How much land-based greenhouse gas mitigation can be achieved without compromising food security and environmental goals? (original) (raw)

Importance of food-demand management for climate mitigation

Nature Climate Change, 2014

Recent studies show that current trends in yield improvement will not be sufficient to meet projected global food demand in 2050, and suggest that a further expansion of agricultural area will be required. However, agriculture is the main driver of losses of biodiversity and a major contributor to climate change and pollution, and so further expansion is undesirable. The usual proposed alternativeintensification with increased resource use-also has negative effects. It is therefore imperative to find ways to achieve global food security without expanding crop or pastureland and without increasing greenhouse gas emissions. Some authors have emphasised a role for sustainable intensification in closing global 'yield gaps' between the currently realised and potentially achievable yields. However, in this paper we use a transparent, data-driven model, to show that even if yield gaps are closed, the projected demand will drive further agricultural expansion. There are, however, options for reduction on the demand side that are rarely considered. In the second part of this paper we quantify the potential for demand-side mitigation options, and show that improved diets and decreases in food waste are essential to deliver emissions reductions, and to provide global food security in 2050. Over 35% of the Earth's permanent ice-free land is used for food production and, both historically and at present, this has been the greatest driver of deforestation and biodiversity loss 1. Food demand has increased globally with the increase in global population and its affluence. Globally, the demand for food will undoubtedly increase in the medium-term future. The United Nations' Food and Agriculture Organisation (FAO) has projected that cropland and pasture-based food production will see a 60%

Impacts of GHG emissions abatement measures on agricultural market and food security

2021

Agriculture, Forestry and Other Land-use (AFOLU) are thought to play a vital role in long-term GHG emissions reduction, especially for their importance in non-CO2 emissions, bioenergy supply and carbon sequestration realized by afforestation. Several studies have noted potential adverse impacts of land-related emissions mitigation on food security, due to food price increases, but these studies have not disaggregated the individual aspects of land-related emissions mitigation that impact food security. Here, we show the extent to which three factors—non-CO2 emissions reduction, bioenergy production, and afforestation—change the food security and agricultural market conditions under 2 °C climate stabilization scenarios, using six global agro-economic models. The results show that afforestation, often implemented in the models by imposing carbon prices on land carbon stocks, causes the largest impacts on food security, followed by non-CO2 emissions policies, generally implemented as e...

Land-based climate change mitigation measures can affect agricultural markets and food security

Nature Food, 2022

Earlier studies have noted potential adverse impacts of land-related emissions mitigation strategies on food security, particularly due to food price increases-but without distinguishing these strategies' individual effects under different conditions. Using six global agroeconomic models, we show the extent to which three factors-non-CO 2 emissions reduction, bioenergy production and afforestation-may change food security and agricultural market conditions under 2 °C climate-stabilization scenarios. Results show that afforestation (often simulated in the models by imposing carbon prices on land carbon stocks) could have a large impact on food security relative to non-CO 2 emissions policies (generally implemented as emissions taxes). Respectively, these measures put an additional 41.9 million and 26.7 million people at risk of hunger in 2050 compared with the current trend scenario baseline. This highlights the need for better coordination in emissions reduction and agricultural market management policies as well as better representation of land use and associated greenhouse gas emissions in modelling.

Chapter 11 - Agriculture, forestry and other land use (AFOLU)

