By Cirino Costa Junior, Leda Tavares, Juliana Monti, and Ângelo Gurgel
In order to prevent the severe and adverse effects of climate change in livelihoods, countries have to get together and cut their greenhouse gas (GHG) emissions by half every ten years. This requires a quick and efficient transition to a low-carbon economy.
In this context, agriculture plays an important role as the second largest global emitter of GHG, behind only the energy sector. It also needs to meet the increasing demand for food and other raw materials. For this sector, in practice, its contribution to avoid climate change means carbon sequestration.
This scenario motivated two events that gathered people from 40 countries in Paris in May this year, and which were attended by the Brazilian Coalition on Climate, Forests and Agriculture. The role of players involved in food production and consumption in relation to climate change and the role of carbon sequestration in soils to reduce GHG emissions were discussed.
The results of the meetings showed the leading role that farming can have. With a massive and uniform adoption of low GHG emissions practices, this sector is able to meet the demand for food from society. Furthermore, only through soil carbon sequestration can it contribute to about 10% of the global emissions reduction goal by 2100.
In order to achieve this, however, one must immediately begin articulating with society by understanding charitable work and by motivating companies to make commitments encouraging the adoption of good practices in their production chains.
This process would further consist of the engagement of the financial system, the establishment of a simple and robust system for quantification and monitoring of emissions, and the development of the carbon market.
But why does soil have this potential to sequester carbon? Carbon is the main component of soil organic matter which is formed by the microbiological processing of organic residues of plants and their roots. This process also provides nutrients for the development of vegetation and returns CO2 to the atmosphere, which is again captured and photosynthesized by plants, forming the so-called carbon cycle.
The relationship between soil, plant and climate determines the amount of carbon stored in the soil, ranging from 30 to 800 tons per hectare, and forms the largest reservoir of the substance in the land system – about 4.5 times greater than the native vegetation stock, and 3.3 times greater than that of the atmosphere.
Soil degradation, in turn, alters this cycle, making it difficult for plants to fix CO2 and contribute enough waste to maintain the original levels of carbon in the soil. In this scenario, as microorganisms continue to process organic matter, the CO2 emissions in the atmosphere exceed the amount stored.
As a consequence, the soil loses fertility, reduces its productive capacity and increases the concentration of CO2 in the atmosphere, therefore contributing to global climate change. Today, it is estimated that approximately 30% of agricultural land in the world presents some degree of degradation; however, if good management practices are adopted, they have the potential to become carbon reservoirs.
Brazil is one of the three largest emitters in the global agricultural sector, and the variation of its stocks in the soil is not yet accounted for by the national inventory. According to data from the System Study Greenhouse Gas Emissions Estimates in 2015, if this accounting is done, the number of emissions reported from the industry would increase by almost 10%.
This is mainly because Brazil has a pasture area with some degree of degradation equivalent to the size of Spain (about 40 million hectares). These areas emit CO2 into the atmosphere in excess of soil carbon sequestration that occurs in well managed areas, such as no-till farming, planted forests, and productive pastures.
This is the opportunity for Brazil to store carbon in the soil, and therefore reduce national emissions in line with its climate commitment to recover 15 million hectares of degraded pastures.
By meeting its climate commitments, the agriculture sector has the potential to cut its emissions by half. But in order for this to happen, the country must improve its GHG emissions monitoring system and act more strongly in territorial management by curbing deforestation and encouraging agricultural expansion in already open areas, as well as rethinking credit, technical assistance and infrastructure recovery of degraded areas.
Amidst the global movement considering production strategies to prevent climate change from affecting our survival, Brazil has the potential to sequester carbon in the soil and to be a protagonist in reducing GHG emissions and increasing its agricultural production with quality and differentiation. And to top this all off, to be anchored in agricultural practices which already exist and which are ready to be implemented in the field. In order to avoid drastic climate changes, we can rely on soils, even for a good sequestration.
CINIRO COSTA JÚNIOR is a climate and agricultural chains analyst for IMAFLORA
LEDA TAVARES is part of WWF’s Agriculture and Food Program
JULIANA MONTI is a sustainability coordinator for ABAG
ANGELO GURGEL is an adjunct professor and coordinator of the professional master’s degree in Agribusiness for FGV-EESP
Imaflora, WWF, ABAG, and FGV are members of the Brazilian Coalition on Climate, Forests and Agriculture. The authors are members of the Low-carbon Agriculture Working Group (ABC).