This chapter highlights that the effects of climate change on crop and terrestrial food production are evident in several regions of the world and are affecting the abundance and distribution of harvested aquatic species, both freshwater and marine, and aquaculture production systems.

It argues that changes in climate and CO2 concentration will enhance the distribution and increase the competitiveness of agronomically important and invasive weeds. The chapter points out that all aspects of food security are potentially affected by climate change, including food access, utilisation, and price stability. For the major crops (wheat, rice, and maize) in tropical and temperate regions, climate change without adaptation will negatively impact production for local temperature increases of 2°C or more above late-20th-century levels, although individual locations may benefit. Projected impacts vary across crops and regions and adaptation scenarios, with about 10 per cent of projections for the period 2030–2049 showing yield gains of more than 10 per cent and about 10 per cent of projections showing yield losses of more than 25 per cent, compared to the late 20th century. After 2050, the risk of more severe impacts increases. Regional Chapters 22 (Africa), 23 (Europe), 24 (Asia), 27 (Central and South America), and Box 7-1 show crop production to be consistently and negatively affected by climate change in the future in low-latitude countries, while climate change may have positive or negative effects in northern latitudes.

On average, the chapter argues, agronomic adaptation improves yields by the equivalent of ~15-18 per cent of current yields, but the effectiveness of adaptation is highly variable ranging from potential dis-benefits to negligible to very substantial. Global temperature increases of ~4°C or more above late-20th-century levels, combined with increasing food demand, would pose large risks to food security globally and regionally. Risks to food security are generally greater in low latitude areas. Changes in temperature and precipitation, without considering effects of CO2, will contribute to increased global food prices by 2050, with estimated increases ranging from 3 to 84 per cent.
The chapter concludes that adaptation in fisheries, aquaculture, and livestock production will potentially be strengthened by adoption of multi-level adaptive strategies to minimise negative impacts. A range of potential adaptation options exist across all food system activities, not just in food production, but benefits from potential innovations in food processing, packaging, transport, storage, and trade are insufficiently researched.

[Adapted from source]