Geoscience Reference
In-Depth Information
Is society made more vulnerable to extreme natural events either by changing
those events or by reducing human ability to respond with corrective action?
How likely is it that the consequences of climate change will be severe or
catastrophic?
What is at risk and when is it a risk?
What are the likely impacts on the landscape and the hydrological system?
How might the boundary conditions and the overall productivity of the forests,
grasslands, and other rangelands be affected?
How might increasing carbon dioxide levels affect crops and food supplies for
humans, livestock, and wildlife?
What are the socio-economic consequences of these physical and biological
changes?
What are the likely consequences for ecosystems of mitigation actions?
Can the costs associated with climate change be reduced through natural
adaptation of ecosystems or policy-initiated adaptation?
Frederick (1994) has emphasized that the accumulated results of many regional
and local climate impact assessments may help provide informed answers to these
questions. Nevertheless, the uncertainties surrounding both the nature and the
impacts of any future climate change are likely to remain very large, precluding
precise estimates of the net bene
ts associated with alternative policy responses.
Even if the range of uncertainty were diminished, it might still be difficult to justify
speci
c measures on narrow economic grounds, because (as noted above) the
impacts on natural resource systems are apt to be poorly re
fl
ected in standard
bene
t-cost analysis.
Mendelsohn and Rosenberg (1994) have formulated the following questions
relevant to global warming effects in the area of ecological and water resources:
Do changes in ecosystems provide important feedbacks to the natural carbon,
nitrogen, and methane cycles? For example, will the natural sinks or emitters be
affected by changing precipitation, temperature, and CO
2
levels?
What are the appropriate output measures of ecosystem component models?
What are the ecological effects of climate change that policy analysts use to
determinate the importance of an ecosystem change?
What climate change-driven shifts in ecosystem boundaries can be predicted?
Will these effects be subtle and small or large and dramatic and over what time
frame and spatial dimensions?
Will climate change cause a change in the productivity of valuable market or
non-market species? For example, to what extent will some forests grow more
quickly or more slowly. Will desired non-market species, such as bear, elk, and
bald eagles, be more or less plentiful?
What species could be lost with rapid climate changes? How do the vulnerable
species break down by type and geographic distribution? How should conser-
vation policies adapt to a world requiring change?
How are the ecosystems likely to change as the climate evolves over time: will
there be a large increase in early succession species and where?
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