Basically, climate change is a long term shift or modification in temperature, precipitation patterns, relative humidity and changes in hydro-logical phenomena. Climate change is a fundamental threat to sustainable development, with devastating impacts on agriculture, water resources, ecosystems, and human health. The evidence is clear that climate change is already hurting the poor particularly in developing countries. It is damaging infrastructure, threatening coastal communities, and depressing crop yields, as well as changing our oceans, jeopardizing fish stocks, and endangering species. Climate change poses great threat to soil environment and soil functions that are performed by soil. Currently, soil being a natural body is under great threats of climate change due to its close relation with changing climate patterns. In agricultural countries, climate change may affect seriously crop production as changes in soil; air temperature and rainfall affect the ability of crops to attain maturity and their potential harvest. As the climate heats up, reductions in the amount of available water may be made up initially by irrigation. However, scarcity of water may prevent water being utilized for irrigation. Increasing damage to the land, or land degradation, will occur in the form of soil erosion, desertification, salinisation, or loss of fertile soils, further impacting on the capability of soils to support the needs of agriculture. The balance between the soils of the world and the climate affects the nature and distribution of the world’s natural ecosystem services, providing water, nutrients and a growing medium. As climate changes, so too will the soil’s ability to support current ecosystems – this will lead to changes in the communities of plants growing in different parts of the world. For example, in certain places plants suited to wetter conditions may lose out to plants able to cope with drier conditions. With changing in temperature pattern, certain crops may even lose their native habitat.

Climate Change has diverse implications over soil resources. The raising temperature, precipitation trends and relative humidity can have dire consequences over global soils. The major constitute of soil fertility, called “Soil Organic Matter” may decompose in soil greater than the amount of incorporation. The problem may be severe in such areas where, there is lack of vegetation and organic manure incorporation is negligible. The fertility status of such soils tends to decline sharply. If appropriate management practices are not taken in to considerations, there are chances of becoming permanent infertile soil.

Another impact of climate change on soil is drought. The higher temperature increases evaporation rate and decreasing relative moisture content of soil essential for nutrient solubility, microbial activity and nutrients transfer to plant roots. Even drought may induce higher irrigation water requirement for soil. The severity of problem may get worst in areas where there is less precipitation or arid environment.

Climate change also poses great threat to soil through soil erosion. Changing rainfall pattern coupled with increasing intensity of rainfall over a period of time will endanger soil resources. Because, intensive rain increases vulnerability of soil to erosion. Water runoff damages soil upper layer and with passage of water runoff, more fertile part of soil will be eroded.  The barren soils are more vulnerable to soil erosion.

The soil microbes may face dire consequences due to climate change coupled with higher temperature, because with raising every 10c temperature, microbial population experiences a dramatic shift in their activities and functions. Soil microorganisms have great say in regulating nutrient transformation, provide nutrients to plants, allow co-existence among neighbors and control plant thickness, changes in soil microorganism-plant interactions could have significant effects on number on number of microbe community, composition and ecosystem functions.

Climate change can also have major impact on fertilizers particularly on nitrogenous fertilizer due to volatilized nature of nitrogen. The nitrogenous fertilizers are susceptible to higher soil temperature. Nitrogenous fertilizer like Urea, if applied as a surface application in temperate region, there are more chances of nitrogen to volatilize as ammonia (a gaseous form of nitrogen). The ammonia is also a green house gas.

Soil salinization is also potential impact of climate change. The higher temperature increases physical weathering of primary minerals and as a result, more saline nature cations such as Na, Ca, Mg and K are released in to soil solution, thereby making soil a saline. Salinity in turn may leave dire impacts on crop production though its role in nutrients imbalance, nutrient precipitation, specific nutrient deficiency and toxicity. This is potential problem in arid and semi-arid regions.

To, conclude the discussion, it can be said that climate change poses severe threats to soil resources across globe. Raising temperature has great impacts on soil health, fertility and its functions. Currently, there is meager knowledge and understanding of nexus between soil and climate change. There is dire need to initiate extensive research in exploring the potential threats of climate change to soil. The soil scientists, research academia, climate change experts and policy makers must collaborate with each other in climate–soil research, as we can explore better soil management and adaptation techniques in order address the climate change impacts on soil resources.

The author of the article is Waqar Ahmed Pahore Lecturer Soil Science Sindh Agriculture University Sub Campus Umerkot.