We have been faced with such uncomfortable choices for millennia it seems, as the saying comes from Homer’s epic poem The Odyssey, composed around the 8th or 7th century BCE. At one stage during his travels Odysseus must pass between a fearsome cliff (rock)-dwelling man-eating monster and a treacherous whirlpool (hard place.)
Now, twenty-seven or twenty-eight centuries after Homer was writing, we might need to rephrase the saying. It is becoming apparent that humanity is going to be caught between the sea and a hot place.
Most of us are aware of the danger of sea-level rise over the near-term. Currently some 270 million people live on land that is less than 2m above sea level. By 2100 that number is expected to exceed 400 million. Although, by then, most of those 400 million will have had to move because of sea-level rise. The NASA Earth Observatory predicts a rise of between 0.6m – 1.1m by the end of the 21st century.
Of the top 20 cities (by population) at risk of severe sea-level impact, 15 of them are in Asian countries. One of those nations, Indonesia, is already taking steps to shift its coastal capital of Jakarta (with the dubious distinction of being labelled the ‘fastest sinking city in the world’) to a new site – some 2,000 km NE of Jakarta to Nusantara in Borneo, where the location is hillier than the alluvial plain on which Jakarta sits.
Another country at severe risk of sea-level rise is the Maldives in the Indian Ocean. The flattest country on Earth, the country has an average elevation of just 1m above sea level. A sea-level rise of just 45cm would see the nation lose 77% of its land area.
Sea-level rise is one half of the dire situation.
The Hot Place
Two years ago a group of scientists from China, USA, UK, Denmark, the Netherlands, and Uruguay published a paper in the Proceedings of the National Academy of Sciences (PNAS) journal calling attention to a vastly increased land area that would be too hot for human inhabitation by 2070.1
Presently humans live in a climatic envelope where the Mean Average Temperature (MAT) is around 11o C to 15o C with a small number living in a MAT of around 26o C.
Very few, if any, humans live in an area with a MAT of 29o C or greater. This is hardly significant at present as only 0.8% of the Earth’s land surface experiences such conditions, concentrated mostly in the Sahara.
However, according to this research, by 2070 the area experiencing a MAT of 29o C or greater is projected to be 19% of the Earth’s surface. That is twenty-four times as much land area as now! That is massive!
Most at risk will be nations in central Africa, parts of the Indian sub-continent, SE Asia. Northern areas of Australia, and much of the Amazon basin.
How many people will this affect? Huge numbers. Around 350 billion, or one-third of the projected global population.
The UN Refugee Agency (UNHCR) estimates that currently there are 103 million forcibly displaced people in the world, a figure that has risen significantly in the past decade.2
The world has trouble coping with this number now. How will the world cope when this number is increased by a factor of 10 or more?
1. Xu, Kohler, Lenton, Svenning, & Scheffer, Future of the Human Climate Niche, PNAS May26, 2020, Vol 117, no. 21
2. Refugee Data Finder on UNHCR website accessed 2 November 2022.