Drought directly impacts on agricultural yields by reducing plant growth and animal production. High winds cause mechanical damage to crops, soil erosion and land degradation. Finally, due to population growth, agriculture had to expand more and more into marginal land, including those with soils with poor water storage capacity. This increases even further vulnerability to climate change. These increases have been from the burning of fossil fuels, land-use changes and agriculture.
Greenhouse gases have a warming effect on surface temperatures.
In contrast, tropospheric aerosols, resulting from fossil fuel combustion and burning of biomass, have a cooling effect on climate. The balance of evidence now suggests a discernible human influence on global climate and that the warming effect of greenhouse gases is outweighing the cooling effect of aerosols. It is now believed that global temperatures could increase at a faster rate than they have up to now. General warming is expected to lead to an increase in high temperature extremes, with decreases in extremes of cold with repercussions on the hydrological cycle with changes in the occurrence of severe droughts and floods. Most climate models indicate an increase in rainfall intensitv leading to more extreme rainfall events.