Deforestation*
The enhanced greenhouse test is exacerbated by deforestation, the systematic removal of trees in forests, particularly rainforest, to use the land for other purposes such as farming and agriculture. This is particularly prevalent in countries in South East Asia and South America, such as Borneo, Columbia, Peru, Paraguay and Bolivia.
The world’s great forests play a vital role in determining the balance of carbon dioxide in our atmosphere. Trees and forests absorb Carbon dioxide using it to build their leaves, stems and roots. By the process of photosynthesis, they have sucked up nearly a third of our CO2 emissions. As Professor Matthew Hansen, Remote Sensing Scientist at the University of Maryland, says, “They are like the lungs of our planet, like big climate regulators on a global scale”.[1]
Yet, they are now being cut down at such a rate that nearly a third of our CO2 emissions are caused by deforestation.
On July 27, 1972 the satellite Landsat was launched, enabling us to see the planet on a global scale, and that picture horrified those who were able to appreciate what they were viewing. In the picture below, the orange areas depict regions of the globe where large scale deforestation and land clearing has taken place. [1]
At the global level, the net loss in forest area during the 1990s was an estimated 2.4% of forest area. This was the combined effect of a deforestation rate of about 150,000 km2 and a rate of forest increase of about 50,000 km2 per year. Deforestation of tropical rainforests averaged about 1% per year. The rate of loss since the year 2000 has slowed but not enough to reduce concern. In the 1990s, almost 70% of deforested areas changed to agricultural land, predominantly under permanent rather than shifting systems.[2]
The Brazilian Amazon [3]
If this process were to continue on a business as usual basis, it obviously presents another dimension compromising our ability to keep our CO2 emissions under control, but in the meantime, a far more insidious and immediate threat looms.
In 2019 the world has been confronted with large swathes of the Brazilian Amazon rainforest, the so-called "lungs of the planet" (there’s that phrase again), going up in flames the primary objective being the conversion of the land for grazing and agricultural purposes. The Brazilian Amazon forest accounts for 60% of the total Amazon and comprises nine states. Between January and July, Brazil’s National Institute for Space Research (INPE) reported that 3,444 square kilometres of rainforest had been lost since January involving some 75,155 fires, at a rate 40% higher than in 2018.
The Amazon, which spans 5.49 million square kilometres over several countries – from Brazil to Colombia, Venezuela, Guyana, Suriname and French Guyana to the north, and Peru, Colombia and Ecuador in the west - sucks about a quarter of the 2.4 billion metric tonnes of carbon that global forests absorb each year. However, the ability of the rainforest to pull in more carbon than it releases is diminishing, weakened by changing weather patterns, deforestation, increasing tree mortality and other factors.
The ongoing fires will further degrade its function as a carbon sink. The fires have led to a clear spike in carbon monoxide emissions as well as planet-warming carbon dioxide, posing a threat to human health and aggravating global warming. If the Amazon were to turn into a consistent source of carbon emissions, it would accelerate global warming while also leading to a huge loss in species that are not found anywhere on Earth.
In a worst-case scenario, without any effective policies to limit deforestation, it is predicted that by 2050, the Amazonian rainforest could become fragmented, harming biodiversity and making the Amazonian ecosystems far less capable of soaking in and storing carbon, reaching a tipping point from which the forests may never recover. And even in a best-case scenario, half the Amazonian tree species will be threatened in the near future. It also poses dire problems for the indigenous people, the Yanomami, who call this place home.
*Header: A fire burns trees and brush along the road to Jacunda National Forest in the Brazilian Amazon Source: AP, SMH 28 Aug 2019
[1] Source: Sir David Attenborough's BBC documentary, Climate Change: the Facts, 2019. This excellent programme is also the source for the graphics and on Landsat. From 11 August 2019, it may be viewed for a limited period of time on ABC iView.
[2] Source: Sir John Houghton, Global Warming: the Complete Briefing, 5th Edition, Cambridge, 2015.
[3] This segment comprises an edited summary of two articles in the Sydney Morning Herald on 23 and 24-25 August by Andrew Freedman and Lia Timson, accessible at https://www.smh.com.au/world/south-america/amazon-fires-rage-sparking-political-battle-in-brazil-20190822-p52jl5.html and https://www.smh.com.au/world/south-america/what-s-happening-in-the-amazon-20190822-p52jvd.html
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