The IPCC report on land: what are the issues?

The Intergovernmental Panel on Climate Change (IPCC) released a special report on the so-called "land" sector (agriculture, pastoralism, forestry, etc.). What are the issues at stake and what are the main lessons to be learned? If the summer period is not the most suitable time to attract attention and make an impression, it is worth taking stock of the issues addressed by the report published today by the Intergovernmental Panel on Climate Change. The report deals with the interactions between climate change and the so-called "land sector" - which includes agriculture, forestry, pastoralism , etc. - and the land itself. There are two reasons why this sector is a major issue in the face of climate change and therefore deserves special attention in the conclusions of this report. On the one hand, the land sector is one of the sectors most directly affected by climate change: droughts, floods and heat waves affect plant growth and the use of space, often with direct consequences on food security, terrestrial biodiversity and more generally the provision of ecosystem services. On the other hand, it is a key sector for achieving the decarbonation objectives that will make it possible to keep global warming below 2°C or even 1.5°C. Indeed, it offers both opportunities for carbon storage in ecosystems and biomass as a substitute for fossil carbon (bio-energy, bio-plastics, other bio-materials). In this context, the report focuses on the interactions between climate change and the land sector through the prism of five main issues: climate change mitigation, climate change adaptation, land degradation , desertification3 and food security.

Three major lessons emerge from the report for us

Mitigating climate change and its impact in drylands: a vital issue for 40% of the world's population The first lesson concerns the interactions between population, climate and the land sector. While the authors rightly point out that the land sector is now responsible for almost a quarter of annual emissions from human activities,4 and that its impact has worsened both in absolute and relative terms (in particular as a result of the intensification of agricultural practices associated with changing diets, which are richer in calories and animal products), they also highlight its very high vulnerability to current and future climate change. This is particularly the case in drylands, which occupy more than 46 per cent of the world's land area and are home to 3 billion people (just under 40 per cent of the world's population), and where the expected impacts of climate change are the most negative, especially in terms of agricultural yields and the occurrence of extreme events. The issue is all the more worrying because, as the authors point out, these are also less developed regions, where opportunities are low. Faced with these factors, limiting global warming appears to be a vital challenge for a large fraction of the world's population, which is little or ill-prepared to suffer the consequences.

Decarbonisation of the economy must not be based on large-scale changes in land use

The land sector has potential for mitigating climate change. For example, three of the four "archetypal" scenarios proposed by the IPCC in its previous special report on the consequences of a 1.5°C warming are based on the extensive development of bioenergy, large-scale reforestation and Bioenergy Carbon Capture and Storage (BECCS) projects, technology projects that are currently immature, involving the afforestation of large areas with fast-growing forest species to exploit the biomass, burn it to produce energy and capture the CO2 emitted during combustion to crystallize it in stable form5. However, the second major lesson of the report is to warn that basing the decarbonation of the economy on these large-scale land-use changes is incompatible with the achievement of many of the Sustainable Development Goals (SDGs) as adopted in New York in 2015. In particular, the focus is on the pressure on space that would be induced by such land-use changes. Such pressure would have important social consequences, particularly in terms of access to land, as well as environmental consequences, such as the risks linked to a dramatic intensification of agricultural practices and thus to an increased use of synthetic pesticides and fertilizers, which in turn would pollute the land, air and atmosphere.

Two priorities: rapidly decarbonising all sectors and improving existing land management practices

In this context, the third and main lesson of this report is that, in order to avoid such large-scale land-use changes, which are likely to have many negative side effects, there is an urgent need to ...:

• decarbonize the economy as quickly as possible and across all sectors (not just the land sector, even though it accounts for nearly a quarter of anthropogenic emissions);
• improve existing land management practices in order to promote carbon sequestration in soils (at the very least not to contribute to its destocking). Reducing the demand for animal products and reducing food losses and wastage must play a key role in this perspective. On the side of agricultural practices, sustainable intensification is put forward as an important factor in reducing emissions.

However, the authors point out that the solutions to be implemented depend fundamentally on the context. Thus, while in some regions of the world it will still be possible to intensify agricultural production (i.e. to increase productivity per hectare or per animal) in a sustainable manner, without affecting the productive capacities of agro-ecosystems or biodiversity, this is not the case in areas where agriculture has been highly intensified as in Western Europe and more generally in OECD countries.