Environmental Engineering Reference
In-Depth Information
5.9 ILLUSTRATIVE ADDITIONAL FACTORS
There are many more climate impacts that could be very important
but are not as well understood as those described above. Some illustrative
examples are briefly provided here.
National Security
Many processes could plausibly connect climate change to national
security concerns. For instance, military experts have pointed to the poten-
tial for climate-induced food and water shortages to contribute to political
instability, which can then be exploited by extremists (CNA Corporation,
2007). The potential for mass migrations associated with resource shortages
or flooding are also potential “threat multipliers.” Climate changes will also
likely affect military operations, such as via inundation of low-lying military
bases, and introduce new geopolitical dilemnas, such as the opening of sea
routes in the Arctic.
Yet perhaps because of the complex nature of national security threats
and the paucity of relevant data, there are relatively few quantitative exam-
ples that document the climate sensitivity of phenomena related to national
security. Some empirical evidence suggests an important role for climate in
domestic and international conflict. Long-term fluctuations of global wars
and death rates since 1400 are correlated with shifts in temperature (Zhang
et al., 2007a). In Africa, civil wars since 1980 have been roughly 50% more
likely in years 1°C warmer than average (Burke et al., 2009). Precipitation
decreases are also associated with conflict in Africa, although projected
rainfall changes are not large relative to historical variability (Miguel et al.,
2004; Hendrix and Glaser, 2007).
Obviously more work is needed to advance understanding of national
security threats from climate change. Specifically, although the implica-
tions of climate change for resource scarcity are uncertain, the complex
relationship between resource scarcity and conflict is even more tenuously
understood (Barnett, 2003; Nordås and Gleditsch, 2007). At the same time,
military experts routinely caution that waiting for quantitative precision
can be very risky, and intuition alone is often used to make major strategic
decisions for national security (CNA Corporation, 2007).
Dynamic Vegetation
Changes in climate and CO
2
beyond 2100 will likely be sufficient
to cause large-scale shifts in natural ecosystems. Although relatively few
