Climate change soil impacts

The main effects of climate change on soils will be through changes in the soil moisture. A decrease in rainfall, for example, coupled with more evaporation due to higher temperatures, will lead to a decrease in the amount of water available to plants with major consequences both for the native flora and fauna and also for agriculture. There is a close relationship between air temperature and soil temperature and an increase in air temperature leads to an increase in soil temperature. Warmer temperatures everywhere will accelerate soil processes, leading to more rapid decomposition of organic matter, increased microbiological activity, more rapid release of nutrients. However, this trend could be reversed if soils become drier.

The main impact of climate change on the soil is likely to be in relation to organic matter. A rise in soil temperature is likely to increase the rate of decomposition and loss of soil organic matter. Although it is recognised that global warming can favour increased plant growth and therefore more organic inputs to the soil, the balance of opinion currently is that losses of organic matter through increased decomposition rates are likely to exceed the extra inputs of organic matter from the increased plant growth. Hence organic matter levels may be subject to decline.

Climate change will also affect many of the soil functions. It will bring about changes in land use capability and eventually may require significant changes to agriculture in a particular region. Even small changes will have an important effect on soil fauna and microflora and this will affect the turnover of nutrients. Although most ecosystems adapt reasonably well to small climatic fluctuations, changes to soils are likely to be reflected in a change to ecosystems. There are also likely to be major changes to the distribution of water, its storage and its availability in the soil under a changed climate.