Refugees from rising seas: no place to call home

Most refugees fleeing persecution, famine or civil strife dream of one thing: going home some day.

But when rising seas displace hundreds of millions of people -- a near certainty, scientists say -- it will be an exodus with no hope of return.

"With sea level rise, we are talking about migrations without the option for a round-trip," Francois Gemenne, an expert on the intersection between geopolitics and the environment, and director of the Hugo Observatory in Liege, Belgium, told AFP.

The global ocean waterline has crept up 15 to 20 centimetres since 1900, a direct effect of climate change. Until recently, that added volume was mostly due to water expanding as it warms.

Today, however, meltwater from glaciers and especially ice sheets atop Greenland and Antarctica has become the main driver.

The pace of sea level rise has also picked up, increasing nearly three-fold in the last decade compared to the previous century, a landmark UN assessment of oceans and Earth's frozen spaces to be unveiled next week will report.

How high the oceans will be lifted by 2100 depends mainly on how much Earth heats up.

If humanity caps global warming at two degrees Celsius above preindustrial levels -- the cornerstone goal of the Paris climate treaty -- seas will rise by about half-a-metre, according to a draft of the Intergovernmental Panel on Climate Change (IPCC) report seen by AFP.

A 3C or 4C world in which efforts to curb greenhouse emissions have fallen short will likely see an increase closer to a metre, enough to wreak havoc in dozens of coastal megacities and render many island nations uninhabitable.

"Some small islands in the Pacific and Indian Ocean are merely one to two metres above sea level," Carlos Fuller, lead climate negotiator for the Association of Small Island States (AOSIS), told AFP. "A 1.2 metre rise would totally submerge these states."
"I shudder to think of the future world when tens of millions of people are moving because the ocean is eating their land."