(CNN) – The planet is rapidly warming, which is caused by Historic droughtsAnd fatal floods And unusual melting in the North Pole. It is also causing a steady rise in sea level, which scientists say will continue during decades.
A new study by Climate Central, a nonprofit research group, shows that about 50 major coastal cities will have to implement “unprecedented” adaptation measures to prevent rising seas from engulfing the most densely populated areas.
The analysis, carried out in collaboration with researchers from Princeton University and the Potsdam Institute for Climate Impact Research (Germany), has led to stunning visual contrasts between the world as we know it today and our underwater future, if the planet’s temperature rises to 3°C above pre-industrial levels.
Scientists who study climate change reported in August The world is already 1.2 degrees warmer than pre-industrial levels. They say temperatures must remain below 1.5 degrees, a critical threshold to avoid the more 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 zero in 2050, the global temperature will continue to cross the 1.5 degree threshold before declining.
In less optimistic scenarios, where emissions continue to rise beyond 2050, the planet could reach 3 degrees as early as 2060 or 2070, and oceans will continue to rise for decades before they reach peak levels.
“The decisions we make today will determine our path,” said Benjamin Strauss, chief scientist at Climate Central and lead author of the report.
Climate Central researchers used global rise and population data to analyze which parts of the world are most vulnerable to sea level rise, which tend to be concentrated in the Asia-Pacific region.
Island nations face ‘almost total loss’
Small island states are at risk of “almost complete loss” of their land, according to the report, and eight of the 10 regions most vulnerable to sea-level rise are in Asia, with nearly 600 million people exposed to grade 3 flooding. warming scenario.
According to Climate Central analysis, China, India, Vietnam and Indonesia are among the five countries most vulnerable to long-term sea level rise. The researchers note that these are also the countries that have increased their use of coal as a fuel in recent years.
in September, Published study In the journal Nature concluded that approximately 60% of the oil and natural gas remaining on the planet and 90% of coal reserves must remain underground by 2050 until They have a better chance of reducing global warming 1.5°C above pre-industrial levels. He said most regions of the world must reach peak fossil fuel production now or in the next decade to avoid the critical climate threshold.
At the United Nations General Assembly in September, China made a big climate promise As one of the Higher greenhouse gas emissions Scientist: The country will stop building new coal-based energy projects abroad, marking a policy shift around the Belt and Road Infrastructure Initiative, which it has already begun to scale back. Your charcoal initiatives.
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If the planet reaches 3 degrees, Climate Central reports that approximately 43 million people in China will live in lands projected to be below high tide by 2100, and 200 million people will live in areas at risk of rising in the long term. sea level.
With every fraction of a degree of warming, the consequences of climate change are getting worse. Even limiting the temperature rise to 1.5 degrees, scientists claim that the types of extreme weather that the world has experienced this summer It will be more intense and more frequent.
After 1.5 degrees, the global climate system can become unknown.
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According to Climate Central, about 385 million people currently live on land that will be flooded by rising tides, even if greenhouse gas emissions are reduced.
If the warming were limited to 1.5 degrees, sea level rise would affect the lands that are inhabited today by 510 million people.
If the planet reaches 3 degrees, the high tide line could invade the lands where more than 800 million people live, according to the study.
In the report, the authors note that a key caveat in their assessment is the lack of global data on current coastal defenses, such as dams and seawalls, to project full exposure to sea rise. However, they acknowledge that given the current impact of recent floods and storm surges, cities are likely to upgrade their infrastructure to avoid worsening impacts.
The authors write that “higher levels of warming will require globally unprecedented defenses or neglect in dozens of major coastal cities around the world”, while the number could be limited to a relatively few by strong compliance with the Paris Agreement, especially limiting warming to 1.5 degrees.
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But coastal infrastructure costs money. Rich countries, such as the United States and the United Kingdom, can afford these measures, but low-income countries can be left behind.
And while many small island nations surround themselves with mangroves and coral reefs that could protect their lands from rising seas, rising temperatures are causing ocean acidification and other forms of environmental destruction that threaten such defensive actions.
During the first two weeks of November, world leaders met He will meet in Glasgow (Scotland) in the UN climate talks.
They will discuss further reducing greenhouse gas emissions, as well as how much money developed countries will pledge to help the global south move away from fossil fuels and adapt to the effects of the climate crisis.
Unless bold and quick action is taken, extreme weather events and rising sea levels caused by climate change will increasingly shape the Earth’s future. Scientists claim that the planet is running out of time to avoid these worst-case scenarios.
“World leaders have a fleeting opportunity to help or betray the future of humanity with their actions today on climate change,” Strauss said. “This research and the images generated from it show just how dangerous the Glasgow climate talks are.”