Rains and Floods Due to Global Warming

There is no clear cause and effect established between global warming and excessive rains and floods.Monsoon rainfall varies on different spatial and temporal scales. Extreme rainfall events that occur at some isolated places (viz. heavy rainfall over Mumbai or in Rajasthan) are highly localized and are part of the natural variability of the Indian monsoon system itself. Although, some recent studies hint at an increasing frequency and intensity of extremes in rainfall during the past 40-50 years, their attribution to global warming is yet to be established. Moreover, the report of the Inter-governmental Panel on Climate Change (IPCC-AR4, 2007) and our country`s own assessment using regional climate models indicate that the extremes rainfall events are likely to be more frequent in the later part of the 21st century in the world including India. As regards other extreme weather phenomena, there are many other reasons for their occurrence, which cannot always be related to climate change.

Although, the monsoon rainfall at all India level does not show any trend but on regional scale, areas of increasing trend is discerned. It is not clear if this increasing trend in the heavy rainfall events is attributable to global warming. Summary of the observed long term changes so far include:

(i) Mean annual surface air temperatures show a significant warming of about 0.5 degree C/100 years during the last century.

(ii) No significant long-term trends are reported in the frequencies of large-scale droughts or floods in the summer monsoon season.

(iii) The total frequency of cyclonic storms that form over the Bay of Bengal has remained almost constant.

(iv) Analysis of past tide gauge records for the Indian coastline regions gives an estimate of sea level rise of 1.30 mm/year.

(v) There is evidence that glaciers in Himalayas are receding, however it is unclear as to how much of this recession is attributable to climate change, as glacial retreat is also due to natural long-term inter-glacial cycles. (vi) Studies were undertaken in four climate sensitive regions of the country, viz. Himalayan Region, Western Ghats, North Eastern Region, Coastal Areas to assess the possible impacts on the four sectors viz. agriculture, water, forests and health. A Report entitled, Climate Change & India: A 4X4 Assessment – A Sectoral and Regional Assessment of Impact of Climate Change in 2030s, has been released by the Government during November, 2010 under the aegis of the Indian Network of Climate Change Assessment (INCCA).

Further, the Government has undertaken the following steps in the area of climate Change:

(i) Prime Minister’s Council on Climate Change has been constituted to coordinate national action for assessment, adaptation and mitigation of climate change.

(ii) Under the National Action Plan on Climate Change (NAPCC), it is proposed to establish a permanent institutional mechanism that will play a development and coordination role. The NAPCC was released by the Prime Minister on 30th June 2008.

(iii) Under the NAPCC, eight missions in specific areas of Solar Energy, Enhanced Energy Efficiency, Sustainable Habitat, Water, Sustaining the Himalayan Eco-system, Green India, Sustainable Agriculture and Strategic knowledge for Climate Change have been identified as a part of multipronged, long term and integrated strategies for achieving key developmental goals in the context of climate change by appropriately dealing with possible adverse impacts.

(iv) Constituted an Expert Committee on Climate Change impacts, which is headed by the Principal Scientific Advisor to the Government of India.

(v) Launched a high-priority Programme to address the Science issues of Global and Regional Climate Change (GRCC) with a well-equipped state-of-the-art Center for Climate Change Research (CCCR) at Indian Institute of Tropical Meteorology (IITM), Pune, a unit under Earth System Science Organization (ESSO) for inter-disciplinary research and training in the area of science of climate change.

Union Minister of Science & Technology and Earth Sciences Shri S.Jaipal Reddy gave this information in reply to a written question in the Rajya Sabha