Climate change is undermining food security, says the latest report by the Intergovernmental Panel on Climate Change (IPCC) after reviewing and comprehensively assessing the scientific understanding of entire climate change scenarios, land-climate interactions and the food system, a key component in the whole system.

The new findings in the Special Report on Climate Change and Land (SRCCL), together with the IPCC's widely-quoted special report on limiting global warming to 1.5 C, will offer solid scientific information to help climate and environment negotiations, global policymaking, national decision-making and more.

According to the SRCCL, as the new report is called, the way humans use land also accelerates climate change. Since pre-industry times, for example, the observed average land surface air temperature has risen considerably (1.53 C), higher than the rise of ocean surface temperature or even the global mean surface temperature. Such quick warming is mainly induced by human activities, including more emissions of greenhouse gases, changes in aerosols and land use.

The most direct impact is food security, which gets undermined by quickened warming, changing precipitation patterns and more frequent occurrence of some extreme weather and climate events.

Warming extends the growing season. The increased atmospheric carbon dioxide (CO2) concentration has a fertilization effect on biomass. These two factors prove beneficial for some crop yields, especially over northern high latitudes.

On the other hand, rise in extreme weather and climate events negatively affects food systems through decline and stagnation in yields, changes in sowing and harvest dates, increased infestation of pests and diseases, resource availability, and pollination services.

Already there is a decline in maize and wheat yield in the lower latitude regions. Climate change is also affecting food security in dry land regions, particularly in Africa, Asia and South America.

Warming can also exacerbate food safety risks during transport and storage.

Based on the IPCC's assessment, climate change in future, depending on level of warming, is going to increasingly impact food security.

The main drivers of global warming are greenhouse gas emissions consisting of CO2, methane and nitrogen oxide. The SRCCL finds that about 25 to 30 percent of total greenhouse gas emissions are attributed to the food system as a whole, from food production to processing, transport, retail, consumption, loss and waste. To be specific, about 10 to 12 percent of greenhouse gas emission comes from crop and livestock activities within the farm gate, 8 to 10 percent from land use and land use change including deforestation and peat land degradation, and about 5 to 10 percent from supply chain activities.

From the food system's perspective, between 2007 and 2016, the major source of GHG emissions, on the supply side, was agricultural production such as crop and livestock activities within the farm gate, and land use changes. On the demand side, food loss and waste contributed mainly to GHG emissions. Between 2010 and 2016, as data shows, global food loss and waste equaled 8 to 10 percent of total GHG emissions.

The food system can partly help future climate change adaptation and mitigation. On the supply side, experts suggest increased soil organic matter and erosion control, improved cropland, livestock, and grazing land management, and genetic improvements to increase tolerance to heat and drought.

Further, diversification in the food system is a key strategy to reduce climate change risks.

On the demand side, adoption of healthy and sustainable diets, together with reduction in food loss and waste, can contribute to adaptation through reduction in additional land area needed for food production and associated food system vulnerabilities.

As for mitigation, supply-side action options include reducing crop and livestock GHG emissions, sequestering carbon in soils and biomass, and decreasing emissions intensity within sustainable productions.

Technically, the total mitigation potential of crop and livestock activities is estimated as 1.5 billion to 4 billion tons of carbon dioxide equivalent per year by 2030.

From the consumption side, about 25 to 30 percent of food produced is lost and wasted. Reducing food loss and waste can greatly help reduce GHG emissions. Producing animal-sourced food (such as meat and dairy) emits larger amount of GHGs than growing crops and vegetables. Grains, nuts and vegetables have a lower carbon footprint than meat.

Change to healthy and sustainable diets can help reduce GHG emissions. The total mitigation potential of dietary changes is estimated as 1.8 billion to 3.4 billion tons of carbon dioxide equivalent per year by 2050.

Combining supply-side action with demand-side interventions such as modification of food choices and reduction of food loss and waste would not only reduce GHG emissions, but also enhance food system resilience.

Appropriate design of policies, markets, institutions and governance are important to ensure the climate change response options are effective throughout the food system.

Food security related climate change responses in China entail multiple dimensions. Agriculture, in China, is not only the foundation of the national economy but also a fundamental guarantee and priority field.

Because of its huge population, limited land resource, the impact of climate change on agriculture and food security has become more challenging in recent years.

Although global warming has benefited rice yields in northeastern China and wheat yields in northern China, it has been noticed that in the past three decades, increased intensity and frequency of extreme weather and climate events, such as drought and floods, and more frequent outburst of plant diseases and insect pests, has affected yield in many regions.

Sustainable solutions are urgently required to address potential risks of climate change on food security in China. As an immediate action, an effective early warning system should be built, based on systematic monitoring and remote sensing technology to monitor and quantify the risks for broad-spectrum stresses such as droughts, heat waves, flooding and pests.

From the supply side, many suggested on-farm adaptation options can be taken, such as increasing soil organic matter, enhancing erosion control in cropland, and improving land management and water management etc. From the consumption side, there is also a considerable potential to reduce GHGs by adopting low GHG-intensity food, and reducing food loss and waste.

Zhai Panmao is chief scientist of Chinese Academy of Meteorological Sciences and Intergovernmental Panel on Climate Change (IPCC) Working Group I Co-Chair; Huang Mengtian is science assistant of Technical Supporting Unit of IPCC Working Group I.

The authors contributed this article to China Watch exclusively. The views expressed do not necessarily reflect those of China Watch.

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