Tide of climate refugees swells as Earth heats up

The Sundarbans mangrove forest in south-western Bangladesh, viewed by satellite. Image: Axelspace  Corporation, via Wikimedia Commons

Prepare for the arrival of more displaced persons, climate refugees driven from their homes by global heating.

LONDON, 11 May, 2021 − Natural hazards − most of them driven by climate change − have forced an estimated 288 million people from their homes since 2008. That is three times the numbers displaced by war and conflict. These people have become, however briefly, climate refugees.

And the number will grow. A new study has found that for every 1°C rise in global average temperatures, the chance of displacement from river flooding alone will rise by 50%. And that calculation is based on population numbers right now. As human numbers rise, so will the risk − by 110%.

Another study makes an even more precise prediction: thanks to rising sea levels and more intense cyclonic storms, an estimated 1.3 million people in Bangladesh will be forced into migration by 2050. Many will move further inland − but many are likely to be forced across national borders, to trigger more displacement.

Drought and famine are climate-related natural disasters. So are forest fires, extreme heat waves, catastrophic windstorms and devastating floods, driven either by torrential rainfall or rising sea levels, or both.

Climate scientists, environmentalists and geographers have been warning for years that the numbers of people driven from their homes by climate change is on the increase: even in the US, as many as 13 million people could be forced from their coastal settlements by sea level rise.

“It is imperative that we have a better understanding of how the risks are changing”

Swiss scientists report in the journal Environmental Research Letters that even if the world keeps to an agreement to limit global warming to no more than 2°C, because the global population is rising, the average risk of displacement by river flooding is likely to rise by 110% by the end of the century.

If however nations take no drastic action, and go on burning ever more fossil fuels, the global average risk of being forced from home by swirling waters could rise by up to 350%.

“Because floods are a major driver of displacement, and due to the fact that they are influenced by climate change, it is imperative that we have a better understanding of how the risks are changing,” said Pui Man Kam of the Swiss Federal Institute of Technology, known as ETH Zurich, who led the study.

An estimated 680 million people worldwide live in low-lying coastal zones. Spanish, Italian and US scientists report in the journal Earth’s Future that they had developed a data model to predict the numbers likely to be displaced by any natural hazard to become climate refugees.

They tested it in the context of sea level rise, storms and floods in one low-lying country laced with rivers: Bangladesh. It is home to 163 million people, of whom 41% live at elevations lower than 10 metres above sea level.

Countrywide unrest likely

Their research found that although people in the coastal districts along the Bay of Bengal would be flooded, a surge of migration would ripple across the landscape and impact all 64 districts, including the capital, Dhaka.

Thanks to climate migration, numbers in the city should grow and eventually decline, as people moved to get away from the new arrivals. That is, flood events at the coast could ultimately trigger human unrest in the entire country.
“Droughts, desertification, floods, earthquakes, and wildfire threaten livelihoods worldwide; from wealthy to developing economies, every country is vulnerable to environmental change,” said Maurizio Porfiri of New York University’s Tandon School of Engineering.

“Mathematical models can assist in providing reliable predictions of environmental migration, which are critical for devising effective policy initiatives and improving our preparedness for future migration patterns.” − Climate News Network