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 1cm 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.
