It is water, not temperature, that determines the habitability of our planet. Furthermore, temperature is a measurement -- not a property.
Temperature does not feature in hydrological analyses: their principal variables are rainfall, river flow and open water surface evaporation.
Their relative values vary greatly from region to region in South Africa.
Moreover, it is the consequences -- such as changes in rainfall and river flow -- that are important, not changes in the atmospheric and oceanic processes that produce them. Proof of global warming is not proof of the postulated undesirable consequences.
In recent years, high losses of life and damage to property in South Africa and elsewhere in the world were primarily the consequence of rising populations and not enough space, so people moved to flood-prone areas.
The floods were worsened by socio-economic conditions -- not increases in flood magnitude or frequency. This is similarly the case with droughts.
Recently some scientists have repeated their predictions that global warming will degrade the natural environment, based on the assumption that future climate will be warmer and drier. This alarmist view suffers from two fundamental errors. First, rainfall is increasing -- not decreasing. Second, the predicted increases in temperature are no more than the temperature increase between dawn and midday, to which vegetation is already well adapted. It is thus unlikely that large swathes of natural vegetation will be destroyed.
Evidence
Sadly, many claims about how global warming will affect us all are not backed up by scientific evidence -- and those who make them appear to be indifferent to the needs of much of humanity. Environmental doomsayers and alarmist scientists have effectively stifled the debate over climate change -- with serious implications for many other issues.
For instance, South Africa is rapidly approaching the limit of its available water resources.
The only large-scale, viable alternative is energy-consuming seawater desalination. The most economical source of this energy is from coal-fired power stations near the site. If this is not possible because it will increase greenhouse gas emissions, the obvious inevitable consequence will be that South Africa's future development will be increasingly constrained by lack of water supplies.
If the present alarmism continues, the poor will be the first casualties of the war on global warming.
Will Alexander is professor emeritus in the department of civil and biosystems engineering, University of Pretoria, South Africa, and was a member of the UN's Scientific and Technical Committee on Natural Disasters from 1994 to 2000.
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