Global mean anomaly / ˚C
0.4
0.2
-0.2
-0.4
-0.6
0
1860 1880 1900 1920 1940 1960 1980
Global SST
Global Air Temperature
8
4
0
-4
-8
1955
1965
Year
1975
1985
1995
Heat content /10 22
J
(a)
(b)
Figure 2 (a) Global air
and sea surface
temperature variations
from 1850 to 1990 and (b)
heat content of the world’s
oceans from 1950 to 1995
anthropogenic pressures are an added, if perhaps dominant, force. It is only in the
last few decades that we have begun to unravel this natural variability and the
multi-decadal, decadal and annual cycles that characterize the Earth systems. To
predict the impact of global change on these cycles we must understand their
dynamics and linkages, as well as their role in shaping the natural processes of the
Earth biota.
This understanding is particularly urgent with reference to the marine systems.
The oceans occupy over 70% of the Earth’s surface and absorb twice as much of
the sun’s radiation as the atmosphere or the land surface, playing a major role in
shaping the Earth’s climate. The oceans move heat from lower to higher latitudes,
contribute to the complexity of the Earth’s climate and maintain regional
differences. However, our knowledge of the functioning of the world’s oceans is
still limited. Historical information seems to indicate that sea surface temperatures
have been warming through the 20th century although at a slower rate than the
atmosphere (Figure 2a). Detailed and strong evidence of warming in all the
major oceans over the period 1948—1998 has recently been reported (Figure 2b).
These results indicate that the mean temperature of the top 300 m of the ocean has
increased by 0.31 °C, corresponding to an increase in heat content of approximately
1 ; 10 joules of energy. Furthermore, the warming signal was observable to
depths of some 3000 m, demonstrating that the oceans are storing part of the
Earth’s excess heat.
The biological responses to the warming of the oceans are complex and
M. A. Cane, A. C. Clement, A. Kaplan, Y. Kushnir, D. Pozdnyakov, R. Seager, S. E. Zebiak and R.
Murtugudde, Science, 1997, 275, 957—960.
A. Kaplan, M. A. Cane, Y. Kushnir, A. C. Clement, M. B. Blumenthal and B. Rajagopalan, J.
Geophys. Res., 1998, 103, 18 567—18 589.
S. Levitus, J. I. Antonov, T. P. Boyer and C. Stephens, Science, 2000, 287, 2225—2228.
Influence of Climate Variability and Change on Marine Ecosystems
59
0.4
0.2
-0.2
-0.4
-0.6
0
1860 1880 1900 1920 1940 1960 1980
Global SST
Global Air Temperature
8
4
0
-4
-8
1955
1965
Year
1975
1985
1995
Heat content /10 22
J
(a)
(b)
Figure 2 (a) Global air
and sea surface
temperature variations
from 1850 to 1990 and (b)
heat content of the world’s
oceans from 1950 to 1995
anthropogenic pressures are an added, if perhaps dominant, force. It is only in the
last few decades that we have begun to unravel this natural variability and the
multi-decadal, decadal and annual cycles that characterize the Earth systems. To
predict the impact of global change on these cycles we must understand their
dynamics and linkages, as well as their role in shaping the natural processes of the
Earth biota.
This understanding is particularly urgent with reference to the marine systems.
The oceans occupy over 70% of the Earth’s surface and absorb twice as much of
the sun’s radiation as the atmosphere or the land surface, playing a major role in
shaping the Earth’s climate. The oceans move heat from lower to higher latitudes,
contribute to the complexity of the Earth’s climate and maintain regional
differences. However, our knowledge of the functioning of the world’s oceans is
still limited. Historical information seems to indicate that sea surface temperatures
have been warming through the 20th century although at a slower rate than the
atmosphere (Figure 2a). Detailed and strong evidence of warming in all the
major oceans over the period 1948—1998 has recently been reported (Figure 2b).
These results indicate that the mean temperature of the top 300 m of the ocean has
increased by 0.31 °C, corresponding to an increase in heat content of approximately
1 ; 10 joules of energy. Furthermore, the warming signal was observable to
depths of some 3000 m, demonstrating that the oceans are storing part of the
Earth’s excess heat.
The biological responses to the warming of the oceans are complex and
M. A. Cane, A. C. Clement, A. Kaplan, Y. Kushnir, D. Pozdnyakov, R. Seager, S. E. Zebiak and R.
Murtugudde, Science, 1997, 275, 957—960.
A. Kaplan, M. A. Cane, Y. Kushnir, A. C. Clement, M. B. Blumenthal and B. Rajagopalan, J.
Geophys. Res., 1998, 103, 18 567—18 589.
S. Levitus, J. I. Antonov, T. P. Boyer and C. Stephens, Science, 2000, 287, 2225—2228.
Influence of Climate Variability and Change on Marine Ecosystems
59