that point of view, we're very hopeful that we are also able to see this type of response in an animal, and that we could eventually do this in humans.' The discovery was first revealed in the journal Nature Communications, with researchers saying they were initially so astonished that they had to re-run the tests. Further research will be needed to determine whether revealing the virus is enough to trigger an immune response, with the tests only being carried out in the lab. And it could still take years before clinical trials for the drug begin, when it would have to go through rigorous testing before reaching consumers. But the advance represents another step forward for the 1.2million Americans currently living with an HIV infection — for which they must take drugs daily. An estimated 31,800 people are infected every year, although this is a 12 percent decline on five years ago. Globally, nearly 40million people have the virus. The nanoparticle is based on mRNA technology, the same that was used in the Covid vaccines made by Pfizer and other vaccine manufacturers. In their paper, the scientists revealed that they could deliver mRNA instructions to cells using the nanoparticle. This mRNA then instructs cells to generate substances that reveal the presence of HIV, but only if the virus is present. The study was done in the lab, and carried out in cells donated by HIV patients. It comes after the Trump administration was reported to have cut funding for research into a potential HIV vaccine. The termination of the $258million research program stunned scientists at Duke University and Scripps Research Institute behind the project. HIV disproportionately affects gay and bisexual individuals in the US, who account for an estimated 67 percent of new infections — according to 2022 data. People who acquire HIV through heterosexual sex made up 22 percent of new diagnoses, or 8,495 cases, while those who were diagnosed after injecting drugs made up seven percent of new diagnoses, or 2,650 cases.
The Independent
12 hours ago
- The Independent
Scientists find the most intense explosion ever seen in the universe
Scientists have discovered the most powerful blasts of energy in the known universe. Dubbed extreme nuclear transients, or ENTs, the cosmic explosions are unprecedented in their intensity. They happen when massive stars – much bigger than our Sun – go too close to a supermassive black hole and are torn to pieces. The resulting collision throws out vast amounts of energy that travel right across the cosmos. "We've observed stars getting ripped apart as tidal disruption events for over a decade, but these ENTs are different beasts, reaching brightnesses nearly ten times more than what we typically see," said Jason Hinkle, who led the study. 'Not only are ENTs far brighter than normal tidal disruption events, but they remain luminous for years, far surpassing the energy output of even the brightest known supernova explosions.' The most energetic ENT, for instance, throws out 25 times more energy than the most powerful known supernova. A supernova can emit as much energy a year as the Sun does over its 10-billion-year lifetime, but ENTs can emit 100 times that over a single year. The discovery came from work looking for flares that were being emitted from the centre of galaxies. In data from the European Space Agency 's Gaia telescope, Jason Hinkle spotted two strange flares that appeared to last longer than normal transients, and had other unexpected characteristics. "Gaia doesn't tell you what a transient is, just that something changed in brightness," said Hinkle. "But when I saw these smooth, long-lived flares from the centers of distant galaxies, I knew we were looking at something unusual." That began a years-long project to find out what the flares were coming from. Eventually, a third was found and further research showed that the ENTs were a new kind of unseen astrophysical event. The ENTs are notable not only for their intensity and unprecedented nature. Researchers also hope they can be used to better understand black holes – and the universe that holds them. "ENTs provide a valuable new tool for studying massive black holes in distant galaxies. Because they're so bright, we can see them across vast cosmic distances – and in astronomy, looking far away means looking back in time,' said Benjamin Shappee, a co-author on the study. 'By observing these prolonged flares, we gain insights into black hole growth when the universe was half its current age when galaxies were happening places—forming stars and feeding their supermassive black holes 10 times more vigorously than they do today." But such ENTs are hard to find, happening at least 10 million times left often than supernovae. Researchers hope that upcoming new equipment such as the Vera C Rubin Observatory and Nasa's Roman Space Telescope will allow for more of them to be discovered.
