Yields of wheat and soybeans, for example, could increase with increased 0O2 concentrations under optimal temperatures. However, while projections of future yields vary according to the scenario, model and time-scale used, there is consistency in the main expected directions of change: yields suffer more in tropical regions than at higher latitudes and impacts are more severe with increased warming (Porter et al., It presents projected estimates of changes in crop yields owing to climate change over the 21st century (Figure 4).