Human activities have been recognized as the primary cause for global warming. The build-up of greenhouse gases (GHGs) threatens to set the earth on the path to an unpredictably different climate. A key challenge, in that instance would be food security, crucial to sustain the growing world population. An enormous amount of water is required to produce food. Irrigation needs vary according to the balance between rainfall and evapotranspiration, and the resultant fluctuations in soil moisture status. Anthropogenically induced climate change is expected to influence rainfall and temperature patterns. Since climate change will influence temperature and rainfall patterns, there are likely to be direct impacts on soil moisture. Changes in soil moisture due to global warming will have other hydrological effects which will, in turn, affect agriculture around the world.
Sri Lanka is no exception to this, as it is also prone to natural disasters. During the last few decades, for instance, Sri Lanka has witnessed a number of extreme rainfall events in south western regions during south west monsoon season (May to September) and in contrast northeast and north central regions experienced severe drought during the paddy and other field crop growing seasons. Farmers used to start paddy cultivation during maha season, expecting the north east monsoonal rains. Sri Lanka is experiencing uncertainty and inadequacy of north east and inter-monsoonal rains, during these years which caused damage to the paddy and other field crop cultivations. Each year, the Government of Sri Lanka spends huge amounts of funds on drought, floods and other, relief services.