A great part of Brazil has been in the grip of one of the worst droughts in its history: reservoirs running dry, water strictly rationed, particularly in Sao Paulo. Such droughts have generally been considered “natural disasters beyond man’s control.” But increasingly now researchers are showing that this is not so. Here is one account of what happens taken from an article by Jim Robbins of the Toronto Star.
“Cutting down forests releases stored carbon dioxide, which traps heat and contributes to atmospheric warming. But forests also affect climate by absorbing more solar energy than grasslands, for example, or releasing vast amounts of water vapor. Many experts believe that deforestation is taking place on such a large scale, especially in South America, that it has already significantly altered the world’s climate.
“A lot of people are scrambling to make observations in the Amazon this year, with the expected big El Nino coming,” says Abigail LS Swann, an eco-climatologist at the University of Washington. “It’s expected to drive significant drought over the Amazon, which will change how much water trees have available.”
“Large forests play a crucial role in generating dependable amounts of rainfall. Trees take up moisture from the soil and transpire it. A fully grown tree releases 1,000 litres of water vapour a day into the atmosphere; the entire Amazon rain forest sends up 20 billion tons a day.
The water vapour creates clouds, which are seeded with volatile gases emitted by the trees naturally, to form rain. These water-rich banks of clouds travel long distances, a conveyor belt for the delivery of precipitation that scientists call flying rivers.
“The sky-borne river over the Amazon carries more water than the Amazon River itself. It begins as moisture that builds over the Atlantic Ocean, and then flows westward over the emerald crown of the Amazon, where it picks up far more moisture.
The laden clouds eventually bump up against the Andes and are steered south and then east, which mean rain for Bolivia and Brazil.
One way forests may move water is known as ‘biotic pumping.’ As water transpires into the atmosphere above the forest, the theory holds, it creates a low-pressure system that sucks in air surrounding it, eventually and continually pumping moisture inland from the ocean. Cutting down forests degrades these low-pressure systems, essentially turning off the pump. Large-scale deforestation is thus believed to be a major contributor to Brazil’s extreme drought.”
Almost 20 per cent of the Amazon forest is gone already and nearly that much again is severely degraded. Antonio Donato Nobre, a veteran climatologist with Brazil’s National Institute for Space Research, recently warned that if just 40 per cent of the Amazon region is deforested there could be an abrupt large-scale shift to grasslands, which could substantially alter global weather patterns “and cause a breakdown of the current climate system.” If deforestation continues, he has said, Sao Paulo will most likely “dry up”.
In the broadest sense, scientists say, forests represent a kind of ecological infrastructure that helps maintain comfortable living conditions on the planet, whether by holding carbon dioxide, cleaning water through their roots, preventing floods by stabilizing soil or, in this case, by regulating climate.
Dr Nobre and other climate experts are urging an immediate halt to deforestation, as well as large-scale planting of new forests, as a way to nurse the Amazon back to full health and stabilize its pivotal role in climate.
The most important international conference of the 21st century so far is about to convene in Paris. It is a conference to discuss what human beings, acting in concert for once and not at daggers drawn, must do to counteract the impact of global warming. It is mankind’s last chance to do something decisive about controlling and halting climate change before its effects lead to multiplying catastrophes – affecting poor countries at first and in particular.
How to reduce carbon emissions will be foremost in the deliberations of this conference. However, the subject of deforestation as a key factor in altering climate will also be on what can only be called a Doomsday Agenda – a conference basically called to avert what has been named a Sixth Extinction – to follow the five other great extinctions of species recorded so far in the natural history of the earth.
Thirty-five years ago I wrote a poem about the primordial sin of destroying great forests. I reproduce it here because in my old age I consider it more relevant than ever.
I am even so bold as to hope that our delegation will take a copy with them to the Paris Conference and note it in the record.
The Sun Parrots Are Late This Year
The great forests of the world are burning down,
Far away in Amazon they burn,
Far beyond our eyes the trees are cut
And cleared and heaped and fired:
Ashes fill the rivers for miles and miles,
The rivers are stained with the blood of mighty trees.
Great rivers are brothers of great forests
And immense clouds shadowing the rose-lit waters
Are cousins of this tribe of the earth-gods
Under the ancient watch of the stars:
All should be secure and beautiful forever,
Dwarfing man generation after generation after generation,
Inspiring man, feeding him with dreams and strength.
But over there it is not so; man is giant
And the forest dwindles: it will soon be nothing,
Shrubs sprouting untidily in scorched black earth.
The sun will burn the earth, before now shadowed
For a hundred thousand years, dark and dripping,
Hiding jeweled insects and thick-veined plants,
Blue-black orchids with white hearts, red macaws,
The green lace of ferns, gold butterflies, opal snakes.
Everything shrivels and dust begins to blow:
It is as if acid was poured on the silken land.
It is far from here now, but it is coming nearer,
Those who love forests also are cut down.
This month, this year, we may not suffer:
The brutal way things are, it will come.
Already the cloud patterns are different each year,
The winds blow from new directions,
The rain comes earlier, beats down harder,
Or it is dry, when the pastures thirst.
In this dark, over-arching Essequibo forest
I walk near the shining river in the green paths
Cool and green as melons laid in running streams,
I cannot imagine all the forests going down,
The great black hogs not snouting for the pulp of fruit,
All this beauty and power and shining life gone.
But in far, once emerald Amazon the forest dies
By fire, fiercer than bright axes.
The roar of the wind in trees is sweet,
Reassuring, the heavens stretch far and bright
Above the loneliness of mist-shrouded forest trails,
And there is such a feel of softness in the evening air.
Can it be that all of this will go, leaving the clean-boned
land?
I wonder if my children’s children, come this way,
Will see the great forest spread green and tall and far
As it spreads now far and green for me.
Is it my imagination that the days are furnace-hot,
The sun-parrots late or not come at all this year?
