Developing countries like India may see
bigger economic crisis while dealing with frequent floods. Debt burden
of poor nations may go up drastically.
Right now, coastal floods and storm surge
damage cost the world between $10 billion a year and $40 billion. But as
the megacities grow – think of Lagos, or Shanghai, or Manila – more
people will be at risk, and, among them, greater than ever numbers of
This has been projected on basis of a
compilation of global simulation results on future flood damage to
buildings and infrastructure on the world’s coastal flood plains. The
compilation is made by Jochen Hinkel from the Global Climate Forum in
Berlin and colleagues.
“If we ignore this problem, the
consequences will be dramatic,” says Hinkel making appeal to to take
action and invest in coastal protection measures, such as building or
raising dykes, amongst other options.
Provoking a response
Hinkel’s co-author Robert Nicholls from
the University of Southampton further warns, “If we ignore sea level
rise, flood damages will progressively rise and presently good defences
will be degraded and ultimately overwhelmed, hence we must start to
All such projections involve assumptions
about the future that cannot be tested, so the authors spread their
bets. They considered a range of scenarios involving crude population
growth, levels of economic growth with time, and a series of predictions
of sea level rise, as icecaps and glaciers melt, and as the oceans warm
and expand according to predictable physical laws.
What they could not predict – because such
things require political decisions of the kind they hope to provoke with
their forecasts – would be the civic and political responses in the next
eight decades as storms become more violent and floods more frequent.
Nor did they try to incorporate the
natural consequences of human settlement such as, how much subsidence,
for instance, would occur as humans pumped groundwater from aquifers or
quarried strata for building material, all things that would lower the
levels of the land already at risk from invasion by the sea.
But their predictions, while alarming, are
only reinforcements of earlier investigation. In August, a World Bank
team calculated that floods would be routinely costing coastal cities $1
trillion a year by 2050.
In July last year, a team from Stanford
University in California looked at the challenge of building sea
defences and proposed that by far the most efficient solutions would all
be natural. The team observed that dune systems, mangrove forests,
reefs, water meadows, kelp forests and natural estuary ecosystems
provided the best protection for many people in many circumstances.
And in December scientists from the
University of Massachusetts considered the devastation wreaked on New
York and other American cities by Super storm Sandy in October 2012 and
warned that such things could happen again and that, once again, natural
systems might provide the most efficient buffers against the buffetings
of the weather.
The PNAS authors consider, for the purpose
of their argument only, the increasing costs of either maintaining sea
barriers such as dykes, or raising them.
By 2100, global average sea level rise
could be as low as 25 cms, or as high as 123 cms; between 0.2% and 4.6%
of the world’s population could be affected by flooding each year; and
losses could be as low as 0.3% or as high as 9.3% of global gross
It doesn’t matter very much whether by the
end of the century the losses hit the low end of these projections, or
the high. They will always be huge. “Damages of this magnitude are very
unlikely to be tolerated by society and adaptation will be widespread,”
the authors warn.
And there will be tracts of land that no
dykes could ever save from the rising waters. The poorest countries are
in any case unlikely to be able to meet the costs of sustained
protection from the sea.
“If we do not reduce
greenhouse gases swiftly and substantially, some regions will have to
seriously consider relocating significant numbers of people in the
longer run”, says Hinkel. He and his co-authors want to see some
significant long-term thinking.
His colleague Professor Nicholls adds,
“This long-term perspective is however a challenge to bring about, as
coastal development tends to be dominated by short-term interests of,
for example, real estate and tourism companies, which prefer to build
directly on the waterfront with little thought about the future.”
(With Inputs from a Report released by
Climate News Network)