Sea levels on Earth are rising several times faster than they have in the past 2,800 years and are accelerating because of man-made global warming, according to new studies.
An international team of scientists dug into two dozen locations across the globe to chart gently rising and falling seas over centuries and millennia. Until the 1880s and the world’s industrialisation, the fastest seas rose was about 3 to 4cm a century, plus or minus a bit.
During that time global sea level really didn’t get much higher or lower than 7.62cm above or below the 2,000-year average. But in the 20th century the world’s seas rose 14cm.
Since 1993 the rate has soared to 30 cm and two different studies published Monday in the journal Proceedings of the National Academy of Sciences, said by 2100 that the world’s oceans will rise between 28 to 131cm, depending on how much heat-trapping gas Earth’s industries and vehicles expel.
“There’s no question that the 20th century is the fastest,” said Rutgers earth and planetary sciences professor Bob Kopp, lead author of the study that looked back at sea levels over the past three millennia.
“It’s because of the temperature increase in the 20th century which has been driven by fossil fuel use.”
If seas continue to rise, as projected, another 45cm of sea level rise is going to cause lots of problems and expense, especially with surge during storms, said study co-author Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany.
The link to temperature is basic science, the study’s authors said. Warm water expands. Cold water contracts. The scientists pointed to specific past eras when temperatures and sea rose and fell together.
If greenhouse gas pollution continues at the current pace, both studies project increases of about 57 to 131cm. If countries fulfill the treaty agreed upon last year in Paris and limit further warming to another 2 degrees Fahrenheit, sea level rise would be in the 28 to 56cm.