Cambridge University Press eBooks, 2014

Agriculture, Forestry, and Other Land Use (AFOLU) is unique among the sectors considered in this volume, since the mitigation potential is derived from both an enhancement of removals of greenhouse gases (GHG), as well as reduction of emissions through management of land and livestock (robust evidence; high agreement). The land provides food that feeds the Earth's human population of ca. 7 billion, fibre for a variety of purposes, livelihoods for billions of people worldwide, and is a critical resource for sustainable development in many regions. Agriculture is frequently central to the livelihoods of many social groups, especially in developing countries where it often accounts for a significant share of production. In addition to food and fibre, the land provides a multitude of ecosystem services; climate change mitigation is just one of many that are vital to human well-being (robust evidence; high agreement). Mitigation options in the AFOLU sector, therefore, need to be assessed, as far as possible, for their potential impact on all other services provided by land. [Section 11.1] The AFOLU sector is responsible for just under a quarter (~10-12 GtCO 2 eq / yr) of anthropogenic GHG emissions mainly from deforestation and agricultural emissions from livestock, soil and nutrient management (robust evidence; high agreement) [11.2]. Anthropogenic forest degradation and biomass burning (forest fires and agricultural burning) also represent relevant contributions. Annual GHG emissions from agricultural production in 2000-2010 were estimated at 5.0-5.8 GtCO 2 eq / yr while annual GHG flux from land use and land-use change activities accounted for approximately 4.3-5.5 GtCO 2 eq / yr. Leveraging the mitigation potential in the sector is extremely important in meeting emission reduction targets (robust evidence; high agreement) [11.9]. Since publication of the IPCC Fourth Assessment Report (AR4), emissions from the AFOLU sector have remained similar but the share of anthropogenic emissions has decreased to 24 % (in 2010), largely due to increases in emissions in the energy sector (robust evidence, high agreement). In spite of a large range across global Forestry and Other Land Use (FOLU) flux estimates, most approaches indicate a decline in FOLU carbon dioxide (CO 2) emissions over the most recent years, largely due to decreasing deforestation rates and increased afforestation (limited evidence, medium agreement). As in AR4, most projections suggest declining annual net CO 2 emissions in the long run. In part, this is driven by technological change, as well as projected declining rates of agriculture area expansion, which, in turn, is related to the expected slowing in population growth. However, unlike AR4, none of the more recent scenarios projects growth in the near-term [11.9]. Opportunities for mitigation include supply-side and demandside options� On the supply side, emissions from land-use change (LUC), land management and livestock management can be reduced, terrestrial carbon stocks can be increased by sequestration in soils and biomass, and emissions from energy production can be saved through Agriculture, Forestry and Other Land Use (AFOLU) Chapter 11 agreement) [11.7]. Implementation challenges, including institutional barriers and inertia related to governance issues, make the costs and net emission reduction potential of near-term mitigation uncertain. In mitigation scenarios with idealized comprehensive climate policies, agriculture, forestry, and bioenergy contribute substantially to the reduction of global CO 2 , CH 4 , and N 2 O emissions, and to the energy system, thereby reducing policy costs (medium evidence; high agreement) [11.9]. More realistic partial and delayed policies for global land mitigation have potentially significant spatial and temporal leakage, and economic implications, but could still be cost-effectively deployed (limited evidence; limited agreement) [11.9]. Economic mitigation potential of supply-side measures in the AFOLU sector is estimated to be 7�18 to 10�60 (full range: 0�49-10�60) GtCO 2 eq / yr in 2030 for mitigation efforts consistent with carbon prices up to 100 USD / tCO 2 eq, about a third of which can be achieved at < 20 USD / tCO 2 eq (medium evidence; medium agreement) [11.6]. These estimates are based on studies that cover both forestry and agriculture and that include agricultural soil carbon sequestration. Estimates from agricultural sector-only studies range from 0.3 to 4.6 GtCO 2 eq / yr at prices up to 100 USD / tCO 2 eq, and estimates from forestry sector-only studies from 0.2 to 13.8 GtCO 2 eq / yr at prices up to 100 USD / tCO 2 eq (medium evidence; medium agreement) [11.6]. The large range in the estimates arises due to widely different collections of options considered in each study, and because not all GHGs are considered in all of the studies. The composition of the agricultural mitigation portfolio varies with the carbon price, with the restoration of organic soils having the greatest potential at higher carbon prices (100 USD / tCO 2 eq) and cropland and grazing land management at lower (20 USD / tCO 2 eq). In forestry there is less difference between measures at different carbon prices, but there are significant differences between regions, with reduced deforestation dominating the forestry mitigation potential in Latin America and Caribbean (LAM) and Middle East and Africa (MAF), but very little potential in the member countries of the Organisation for Economic Cooperation and Development (OECD-1990) and Economies in Transition (EIT). Forest management, followed by afforestation, dominate in OECD-1990, EIT, and Asia (medium evidence, strong agreement) [11.6]. Among demand-side measures, which are under-researched compared to supply-side measures, changes in diet and reductions of losses in the food supply chain can have a significant, but uncertain, potential to reduce GHG emissions from food production (0.76-8.55 GtCO 2 eq / yr by 2050), with the range being determined by assumptions about how the freed land is used (limited evidence; medium agreement) [11.4]. More research into demand-side mitigation options is merited. There are significant regional differences in terms of mitigation potential, costs, and applicability, due to differing local biophysical, socioeconomic, and cultural circumstances, for instance between developed and developing regions, and among developing regions (medium evidence; high agreement) [11.6]. Agriculture, Forestry and Other Land Use (AFOLU) Chapter 11 11.2 New developments in emission trends and drivers Estimating and reporting the anthropogenic component of gross and net AFOLU GHG fluxes to the atmosphere, globally, regionally, and at country level, is difficult compared to other sectors. First, it is not always possible to separate anthropogenic and natural GHG fluxes from land. Second, the input data necessary to estimate GHG emissions globally and regionally, often based on country-level statistics or on remote-sensing information, are very uncertain. Third, methods for estimating GHG emissions use a range of approaches, from simple default methodologies such as those specified in the IPCC GHG Guidelines 2 (IPCC, 2006), to more complex estimates based on terrestrial carbon cycle modelling and / or remote sensing information. Global trends in total GHG emissions from AFOLU activities between 1971 and 2010 are shown in Figure 11.2; Figure 11.3 shows trends of major drivers of emissions. 2 Parties to the United Nations Framework Convention on Climate Change (UNFCCC) report net GHG emissions according to IPCC methodologies (IPCC, 2006). Reporting is based on a range of methods and approaches dependent on available data and national capacities, from default equations and emission factors applicable to global or regional cases and assuming instantaneous emissions of all carbon that will be eventually lost from the system following human action (Tier 1) to more complex approaches such as model-based spatial analyses (Tier 3). Figure 11�1 | Multiple ecosystem services, goods and benefits provided by land (after MEA, 2005; UNEP-WCMC, 2011). Mitigation actions aim to enhance climate regulation, but this is only one of the many functions fulfilled by land.