‘THE AMAZON RECYCLES WATER’
Improve efficiency in farming and cattle rearing to reduce pressure on forestland
BRAZILIAN SCIENTIST Carlos Nobre estimates that the Amazon could reach a tipping point if another 25 per cent of the forest were lost.This would trigger changes in regional rainfall and temperature patterns, increasing tree mortality and enhancing the risk of catastrophic fires. Ultimately,the forest would be replaced by shrubbier,sparser vegetation.
But the immediate impact will be on humans as well as on the plants and animals of the rainforest.Fires create terrible pollution. They also force pollinators and seed dispersers to flee—this affects both natural ecosystems and food crops.Rare plants that live in the crevices of bark or the branches of trees,or even in the shade of the forest canopy cannot flee,leading to local extinctions.Clearing forest also increases daytime temperatures by several degrees.That makes it harder for plants to grow,and it makes it harder for people in surrounding areas to work and sustain themselves. Through evapotranspiration,forests recycle water into the atmosphere,so that agricultural areas downwind of large tracts of continuous forest get more rainfall than areas downwind of deforested patches.Deforestation in the Amazon is likely to affect agriculture elsewhere in the Americas. Massive amounts of carbon would be lost to the atmosphere as trees succumb to drought and fire—all the CO2 stored over centuries or millennia would go up in smoke.Research shows that losing major areas of rainforest in the Congo or Indonesia could also result in disruptions to the global climate system. We need to keep our forests intact to protect people nearby and far,far away.
Deforestation of the Amazon is occurring because farmers seek to expand the area of production for agriculture.One way to reduce this is to increase production without increasing the area of land.This means increasing efficiencies,improving practices such that existing agricultural land produces more cattle,more soy.Cattle production in the Amazon is very land-intensive. With better management, they could raise more cattle per hectare and deforest fewer hectares.
(Deborah Lawrence is professor of environmental sciences at the
University of Virginia, USA)