Even if the world meets its most optimistic climate goals, rising sea levels will likely intensify throughout the 21st century and beyond, reshaping coastlines and threatening hundreds of millions of lives.
Oceans Rising Twice as Fast, With No Signs of Slowing Down Over the past three decades, the pace of sea level rise has doubled—and it’s expected to double again by the year 2100.
If current warming trends persist, oceans could be rising by one centimeter per year within just a few generations.
Ice Sheets at the Edge: Greenland and Antarctica Nearing Tipping Points One of the most alarming findings of the study concerns the sensitivity of polar ice sheets to even modest warming.
These ancient analogues strongly suggest that current warming has already committed the planet to long-term sea level rise far beyond what is currently visible.
Rising sea levels will probably get worse during the 21st century and beyond, changing coastlines and endangering hundreds of millions of lives, even if the world achieves its most optimistic climate goals. Keeping global warming below 1 to 5°C, the aspirational target of the 2015 Paris Agreement, will not stop significant and accelerating ocean encroachment, according to a new study published in Communications Earth and Environment. The research presents a startling picture, based on satellite data, paleo-climatic comparisons, and updated projections: even slight warming will set off feedback loops in the planet’s ice sheets, pushing sea level rise past controllable bounds.
There are no signs of slowing down as the oceans rise twice as quickly.
Sea level rise is predicted to double again by the year 2100, having doubled over the last three decades. If the present warming patterns continue, ocean levels may rise by one centimeter annually in a matter of generations. Chris Stokes, a professor at Durham University in the UK and the study’s lead author, stated that “limiting global warming to 1 point 5°C would be a major achievement” and prevent many negative climate effects. He cautioned, however, that even if this goal is accomplished, sea level rise will probably quicken to a point where adaptation will be extremely challenging. Even a slight rise could result in devastating urban flooding, mass migration, and trillions of dollars in economic damages by the middle of the century, since over 230 million people live within one meter of the current sea level, and over a billion within ten meters.
Antarctica and Greenland are getting close to tipping points as ice sheets near the edge.
One of the study’s most concerning conclusions is how vulnerable polar ice sheets are to even slight warming. A total of 400 billion tonnes of ice are melting or calving annually between the West Antarctic and Greenland ice sheets, which together contain enough frozen water to raise sea levels by 65 meters, according to satellite observations. These alterations are not straight-line. Stokes stated, “We are most likely moving toward the higher numbers within that range, possibly higher.”. He also pointed out a significant change in scientific knowledge, saying, “We used to think that Greenland wouldn’t do anything until the world warmed 3°C.”. Currently, tipping points for West Antarctica and Greenland are estimated to be between 1 and 5°C. Even if emissions were stopped right away, this would lock in centuries of ocean rise by drastically lowering the threshold at which irreversible ice sheet collapse could start.
There are some chilling lessons to be learned from Earth’s ancient climate.
In order to predict the future, scientists also examined Earth’s past climate, contrasting current conditions with earlier warm epochs in the planet’s history. Even though there were somewhat lower temperatures and much less CO2 in the atmosphere during the last interglacial, some 125,000 years ago, sea levels were between 2 and 9 meters higher than they are today. Sea levels were 10 to 20 meters higher approximately three million years ago, when CO2 levels last equaled the current 424 parts per million. The planet has already committed to long-term sea level rise that is significantly higher than what is currently visible, according to these ancient analogs. Even with rapid decarbonization, this slow but unstoppable process highlights the climate system’s inertia, as what appears manageable today could turn into a crisis in the coming centuries.
Without drastic cooling, it would be difficult to adapt to the future.
