Adaptation to climate change and limits in food production systems: Physics, the chemistry of biology, and human behavior

Abstract

This special issue of Global Change Biology grew out of a recognition by the Sixth Assessment of Intergovernmental Panel on Climate Change Working Group 2 (IPCC AR6 WG2) authors of chapter 5 (“Food, fibre, and other ecosystem products”) (Bezner-Kerr et al., 2022) that literature on limits to climate change adaptation in food production was lacking. The IPCC defines limits to adaptation as: “The point at which an actor's objectives (or system needs) cannot be secured from intolerable risks through adaptive actions.” (Intergovernmental Panel on Climate Change, 2022). “Hard” limits to adaptation are when no adaptive actions are possible to avoid intolerable risks. “Soft” limits are when options are currently not available to avert intolerable risks through adaptive action. Few peer-reviewed papers were available that dealt with either soft or hard limits to adaptation in food systems. Furthermore, the literature available for AR6 was almost always based on earlier Earth System Model simulations (Coupled Model Intercomparison Project Phase 5—CMIP5—and earlier versions) rather than the latest version (CMIP6) that became available during the writing of the IPCC AR6 WG2 report. Comparisons of the CMIP products suggest that projections from Earth system models in CMIP6 are more sensitive to greenhouse gas (GHG) concentrations than earlier model results. Thus, the impacts of climate change on food production systems from CMIP6 are likely to occur earlier and at a higher rate and intensity than previously expected, with potentially large implications for adaptations and their limits.

These papers are driven for the most part by scenarios and Earth system model projections from CMIP6 for the 21st century, focusing on the Shared Socio-economic Pathway (SSP) 1–2.6 (a scenario with “strong mitigation”) and SSP5-8.5 (a scenario with “no mitigation”). Collectively, these papers help paint a picture of the potential futures of a range of food production systems in the world under contrasting climate scenarios.

Different combinations of climate variables are used in each paper to illustrate different mechanisms of potential impact and challenges posed by climate change, as well as potential adaptation options and their limits. The primary climatic drivers affecting food systems differ by location. On land, these drivers include temperature, precipitation, humidity, wind speed, solar radiation and CO₂ concentration while in the oceans, they encompass warming, deoxygenation, acidification, salinity, and changes in net primary production.

Table 1 summarizes systems analyzed and the key results in this special issue. It is followed by a more extensive discussion of each paper and a summary section on what has been learned.

The papers in this special issue cover a range of food production systems, and they discuss how challenging it will be to adapt to climate change, particularly if the most severe climate scenario examined (SSP5-8.5) becomes a reality. Adaptations considered include three types—shifting production to regions where climate changes are less severe, changing the varieties/species grown or harvested, reducing aquatic harvest, and modifying the production/harvest methods and societal changes to address the human dimensions of these changes.

Gerald C. Nelson: Conceptualization; project administration; writing – original draft; Writing – review and editing. William W. L. Cheung: Conceptualization; project administration; writing – original draft. Rachel Bezner Kerr: Writing – original draft. James Franke: Writing – original draft. Francisco Meza: Writing – original draft. Muhammed A. Oyinlola: Writing – original draft. Philip Thornton: Writing – original draft. Florian Zabel: Writing – original draft.

All authors have indicated they have no conflict of interest.