Our underwater future: what will sea levels look like around the world?


A new study by Climate Central, a non-profit research group, suggests that nearly 50 major coastal cities will need to implement “unprecedented” adaptation measures to prevent rising seas from swallowing up their most populous regions .

The analysis, in collaboration with researchers from Princeton University and the Potsdam Institute for Climate Impact Research in Germany, resulted in striking visual contrasts between the world as we know it today and our underwater future, if the planet is 3 degrees below pre-industrial. The level warms up.

climate scientist reported in august The world is already about 1.2 degrees warmer than pre-industrial levels. Temperatures must remain below 1.5 degrees, he says – a critical threshold to avoid the most severe effects of the climate crisis.

But even in the most optimistic scenario, where global greenhouse gas emissions begin to decline today and fall to near zero by 2050, global temperatures will remain above the 1.5-degree threshold before falling.

In less-optimistic scenarios, where emissions continue to rise beyond 2050, the planet could reach 3°C in the 2060s or early 2070s, and the oceans would continue to rise for decades before reaching peak levels.

“Today’s choice will go our way,” said Benjamin Strauss, chief scientist at Climate Central and lead author of the report.

Researchers at Climate Central used global elevation and population data to analyze the parts of the world that would be most vulnerable to sea level rise, concentrated in the Asia-Pacific region.

Small island nations are at risk of “almost total loss” of land, and eight of the top 10 regions most exposed to sea level rise are in Asia, with nearly 600 million people at 3-degree warming, the report said. Under the scenario are exposed to floods. .

According to an analysis by Climate Central, China, India, Vietnam and Indonesia are among the top five countries most vulnerable to long-term sea level rise. The researchers note that these are also the countries that have added additional coal burning capacity in recent years.

In September, a Study published in the journal Nature About 60% of the planet’s remaining oil and natural gas is found and 90% of its coal reserves should remain in the ground by 2050 to make it more likely limiting global warming 1.5 °C above pre-industrial levels. It has been said that most regions around the world should reach peak fossil fuel production now or within the next decade to avoid significant climate limits.
At the United Nations General Assembly in September, China major climate pledge as one of The world’s largest emitter of greenhouse gasesThe country will no longer build any new coal-fired power projects overseas, marking a change in policy around its expansion. Belt and Road Infrastructure Initiative, which had already begun to scale down its coal initiatives.

If the planet hits 3 degrees, Climate Central reports that about 43 million people in China will live on land below high-tide levels by 2100, with another 200 million at risk of prolonged sea-level rise. living in the areas.

With every fraction of a degree of heat, the consequences of climate change worsen. What kind of extreme weather the world experienced, scientists say, even while limiting temperatures to 1.5 degrees this summer Will be more severe and more frequent.

Over 1.5 degrees, the climate system may seem unrecognizable.

As Climate Central reports, about 385 million people currently live on land that will eventually be submerged by high tide, even as greenhouse gas emissions subside.

If warming is limited to 1.5 degrees, sea level rise would affect the land of 510 million people today.

If the planet reaches 3 degrees, the high-tide line could encroach on the land where more than 800 million people live, the study found.

The authors note in the report that an important caveat in their assessment is the lack of global data on existing coastal defenses such as levees and seawalls to fully project exposure to rising seas. Still, they believe that due to recent flood events and the effects seen today with storm surges, cities are likely to improve infrastructure to avoid worsening impacts.

“High levels of warming would require globally unprecedented rescue or abandonment in major coastal cities around the world,” the authors wrote, while the count could be narrowed down to a relative handful through strong adherence to the Paris Agreement. , specifically limiting warming to 1.5 degrees.”

But coastal infrastructure costs money. Wealthy nations such as the United States and the United Kingdom could afford these measures, but low-income countries could be left behind.

And while many small island nations are surrounded by mangroves and coral reefs that could protect their lands from rising seas, warmer temperatures are causing ocean acidification and other forms of environmental destruction that threaten such defense measures.

During the first two weeks of November, world leaders will gather here UN brokered climate talks in Glasgow, Scotland. They will discuss further limiting greenhouse gas emissions, as well as pledge funds to developed countries to help the global South move away from fossil fuels and adapt to the effects of the climate crisis.

Unless bold and swift action is taken, sea level rise due to extreme weather events and climate change will rapidly fill Earth’s future. Scientists say that the time for the planet to escape from these worst-case scenarios is running out.

“World leaders today have a fleeting opportunity to help or betray humanity’s future with their actions on climate change,” Strauss said. “This research and the images it creates represent the huge stakes behind the climate talks in Glasgow.”

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