Geoscience Reference
In-Depth Information
We are currently changing the composition of the atmosphere beyond anything that has
been experienced over the last few millions of years. We are headed for unknown territory
and therefore scientific uncertainty can be large. However, we know from the study of past
climates that the climate system can switch into a new state very quickly once a threshold
has been past. For example, ice-core records suggest that half the warming in Greenland
since the last ice age was achieved in only a few decades. This chapter examines the pos-
sibility that there are thresholds or tipping points in the climate system that may occur as
we warm the planet.
Figure 27
shows the main tipping points which scientists have been
concerned about over the last two decades. Irreversible melting of the Greenland and/or
Western Antarctic ice sheet, slowing down of the North Atlantic deep ocean circulation,
gas hydrates, and the Amazon rainforest dieback will all be discussed.
