Union Minister of State (Independent Charge) Science & Technology; Minister of State (Independent Charge) Earth Sciences; MoS PMO, Personnel, Public Grievances, Pensions, Atomic Energy and Space, Dr Jitendra Singh said that recent scientific studies have projected a decrease in annual rainfall for Chennai at the rate of 6.398 mm/year during the next three decades (2020-2050). However, these results are based on projections using a single regional climate model and there are large uncertainties in projecting rainfall changes at regional / local scales.
In a written reply to a question in the Lok Sabha today, Dr Jitendra Singh said, the reduction in the projected rainfall would lead to reducing the recharge of the coastal aquifer and in addition to this, increased extraction of groundwater will also affect the coastal aquifers.
The Minister also informed that it is expected that the sea level will continue to rise in the coming several decades. As per the 6th Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC), relative to 1995-2014, the global mean sea level is expected to rise by 0.28 – 0.55 m under the very low greenhouse emission scenario (SSP1-1.9), 0.44 – 0.76 m under the intermediate emission scenario (SSP2-4.5) and 0.98 – 1.88 under the very high emission scenario (SSP5-8.5) by 2100. However, the regional sea level change can differ significantly from the global mean. The regional sea level rise estimate for the Chennai coast and its impact on freshwater aquifers have not yet been studied.