Climate, Climate Variability and Impacts in the Mediterranean Area: An Overview
73
2100 to 850 ppm and the global temperature increase is 3,8 K - models predict for
2100 a substantial decrease (-20%) of summer precipitation while the change will
be only -1 to -2% in winter. The temperature increase will be a little bit higher than
its global mean in winter and significantly higher in summer. It is astonishing that
for a less strong rise of the carbon dioxide concentration (scenario B2, 600 ppm,
+2,8 CC) the effect is much less than proportionally smaller. For the popUlation that
experiences present Mediterranean climate these results may sound somewhat
curious because in regions where there is hardly any rain during the summer
months it is very unlikely that there will be dramatically less in the future and in
areas where during the last years extreme floods occurred in autumn or winter
people ask themselves whether this is a first sign of climate change, Consequently
there is need for interpretation and clarification, Firstly the scenarios of 2100 are
compared with those of 1969-1990. Secondly the model output may need a different
interpretation such as that the summer droughts may become longer. Or, thirdly, the
Mediterranean climate gradients are so strong that a general statement for the whole
basin is of not much relevance for its sub-regions. The conclusion would be that the
Mediterranean system is not understood well enough to simulate regional climate
development.
The problems of the water input into the region, its net water budget under the
impact of changing global climate, the role of the vegetation which is changed by
man and fires, and the role ofthe Mediterranean in the global carbon cycle must in
the future be studied in an integrated way because these issues are so much
interlaces that picking out one specific problem, as it has been done so much in the
past, will not provide further deeper insight. One of the unknowns in this system
still is the Mediterranean Sea the internal dynamics of which seems to undergo
considerable changes. In other regions of the world where similar problems existed
to understand the interaction of processes, scientists and governments found
together and initiated a thorough study, a regional GEWEX experiment, to assess
and integrate the available data, to improve the modelling of climate variability by
combining regional with global climate models, and to study the less known
processes and their interactions. The Mediterranean area because of its manifold of
surface structures and its very critical geographical position with respect to climate
change is predestinated to become in the future a focal point of such integrative
research.
References
Abcr JD (\ 998) Can we close the water/carbon/nitrogen budget for complex landscapes? In:
Tenhunen JD and Kabat P (eds.): Integrating hydrology, ecosystem dynamics, and
biogeochemistry in complex landscapes. Dahlem Workshop report. John Wiley & Sons,
Chichester, pp 313-333
Abrate T (1999) Water availahility and data availability - WMO policy and activity. International
Workshop on Desertification Convention: Data and Information Requirements for
73
2100 to 850 ppm and the global temperature increase is 3,8 K - models predict for
2100 a substantial decrease (-20%) of summer precipitation while the change will
be only -1 to -2% in winter. The temperature increase will be a little bit higher than
its global mean in winter and significantly higher in summer. It is astonishing that
for a less strong rise of the carbon dioxide concentration (scenario B2, 600 ppm,
+2,8 CC) the effect is much less than proportionally smaller. For the popUlation that
experiences present Mediterranean climate these results may sound somewhat
curious because in regions where there is hardly any rain during the summer
months it is very unlikely that there will be dramatically less in the future and in
areas where during the last years extreme floods occurred in autumn or winter
people ask themselves whether this is a first sign of climate change, Consequently
there is need for interpretation and clarification, Firstly the scenarios of 2100 are
compared with those of 1969-1990. Secondly the model output may need a different
interpretation such as that the summer droughts may become longer. Or, thirdly, the
Mediterranean climate gradients are so strong that a general statement for the whole
basin is of not much relevance for its sub-regions. The conclusion would be that the
Mediterranean system is not understood well enough to simulate regional climate
development.
The problems of the water input into the region, its net water budget under the
impact of changing global climate, the role of the vegetation which is changed by
man and fires, and the role ofthe Mediterranean in the global carbon cycle must in
the future be studied in an integrated way because these issues are so much
interlaces that picking out one specific problem, as it has been done so much in the
past, will not provide further deeper insight. One of the unknowns in this system
still is the Mediterranean Sea the internal dynamics of which seems to undergo
considerable changes. In other regions of the world where similar problems existed
to understand the interaction of processes, scientists and governments found
together and initiated a thorough study, a regional GEWEX experiment, to assess
and integrate the available data, to improve the modelling of climate variability by
combining regional with global climate models, and to study the less known
processes and their interactions. The Mediterranean area because of its manifold of
surface structures and its very critical geographical position with respect to climate
change is predestinated to become in the future a focal point of such integrative
research.
References
Abcr JD (\ 998) Can we close the water/carbon/nitrogen budget for complex landscapes? In:
Tenhunen JD and Kabat P (eds.): Integrating hydrology, ecosystem dynamics, and
biogeochemistry in complex landscapes. Dahlem Workshop report. John Wiley & Sons,
Chichester, pp 313-333
Abrate T (1999) Water availahility and data availability - WMO policy and activity. International
Workshop on Desertification Convention: Data and Information Requirements for