However, climatic variability creates hazards to which agricultural ecosystems are not well adapted. High temperatures exacerbate the effects of drought, damage crops and their establishment, and reduce yields. Low temperatures, frost and heavy snowfall curtail yields and destroy crops. Heavy rainfall and flooding cause inundation and waterlogging of productive land. 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.