Without international political action to cap carbon emissions, the warming climate will cause the ice caps, icebergs and glaciers of the earth to melt, raising global sea level. This poses a serious threat to tens of millions of people living in cities along the coast of every continent.
Some scientists are now saying that even more people than they originally predicted may be displaced from their homes, as previous estimates of sea level rise are reassessed. According to a report published in New Scientist, the European Geosciences Union states that the sea level may rise by as much as 0.8 to 1.5 meters by the end of the twenty-first century. This estimate is in disagreement with the Intergovernmental Panel on Climate Change, who previously hypothesized that sea levels would rise 18 to 59 centimeters in that time -- a much less dramatic change. The EGU states that this “wildly inaccurate” estimate does not account for the effect of climate change on the flow of the Antarctic ice sheets.
The researchers said the IPCC had not accounted for ice dynamics - the more rapid movement of ice sheets due to melt water which could markedly speed up their disappearance and boost sea levels.
But this effect is set to generate around one-third of the future rise in sea levels, according to Steve Nerem from the University of Colorado, US.
Currently working to create an international plan for mitigating climate change is the Conference of Parties, now meeting in Poznan, and then in Copenhagen for the COP 15 next fall. At these events, many hope that global leaders can come to an agreement on how to equitably mitigate the effects of climate change, as the countries who have done the least emitting will be some of the most affected:
Scientists might debate the levels, but they agree on who will be hardest hit - developing nations in Africa and Asia who lack the infrastructural means to build up flood defences. They include countries like Bangladesh, almost of all of whose land surface is a within a metre of the current sea level.
"If [the sea level] rises by one metre, 72 million Chinese people will be displaced, and 10 percent of the Vietnamese population," said Svetlana Jevrejeva of the Proudman Oceanographic Laboratory, UK.
In the meantime, those of us not attending these conventions can do something about the problem by helping ourselves and our neighbors understand the need for action and the importance of supporting our political leaders to take it.
One organization helping to make the problem more immediately visual is Future Sea Level. An art/activism group based in San Francisco, Future Sea Level uses water-patterned crime scene tape to show exactly how big an impact rising seas could have. The group has instructions on how to create an art event in your town on their site.
A new tool from Architecture 2030 to familiarize yourself with is the Costal Impact Study: Nation Under Siege. Their maps allow you to see with the wave of your computer arrow, just how much water would cover up coastal cities in the United States. Currently, they’ve created digital coastal impact models for cities in Washington, California, Texas, Louisiana, Florida and on much of the East Coast.
A similar, yet more interactive tool is Flood Maps, a mashup of NASA elevation data and Google Maps that allows you to see how areas from around the globe would be affected by differing amounts of sea level rise. According to a past article by Jamais Cascio: "The default increase of seven meters -- about 23 feet for those who avoid the whole metric thing -- is the amount the world's oceans will rise once Greenland's glacial ice pack melts completely. This melting is already underway, and is happening with startling speed."
Understanding the severity of this issue can help us grasp why action on climate change is so necessary. Rising sea levels will displace millions, turning many who are already disadvantaged into environmental refugees. Instead of being frozen by fear with this information, we can use it to educate ourselves, and hopefully others so that when initiatives that help decrease our carbon footprint and make our cities more resilient appear, we can have the information we need to support them.
Image credits: Wikipedia, Future Sea Level, Architecture 2030
Just one important point: The IPCC conclusion about the extent of sea-level rise by 2100 was not an upper bound, but stated as a projection based on known/modeled processes (like the expansion of warming water). The report did not exclude the possibility of higher levels.
At the same time, there's been quite a bit of recent science pointing to the lower end of the range of possible rise in the near term (by 2100).
To my mind, however, that's all a distraction:
Here's one post on Greenland's role in raising sea levels that helps. This back-and-forth on Realclimate.org is an excellent review of where things stand. Overall, the legitimate scientific debate about the extent of possible (as opposed to probable) coastal retreats in this century, to my mind, is an utter distraction from the noncontroversial reality that a warming world will have no new normal coastline for centuries to come.