chapter - Atmospheric and Oceanic Science

Global climatic change
In the food production, no great difficulties are foreseen at a global scale, but
they surely will occur in some regions. The productivity losses in certain areas,
principally tropical and subtropical, would be compensated by increases in other
regions, particularly in middle and high latitudes. Nevertheless, the expected rapid
advances in biotechnology would allow a rapid adaptation to the new climatic conditions
in almost the whole world.
Finally, there exists consensus regarding the impact to be major in every sense
in developing countries since they lack knowledge, the organization and the material
resources to anticipate and to adapt to Climatic Change.
9.8. The Climatic Change is already unavoidable: mitigation and adaptation
When the warming potential of GHG emissions is calculated according with
the different human activities, 48% corresponds to energy, mainly due to the burning
of fossil fuels. 24% corresponds to the emission of chlorofluorocarbons. 13% is
attributed to deforestation, particularly in the Amazon and Borneo. A 9% is
accountable to the agricultural sector, due to the bovine cattle and rice cultivation
with flooding, which is the principal source of food for half of the world population.
The remaining 6% is a consequence of the managing of organic residues and
of some few industrial processes. Regarding the emission of the chlorofluorocarbons
and of other substances that damage the ozone layer, there are reductions in
force agreed by the Montreal Protocol. Therefore, the energetic sector contributes
with two thirds of the warming potential of the remaining emissions.
Any attempt to seriously mitigate the Climatic Change must include a drastic
reduction (of the order of 50%) of the burning of fossil fuels and in the future, its
elimination. As fossil fuels are the principal source of energy (more than 80% of the
world total), this would not be possible at once without causing an economic catastrophe
in the world. Besides, the substitution of a primary source of energy is a
process shown by the historical experience to take, at least, several decades. Hence,
a substantial substitution of the hydrocarbons as energy source does not seem to be
feasible in a horizon ranging from 10 to 20 years.
Apart from this inertia in the socioeconomic system, as aforementioned, GHG
concentrations remain for long time in the atmosphere and the thermal adjustment
of the climate system to them is also slow. Consequently, the temperature will
increase in the next decades in any of the possible scenarios. This implies that in
spite of the little or much that would be achieved to diminish the GHG emissions,
the Climatic Change in the next decades and its consequences are already
inevitable. Indeed, no significant differences until the year 2040 among the different
scenarios can be appreciated (Table 13.2 in chapter 12).
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