The U.N. Intergovernmental Panel on Climate Change (IPCC) claims that agriculture is one of the main sources of greenhouse gases, leading many observers to consider the industry a climate villain. This conclusion, however, is based on a paradigm that can be questioned, Linköping University associate professor Per Frankelius wrote in an article in Agronomy Journal.
In 2014, IPCC stated that "agriculture, forestry and other land use" accounted for 24% of global emissions, and only the “energy and heat production” sector accounted for more, at 25%. This perspective on agriculture as a climate villain has become established now, with the consequence that politicians have taken initiatives to “change the climate-negative agriculture.”
New research Frankelius published in the July/August 2020 issue of Agronomy Journal challenges the accepted view. According to the author, IPCC has, strangely enough, not taken into account photosynthesis.
The fundamental process in agriculture is large-scale photosynthesis, whereby crops capture carbon dioxide and, at the same time, produce oxygen. A fraction of the carbon is bound in the plant roots, while most of it is bound in the form of carbohydrates that are harvested and used in other sectors of society. This involves various forms of cereals, oilseed crops, vegetables and grasslands.
“The fact that the carbon is bound in the crops, which at the same time produce oxygen, just as a growing forest does, is a positive effect that is not included in the IPCC calculations,” Frankelius said. "These only consider the greenhouse gases that have a negative impact on the climate. This is also the case in The Greenhouse Gas Protocol, which is a well-established standard for calculating the emission of greenhouse gases."
Agriculture, in contrast to many other sectors, binds carbon and produces oxygen in the atmosphere. The world has an estimated 9.2 billion metric tons of crops in total, which contain about 40% water, resulting in 5.5 billion mt of dry matter. Of this dry matter, 45% is carbon, which corresponds to about 9.1 billion mt of carbon dioxide. This is substantial but is not included in the IPCC calculations, Frankelius noted.
In 2019, global production of cereal crops, such as wheat, totaled 2.7 billion mt. This corresponds to approximately 1 billion mt of carbon, which, in turn, corresponds to 3.8 billion mt of carbon dioxide. The figure would be significantly higher if it included other crops such as oilseeds and sugar beets.
Frankelius said FAOSTAT has estimated total agricultural production at 9.2 billion mt. "Different crops have different water content, but a good guess is that the total production corresponds to approximately [9.1 million mt] of carbon dioxide,” he added.
The agriculture industry also includes grasslands and grazing lands that bind carbon, with a further 2.7 billion mt of carbon bound in the soil.
The bottom line is that agriculture may be a climate-neutral sector already or even climate positive, which is in contrast to the common view based on the IPCC assumptions.
Still, Frankelius said even more can be done to make agriculture more climate positive.
Frankelius, who is also process manager at Agtech 2030, an innovation platform at Linköping University in Sweden, presented seven concrete measures that can both advance the agriculture sector and reduce emissions.
The measures include ensuring that fields are green throughout the year, marketing animal ecosystem services, using fossil-free, mineral-based fertilizers, spreading biochar, replacing diesel with fossil fuel-free biodiesel, electricity, fuel cells or even steam to power engines, planting trees in rows along the edges of fields, placing solar panels there to follow the sun with a recently patented technology and various ways to reduce soil compaction.