IPCC warned that climate crisis and poor planning will lead to sinking cities

Published on Sep 08, 2022 08:11 PM IST

Situations similar to the Bengaluru floods have been described in detail in IPCC’s sixth assessment report titled Climate Change 2022: Impacts, Adaptation and Vulnerability released in March.

Lack of planning makes cities like Bengaluru extremely vulnerable. (HT Photo) PREMIUM
Lack of planning makes cities like Bengaluru extremely vulnerable. (HT Photo)
ByJayashree Nandi

What led to unprecedented flooding in the eastern suburbs of Bengaluru — a hub for several IT companies and upscale residential colonies — is a classic representation of how cities will crumble under the weight of the climate crisis combined with poor planning in recent years.

Situations similar to the Bengaluru floods have been described in detail in the Intergovernmental Panel on Climate Change (IPCC)’s sixth assessment report titled Climate Change 2022: Impacts, Adaptation and Vulnerability released in March.

“Urban flooding risks are increased by urban expansion and land use and land cover change which enlarges impermeable surface areas through soil sealing, impacting drainage of floodwaters with consequent sewer overflows,” IPCC stated with confidence, adding that “these risks are also driven by increasing societal complexity, urban developmental policy on flood control and long-term economic growth including in mega-cities.”

IPCC further said that Asian cities are highly exposed to future flood risks due to urbanisation processes. Between 2000 and 2030, rapid urbanisation in Indonesia will increase flood risk by 76-120% for river and coastal floods, while sea level rise will further increase the exposure by 19-37%. Flooding in urban areas is exacerbated both by the encroachment of urban areas and by the lack of infrastructure such as embankments and flood walls. This is the case for large areas of Dhaka east and for Hohhot in China, the increase in impervious surfaces contributes 2-4 times more to annual flood risk compared with risk induced by the climate crisis.

Lack of planning makes cities like Bengaluru extremely vulnerable. Informality is one way by which urbanisation increases exposure and susceptibility of physical structures and people to climate-related risks, IPCC said giving examples of cities including Guadalajara in Mexico, Kampala in Uganda, and Dar es Salaam in Tanzania, which are facing water and heat-related risks, IPCC said.

The number of people expected to live in urban areas highly exposed to climate crisis impacts has increased substantially, IPCC flagged. An additional 2.5 billion people are projected to be living in urban areas by 2050, with up to 90% of this increase concentrated in Asia and Africa, particularly in India, China and Nigeria, where 35% of this urban growth is projected to occur.

In the past eight months, parts of India and neighbouring Pakistan have suffered most of the climate impacts that IPCC flagged in its March report.

The March-April spring heatwave spell in India and Pakistan was about 30 times more likely to happen because of the human-caused climate crisis, a rapid attribution analysis by an international team of leading climate scientists who are part of the World Weather Attribution network, said in May. The results of their rapid analysis showed that the unusually long and early onset heatwave spell in India and Pakistan is very rare, with a chance of occurring only once in 100 years. But “human-caused climate change” has made it about 30 times more likely to happen.

The heatwave triggered an extreme Glacial Lake Outburst Flood (GLOF) in northern Pakistan and forest fires in India, particularly in the hill states of Uttarakhand and Himachal Pradesh; extreme heat also reduced India’s wheat crop yields, causing the government to stop wheat exports; shortage of coal led to power outages that limited access to cooling by affected people, the analysis said.

This was followed by the monsoon that caused floods in Assam and Meghalaya in June, several incidents of landslides and mudslides in Uttarakhand and Himachal Pradesh in July and August and floods and extreme rainfall in Odisha, parts of Madhya Pradesh and Chhattisgarh. In August end, catastrophic floods destroyed infrastructure and displaced hundreds of thousands of people in the Sindh and Balochistan region. At least 1,000 people have died already in Pakistan, on an account of floods that are already being described as once-in-a-lifetime; millions have been displaced. The flash floods in vast swathes of the country, from north to south, with most rivers, including the Indus, Kabul, and Swat in spate. The trigger for the flooding was extreme rain arising from a well-marked low-pressure area which formed over the Bay of Bengal on August 19 and travelled across central India to Pakistan.

IPCC in March also flagged extreme heat in South Asia, urban flooding, urban water scarcity, and risks to key infrastructure like transport, energy and housing.

