Air Pollution and Global Change 183
9.4.3 the danger of climatic change
Monitoring of the temperature since the middle of the 19th century shows
that the average temperature of the planet has increased by approximately
0.5°C in the last 100 years. This change is compatible with the warming
that would be caused by the observed increase of greenhouse gases during
the same period. However, this finding is not enough to prove that global
warming due to intensifying greenhouse effect has already been manifested, because for the time being, the alterations are still within the limits
of “climatic noise” and could be attributed to natural fluctuation.
The manifestation of an intensifying greenhouse effect during the coming decades is a serious scientific prediction. There are, however, great
uncertainties in relation to the changes that it will bring about both to the
average climate of the planet and—even more so—to the local climates of
different geographic regions. The main factors of uncertainty that prevent
a more accurate prediction about the expected climatic change are:
• The future course of gases’ concentrations and the ensuing strengthening of the greenhouse effect
• The climatic system’s sensitivity, i.e. the degree of its response to the
increase of the quantity of trapped radiation in the atmosphere
• The “thermal inertia” of the sea, which decelerates the rate of atmosphere warming
Most of the greenhouse gases will probably have increased concentrations in the atmosphere of the coming decades. However, forecasts are
uncertain due to insufficient knowledge about biogeochemical cycles, but
mainly about the future policies for energy, agriculture and the forests.
Increasing CO 2 emissions are probable, especially in developing and new
industrial countries, because of increased coal and natural gas usage,
although decreased petroleum usage is expected due to increased cost and
tion of CFC concentrations through the application of international agreements for the protection of the ozone layer. The predictions usually refer
to the “equivalent ” CO 2 concentration in which the contributions of the
rest of greenhouse gases are included. A symbolic date is that at which
“equivalent ” CO 2 will be doubled in relation to its concentration before the
industrial era. Estimations place this symbolic event at around 2050.
The estimation of the climate’s sensitivity is carried out through the general circulation models (GCMs) of the atmosphere coupled with the ocean
and the vegetation, which are simplified representations of the climatic
system’s operation and “run” on the biggest modern computers. Based on
these techniques, it is predicted that the doubling of equivalent CO 2 will
cause an increase of Earth’s average temperature by 1.5°C to 4.5°C. The
9.4.3 the danger of climatic change
Monitoring of the temperature since the middle of the 19th century shows
that the average temperature of the planet has increased by approximately
0.5°C in the last 100 years. This change is compatible with the warming
that would be caused by the observed increase of greenhouse gases during
the same period. However, this finding is not enough to prove that global
warming due to intensifying greenhouse effect has already been manifested, because for the time being, the alterations are still within the limits
of “climatic noise” and could be attributed to natural fluctuation.
The manifestation of an intensifying greenhouse effect during the coming decades is a serious scientific prediction. There are, however, great
uncertainties in relation to the changes that it will bring about both to the
average climate of the planet and—even more so—to the local climates of
different geographic regions. The main factors of uncertainty that prevent
a more accurate prediction about the expected climatic change are:
• The future course of gases’ concentrations and the ensuing strengthening of the greenhouse effect
• The climatic system’s sensitivity, i.e. the degree of its response to the
increase of the quantity of trapped radiation in the atmosphere
• The “thermal inertia” of the sea, which decelerates the rate of atmosphere warming
Most of the greenhouse gases will probably have increased concentrations in the atmosphere of the coming decades. However, forecasts are
uncertain due to insufficient knowledge about biogeochemical cycles, but
mainly about the future policies for energy, agriculture and the forests.
Increasing CO 2 emissions are probable, especially in developing and new
industrial countries, because of increased coal and natural gas usage,
although decreased petroleum usage is expected due to increased cost and
tion of CFC concentrations through the application of international agreements for the protection of the ozone layer. The predictions usually refer
to the “equivalent ” CO 2 concentration in which the contributions of the
rest of greenhouse gases are included. A symbolic date is that at which
“equivalent ” CO 2 will be doubled in relation to its concentration before the
industrial era. Estimations place this symbolic event at around 2050.
The estimation of the climate’s sensitivity is carried out through the general circulation models (GCMs) of the atmosphere coupled with the ocean
and the vegetation, which are simplified representations of the climatic
system’s operation and “run” on the biggest modern computers. Based on
these techniques, it is predicted that the doubling of equivalent CO 2 will
cause an increase of Earth’s average temperature by 1.5°C to 4.5°C. The