(CNN) -
The planet is warming rapidly, leading to historic droughts, deadly floods and unusual thaws in the Arctic.
It is also causing a steady rise in sea level, which scientists say will continue for decades.
A new study by Climate Central, a nonprofit research group, shows that some 50 major coastal cities will have to implement "unprecedented" adaptation measures to prevent rising seas from engulfing their most populated areas.
Dhaka, Bangladesh:
The analysis, carried out in collaboration with researchers from Princeton University and the Potsdam Climate Impact Research Institute (Germany), has led to striking visual contrasts between the world as we know it today and our underwater future, if the planet it heats up to 3 degrees Celsius above pre-industrial revolution levels.
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Rising temperatures
Scientists studying climate change reported in August that the world is already 1.2 degrees warmer than pre-industrial levels.
Temperatures should stay below 1.5 degrees, they say, a critical threshold to avoid the most serious impacts of the climate crisis.
Havana Cuba:
But even in the most optimistic scenario, in which global greenhouse gas emissions begin to decline today and drop to zero in 2050, global temperature will continue to exceed the 1.5 degree threshold before dropping.
In less optimistic scenarios, where emissions continue to rise beyond 2050, the planet could reach 3 degrees as early as the 2060s or 2070s, and the oceans will continue to rise for decades before reaching peak levels.
"The decisions we make today will mark our path," said Benjamin Strauss, chief scientist at Climate Central and lead author of the report.
Mumbai, India:
Climate Central researchers used global elevation and population data to analyze the parts of the world that will be most vulnerable to sea level rise, which tend to be concentrated in the Asia-Pacific region.
Island nations face "near total loss"
Small island nations are at risk of "near total loss" of their land, according to the report, and eight of the 10 areas most exposed to rising sea levels are in Asia, with approximately 600 million people exposed. to flooding in a 3 degree warming scenario.
According to Climate Central's 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 countries that have increased their use of coal as fuel in recent years.
Hanoi, Vietnam:
In September, a study published in the journal Nature concluded that almost 60% of the planet's remaining oil and natural gas and 90% of its coal reserves should remain underground by 2050 to have a better chance of limiting warming global to 1.5 degrees Celsius above pre-industrial levels.
Most regions of the world, he said, must reach peak fossil fuel production now or in the next decade to avoid the critical climate threshold.
China promises
At the UN General Assembly in September, China made a major climate promise as one of the world's largest greenhouse gas emitters: the country will stop building new coal-based power projects abroad, marking a change in the policy surrounding its Belt and Road infrastructure initiative, which had already begun to scale back its coal initiatives.
Durban, South Africa:
If the planet reaches 3 degrees, Climate Central reports that approximately 43 million people in China will live in lands that are projected to be below the level of high tides by 2100, and 200 million people will live in areas at risk of rising long-term sea level.
With every fraction of a degree of warming, the consequences of climate change get worse.
Even limiting warming to 1.5 degrees, scientists say the types of extreme weather the world experienced this summer will be more severe and more frequent.
Unrecognizable weather
Beyond 1.5 degrees, the global climate system could become unrecognizable.
Santa Monica, United States:
According to the Climate Central report, some 385 million people currently live on land that will be flooded by high tide, even if greenhouse gas emissions are reduced.
If the warming is limited to 1.5 degrees, the rise in sea level would affect the lands that today inhabit 510 million people.
If the planet reaches 3 degrees, the high tide line could invade lands where more than 800 million people live, according to the study.
London England:
The authors note in the report that a key caveat in their assessment is the lack of global data on existing coastal defenses, such as levees and seawalls, to fully project exposure to sea rise.
However, they acknowledge that due to the current impact of recent floods and storm surges, cities are likely to upgrade their infrastructure to avoid worsening the effects.
"Unprecedented defenses"
"Higher levels of warming will require unprecedented defenses globally or neglect in dozens of major coastal cities around the world," the authors wrote, "while the count could be limited to a relative handful through strong compliance with the Paris Agreement, especially limiting warming to 1.5 degrees ".
Hoboken: United States:
But coastal infrastructure costs money.
Rich nations, like the United States and the United Kingdom, could afford these measures, but low-income ones 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, warming temperatures are leading to ocean acidification and other forms of environmental destruction that threaten such measures. defense.
During the first two weeks of November, world leaders will meet in Glasgow, Scotland for a UN-sponsored climate talks.
Glasgow, Scotland:
They will discuss further limiting greenhouse gas emissions, as well as the amount of funds that developed nations will pledge to help the Global South move away from fossil fuels and adapt to the impacts of the climate crisis.
Unless bold and swift action is taken, extreme weather events and rising sea levels caused by climate change will increasingly shape the future of the Earth.
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 created from it illustrate how much is at stake in the climate conversations in Glasgow."