Hindu: The earth is clearly facing a catastrophe of substantial dimension and lack of climate stability can have an impact on agriculture and food security, Chairman of the Intergovernmental Panel on Climate Change (IPCC), Dr R K Pachauri, said on Tuesday. "Climate change is not smooth and linear. The factors of a fairly balanced climate have been disturbed quite systematically leading to increase in precipitation — rain and snow — in the upper latitudes and decline in the lower …