We don’t pay much attention to it when we talk about climate change, but after the oceans, the soil is the world’s most important carbon sink. The Intergovernmental Panel on Climate Change (IPCC) has just released a special report on climate change and soil . It is the second of the three special reports that will be prepared during this work period, which will also culminate in the publication of the sixth evaluation report, scheduled for 2021. The first special report was made public at the end of 2018 and dealt with the impacts of global warming of 1.5 ° C. The last one, dedicated to the oceans, will be published at the end of September.
The new IPCC special report states that it will be impossible to keep global temperatures at safe levels unless there is a profound transformation in the way we produce food and use the land. During the two years that the document has lasted, experts have explored the relationships between climate change and soil in two directions: how the way we use land contributes to climate change, and how climate change affects our land.
“Governments challenged us to develop the first comprehensive analysis of the climate-earth system on a global scale,” explained Hoesung Lee, Chairman of the IPCC. “We have done this through many contributions from experts and governments around the world. This is the first time in the history of the IPCC report that the majority of the authors, 53%, are from developing countries ” , he added.
“The land is a critical resource, we rely on it for food, water, health and well-being, but it is under increasing human impact , and climate change adds to these pressures,” explained the experts at the wheel of press presentation of the report.
On the one hand, the soil can act as a storehouse for carbon, which is fixed by plants through photosynthesis. Carbon that is not used for growth is distributed through the roots and deposited in the soil, as explained by the European Environment Agency. Left unchanged, carbon can be trapped there for thousands of years, and healthy soils help mitigate climate change. A good example is peatlands, a very valuable type of soil in that sense, as it is extremely rich in carbon.
Conversely, climate change can alter the way the soil stores carbon, for example high levels of carbon dioxide in the atmosphere cause microorganisms to break down organic matter in the soil and release carbon at a higher rate.
In addition, the way we use the soil can also cause it to go from being a sink to a source of carbon. The new IPCC report is clear: we must manage the land in a much more sustainable way so that it releases less carbon than it does today.
Desertification and land degradation
When land degrades, it becomes less productive and its ability to absorb carbon is also reduced. This increases climate change, while climate change in turn enhances land degradation. “In a future with more intense rains, the risk of soil erosion on farmland increases, and sustainable land management is a way to protect communities from the damaging impacts of this soil erosion and landslides. . However, in some cases this degradation could be irreversible, “explained Kiyoto Tanabe, co-chair of the working group on national greenhouse gas inventories.
Approximately 500 million people live in areas that experience desertification. These areas are more vulnerable to climate change and extreme events, such as drought, heat waves, and dust storms, with a growing global population that in turn puts more pressure on the land.
Proposed measures in relation to climate and land
It is necessary to restore peatlands, reduce meat consumption to produce less methane and avoid the enormous waste of food that is generated today.
Among the measures proposed by the report to reduce greenhouse gas emissions: follow vegan and vegetarian diets, which are also healthier and more sustainable, such as those based on legumes, vegetables, nuts and seeds. “Some dietary options require more soil and water, and cause more heat-trapping gas emissions than others,” explained Debra Roberts, Co-Chair of IPCC Working Group II. “Diets balanced with plant-based foods, such as coarse grains, legumes, fruits and vegetables, and animal-based foods produced sustainably in systems with low greenhouse gas emissions, present great opportunities to adapt and limit climate change “, added the expert.
Food safety
Coordinated action to address climate change can simultaneously improve land, food security and nutrition, and help end hunger. The report highlights that climate change is affecting the four pillars of food security: availability (yield and production), access (prices and ability to obtain food), utilization (nutrition and cooking) and stability (interruptions in availability). “Food security will be increasingly affected by climate change through declining yields, especially in the tropics, rising prices, reduced nutrient quality, and supply chain disruptions.” , explained Priyadarshi Shukla, co-chair of IPCC Working Group III. “There will be more drastic impacts in low-income countries in Africa, Asia, Latin America and the Caribbean,” he added.
Reducing inequalities, improving incomes and ensuring equitable access to food so that some regions (where the earth cannot provide adequate food) are not at a disadvantage, are other ways to adapt to the negative effects of climate change.
It is necessary to develop a more resilient food system and make more land available for bioenergy, while protecting forests and natural ecosystems. “Policies that support sustainable land management, ensure food supplies for vulnerable populations, and maintain soil carbon while reducing greenhouse gas emissions are important, ” summarized Eduardo Calvo, co-chair of the Working Group on National Greenhouse Gas Inventories.
Against food waste
About a third of the food produced is lost or wasted. Reducing this loss and waste would reduce greenhouse gas emissions and improve food security, the report concludes.
“Our diet is, in many cases, responsible for more greenhouse gas emissions than our means of transport,” explains climate change expert and disseminator Andreu Scrivá in his book ‘It’s not too late’. “If we have an electric car and we usually move by bicycle, but we eat red meat twice a week and fruit out of season, the emissions from our menu will far exceed those from transport.”
It is necessary to change the model of food production and make it more sustainable, but consumers also have a lot to do: “Some solutions depend on farmers. But in others they are in the hands of each one of us, when we buy food and when we do not. we waste them “, explained Valérie Masson-Delmotte, one of the IPCC experts who spoke at the press conference.
The report shows that more sustainable land management can help combat climate change, but it is not the only solution. Reducing greenhouse gas emissions from all sectors is essential to keep global warming well below 2 ° C, if not 1.5 ° C.
The full name of the report is “ Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security and Greenhouse Gas Fluxes in Terrestrial Ecosystems ” , and You can find out more by consulting the IPCC website.
