Latest IPCC report predicts dismal consequences for global agriculture due to climate change
On March 20, 2023, the Intergovernmental Panel on Climate Change (IPCC), released its 6th Assessment Report (AR6), which looks at the likelihood that current and planned climate change mitigation activity will succeed in keeping the global temperature rise below 1.5 degrees Centigrade (C), and the implications of the likely path of climate change for the global economy. Data on greenhouse gas emissions used in the analysis are from 2019, and do not reflect any changes in economic activity that occurred as a result of COVID-19 pandemic shutdowns that occurred worldwide. The previous report (AR5) was released in 2014, prior to the commitments that 195 countries made to reduce their greenhouse gas (GHG) emissions under the Paris Accord, which was negotiated in December 2015.
The IPCC is the arm of the United Nations charged with advancing scientific knowledge about climate change and its likely impact on the world we live in. They recruit scientific experts from multiple relevant disciplines from around the world to produce and assemble peer-reviewed reports on a periodic basis that reflect the most recent credible research about how climate change impacts both the natural environment and man-made infrastructure, and the physical and economic implications of those impacts. The Summary for Policy Makers (SPM) for the sixth round of IPCC assessments can be found here.
Overall, the report finds that, to date, the planet has warmed approximately 1.1 degrees C since the end of the 19th century due to a steady increase in greenhouse gasses in the atmosphere, and that countries which are signatories to the Paris Accord have not implemented policies that will put the planet on a path to keep us below that crucial 1.5 degrees C threshold. In fact, at our current rate of GHG emissions, the authors estimate that we will have cumulatively exhausted the global carbon budget that would keep us below 1.5 degrees by about 2030, or less than ten years from now. In order to avoid that likely scenario of overshooting that 1.5 degree C target, governments will need to undertake immediate and deep GHG emission reductions in all sectors during this decade.
Globally, the agricultural sector (including forestry) accounted for about 22 percent of GHG emissions in 2019, when land use changes stemming from agriculture are included. The increasing temperatures and more frequent extreme weather events (such as droughts and floods) that have occurred already due to the current levels of GHG gasses in the atmosphere have exposed millions of additional people in developing countries to both food security and water security problems. Although agricultural productivity has increased in recent years, that rate is slower than it otherwise might have been due to climate change. A 2021 article published in Nature Climate Change found that climate change has hampered growth in agricultural productivity in recent decades, estimating that agricultural productivity growth cumulatively is 21 percent lower than it otherwise would have been since 1961 if climate change were not a factor. Ocean warming and acidification has impacted the health of the fisheries and aquaculture sectors worldwide. Studies that separate out climate change from other factors affecting crop yields have shown that yields of some crops (e.g., maize and wheat) in many lower-latitude regions have been affected negatively by observed climate changes, while in many higher-latitude regions, yields of some crops (e.g., maize, wheat, and sugar beets) have been affected positively over recent decades.
The SPM report identifies a number of steps that can be taken in the food and agriculture sector to help farmers adapt to the effects of climate change. They include:
• cultivar (seed) improvements,
• on-farm water management and storage,
• soil moisture conservation,
• irrigation,
• agroforestry,
• community-based adaptation,
• and farm and landscape level diversification in agriculture.
However, some farmers, especially those with limited resources in developing countries, face financial or institutional constraints in adapting their operations to climate change. To date, there has been very limited funding made available from either public or private sources to help smallholder farmers with adaptation strategies. According to the United Nation’s International Fund on Agricultural Development (IFAD), smallholder farmers receive only 1.7 percent of global climate finance funding, despite cumulatively accounting for roughly one-third of global agricultural production.
The report warns that the effectiveness of adaptation measures will wane with increasing warming over time. The higher the magnitude and the longer the duration of overshoot of the 1.5 degree C target, the more ecosystems and societies are exposed to greater and more widespread changes in climatic impact-drivers, increasing risks for many natural and human systems.
A lengthy separate report entitled Special Report on Climate Change and Land issued in 2022 has a chapter on food security which provides more detailed information than the SPM report. Modeled estimates of corn (maize) production suggest yield declines of 10 to 20 percent in many parts of the world if we overshoot the 1.5 degrees C target by a significant amount, and that modeled results reflect only changing climatic conditions and not the likely impact of increased pest and crop disease pressure, which would further increase losses. On the livestock side, higher temperatures would adversely impact the health and reproductive capability of ruminant animals, decrease the nutrient uptake from forage and grazing, and increase the cost of operating intensive livestock facilities such as confined animal feeding operations (CAFO’s), due both to higher feed costs and higher energy costs to keep the animals cool in summer and warm in the winter. The global aquaculture sector will also be impacted, due to short-term losses due to extreme weather events to both current production and infrastructure damage, while in the longer-term, aquaculture operations could suffer from lack of access to fish seed and fresh water and eutrophication of their water-holding facilities.
