Figure 2-6a: Precipitation
during the 20th century has on average increased over continents outside the tropics
but decreased in the desert regions of Africa and South America. While
the record shows an overall increase consistent with warmer temperatures and more
atmospheric moisture, trends in precipitation vary greatly from region to region
and are only available over the 20th century for some continental regions. Over
this period, there were relatively small long-term trends in land areas experiencing
severe drought or severe wetness, but in many regions these changes are dominated
by inter-decadal and multi-decadal climate variability that has no trends evident
over the 20th century.
