City’s greenhouse emissions predicted to peak in 2030

The city’s greenhouse gas emissions are projected to peak in 2030, with an annual output of 26.80 million tonnes of carbon dioxide equivalent (tCO2Eq) greenhouse gas emissions (GHGs)

MUMBAI: The city’s greenhouse gas emissions are projected to peak in 2030, with an annual output of 26.80 million tonnes of carbon dioxide equivalent (tCO2Eq) greenhouse gas emissions (GHGs), as per an analysis carried out by the World Resources Institute (India) for the Brihanmumbai Municipal Corporation’s (BMC) recently unveiled Mumbai Climate Action Plan (MCAP).

Carbon dioxide equivalence is a measure that describes, for a particular mix of greenhouse gases, the amount of CO2 which would have the same global warming potential (GWP) over a defined period of time (HT File)

According to Mehul Patel, program lead at WRI (India), and one of the authors of the MCAP,

“Post 2030, emissions are expected to show a year-on-year decline under the ‘Ambitious’ scenario of the MCAP. The peak of 26.80 million tCO2eq is relative to the city’s baseline emissions for 2019, which stood at 23.42 million tCO2eq.”

Carbon dioxide equivalence is a measure that describes, for a particular mix of greenhouse gases, the amount of CO2 which would have the same global warming potential (GWP) over a defined period of time.

In Mumbai, specifically, 72% of the city’s greenhouse gas mix comes from the use of coal-fired electricity, piped natural gas (PNG), liquefied petroleum gas (LPG), coal, fuelwood and kerosene across residential, commercial and industrial establishments. Another 20% originates from the transport sector, and 8% from the waste sector, in 2019, as per MCAP’s analysis.

What this means in simpler terms is that in 2019, every resident in Mumbai emitted about 1.8 tonnes of CO2eq greenhouse gases into the atmosphere through largely these three routes, i.e. consumption of energy, transport and waste. The broad sources of these emissions, respectively, would be thermal (coal-driven) power plants, tailpipe exhausts, and landfills and sewers that emit biogas.

“Someone who takes a lot of flights, drives a fuel-heavy car, keeps the air conditioner running the whole day, and does not segregate waste will have a much higher carbon footprint than someone who travels by train, and does not lead a very high-consumption lifestyle. But the cumulative emissions from all these activities within the boundary of Greater Mumbai is expected to fall after 2030, the peak year,” said Patel.

Notably, in MCAP’s draft version, Mumbai’s baseline emissions in 2019 stood at a total of 34.3 million tCO2eq, a number significantly higher than both, the revised emissions baseline and the projected peak under the final version which was released to the public on March 13. This also reduced the city’s per capita carbon footprint from 2.67 to 1.8 tonnes per year.

“The baseline was revised because our draft projections did not take into account the proposed share of renewables in the power grid by 2030 and 2050, and steps the BMC is already taking to control landfill emissions. After considering additional data relating to these parameters, the baseline estimate was revised from about 34 million tonnes to 23 million tonnes,” Patel said.

Under the MCAP’s ‘business as usual’ scenario, without taking any action to mitigate emissions, Mumbai’s annual carbon footprint by the year 2050 is expected to reach 64.8 million tCO2e/year by 2050, increasing 2.7 times between 2019 and 2050, the MCAP states.

In the ‘Existing and and Planned’ scenario – which is the third outcome modelled by the MCAP – Mumbai’s annual GHG emissions are projected to touch 33.31 tCO2eq in 2040, and 53.1 million tCO2eq by 2050. This scenario “considers effects of existing or planned city actions along with regional and national policies,” but is not sufficient to meet the 1.5°C Paris Agreement goals.

But the ‘Ambitious’ scenario, which would enable Mumbai “to meet a fair-share 1.5°C warming scenario” now forms the basis for the various, city-level mitigation actions and emissions reductions targets prescribed within the MCAP.

“MCAP has an overall mitigation goal of attaining net-zero emissions by 2050. The plan’s interim and long-term objectives include a 30% decrease in emissions by 2030, a 44% reduction by 2040, and a net-zero reduction by 2050 compared to base year emissions (2019),” the BMC said in a statement on March 13 at the time of the document’s public release.

However, as the MCAP itself reveals, a truly net zero carbon balance for the city is virtually impossible within this time frame. “In the Ambitious scenario, emissions are forecasted to

reduce by 27% by the year 2030 and by 72% by the year 2050 as compared with the emission levels in 2019. This implies that the city will have a residual emission amounting to a 30% gap in meeting the 2050 target of net-zero emissions,” the document states on Page 84.

“This residual gap comes mainly from older buildings and informal housing settlements in the city which are not very energy efficient, emissions from facultative waste management and use of LPG in households. Unless there is some roadmap to retrofit old buildings and increase their energy efficiency, they will continue to emit GHGs,” Patel said.

However, experts worried that even this partial goal may be “dangerously optimistic” in its hopes of meeting the Paris Agreement’s goals. The MCAP assumes that 50% share Mumbai’s total grid electricity – which contributes about 72% of the city’s total GHG emissions – will come from renewable sources by 2030, and 90% by 2050. It also assumes 96% electrification of cars, recycling of 80% of paper and plastic waste, increasing the share of public transport from 32% to 42%, and 100% of electrification of public buses, light duty trucks, three-wheelers and taxis – all by the year 2050, if not sooner.

Not everyone agrees. “These are assumptions are unwarranted,” said Hussain Indorewala, teacher and urban researcher at the Kamla Raheja Vidyanidhi Institute of Architecture. “The MCAP, despite being presented as a ‘planning’ document, relies on a lot of other institutions, from private industries to regulatory authorities, to meet net zero goals. But it does not make it binding on them to do so. Besides, this is not in itself enough to stave off the worst effects of climate change in Mumbai.”

Meanwhile, the city administration is also going ahead with projects like underground tunnels, coastal roads and sea links which are extremely emissions intensive, but whose impacts have not been examined in the MCAP. “The Coastal Road has been called ‘maladaptive’ by the Intergovernmental Panel on Climate Change (IPCC, a United Nations body), but there is no mention of this in the plan,” Indorewala added.

Experts have also criticised the MCAP for lack of transparency, in that it does not provide the calculations based on which emissions reduction targets have been set, making it difficult for citizens to independently validate WRI India and the BMC’s analysis.

Anjal Prakash, a lead author of the IPCC’s sixth assessment report, said, “Without an independent peer review of the methodology, the MCAP leaves out some important nuances. For one, if the baseline GHGs emissions were revised with a difference of 11 million tonnes, it needs to be explained transparently so that there can be public trust in the numbers.”

The 30% residual emissions gap projected in 2050 is also concerning. While advancements in technology, or carbon offsetting, may help tackle these issues in the future, Prakash said that the gap is too big to not plan for in the present day.

“The Maharashtra government’s efforts at creating a Climate Action Plan for Mumbai is laudable. It sets a positive precedent for other states and policymakers. But to present the MCAP as a pathway to net zero when the emissions gap is nearly a third of your baseline, that is a bit misleading,” Prakash said.

Sunil Godse, head of the BMC’s environment wing, did not respond to repeated requests for comment.