Regenerating poor soils in southern EU and Mediterranean countries, an essential step in the fight against climate change – Eurasia Review
The European Union (EU) aims to be climate neutral, with net zero greenhouse gas (GHG) emissions, by 2050. Transforming the agricultural sector, which generates 11% (429 megatonnes of CO2-eq in 2019) of total EU GHG emissions, is vital, not only to mitigate climate change, but also to ensure food security in increasingly extreme environmental conditions. The new EU Common Agricultural Policy includes improvements in this respect, but needs to be more ambitious. The European Parliament’s Committee on Agriculture and Rural Development (AGRI) has therefore commissioned a report from experts to learn more about the potential of agricultural soils in the EU to sequester carbon and how to increase their ability to do so.
The report “Agricultural potential for carbon sequestration. Humus content of land used for agriculture and CO2 storage” concludes that agricultural soils contain 31% of total soil carbon stocks in the EU and have great potential to store more carbon. It places their carbon sequestration capacity between 9 and 24 Mt CO2-eq/year, depending on the uncertain evolution of climatic, political, economic and technical scenarios.
The report is led by Pilar Andrès, from the Center for Ecological Research and Forest Applications (CREAF), and includes the participation of CREAF experts Enric Doblas-Miranda, Stefania Mattana and Àngela Ribas, also a researcher at UAB; Joan Romanyà, from the Faculty of Pharmacy and Food Sciences of the University of Barcelona; Pere Rovira, from the Forest Science and Technology Center of Catalonia (CTFC), and August Bonmatí, from the Institute of Agro-Food and Technology (IRTA).
To fully realize this carbon storage potential, the report suggests regenerating the poorest soils in Europe ― those in the south and the Mediterranean ― which have lost organic matter due to agricultural intensification. It also recommends restoring and protecting peatlands in northern and northeastern Europe to prevent their huge carbon stocks from being lost to agriculture.
Tons of sequestered carbon lie under EU crops
According to the study carried out for the report, estimates of carbon stocks in EU agricultural soils range from 34 gigatonnes (Gt) in the top 20 centimeters of soil to 75 Gt in the top 30 centimeters. The geographic distribution of this carbon is uneven, depending on climate, land cover, geological characteristics and history of use. About 31% of total soil organic carbon in the EU is in agricultural soils (9.3% in grassland and 21.4% in cropland) and about 25% in peatlands, although the latter are not cover only 6% of the land area of the EU.
In general, soils in northern and north-eastern Europe are the most carbon-rich, with Ireland, Finland, Sweden and the UK accounting for around 50% of the territory’s soil organic carbon. The soils of the countries in the south of the continent tend to be the poorest, while Portugal, Italy, Spain and Greece, alongside Poland and Hungary, have the average organic carbon concentrations of weakest ground.
In general, soils in northern and northeastern Europe are the richest in carbon, while soils in countries in the south of the continent tend to be the poorest.
How will the size of EU soil carbon stocks vary in the future? It is very difficult to say, according to the study, because the answer will depend on the evolution of the climate and land use. Overall, however, based on the two factors in question, the simulations predict that carbon stocks in the richest soils will increase and that the currently carbon-poor soils will experience further depletion.
It is possible to store more carbon
The report notes that each type of soil has a specific and limited capacity for carbon sequestration. While this may seem like a problem, it also represents an opportunity, as the most carbon-depleted soils, i.e. those in the southern and Mediterranean countries of the EU, have the greatest capacity to store more carbon. Changing current management practices to one focused on carbon sequestration and fertility regeneration would give cropland in the EU a sequestration potential of 67.5 Mt CO2-eq.
In addition to this, there is potential for reducing emissions from highly organic and carbon-rich soils, such as peatlands. With this in mind, the report calls for the peatlands of northern Europe to be restored to a state of natural use or wet cultivation, in order to avoid their drying out and degradation. Restoring and rewetting these peatlands would increase Europe’s mitigation potential by 54 Mt CO2-eq for the period 2020-2050.
When peatlands are drained for cultivation or grazing, the net result is the emission of GHGs into the atmosphere. As European peatlands become increasingly dry and degraded, my co-authors and I focus on measures for their restoration in the report. Ensuring that they retain their carbon storage capacity is crucial in the fight against climate change,” says Pilar Andrés, researcher at CREAF and leader of the study.
The approaches in question are feasible insofar as they are profitable (cost less than 100 euros per ton of CO2 sequestered). The report distinguishes between feasible measures (technical mitigation potential) and feasible measures (realistic mitigation potential). The study confirmed that carbon sequestration in agricultural soils is a cost-effective option in both cases.
With regard to the goal of reducing emissions in the whole agricultural sector, from farm to fork, the report indicates that more than 55% of the sector’s entire technical mitigation potential lies in the improvement of agricultural soil and manure management. This statistic indicates how desirable it is to improve the carbon sequestration capacity of agricultural soils.
As the speaker Joan Romanyà (UB) points out, “currently most agricultural soils are not in good condition to cope with the increase in food demand in the coming decades in the climate change scenario (droughts and torrential floods ) and the energy crisis. , which includes an increase in the price of fertilizers. In this context, it is necessary to apply new agricultural technologies that allow soil regeneration while maintaining high agricultural productivity. Because of these needs, organic agriculture has been proposed as a useful element for the development of a policy framework to trigger the transition needed to achieve the United Nations Sustainable Development Goals”.
Agriculture that nourishes and regenerates the soil
The report states that if agricultural GHG emissions decreased by 108 Mt of CO2-eq over the period from 1990 to 2018, the effective reduction only took place until 2005, when the emission rate remained stable. In the authors’ view, achieving substantial further reductions will require significant changes in human food preferences, farming practices and agricultural policies.
“We have the technology and the knowledge to increase the organic matter content of the soil, while increasing its fertility and mitigating climate change,” remarks Pilar Andrés. “What we need now is political commitment. Only true commitment will bring about real, large-scale change.
The challenge is therefore twofold, consisting of improving the quality of the soils of southern EU and Mediterranean countries to increase their capacity for carbon sequestration on the one hand, and restoring and protecting peatlands to avoid the loss of their carbon stocks on the other. To answer this, the report proposes integrated management strategies, such as organic farming, malaria cultivation, agroforestry and regenerative agriculture.
All the practices in question promote soil fertility and facilitate carbon sequestration. They also have other benefits, including reduced tillage; an increase in vegetation cover, which protects the soil against erosion and maintains its humidity; greater plant diversity; and fertilization using natural organic matter, such as manure or compost.
“Neither biochar nor urban waste compost can be offered as large-scale solutions yet,” says Pere Rovira from the CTFC. “This will not be possible until the quality of the product is guaranteed, perhaps by a specific labeling system,” he explains.
The report also mentions precision agriculture, which would not necessarily increase carbon sequestration but could help reduce the input of mineral fertilizers, especially ammonia nitrogen. This could be positive in terms of avoiding soil acidification and subsequent carbon emissions from carbonate-rich soils.
“About 44% of total emissions from the agricultural sector are due to excessive fertilization, which causes N2O emissions”, points out August Bonmatí, researcher at IRTA, who co-wrote the report.
The authors warn that achieving a significant increase in carbon sequestration will mean that large agricultural areas will have to be managed accordingly, and public bodies may not be able to pay farmers the corresponding compensation. The report concludes that it is therefore necessary to consider complementary actions that could be taken by private actors or public-private partnerships, such as the establishment of carbon markets.