• For instance, impacts on rice yield, wheat yield and sorghum yield suggest that any increase in production associated with CO2 fertilization will be more than offset by reductions in yield from temperature or moisture changes.

• Past debates about the “sustainability” of large-scale logging operations and indigenous farming systems in PNG have mainly been concerned with yields of timber and food respectively.

• A warming of 1°C, with no change in precipitation, may decrease yields of wheat and maize in the core cropping regions such as the US by about 5 %.