Principles of terrestrial ecosystem ecology.pdf

Figure 2.16. Time course of the
average surface temperature of
the Northern Hemisphere over
the last 1000 years. The data
are presented as a 40-year
running average of the difference
(anomaly) in temperature
between each year and the
average 1902–1980 temperature.
Note that 1998 was the warmest
year of the last millennium.
(Redrawn with permission from
Geophysical Research Letters;
Mann et al. 1999.)
Temperature anomaly ( o C)
1.0
0.5
0.0
-0.5
-1.0
Figure 2.17. Sources of evidence that Earth’s
climate is warming. Reduction in stratospheric ozone
causes less energy to be absorbed by the stratosphere;
this causes the stratosphere to cool and
allows more energy to penetrate to Earth’s surface.
Temporal Variability in Climate 37
1998
1000 1200 1400 1600 1800 2000
Year
Warming is most pronounced at Earth’s surface and
has caused the surface air and oceans to warm and
glaciers and sea ice to melt. (Adapted from IPCC
Assessment Report 2001; Folland et al. 2001.)