For a long time it has been believed that the effects of global warming on agriculture and food supply is going to be a positive one. This is because the rising level of carbon-dioxide resulted for global warming will help the greeneries for photosynthesis.

Thus there will be a rise of agricultural production and food supply. The theorem received a boost after the evidence of a sharp rise of barley production as one of the effects of global warming in Iceland which was quite impossible even few years ago.

But more recent experiments and researches have revealed that the effects of global warming on agriculture and food supply are not that good after all. AN UNEP 2001 report on the global warming has predicted that USA is going to have more droughts, floods, landslides and storms.

Winter will gradually be shortened and sobered down, while summer will rise in expansion and severity. Along with this heavy rain, big storm, heavy snowfall, high sea level, increasing coastal erosion and other problems will occur.

Though as one of the effects of global warming, the overall food supply and production level is supposed to rise in USA, but the Great Plains will suffer with more droughts resulting for global warming.

Even now many effects of global warming on agriculture and food supply have been perceived. The popular maple syrup production of North east USA has diminished by 10%, moving its production zone to farther north for shorter and warmer winter.

On the other hand as one of the effects of global warming the south west USA is suffering from a water shortage which will increase in coming days. The zone has become dry for any standard agricultural production with an apprehension of resettling Dust Bowl of 1930s’ by the year 2030 for global warming.

Following a report of IPCC on the global warming, California’s snow covered Sierra Mountains can reduce in near future by up to 60-90%. This will create dire water shortage in summer, making the Central Valley area unsuitable for agricultural production for global warming. The State University of Colorado has declared that the area is going to be less productive due to effects of global warming on agriculture and food supply.

As the effects of global warming, the food supply production in Florida is going to suffer a lot due to frequent and large scale floods. Also one of the most profitable agricultural products of USA – corn will suffer a bad condition due to dry and hot atmosphere for global warming.

As another example of the effects of global warming on agriculture and food supply – with the rise of temperature by 3 to 11 degrees in this century, the production rate of the main crops – the rice, corn, wheat, barley, soybeans and sorghum – will be cut down by 3-5% for each point rise of temperature for global warming.

However with all these effects of global warming on agriculture and food supply, new attempts have been made to adjust the agricultural and food production method according to the changing atmosphere. So to fight the effects of global warming, the researchers have established new methods of production with continuous revision of models. But still the best possible process to reduce the effects of global warming on agriculture and food supply is to be established.