Summary: Polar bears and pacific atolls (flooded by rising seas) are the poster children for climate change. Oddly, both are weak examples. Previous posts discussed polar bears. Here Judith Curry (Prof Atmospheric Science, GA Inst Tech) discusses the effect of rising sea levels on coral atolls.
Small atoll islands may grow, not sink, as sea level rises.
Judith Curry, posted at Climate Etc, 1 November 2015
Reposted under her Creative Commons License
Recent headlines highlight the plight of Kiribati:
- Kiribati’s dilemma: Before we drown we may die of thirst
- Kiribati crumbles
- Kiribati climate change refugee crisis
Can we blame climate change, or more specifically sea level rise, for the problems of the atoll islands? From a June 2 article in the New Scientist Small atoll islands may grow, not sink, as sea level rises, we find:
Rising seas are eating away at small islands and will eventually turn their inhabitants into climate refugees, right? Not so for some of the world’s most threatened islands, which have grown despite experiencing dramatic sea level rise.
After poring over more than a century’s worth of data, including old maps and aerial and satellite imagery, they conclude that 18 out of 29 islands have actually grown. As a whole, the group grew by more than 18 hectares, while many islands changed shape or shifted sideways. “There is still considerable speculation that islands will disappear as sea level rises,” says Kench. “Our data indicates that the future of islands is significantly different.”
Storms and other disturbances that churn up the sea seem to be more important than sea level in influencing stability, says Kench. Storms break up coral, which then gets deposited on the atolls. He says other coral reef islands are likely to evolve in the same way, and that the Maldives seem to be showing a similar effect.
“There will be less emphasis on external migration of ‘environmental refugees’ from atoll nations that has gained such prominence in the last few years,” he says. But he notes that the atoll-building sediment comes from productive coral reefs, which face a range of threats such as warming oceans and pollution.