Soy & climate change

The soy industry is feeling the brunt of climate change – but it also contributes to the problem. The expansion of soybean plantations is often at the expense of valuable forests or other native vegetation, meaning that the carbon storage services they provide are lost forever. This disrupts the balance of the climate and contributes to global climate change.

And as climatic patterns become more extreme and less predictable, agriculture in turn suffers.
 / ©: Adriano Gambarini / WWF-Brazil
Center-pivot irrigation in a dry soy monoculture, Barreiras, Brazil.
© Adriano Gambarini / WWF-Brazil

What does climate change mean for agriculture?

The productivity of crop and livestock systems is extremely vulnerable to climate change. US crop yields could decrease by 30-46% over the next century under slow global warming scenarios, and by 63-82% under the most rapid global warming scenarios.

Crop yields increase gradually between roughly 10-30 °C, but when temperature levels go over 30°C, soybean yields fall steeply. In a warming world, this spells problems for the agricultural industry globally.

Soybean will be one of the crops that suffers most from climate change, if current production practices stay the same.

By 2070, the area suitable for soy plantations could drop by 60% compared to the current production area, because of water deficiency and more intense summers.

The southern and northern Brazilian Cerrado (a biodiversity hotspot larger than Mexico covered by soybean agriculture) faces the most damage, with costs up to Real $7.6 billion (almost US$4 billion) until 2070, in the worst case scenario.

In addition, warmer temperatures are expected to lead to more extreme rainfall events, with erosion and soil degradation more likely to occur. Global warming would also affect soil fertility.

How agriculture contributes to climate change

Agriculture directly accounts for approximately 14% of global greenhouse gas emissions, mainly in the form of methane and nitrous oxide from fertilized soils, enteric fermentation, biomass burning, rice production, and manure and fertilizer production.

However, since vast swathes of forest are cleared for agricultural land, agriculture  is indirectly responsible for the majority of forestry’s share of global emissions, around 17.4%. Therefore, agriculture accounts for approximately 30% of global greenhouse gas emissions.

Various aspects of soy production can cause greenhouse gas emissions, including carbon dioxide from fossil fuels, deforestation, and emissions from soil management and tillage practices.

When forests are cleared...

When forests and other valuable ecosystems are cleared to make room for soybean plantations, it's not only forests and vegetation that are lost, but also their function as carbon storage. The tropical forests of the Americas, such as the Amazon, are estimated to store over half of the world's carbon.

Soy expansion threatens not only forests, but other valuable ecosystems that also store carbon.

One example is the Cerrado, which has already lost half its native vegetation to soybean plantations. The Cerrado is globally important because of the large stock of carbon it stores in its vegetation and soil.

Although the Cerrado would appear to be much sparser than the well-known carbon store of the Amazon, it has been described as a forest standing on its head, with about 70% of biomass underground.

Recent studies suggest that the carbon stock in its trees, bushes, litter, roots and soil may be nearly double the figure given by the Intergovernmental Panel on Climate Change (2000), at some 265 tonnes of carbon per hectare.

In the Cerrado, conversion to soybean plantations has released the equivalent of more than half UK’s the total emissions of carbon dioxide emissions for 2009, according to data from the Brazilian government.

As the global demand for soy continues to grow, the environmental impact of the crop is only likely to increase.

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