Food and climate Change
Climate change is an even more pressing problem than peak oil. Climate change is already impacting on food supplies through changes in water availability (for example as a result of glacial melt) as well as unpredictable weather events such as floods and droughts. In the medium term climate change will reduce world food supply as rising temperatures decrease yields (particularly in hotter countries) and rising sea levels threaten low-lying farmland.
Fortunately, many of the changes we need to make in order to respond to peak oil - such as reducing consumption of goods, transport and heating - will also help to reduce our climate change impact.
There are however some important areas in which solutions to peak oil are not solutions to climate change or vice versa. For example, one of the most worrying responses to peak oil (and gas) would be a switch to coal. Coal reserves may well be more limited than most people assume, but there is probably enough to have a devastating impact on our climate if we simply attempt to substitute coal for oil and gas, for example by manufacturing vehicle fuels from coal. This is because coal is a dirtier fuel in climate-change terms (more carbon is emitted per unit of energy).
Food and farming is another key area in which reducing climate change impacts is a slightly different proposition from reducing energy use. We tend to think of climate change as being caused by carbon dioxide, and of this mainly arising from the burning of fossil fuels. In much of our economic activity this is a reasonable approximation. And sure enough the food and farming system are responsible for burning large amounts of fossil fuels, in transport, refrigeration, food processing, tractors etc.
However, if we focus on farming in particular, we see that, while farms contribute significant amounts of carbon dioxide, they emit even larger amounts of nitrous oxide and methane, two much more potent greenhouse gases. In fact, even if we look at the food system as a whole, reducing emissions of these gases remains a bigger priority than reducing carbon dioxide.
Methane is emitted whenever organic matter breaks down anaerobically, but more importantly in the digestive systems of ruminant animals such as cattle and sheep. This is the main reason that it has been estimated that livestock farming contributes more to global warming worldwide than all transport.
Nitrous oxide is emitted by soil organisms breaking down nitrate in the soil. The intensive use of artificial nitrate fertilisers tends to add to this problem. Conversely, farming that focuses on building soil fertility and the careful application of natural fertlisers will tend to reduce nitrous oxide emissions, as will a food system that minimises the amount of food we need to produce.
For further information on the interations between climate change and the food system visit the Food Climate Research Network website.