Changement climatique et sécurité alimentaire

Introduction

• The presentation is about climate change and food security, examining the risks and potential solutions.
• The presenter is Benjamin Sultan, from IRD/ESPACE-DEV in Montpellier.

Food Needs by Continent in 2050

• Africa: 5.14 times the 2000 level
• Asia: 2.34 times the 2000 level
• Europe: 0.91 times the 2000 level
• Latin America: 1.92 times the 2000 level
• North America: 1.31 times the 2000 level
• Oceania: 1.61 times the 2000 level
• These figures take into account population growth, changes in age and sex distributions, and dietary patterns.

Food System and Climate

• The food system is under pressure due to factors beyond climate change (e.g., population growth).
• A diagram illustrates the complex interactions between the climate system, ecosystems, and the food system, highlighting emissions, impacts, mitigation, and adaptation.
• Key components include: ecosystems (land, water, biodiversity, soils), food system (production, processing, supply chains, consumption), food security (availability, access, utilization, stability), socio-economic factors (demographics, economics), and well-being.

IPCC Special Report on Climate Change and Land

• Focuses on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems.
• Published in 2019.

Presentation Outline

• Impacts of climate change on the food system
• Impacts of the food system on climate change
• Potential solutions
• Short-term actions (immediate steps that can be taken).

Direct Effects of Climate Change

• Global temperature increases affect crop yields, particularly maize.
• Changes in rainfall patterns, frequency of heatwaves, and droughts negatively influence agriculture.
• Shifts in climate zones affect plant and animal species.

Impact of Temperature on Maize Yields

• A scatterplot highlights the relationship between average growing season temperatures and maize yields globally, demonstrating a negative correlation.

Climate Change Impacts on the Earth's Surface

• Since 1850–1900, global temperature has increased by 0.87°C (0.75-0.99°C).
• An increase in frequency and intensity of heat waves, droughts, and heavy rainfall.
• Shifts in climate zones are affecting various plant and animal species.

Already Observable Impacts on Natural Systems

• Present-day effects of climate change on terrestrial, freshwater, and marine ecosystems around the world are noted.
• Species relocation is prominent.
• Note that confidence levels regarding attribution to climate change vary across regions and ecosystems.

Impacts on Human Systems

• Impacts of climate change on human food security, cities, infrastructure, and health are highlighted.
• Examples of how climate change may affect food production, nutritional value of crops in the context of CO2 concentrations or water shortage are emphasized.

Climate Models and Projections

• Models illustrate the interconnectedness of climate, vegetation, and the global water cycle.
• Mention of specific models like LMDZ, ORCALIM-OPA.
• Focus on the impact of emissions on climate, emphasizing attribution and scenarios for future.

Agronomic Modeling (the SARRAH model)

• Describes a model for estimating water balance and carbon budget (photosynthesis, biomass/organic matter).

Yield Losses from Climate Change

• Charts show the projected percentage loss in crops like millet and sorghum due to climate change.

Future Yield Projections

• Diagram of the process for simulating future yield projections under various emission scenarios (e.g., SRES, RCP).
• Mention of empirical and mechanistic models.

Negative Effects of Increased CO2 on Nutrition

• A graph highlighting the decline in nutritional value of several crops in response to increased carbon dioxide in the atmosphere.

Positive Effects of Increased CO2 on Crops

• Elevated CO2 can boost crop water productivity.
• Illustrates how higher CO2 may increase photosynthesis and diminish leaf-level transpiration, potentially mitigating yield losses.

Comprehensive Evaluation of Risks

• Assessment of various impacts/risks, categorized by level of severity (Very High to Undetectable).
• Focus on food supply instability.
• Confidence levels are given regarding the attribution of impacts to climate change.

Risks in Emerging Lands

• Note impacts on water scarcity, land erosion, vegetation loss, wildfires, permafrost degradation, tropical crop yield, and food security.
• Illustrates the connection between these risks and desertification, land degradation, and food security.
• Shows a graph of temperature changes relative to pre-industrial times for the past century.

Indirect Effects of Climate Change

• Note indirect effects of climate change on the food system, including resource management.

Two Scenarios for a +1.5°C World

• Presentation of two projected scenarios (one fast, one slower).
• Both address the impacts of climate change and provide potential mitigation strategies.

Negative Emissions

• Introduction of negative emissions technology that can remove CO2 from the atmosphere and store it.
• Discusses carbon capture and storage (BECCS) and reforestation, methods to counteract emissions.

Indirect Effects on Food Security

• The costs of negative emissions technologies could be higher than initially estimated, potentially affecting food security in various ways.
• Suggests that a substantial portion of land use may be needed to address existing emissions and avert substantial increases in food price and malnutrition.

Solutions Related to Land Use

• Different strategies (e.g. irrigation efficiency, drought-resistant crops) to enhance the resilience and sustainability of agriculture are emphasized.
• Examples of solutions to mitigate the impact of climate change on food security through adaptive land use strategies are mentioned.

Short-Term Actions

• Actions that can be taken now to enhance adaptation and mitigation of climate change and food security, focusing on the empowerment of stakeholders, local communities, and vulnerable populations.

Food Policy Choices

• Policies impacting the food system, including food loss reduction, dietary shifts, and land management are outlined.
• Strategies to improve food security and sustainability are prioritized, encompassing land management choices, poverty eradication, and improvement in access to resources and knowledge.

Involving Stakeholders

• Highlighting the roles of stakeholders and local communities is emphasized in policy implementation and governance.
• The approach to adaptation and mitigation involves empowering local communities, marginalized populations, and indigenous peoples.

Near-Term Options

• Near-term actions to address adaptation, mitigation of land degradation, desertification, and food security problems are brought up.
• Near-term actions aim to bring social, ecological, economic, and developmental co-benefits.

Conclusions

• Climate change and mitigation efforts affect food security.
• Food systems and their emissions are also part of the climate change solution.
• The more time is taken to adapt and to tackle climate change, the more detrimental the effects will become with increasingly dire implications for food security.

Acknowledgements and Contact Info

• Presentation concludes with gratitude to the audience and contact information for the presenter.