The rise in sea levels could be much higher if global warming is not limited
If all of the Antarctic ice sheets melt, the rise could be double meaning as high as 2.4 meters by 2100. By the year 2500, sea level rise is projected to 5.5 meters (upper medium estimate). In the long run, a catastrophic 14 meter rise in sea levels could take place.
Rise in sea levels has potentially disastrous consequences
Rises in sea levels will affect the lives of millions of people. In a high rise scenario, up to 630 million people live on land below the projected annual flood levels for 2100. 340 million already by 2050.
One billion people already live on land less than 10 meters above current high tide lines, including 230 million below 1 meter. Hundreds of million of people will essentially be turned into environmental refugees.
More than 70 percent of the world's population lives on coastal plains, and 11 of the world's 15 largest cities are on the coast.
It could go really wrong
In the long run, the ice sheets of Greenland ice and Antarctic could cause a 14 meter (46 feet) rise in sea levels. Even a small fraction of this would be an economic and humanitarian disaster.
Antarctica faces a tipping point where glacial melting will accelerate and become irreversible even if global warming eases, according to a Nasa-funded study.
Even if greenhouse gas emission targets are met, sea levels will keep rising for centuries.
“Sea level has a very long memory, so even if we start cooling temperatures the seas will continue to rise. It’s a bit like trying to turn the Titanic around, rather than a speedboat.”
- Peter Clark, climate scientist at Oregon State University.
The causes of rising sea levels
Sea levels are rising because of global warming. The warming itself causes the sea to rise because of the thermal expansion of water (the higher the temperature, the higher the volume). Besides, global warming causes the ice to melt, adding to the rise.
In total, sea level rises can be attributed to:
- Thermal expansion of the oceans: 42%
Melting of:
- Temperate glaciers: 21%
- The Greenland ice sheets: 15%
- The Antarctic ice sheets: 8%.
