Halting Global Warming May Make a Huge Difference in Rising Sea Levels

It's a good thing that global warming has been ultimately recognized and addressed not just in surface, but also in depth by global leaders. One cannot say that there has not been worldwide effort to protect biodiversity on the nature's behalf. Nonetheless, experts believe global sea rise is still inevitable.

However, it will make a huge difference if global warming is limited, out and about.

Researchers warned on Tuesday that sea level still rises for coming centuries and flood cities and homes of half-a-billion people, even if we 'beat the odds' and limit global warming at 1.5 degrees Celsius - the global average air temperature mark over pre-industrial levels between 2021 and 2040.

This 'multi-century sea level rise' is expected to bring unprecedented threats to more than 200 million of today's urban population, if the world heats up another half-degree above that benchmark.

According to a recently published study, the worst hit would reach 50 major cities, mostly in Asia, which includes nine of the ten mega-cities at highest risk.

Only a matter of time

Part of the human-caused carbon dioxide emissions are seen to remain in the atmosphere for hundreds of years, increasing temperatures and sea levels around the world, and no emissions-reduction policies and actions seem to address this long-term threat.

"Roughly 5 percent of the world's population today live on land below where the high tide level is expected to rise based on carbon dioxide that human activity has already added to the atmosphere," said lead author Ben Strauss, CEO and chief scientist of Climate Central.

Strauss noted that the Earth's average surface temperature which has already risen to 1.1 °C. "That's enough to eventually push up sea levels nearly 2 meters (more than six feet), whether it takes two centuries or 10."

Unless these massive amounts of CO2 are removed from the atmosphere, that amount of sea level rise is not a matter of 'if' but 'when', according to the study.

What we could do is buy time

The study warns that these cities prone to surge "would need to defend against globally unprecedented levels of exposure, if feasible, or face partial to near-total extant area losses."

In China alone, over 200 million people would lose its land. Without massive sea walls, "Chinese cityscapes home to tens of millions could become unlivable within 80 years."

"1.5 °C of warming will still lead to devastating sea level rise, but the hotter alternatives are far worse," said Strauss. However, "it is almost certain that seas will rise more slowly in a 1.5 °C or 2 °C warmer world."

"We're in bad shape but it is never too late to do better, and the difference we could make is enormous," he added.

One among other things that could possibly reduce exposure by roughly half and may avoid globally unprecedented defense requirements is the Paris Climate Agreement, an international treaty on climate change that covers climate change mitigation, adaptation, and finance.