5.1.3 Important findings of the Third Assessment Report

The key findings of the 2001 Third Assessment Report (TAR; IPCC, 2001) with respect to food, fibre, forestry and fisheries are an important benchmark for this chapter. In reduced form, they are:

Food crops

• CO₂ effects increase with temperature, but decrease once optimal temperatures are exceeded for a range of processes, especially plant water use. The CO₂ effect may be relatively greater (compared to that for irrigated crops) for crops under moisture stress.
• Modelling studies suggest crop yield losses with minimal warming in the tropics.
• Mid- to high-latitude crops benefit from a small amount of warming (about +2°C) but plant health declines with additional warming.
• Countries with greater wealth and natural resource endowments adapt more efficiently than those with less.

Forestry

• Free-air CO₂ enrichment (FACE) experiments suggest that trees rapidly become acclimated to increased CO₂ levels.
• The largest impacts of climate change are likely to occur earliest in boreal forests.
• Contrary to the findings of the Second Assessment Report (SAR), climate change will increase global timber supply and enhance existing market trends of rising market share in developing countries.

Aquaculture and fisheries

• Global warming will confound the impact of natural variation on fishing activity and complicate management.
• The sustainability of the fishing industries of many countries will depend on increasing flexibility in bilateral and multilateral fishing agreements, coupled with international stock assessments and management plans.
• Increases in seawater temperature have been associated with increases in diseases and algal blooms in the aquaculture industry.