Geoscience Reference
In-Depth Information
These trends are assumed to continue in the long-term economic
projections of climate-economy models. If countries do in fact show the
rapid growth in output and emissions assumed in the standard projec-
tions, then market economies will become increasingly less vulnerable
to climate change as activity shifts from farming and land-based activi-
ties to industry and services. This pattern is not inevitable. But it is per-
vasive across time and space, and we should consider it to be one of the
central fi ndings of the economics of climate change.
ESTIMATES OF AGGREGATE DAMAGES
Economists have labored for many years to estimate the aggregate
damages from climate change. They gather all the available fi ndings
from studies for different sectors and different countries. There are stud-
ies for market or near-market areas like agriculture, forestry, fi sheries,
energy, sea-level rise, and health. Inevitably, analyses primarily exam-
ine regions with plentiful data, such as the United States and western
Europe. Estimates for developing countries and nonmarket sectors cover
only a few sectors in a few countries.
Figure 22 shows the results of a comprehensive survey of the aggre-
gate damages from climate change for different levels of warming. The
dots indicate the results of different studies as compiled by a leading
scholar in this area, Richard Tol.
3
Several interesting fi ndings emerge from these results. The fi rst sur-
prise is that, for the range of changes that have been calculated, the
estimated impacts of climate change are relatively small. The largest
damage estimate is around 5 percent of output. The most carefully stud-
ied scenario shows 2
1
⁄
2
°C of warming (which we estimate to occur
around 2070). For this warming, the central damage estimate is around
1.5 percent of global output.
Additionally, Figure 22 shows estimates from the DICE model as a
solid line. These aggregate estimates are drawn from a number of differ-
ent areas (agriculture, sea-level rise, hurricanes, and the like) and take the
global damages as a percentage of global output for different temperature
increases. They are subject to large uncertainties, as I have emphasized in
