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
On 8 August 2019, the Intergovernmental Panel on Climate Change (IPCC) issued a new special report on climate change and land. This comprehensive report was prepared by 107 experts from 52 countries. It is the first IPCC report in which a majority of the authors are from developing countries. Women also account for 40% of the Coordinating Lead Authors. The author team drew on the contributions of 96 Contributing Authors; included over 7,000 cited references in the report; and considered a total of 28,275 expert and government review comments.
In its press release, the IPCC states that Land is already under growing human pressure and climate change is adding to these pressures. At the same time, keeping global warming to well below 2ºC can be achieved only by reducing greenhouse gas emissions from all sectors including land and food.
The report shows that food security will be increasingly affected by future climate change through yield declines “ especially in the tropics“ increased prices, reduced nutrient quality, and supply chain disruptions, according to Priyadarshi Shukla, Co-Chair of IPCC Working Group III.
Different countries will experience different effects, but poor countries in Africa, Asia, and Latin America and the Caribbean will suffer the most adverse impacts.
About 500 million people are already living in areas of desertification, which is an increasing problem with climate change. The following statement in the press release is one of many issues stated in the report that show the interconnectedness in the natural systems: When land is degraded, it becomes less productive, restricting what can be grown and reducing the soil's ability to absorb carbon. This exacerbates climate change, while climate change in turn exacerbates land degradation in many different ways.
The report points out that about one third of food produced is lost or wasted and that reducing such waste and changing diets to more plant-based foods will both reduce greenhouse gas emissions and help food security.
The following is an edited version of the main headline statements from the IPCC report.
People, land, and climate in a warming world
Land provides the principal basis for human livelihoods and well-being including the supply of food, freshwater, and multiple other ecosystem services, as well as biodiversity. Human use directly affects more than 70 percent of the global, ice-free land surface. Land also plays an important role in the climate system.
Since the pre-industrial period, the land surface air temperature has risen nearly twice as much as the global average temperature. Climate change, including increases in frequency and intensity of extremes, has adversely impacted food security and terrestrial ecosystems as well as contributed to desertification and land degradation in many regions.
Agriculture, Forestry, and Other Land Use (AFOLU) activities accounted for around 13% of CO2, 44% of methane (CH4), and 82% of nitrous oxide (N2O) emissions from human activities globally during 2007-2016, representing 23% of total net anthropogenic emissions of GHGs. The natural response of land to human-induced environmental change caused a net sink about the equivalent of 29% in total CO2 emissions; the persistence of the sink is uncertain due to climate change. If emissions associated with pre- and post-production activities in the global food system are included, the emissions are estimated to be 21-37% of total net anthropogenic GHG emissions.
Changes in land conditions, either from land-use or climate change, affect global and regional climates. At the regional scale, changing land conditions can reduce or accentuate warming and affect the intensity, frequency and duration of extreme events. The magnitude and direction of these changes vary with location and season.
Climate change creates additional stresses on land exacerbating existing risks to livelihoods, biodiversity, human and ecosystem health, infrastructure, and food systems. Increasing impacts on land are projected under all future GHG emission scenarios. Some regions will face higher risks, while some regions will face risks previously not anticipated. Cascading risks with impacts on multiple systems and sectors also vary across regions.
Adaptation and mitigation response options
Many land-related responses that contribute to climate change adaptation and mitigation can also combat desertification and land degradation as well as enhance food security. The potential for land-related responses and the relative emphasis on adaptation and mitigation is context specific: it includes the adaptive capacities of communities and regions. While land-related response options can make important contributions to adaptation and mitigation, there are some barriers to adaptation and limits to their contribution to global mitigation.
Most of the response options assessed contribute positively to sustainable development and other societal goals. Many response options can be applied without competing for land and have the potential to provide multiple co-benefits. Thus, a further set of response options has the potential to reduce demand for land, thereby enhancing the potential for other response options to deliver across each of climate change adaptation and mitigation measures, combating desertification and land degradation, and enhancing food security.
Although most response options can be applied without competing for available land, some can increase demand for land conversion. At the deployment scale of several gigatons of CO2 per year (GtCO2yr-1), this increased demand for land conversion could lead to adverse side effects for adaptation, desertification, land degradation and food security. If applied on a limited share of total land and integrated into sustainably managed landscapes, there will be fewer adverse side-effects and some positive co-benefits can be realised.
