Impact of Climate Change on Food and Fibre Production
The concentration decreases each year in the northern hemisphere spring as trees grow new leaves, and increases again in the autumn as they drop their leaves and return carbon dioxide to the atmosphere. The dominance of the northern hemisphere forests is illustrated by this distinct pattern that can be detected worldwide. The underlying concentration increases each year despite this annual cycle. The fixation of CO2 by plants also varies dramatically throughout the day as the plants respond to the daily cycle of light and dark, using the light energy to capture CO2 to produce carbohydrates (Darbyshire et al, 1979).