Geoscience Reference
In-Depth Information
tipping points in climate change is in its infancy. But we know in many
areas from biology to economics that large and potentially dangerous
discontinuities can occur suddenly and unexpectedly in complex sys-
tems. Current research indicates that a number of particularly danger-
ous risks may be incurred over the next century or so once the earth
has warmed by 3°C or more. So on this basis, the target threshold
might be set at 3°C rather than 2°C. At the same time, there is a large
margin of error in these estimates. Since we don't have a clear idea of
where the different thresholds are crossed, it might be prudent to target
a lower limit for temperature increase.
From this evidence, I conclude the following. If the costs are small,
then we would surely want to keep climate change and increases in
CO
2
concentrations to the bare minimum. Why risk any damages to
coastlines, ecosystems, and small islands if we can avoid them at a small
cost? On the other hand, if aiming for a very low temperature increase
involves cutting back drastically on central human priorities such as
food, shelter, education, health, and safety, then we would need to take
a careful look at the trade-offs. We might be willing to run some risks
on wheat yields or sea-level rise rather than spend a fortune limiting
warming to the lowest feasible level. After all, we might be able to spend
that money more fruitfully on improving seeds, water management,
and infrastructure. Moreover, we might fi nd inexpensive technologies
for carbon removal—the carbon capture and carbon-eating trees that
technologists are designing—so that we can drive down CO
2
concentra-
tions quickly in a few decades. So short of catastrophic impacts, we should
look at the price tag before committing to any specifi c target.
The implication is that we cannot realistically set climate-change tar-
gets without considering both the costs of slowing climate change and
benefi ts of avoiding the damages. This is where economics comes back
into the picture.
