Brazil accounts for around 40% of the world’s rain forests and around 10-15% of the world’s biodiversity. Over the last fifty years, it has lost about 20% of the original 4 million km2 of rainforest due to farming, logging, dam construction, mining and other infrastructural developments. At the same time, average temperatures have increased by 0.6ºC, and the area has experienced a number of severe droughts.
Between 2004 and 2012, the rate of deforestation slowed down, but by 2017 it had increased again. In the year up to July 2018 Brazil lost 7900 km2 of the Amazon rainforest, about a billion trees. under Brazil’s new president, Jair Bolsonaro, the rate has increased rapidly. In the first six months after he became president a further 4300 km2 was destroyed. He appears to be in favour of large-scale infrastructure projects and ‘development’ of the Amazon.
Satellite data from May to July 2019 shows the rate of deforestation was three times higher than in the same period of 2018. May is the start of the dry season and it is expected that the number of fires will continue to increase until October/November, when the rains return.
Deforestation is reducing the Amazon’s capacity to recycle water. A study in 2007 suggested that if the Amazon were to lose 40% of its trees, the loss of water recycling would mean that most of the rest of the trees would not have enough water to survive. This would lead to rising temperatures, as the water has a cooling effect, which could lead to more drought and fires.
Another study found that converting forest to pasture led to an increase in temperature of over 4℃ and that change to arable led to an even higher increase in temperature. If temperatures reach 40℃, trees tend to lose more water and are in danger of falling.
By 2050, continued clearances could cause rainfall in the Amazon to fall by 12% in the wet season and 21% in the dry season. The dry season has also lengthened since the 1970s. However, arguably the most dramatic change has been the increase in the number of severe droughts since 2000. Major droughts occurred in 2005, 2010 and 2015. These droughts, associated with El Nino events, are more severe than the droughts associated with earlier events.
Fires appear to have become more frequent and more severe. This leads to a positive feedback in which dead trees produces gaps in the canopy, which allows more sunlight to reach the ground, which makes the forest floor hotter, and more likely to catch fire. Some scientists believe that the recent increases in droughts have been caused by the cumulative land clearances. These have pushed the Amazon towards a tipping point, which could lead to permanent change in the Amazon i.e. the creation of a savanna-like landscape.
The Amazon is a classic example of the conflict between the environment and economics. It is also a conflict between local- and national-scale against global scale. The whole world benefits from the Amazon but many Brazilians do not benefit from it as much as they would like. The future of the Amazon is in balance and the world could suffer if it is not managed.