The large-scale expansion of agriculture in the Amazon through deforestation will be a no-win scenario, according to a new study.
Published today, 10 May, in IOP Publishing's journal Environmental Research Letters, it shows that deforestation will not only reduce the capacity of the Amazon's natural carbon sink, but will also inflict climate feedbacks that will decrease the productivity of pasture and soybeans.
The researchers used model simulations to assess how the agricultural yield of the Amazon would be affected under two different land-use scenarios: a business-as-usual scenario where recent deforestation trends continue and new protected areas are not created; and a governance scenario which assumes Brazilian environmental legislation is implemented.
They predict that by 2050, a decrease in precipitation caused by deforestation in the Amazon will reduce pasture productivity by 30 per cent in the governance scenario and by 34 per cent in the business-as-usual scenario.
Furthermore, increasing temperatures could cause a reduction in soybean yield by 24 per cent in a governance scenario and by 28 per cent under a business-as-usual scenario.
Through a combination of the forest biomass removal itself, and the resulting climate change, which feeds back on the ecosystem productivity, the researchers calculate that biomass on the ground could decline by up to 65 per cent for the period 2041-2060
Brazil faces a huge challenge as pressure mounts to convert forestlands to croplands and cattle pasturelands in the Amazon. A fine balance must be struck, however, as the natural ecosystems sustain food production, maintain water and forest resources, regulate climate and air quality, and ameliorate infectious diseases.
Lead author of the study, Dr Leydimere Oliveira, said: "We were initially interested in quantifying the environmental services provided by the Amazon and their replacement by agricultural output.
"We expected to see some kind of compensation or off put, but it was a surprise to us that high levels of deforestation could be a no-win scenario - the loss of environmental services provided by the deforestation may not be offset by an increase in agriculture production."
The researchers, from the Federal University of Viçosa, Federal University of Pampa, Federal University of Minas Gerais and the Woods Hole Research Center, show that the effects of deforestation will be felt most in the eastern Pará and northern Maranhão regions.
Here the local precipitation appears to depend strongly on forests and changes in land cover would drastically affect the local climate, possibly to a point where agriculture becomes unviable.
"There may be a limit for expansion of agriculture in Amazonia. Below this limit, there are not important economic consequences of this expansion. Beyond this limit, the feedbacks that we demonstrated start to introduce significant losses in the agriculture production," continued Dr Oliveira.
From Friday 10 May, the paper can be downloaded from http://iopscience.
Notes to Editors
1. For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Press Officer, Michael Bishop:
Tel: 0117 930 1032
IOP Publishing Journalist Area
2. The IOP Publishing Journalist Area gives journalists access to embargoed press releases, advanced copies of papers, supplementary images and videos. In addition to this, a weekly news digest is uploaded into the Journalist Area every Friday, highlighting a selection of newsworthy papers set to be published in the following week.
Login details also give free access to IOPscience, IOP Publishing's journal platform.
To apply for a free subscription to this service, please email Michael Bishop, IOP Press Officer, email@example.com, with your name, organisation, address and a preferred username.
Large-scale expansion of agriculture in Amazonia may be a no-win scenario
3. The published version of the paper 'Large-scale expansion of agriculture in Amazonia may be a no-win scenario' (Leydimere J C Oliveira, Marcos H Costa, Britaldo S Soares-Filho and Michael T Coe 2013 Environ. Res. Lett. 8 024021) will be freely available online from Friday 10 May. It will be available at http://iopscience.
Environmental Research Letters
4. Environmental Research Letters is an open access journal that covers all of environmental science, providing a coherent and integrated approach including research articles, perspectives and editorials.
5. IOP Publishing provides a range of journals, magazines, websites and services that enable researchers and research organisations to reach the widest possible audience for their research.
We combine the culture of a learned society with global reach and highly efficient and effective publishing systems and processes. With offices in the UK, US, Germany, China and Japan, and staff in many other locations including Mexico and Russia, we serve researchers in the physical and related sciences in all parts of the world.
IOP Publishing is a wholly owned subsidiary of the Institute of Physics. The Institute is a leading scientific society promoting physics and bringing physicists together for the benefit of all. Any profits generated by IOP Publishing are used by the Institute to support science and scientists in both the developed and developing world. Go to ioppublishing.org.
The Institute of Physics
6. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application. We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications. Go to http://www.