Many activities for combating desertification can contribute to climate change adaptation with mitigation co-benefits, as well as to halting biodiversity loss with sustainable development as co-benefits to society. Avoiding, reducing, and reversing desertification would enhance soil fertility, increase carbon storage in soils and biomass, and at the same time benefit agricultural productivity and food security. Preventing desertification is preferable to attempting to restore degraded land due to the potential for residual risks and maladaptive outcomes.
Sustainable land management, including sustainable forest management, can prevent and reduce land degradation, maintain land productivity, and sometimes reverse the adverse impacts of climate change on land degradation. It can also contribute to mitigation and adaptation. Reducing and reversing land degradation, at scales from individual farms to entire watersheds, can provide cost effective, immediate, and long-term benefits to communities and support several Sustainable Development Goals (SDGs) with co-benefits for adaptation and mitigation. Even with implementation of sustainable land management, limits to adaptation can be exceeded in some situations.
Response options throughout the food system, from production to consumption, including food loss and waste, can be deployed and scaled up to advance adaptation and mitigation. The total technical mitigation potential from crop and livestock activities, and agroforestry is estimated as 2.3-9.6 GtCO2e.yr-1 by 2050. The total technical mitigation potential of dietary changes is estimated as 0.7-8 GtCO2e.yr-1 by 2050.
Future land use depends, in part, on the desired climate outcome and the portfolio of response options deployed. All assessed modelled pathways that limit warming to 1.5ºC or well below 2°C require land-based mitigation and land-use change, with most pathways requiring different combinations of reforestation, afforestation, reduced deforestation, and bioenergy. A small number of modelled pathways could achieve warming of only 1.5ºC with reduced land conversion and, thus, reduced consequences for desertification, land degradation, and food security.
Enabling response options
Appropriate design of policies, institutions, and governance systems at all scales can contribute to land-related adaptation and mitigation while facilitating the pursuit of climate-adaptive development pathways. Mutually supportive climate and land policies have the potential to save resources, amplify social resilience, support ecological restoration, and foster engagement and collaboration between multiple stakeholders.
Policies that operate across the food system (including those that reduce food loss and waste and influence dietary choices) enable more sustainable land-use management, enhanced food security and low emissions trajectories. Such policies can contribute to climate change adaptation and mitigation, reduce land degradation, desertification, poverty, and improve public health. The adoption of sustainable land management and poverty eradication can be enabled by improving access to markets, securing land tenure, factoring environmental costs into food, making payments for ecosystem services, and enhancing local and community collective action.
Acknowledging co-benefits and trade-offs when designing land and food policies can overcome barriers to implementation. Strengthened multilevel, hybrid, and cross-sectoral governance, as well as policies developed and adopted in an iterative, coherent, adaptive and flexible manner can maximise co-benefits and minimise trade-offs, given that land management decisions are made from farm level to national scales, and both climate and land policies often range across multiple sectors, departments, and agencies.
The effectiveness of decision-making and governance is enhanced by the involvement of local stakeholders (particularly those most vulnerable to climate change such as indigenous peoples and local communities, women, and the poor and marginalised) in the selection, evaluation, implementation and monitoring of policy instruments for land-based climate change adaptation and mitigation. Integration across sectors and scales increases the chance of maximising co-benefits and minimising trade-offs.
Action in the near-term
Actions can be taken in the near-term, based on existing knowledge, to address desertification, land degradation and food security while supporting longer-term responses that enable adaptation and mitigation to climate change. These include actions to build individual and institutional capacity, accelerate knowledge transfer, enhance technology transfer and deployment, enable financial mechanisms, implement early warning systems, undertake risk management and address gaps in implementation and upscaling.
Near-term action to address climate change adaptation and mitigation, desertification, land degradation, and food security can bring social, ecological, economic, and development co-benefits. Co-benefits can contribute to poverty eradication and more resilient livelihoods for those who are vulnerable.
Rapid reductions in anthropogenic GHG emissions across all sectors following ambitious mitigation pathways reduce negative impacts of climate change on land ecosystems and food systems. Delaying climate mitigation and adaptation responses across sectors would lead to increasingly negative impacts on land and reduce the prospect of sustainable development.
For the complete Summary for Policymakers of the report Climate Change and Land, go here: https://www.ipcc.ch/site/assets/uploads/2019/08/3.-Summary-of-Headline-… For links to the full report and specific chapters, go here: https://www.ipcc.ch/srccl-report-download-page/
Last updated 14 August 2019