Rhein on Energy and Climate

The Sao Paulo metropolitan area, with its 20 million people population one of the biggest and most densely inhabited urban concentrations on earth, is being haunted by a devastating drought which threatens to put an end to the prosperity of Latin America’s fastest growing economic hub.

For a big city that has indulged in excessive water consumption in a vast country endowed with 12 per cent of global sweet water resources the water shortage has come as a shock, though it had long been foreseen by eminent Brazilian climate experts.

Several factors account for the catastrophe.

Investments in water supply and sewage systems have not kept pace with fast growing population and industrial development.

The water utility, failing in long-term planning, has not taken the necessary measures to avert the creeping disaster. It has ignored wasteful leakages in the pipe system and failed to curb rising demand by appropriate pricing. It has allowed rain water to rush down the streets into polluted local rivers without replenishing the ground water level, an increasingly common problem world-wide.

But these short-comings do not tell the essence of the story. Rain falls have been declining during the last decades, essentially due to the deforestation of the Amazon tropical forests in the course of last century that used to bring rain to central and southern Brazil thanks to the “flying rivers”, the huge amounts of vapour produced by the Amazon forests and sent down to central and southern Brazil.

Greed has prevailed over respect of the forests that are vital for agriculture and Brazil`s hydro-electrical potential. Cattle herds, soya, maize and sugar cane that have replaced virgin forests cannot produce steady rainfall.

It might take a century to restore conventional rain levels. But this would require a complete stop of deforestation and costly reforestation programmes, a very unlikely perspective. Sao Paulo will therefore have to adapt to much lower and variable rain falls. That should be possible, however painful and costly.

Citizens will have to reduce their consumption to European levels of some 150 litre/day and pay much more for their water. The water utility will have to double the capacity of its water reservoirs to at least 500 days and build additional canals to transport big quantities of water from the northern parts of the country where the rain miracle continues to function, as long as the forests are being preserved.

In addition, it must invest billions of US dollars in water cleaning and re-cycling.

Hopefully, the city’s water debacle will finally raise a nation-wide awareness and oblige citizens and politicians to put an end to further deforestation. The Amazon forests are crucial to slow down climate change. For Brazil they are vital: without them the country will lose its precious treasure- sweet water- without which it might turn one day into a Latin American Savannah or even Sahara.

Humanity should also learn from this disaster, especially Africa and South-East Asia, the last remaining regions with extensive tropical forests. For the climate conference in Paris halting deforestation must therefore be a top priority, as deforestation might add as much as 15 per cent to global C02 emissions, over and above the serious environmental damage produced by it.

Eberhard Rhein, Brussels, 20/2/2015

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