A few millimeters in sea rising level each year might not sound like much, but when those millimeters get together and enter the world’s oceans, we might have a problem on our hands. In end then, the rising tide could even flood cities around the world.
Since our planet has only a few tide gauges placed in various spots, researchers turned to the satellite data to get a better picture of how the sea level has risen since the 1990s. The Nature Climate Change journal issued a new study on Monday showing what the satellites estimate based on the patterns of the last 25 years.
There some good news and some bad news. The good news is that previous researchers estimated the total sea level rise is higher than it actually is. But the bad news, on the other hand, is that the sea level is rising on a gradually but continuing acceleration.
Adjusting global satellite estimates
Geodesist Christopher Watson from the University of Tasmania was the scientist leading the latest research on small changes in the sea level. Even if they are hundreds of miles above the Earth, satellites provide rather accurate readings on global sea levels.
Watson was surprised to see how consistent the study’s findings were with the predictions that the Intergovernmental Panel on Climate Change made on sea levels – their records estimate that by 2100, sea level could go up to 98 centimeters (39 inches).
The problem isn’t just the fact that the sea level is rising, it’s also the consequences it will have on coastal areas, unless governmental authorities will initiate damage control efforts. In the present, shorelines are hosts to more than 1 billion people around the globe; assets amounting to $11 trillion are currently located below the 100-year flood mark on world’s coasts.
By 2100, experts predict this number could go as high as $210 trillion, and with the sea levels having risen by almost a foot since 1900, we could expect a lot of those assets to be flooded and swamped over the next century by the accelerated rising of the sea.
But we don’t have to wait a century to see the effects; the sea level rise is already threatening a lot of coastal cities in the U.S. which could experience minor coastal flooding any time now.
Baltimore and Honolulu, for example, are already threatened by coastal flooding 10 times more than they were in 1940. By 2050, twenty-five major U.S. cities are going to be crossing the tipping point, which means they will expect to be flooded at least on 30 days each year.
Policymakers have reason to worry
But the tides and the floods are not waiting for 2050s to show us the risen sea level – we could see it clearly during big storm events, as Sandy was back October 2013. Unlike the 1950, sea level rise has caused the risk of more Sandy-like flooding to double.
According to Watson, the new estimates could help concerned authorities better understand and identify the red-flagged spots for sea level rise around the globe. Building better infrastructure and reinforcing the existing one with protecting against flooding could save trillions of dollars.
At the same time, it is important to continue to update and refine the measurements of current sea level rise, as they contribute to making future projections more accurate. Earlier this year, another sea level rise study showed acceleration in sea level rise.
That analysis covered a larger period, going back to the early 20th century, and explains that the apparent acceleration is a consequence of overestimating sea level rise rates during the beginning of the 20th century.
Watson’s study analyzed satellite records since 1993 and he suggests the issue is likely cause by the instruments aboard satellites. He added that it’s possible that the different tools measuring sea levels might be slightly off.
Watson adjusted his results taking this conclusion into consideration, thus making them more accurate and in line with how much water Greenland’s melting ice sheet is contributing to the global oceans each year.
It is expected that sometime in the future, Antarctica’s and Greenland’s ice will most likely melt due to the increasing warmth of the planet – providing even more water that will increase the sea levels. The melt of the West Antarctic Ice Sheet might take centuries, but it’s estimated to add up to 13 feet of sea level rise.
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