Environmental Engineering Reference
In-Depth Information
confluence of these complications is a noticeable threshold of accelerating
risk around 0.3 m of sea level rise that is captured even by global aggregates
regardless of adaptation effort. As a result, even 50 cm of SLR could put
between 5 and 200 million more people annually at risk of flooding.
Tol (2007) used a specific integrated assessment model of his own
creation to portray aggregate measures of erosion that parallel estimates of
populations facing complete displacement and/or significant economic loss
derived from economically efficient abandonment and/or growing protec-
tion costs across developed and developing countries. Figure 5.4 calibrates
his results graphically in relation to sea level rise; they were derived from
a socioeconomic portrait that was crafted to be consistent with the IS92a
emissions scenario for which seas rise by roughly 60 cm through 2100. This
work suggests that 50 cm of sea level rise could permanently displace up to
4 million people and cause more than 250,000 km
2
of wetland and dry-land
to be lost to erosion worldwide (with 90% of these losses projected to occur
in developing countries). The human faces behind the global displacement
results portrayed here can, of course, be seen in examples of erosion from
coastal storms and rising seas. In the Arctic, Newtok, Alaska is already pre-
paring for complete displacement, for example, and several neighboring
towns face the same fate in the near future. Meanwhile, many small island
states like Tuvalo, the Maldives, and the Cook Islands foresee similar futures
this century if sea level rise continues.
Geographic detail for physical processes like erosion and inundation
FIGURE 5.4 Losses attributable to sea level rise. Estimates of wetland and dry-land losses for developed
(Panel A) and developing countries (Panel B) correlated with sea level rise along a socioeconomic scenario
that tracks IS92a. Source: Derived directly from Tol (2007) as depicted in Nicholls et al. (2007: Figure 6.10).
