Reduce greenhouse gas emissions and do it PDQ!

The San Joaquin River is used to irrigate crops grown on some 4,000 sq km of the Central Valley. The river has its sources in glaciers of the Sierra Nevada which are already melting and are expected to continue doing so with increasing speed if temperatures continue to rise. During the next 50 years this is expected to result in a massive decrease of water available for irrigation and, even with supplementation of ground water, will result in a significant reduction in crop yields.

Global warming has already brought about climate change characterised by widespread and prolonged drought conditions affecting the southern parts of South America, Africa and Australia. These problems are compounded by growing populations and increasing evaporation from water storage as the climate grows warmer. Both problems can be resolved: neither has been.

Water evaporation is avoidable. Three thousand years ago in ancient Persia, irrigators took water sparingly from underground canals built to successfully prevent water loss from evaporation.

Drought combined with reduced water supply from shrinking glaciers in the Andes is already posing problems for inland cities such as Quito, Bogota, Sucre and Santiago, particularly in the dry season. They lack ready access to the sea and can not replace water loss with desalination. Many cities depend on hydro-electricity for their power needs but this source of energy is now coming under increasing threat since water used to drive turbines in not being replaced from diminished glaciers at the same rate as it is being used.

Threats to water supply in South America are compounded by soil degradation on a massive scale, air and soil pollution in cities such as Sao Paulo, Bogota and Cordoba and, in practice, unrestrained tree clearing. The latter has reduced the capacity of Amazonian and other rain forests to absorb global CO2 emissions. Atmospheric CO2 has increased with consequential effects of raising global temperatures.

Over the past 12 months drought in Argentina has resulted in the loss of more than 1 million head of cattle and almost half the normal grain crop. This has had profound effects on the Argentine economy. It has reduced food security for those reliant on Argentine meat and grain and increased the price of substitutes.

A further consequence of climate change is desertification. The area covered by all of the great deserts is increasing as their edges gradually spread into marginal agricultural land. As a result of reduced rainfall, previously good agricultural land has become marginal and vulnerable to further encroachment by deserts. This is most noticeable at the southern edges of the Gobi and Sahara deserts. It may also be occurring in Australia where rising salt is reducing the area which can sustain commercial farming.

In Australia, mal-administration has resulted in over-licensing the right to water for irrigation, particularly in the Murray-Darling basin. Warmer temperatures and lack of continuous water flows has led to algae blooms over vast stretches of the river, further reducing the supply of useable water. Inefficient use of water by irrigators continues to cause significant waste, particularly through excessive use and evaporation, the production of thirsty crops and the protectionist policies and practices of state governments.

The present state of affairs is one of increasing competition between the needs of people living in major cities and farmers dependent on irrigation for production of food crops. In the event of continuing drought, priority will be given to supplying cities such as Adelaide, Melbourne and Geelong. At the very least, assuming poor rainfall, this will result in reduced food production both for export and domestic consumption.

Australian agriculture is at greater risk than the major population centres, all of which are located on the coast and can supplement water required for human consumption with desalination. However, this process is too expensive to sustain agriculture. The problems facing Australia are those which affect most other countries, lack of planning, lack of appropriate policies and failure to act in a timely way on the causes of global warming or the effects of climate change.

Given the lack of political will to address these issues, the disasters arising from glacial melting now seem unavoidable. Many people hold the view that it is alarmist doom and gloom which will never happen and even if it does, it is all 50 years away. The fact is that it has started. Glaciers are melting, rapidly and increasingly so. And we have been warned of the consequences.

“Nature” will address human failure to control population growth through climate change resulting in the death of millions, ironically brought about by man-made emissions of greenhouse gasses.

The antidote is well known. Reduce greenhouse gas emissions and do it PDQ!