A startling number of major cities could be under water by 2050

Hundreds of millions of people around the world live near oceans and seas. And within the next 30 years, they may have to abandon the places they call home because of climate change. A new study by Climate Central published in Nature Communications this week warned that the devastation of rising rides resulting from human-caused climate change could affect as many as 300 million people, pushing them from their homes by the year 2050.

The latest estimate suggests that the situation is more than three times as bad as originally imagined; previous studies estimated that as many as 80 million people could be displaced by rising tides. The significant uptick in the number of people affected isn't related to an increase in the rate of tides rising, but rather a reflection of the fact that more people are living on low ground, below the expected high-tide level. The new calculations reflect the number of people living in at-risk areas, including those who would, in theory, be protected by some forms of infrastructure like New Orleans. The nations of China, Bangladesh, India, Vietnam, Thailand and Indonesia are most at-risk of rising sea levels, where as many as 237 million people could be displaced. Indonesia is perhaps the ultimate bellwether for this issue, as the nation has already been forced to move its capital city from Jakarta to Borneo because Jakarta, located on the island of Java, is the fastest sinking city in the world.

If the fact that sea levels aren't projected to rise faster than expected is a slight silver lining that can be taken from the findings, the rest of it is pretty explicitly bad news. Even in a scenario in which the governments of the world manage to quickly address the concerns of climate change, working to limit the amount of carbon emissions and keep the increase to the earth's temperature to a relatively modest uptick, there will be millions of people displaced by rising sea levels. The best-case outlook results in about 150 million people forced from their homes by 2050, and 190 million by 2010. If we continue on the path that we are currently on, those figures will be significantly higher. As many as 630 million people would be sent from their homes by 2100 if we fail to decrease our carbon emissions.

Rising sea levels are not a new phenomenon. According to the Natural Environment Research Council's National Oceanography Centre (NOC), sea levels have risen and fallen in a natural and predictable cycle for millions of years, dictated by the Earth's distance from the Sun and the amount of carbon dioxide in the atmosphere. However, that cycle stopped being so predictable in the 19th century, when sea levels began to rise more than expected. That accelerated in the 20th century, which NOC attributed to the melting of land ice, largely the Greenland Ice Sheet and Arctic glaciers. Those massive glaciers would typically trap glacier water but were instead melted by the rising temperature of the planet, caused by a significant increase in the amount of carbon emissions being trapped in the atmosphere. The release of that melted water results in unnaturally high sea levels.

In 2018, the National Oceanic and Atmospheric Administration (NOAA) reported that sea levels had risen for the seventh consecutive year and were 3.2 inches above the 1993 average, making it the highest annual average on record. It's likely to be surpassed basically every year for the foreseeable future, as NOAA warns that water levels have been consistently rising for at least the last two decades and the rise has been accelerating recently. According to the agency, scientists are confident that the global mean sea level will rise at least eight inches by 2100, even if we choose to take drastic action to curb our greenhouse gas emissions. If we fail to take any action, we could see our sea levels rise by 6.6 feet. The devastation felt by that level of change is difficult to fathom, though this weeks' study from Climate Central starts to put it in perspective by imagining more than half a billion people needing to be relocated.

That many people moving in a short period of time could result in cascading humanitarian crises. Millions of people will be turned into environmental refugees, forced from their homes and potentially from their country in order to find a safer living situation. Most of the land hit by rising sea levels will become entirely uninhabitable, as the water will permanently cover land that is currently occupied by more than 150 million people, according to researchers. In 2019 alone, extreme weather events have done more than $1.2 billion worth of damage to infrastructure. That will only increase as sea levels rise and start to subsume low-lying structures. Even for those who don't have their homes destroyed, resources will become sparse as water starts to flood essential lands. Agriculture business, including crops that serve as primary food sources, could be drowned by the rising tides. One only has to look at the devastating flooding that occurred in Nigeria in 2012 to see these outcomes in action. Following unprecedented levels of flooding believed to be in part the result of climate change, the nation sustained $16.9 billion in damages to farmland and infrastructure and suffered massive food shortages. There were at least 431 deaths related to the flooding, according to Global Citizen. A recent United Nations report has also highlighted some of the damages that could result from allowing sea levels to continue to rise at historic rates. Among the concerns are an increased number of extreme weather events like tropical cyclones, which the UN warns could become "common by 2100." It will also make natural occurrences like king tides — exceptionally high tides that happen several times per year — more damaging and difficult to prepare for. The study also warned that many low-lying cities and small islands will be affected to varying degrees by rising sea levels by the year 2050.

There is no stopping sea levels from rising at this point, there is only limiting the rise by cutting back on our emissions levels. If countries around the world can reach the goals established by the Paris Climate Agreement, it's likely that the number of displaced people can be limited to the lower estimates established by the Climate Central study. It will still result in massive amounts of movement and billions of dollars of lost property and infrastructure, but it should at least be manageable and at this point, that is the best we can hope for.