Climate change: Delhi may suffer losses of Rs2.75 trillion by 2050

“At an aggregate level, the total cost of climate change for Delhi by mid century is expected to be ₹2.75 trillion,” the draft action plan states. It also estimates “the losses from the agriculture and allied sectors at ₹80 billion, manufacturing at ₹330 billion and services at ₹2.34 trillion.”

According to draft action plan–pending approval– the national capital may confront “heat waves/higher temperature and heavy precipitation events over fewer number of days” in the upcoming years.

The projections show a rise in maximum temperatures in Delhi by 1.5 degrees Celsius based on the RCP 4.5 scenario, and a 2.1-degree Celsius increase based on the RCP 8.5 scenario by mid-century.

During the formulation of the new action plan for the national capital, the Intergovernmental Panel on Climate Change Sixth Assessment Report (IPCC AR6) was examined.

Excerpts of the draft action plan indicated a decrease in cold days and nights, an anticipated reduction of 8.4 dry days, an increase of 1.4 consecutive wet days, and a rise of 0.9 heavy precipitation days compared to the baseline period of pre-industrial levels.

A detailed district-specific vulnerability assessment was conducted for the national capital in which south Delhi was identified as the most vulnerable and New Delhi the least.

On July 8-9, Delhi witnessed its highest single-day rainfall (153 mm) in the month since 1982 due to the interaction of a western disturbance, monsoon winds and a cyclonic circulation over northwest India. The city received an additional 107 mm of rain in the subsequent 24 hours.

In the 36 hours beginning at 8.30 am on July 8, Delhi recorded an unprecedented 260 mm of rainfall — prompting the government to issue a flood warning and shut schools temporarily.

The heavy rain transformed roads into gushing streams, parks into watery labyrinths and marketplaces into submerged realms.

Subsequently, heavy rain in the upper catchment areas of the Yamuna, including Himachal Pradesh, Uttarakhand and Haryana, led to the river swelling to record levels.

The water level in the river reached 208.66 metres on July 13, surpassing the previous record of 207.49 metres set in September 1978 by a significant margin. It breached embankments and penetrated deeper into the city than it has in more than four decades.

The consequences of the floods have been devastating with more than 27,000 people evacuated from their homes. 

Experts attributed the unprecedented flooding to encroachment on the river’s floodplain, extreme rainfall within a short span and silt accumulation that has raised the riverbed.

The existing stormwater drainage system in Delhi is prone to congestion, primarily caused by waste and sewage, leading to sluggish water flow.

Different parts of Delhi experience annual flooding due to factors such as excessive concrete structures, the disappearance of water bodies, encroachments on the stormwater drains and the discharge of untreated sewage and waste.

The last drainage master plan for Delhi was created in 1976 when the city’s population was approximately six million.

The government had asked IIT-Delhi to prepare a new ‘Drainage Master Plan for the NCT of Delhi’. The institute submitted a final report in 2018 but a technical panel of the city government rejected it, citing “discrepancies in data”.

Earlier this year, the government tasked the Public Works Department, which manages the largest part (2,064 kilometres of a total 3,741 kilometres) of the storm run-off system in Delhi, to prepare a new plan.

The draft action plan for climate change acknowledges a concerning lack of formal records and practices among various agencies responsible for stormwater drainage management in Delhi. Currently, there is no legislative mandate for these agencies to prepare comprehensive records of inundation extents in different parts of the capital territory.

Updated: 20 Jul 2023, 07:19 PM IST