The Bangalore floods are a result of mindless urbanisation and the climate crisis. “On September 5, parts of Bangalore received around 14 cm rainfall. It's not the first time that such heavy rainfall has occurred in the city. There was a cyclonic circulation over the region and monsoon was active over interior peninsular India. When there are weak monsoon conditions over the country, rainfall is heavy and active over interior parts of south India and northeast India. Peninsular India had been receiving excess rains since June, they have a surplus of 30%. So, the soil was moist and saturated with water. In a highly populated region like Bengaluru, which also has a large number of lakes and water bodies, the lakes will overflow. Nothing can stop them because the runoff is high,” explained M Mohapatra, director general, IMD.

He added that IMD had predicted very heavy rains over the city days in advance in their city forecast. IMD’s data showed Bangalore city station had recorded 13.16 cm of rain on September 5, but in the past, other parts of the city had recorded more rain like on September 12, 1988, there was rainfall of 17.76 cm; on September 7, 1953, there was 16.92 cm rainfall.

“Most cities were developed before climate crisis impacts became perceptible. Bangalore for example started developing 50-60 years ago but the climate crisis became a major issue in the past 30 years. Nobody had the imagination to foresee how climate change will impact the city. Now we need an adaptation strategy for Indian cities. Tomorrow this can happen in Chennai or Hyderabad. When the IT industry came up in Bengaluru, the population increased manifold leading to a higher demand for accommodation and office space. Obstructing the water flow by building on water bodies is bound to trigger severe flooding. This is also because of increased water vapour in the atmosphere, sometimes when it rains it will be unprecedented rain. We are seeing this happen in different parts of the country every monsoon. In European cities also, flooding has increased but it's not being felt as often as in India, which is recording floods every monsoon. The only answer is adapting our infrastructure to the changing climate,” said M Rajeevan, climate scientist and former secretary, ministry of earth sciences.

Indian cities now need to prepare for 1.5 degrees C global warming over pre-industrial levels which are expected in the next 20 to 30 years according to IPCC’s projections, experts said.

“The Bengaluru story has two sides – first, the way the city has expanded without much planning and supporting infrastructure needed for the growth. In the process, the numerous lakes and ponds, which had a huge network for a city like Bengaluru, have been systematically destroyed. The network of lakes which were interconnected was shattered in the wake of grabbing land, making each lake becoming independent. Their capacity was reduced, and so during this rainy season, most of the lakes were overflowing. The second side is climate change," Anjal Prakash, research director and adjunct professor, Bharti Institute of Public Policy, Indian School of Business and co-author of the March 2022 IPCC report.

"The recent IPCC reports had predicted already that the climate-induced extreme weather events would be a marked change in a 1.5-degree warming world. What we see is that these events are not only more pronounced but also increased in frequency and severity. Bengaluru or any other Indian city do not have the necessary infrastructure to withhold 130 mm of precipitation that happened in just 24 hours. The only way by which we can prepare ourselves is to first, recognize that climate-induced changes are impacting cities. Second, we must work towards a city-level adaptation plan and scan all infrastructure development plans through a climate lens. Third, a special purpose vehicle must be instituted which has short, medium and long term plans to see that the same scene is not repeated in 2023,” she added.

Several experts from Bengaluru have already captured satellite maps and information from local agencies. Malini Ranganathan, urban geographer and associate Professor in the School of International Service at American University in a series of tweets explained how land grabbing by various agencies led to the filling up of lakes and wetlands. “Bengaluru’s land market is profitable & risky. Land comprising wetlands, lakes, and storm drains ("raja kaluves"), known as kharab–B [non-cultivable] land in the Karnataka Land Revenue Act 1964, is technically owned by the state”.

“For instance, state players such as the Karnataka Industrial Areas Development Board and the Bengaluru Development Authority have enabled high-end real estate on the sensitive Bellandur-Agara wetlands. There are countless examples of ex-post facto legalization of land grabbing.” MD Madhusudan, ecologist tweeted with satellite images: “In 20 y, mega construction has gobbled up parts of the Bellandur wetland, with a particularly egregious example—a high-profile tech park, presumably—coming up right across the wetland’s main drainage channels.”

Anumita Roychowdhury, executive director, the Centre for Science and Environment who focuses on sustainable habitats, said the time has come to shift the conversation from mitigation of the climate crisis to adaptation to climate impacts in Indian cities. “Development in Indian cities are disregarding the ecological limits of these cities, going against natural drainage and catchment."

"Cities that usurped the natural environment in the name of development are bound to face the worst impacts of extreme weather events such as heatwaves, storms and floods which are becoming more frequent and severe due to global warming. Planners now need to recognise the importance of green spaces, wetlands and water bodies in urban and peri-urban areas that reduce the impacts of such weather events and build natural resilience to climate disasters,” said Harjeet Singh, head of Global Political Strategy, Climate Action Network International.

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