Threat of Rising Sea Levels Could Be three Times Worse

Street scene as Hurricane Irma hits the Miami area Sept. 10, 2017.

Living in the Hampton Roads area of Virginia - like many areas on the East and Gulf coasts - where tidal water is everywhere, causes most residents (other than perhaps Trump supporters on slowly drowning Tangier Island) to grasp that climate change and the attendant sea level rise is a real threat to the region's way of live, not to mention property values.  Meanwhile, the Trump/Pence regime continues to roll back regulations aimed at slowing climate change - as well as clean air and clean water protections - to the cheers of much of the Republican Party.  As new studies reveal, while the GOP and its ignorance embracing party base deny that climate change is real, the problems facing mankind are likely far worse than previously estimated.  Here are highlights from a piece in the Washington Post:

Rising seas will be much worse and more expensive to deal with than previously thought, new research finds, not because of faster changes in sea levels but because of an increase in estimates of the number of people living on low ground.

The upshot of the study is that 110 million people worldwide live below the high-tide level — including many partly protected by sea walls or other infrastructure, as in New Orleans. Even under a scenario of very modest climate change, that number will rise to 150 million in 2050 and 190 million by 2100.

If climate change and sea level rise follow a worse path, as many as 340 million people living below the high-tide level could be in peril, to say nothing of how many could be affected by floods and extreme events.

Such figures are three times — or more — higher than earlier estimates.

The reason for the big change is that prior research has relied on data about coastal elevations that comes from radar measurements from the 2000 space shuttle Endeavor mission. But that data set has problems. The instrument detected the height not only of the coastal land surface but anything else that was on it, such as houses and trees. This introduced errors in land-elevation estimates averaging about 6½ feet globally, the new study says.

The new study uses the more accurate U.S. measurements as a guide, training an algorithm to apply similar adjustments to the global data set from the space shuttle. This is where the much higher numbers for exposed populations come from, with the biggest changes in exposure coming for countries in Asia. . . . “We are talking about hundreds of millions of people who will be directly exposed.”

The changes are certainly very large. The study estimates that 110 million people live below the current high-tide level vs. an estimated 28 million for the older data set. About 250 million people would fall below the level of the worst yearly flood, the study says, up from the previous estimate of 65 million.

If key instabilities kick in in Antarctica, 480 million people would be exposed to an annual flood in 2100.

The findings are worst for Asia, notably in China, Bangladesh and India. In the worst-case scenario, 87 million, 50 million and 38 million people in these countries, respectively, would fall below the high-tide level in 2100.

The situation is, if anything, more ominous than these figures suggest, according to the World Bank’s Hallegatte. That’s because in addition to high-tide and annual worst-case flood events, there are major floods from hurricanes and other storms and disasters to consider, even if they do not occur every year. The impact of these severe events will be worsened and affect larger populations as seas continue to rise.

“Most dikes and protection systems have been built for the sea level of 50 years ago or more, and will be increasingly ill-designed to protect people against floods, leading to rapidly increasing coastal flood losses in the absence of large upgrades,” Hallegatte said. “Upgrading those systems will be expensive but is unavoidable if one wants to avoid unacceptable economic losses in large cities.”

“This new study suggests that a lot of the assessments published on climate change risks are underestimated and would need to be revised,” Hallegatte said.

How does one act to make a difference?  The first step is voting a straight Democrat ticket here in Virginia on November 5, 2019.   Virginia can send a shock wave through the GOP - and perhaps be a precursor to 2020 - by putting Virginia Republicans in minority status across the board.