187 Mil to be displaced, or hardly any? Depends on Adaptation.
Sea Level will rise this century and almost surely by a greater amount during the next century. Many figures are cited for how many people might be displaced by the change. How big a variation? How about somewhere between 41,000 and 187 million people. Now that’s a range. More bogus science? Quite the opposite.
A new study yields those figures, and it comes from a well-qualified British scientist, Dr. Robert J. Nicholls of the University of Southampton, and published in the prestigious “Philosophical Transactions of the Royal Society A.”
How could there be a projection of SUCH a wide range? 187 million or only 41,000. It depends on two considerations.
First obviously is how far will sea level rise. Based on their rigorous review of the latest science they conclude the possible range for sea level rise (SLR) this century is between 0.5 – 2.0 meters (1.5 – 7 feet). That is a big range to be sure, but is realistic considering that we can’t know for certain how much CO2 and other greenhouse gases will be put in the atmosphere. That depends on how much energy we need to produce; whether it is from coal, petroleum, natural gas, or clean technologies; the population level in the latter part of the century is also unknown — there are more than three generations yet to come this century.
Simply, there is no honest way to know for certain, what will happen over the next 89 years in the US, in China, in India, etc. But good planning, whether it be at the household level, the community, or national security, dictates that we consider a range of possibilities, or scenarios.
That would determine how many people are affected or displaced and yields the range of possible SLR, from 1.5 – 7 feet. Assuming nothing significant changes in our coastal defense and adaptation, a catastrophic number of people estimated at between 72 and 187 million globally would be displaced, based on present population levels and locations.
However, if we take steps to do what I call “Intelligent Adaptation” those numbers could plummet to between 41,000 and 305,000 for the same respective SLR. Adaptation would include coastal protection including seawalls, dykes, levees, increased setbacks and restrictive zoning, and planned “retreat.”
Nicholls and his colleagues estimate that the cost of adaptation would be rather significant, but need to be looked at in terms of cost of not adapting ahead of time.
The point is that it is misleading to cite an extrapolated number on the high side or the low side, without using the teaching opportunity to explain the two unknowns:
- Whether sea level rises by 1.5 feet or 7 feet, which depends on how high the level of greenhouse gases get by end of the century. (See my earlier blog for a single graphic about CO2 levels. “Best Image to Illustrate Climate Problem.”)
- Whether we will begin Intelligent Adaptation to prepare for inevitable rising sea level, or continue our general tendency to dither, delay, distort, distract, and deny. (There are a few good exceptions where communities are starting to look to the future with clarity.)
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FYI, the reference to the full Nicholls article is http://rsta.royalsocietypublishing.org/content/369/1934/161.short