Environmental change
613
during the last 70,000 years, several glacial sedimentary layers coming from icebergs
have been identified from cores in the northern Atlantic Ocean. These six synchronic
stages are called Heinrich events (Heinrich, 1988; Bond et al., 1993, 1997). The increment
of freshwater and the temperature decrease in the upper part of the oceans produced
significant changes in some of the climatic parameters. Therefore, the occurrences of
rapid climate variations in the past make feasible the triggering of these types of climate
modifications in the future.
Without doubt, climate change modelling is uncertain and complex, due to the quantity
of parameters needed and the difficulty in comprehension of their relationships. This
debate is not about if climate change is due to human activities, but rather how quickly, to
what magnitude, and with what regional implications (Weaver, 2003). An alternative
methodology for the study of climate changes is the study of the geological records (PetitMaire, 1999), wherein valuable data about climate change can be obtained.
In order to study the consequences of warming on landscape, researchers can go into
the past, mainly to the Climate Optimum or Altithermal, which occurred about 7000 BP,
and compare it with the last maximum interglacial at about 120,000 BP, so that the
response of the landscape in warmer phases can be analysed. Thus, landscape changes can
show the geomorphologic setting for the future and the attached consequences. This
prognostic approach is an important contribution from geomorphology.
If the change predicted by IPCC becomes evident, it would affect areas very differently
depending on the climatic environment. For example, in arid regions an increase of the
existing problems is expected (Boer and De Groot, 1990), such as soil degradation,
hydrologic and aeolian erosion, decrease of soil fertility, salinization, sedimentation, and
flooding. Moreover, an expansion of semiarid areas, an increase in fire risk, and a decrease
in the quality and quantity of subterranean water would be expected.
613
during the last 70,000 years, several glacial sedimentary layers coming from icebergs
have been identified from cores in the northern Atlantic Ocean. These six synchronic
stages are called Heinrich events (Heinrich, 1988; Bond et al., 1993, 1997). The increment
of freshwater and the temperature decrease in the upper part of the oceans produced
significant changes in some of the climatic parameters. Therefore, the occurrences of
rapid climate variations in the past make feasible the triggering of these types of climate
modifications in the future.
Without doubt, climate change modelling is uncertain and complex, due to the quantity
of parameters needed and the difficulty in comprehension of their relationships. This
debate is not about if climate change is due to human activities, but rather how quickly, to
what magnitude, and with what regional implications (Weaver, 2003). An alternative
methodology for the study of climate changes is the study of the geological records (PetitMaire, 1999), wherein valuable data about climate change can be obtained.
In order to study the consequences of warming on landscape, researchers can go into
the past, mainly to the Climate Optimum or Altithermal, which occurred about 7000 BP,
and compare it with the last maximum interglacial at about 120,000 BP, so that the
response of the landscape in warmer phases can be analysed. Thus, landscape changes can
show the geomorphologic setting for the future and the attached consequences. This
prognostic approach is an important contribution from geomorphology.
If the change predicted by IPCC becomes evident, it would affect areas very differently
depending on the climatic environment. For example, in arid regions an increase of the
existing problems is expected (Boer and De Groot, 1990), such as soil degradation,
hydrologic and aeolian erosion, decrease of soil fertility, salinization, sedimentation, and
flooding. Moreover, an expansion of semiarid areas, an increase in fire risk, and a decrease
in the quality and quantity of subterranean water would be expected.