Half of world’s biggest cities will face climate hazards by 2050

Half of the largest cities on the planet will be at risk of one or more climate hazards by 2050, according to the latest report from the London Stock Exchange Group (LSEG).

Floods, heatwaves, cyclones and water stress will increasingly pummel these populous hubs unless greenhouse gas emissions are brought under control.

LSEG’s ‘Net Zero Atlas’ report sets out what level of emissions cuts countries should be targeting to avoid such climate catastrophes, ahead of the next round of Nationally Determined Contributions (NDCs) due early next year. 

“The cities in our study – nerve centres of the world economy that contribute almost 20 per cent of global GDP and are home to 440 million people – are particularly exposed to climate risk,” says LSEG’s global head of sustainable investment research, Jaakko Kooroshy.

“Impacts are already beginning to materialise at only 1.3°C of warming.” 

Those climate impacts were felt on a shocking scale in the Spanish city of Valencia this week, where a year’s worth of rain fell in eight hours on Tuesday – causing deadly floods that have claimed more than 200 lives.

Major European cities will face increasing climate hazards

LSEG predicts that global heating will reach 2.6°C under current policies. The UN Environment Programme puts it at 2.6°C to 2.8°C by the end of the century if current commitments are met.

Under this high emission scenario, the share of the world’s 49 largest cities with high-risk exposure would increase from less than one in five (18 per cent) to almost one in two (47 per cent). 

Major cities in the Middle East and Southeast Asia will suffer the brunt of this crisis, according to LSEG’s report. Six cities in these regions – Singapore, Surabaya, Dubai, Riyadh, Jeddah and Jakarta – are expected to experience more than 50 days of extreme heat a year by 2050.

In the EU, the analysts highlight the increasingly precarious position of Amsterdam and Madrid.

The low-lying Dutch capital faces high-level risk from sea level rise and flooding, which could increase by 60 per cent, despite its defences. 

In Madrid, heatwave days could soar by 135 per cent to a ‘medium-risk’ number of 41 days by 2050. Water stress in the Spanish capital is further projected to rise by 65 per cent, becoming high-risk in 2050.

When it comes to emissions cuts, the EU is not doing enough to protect its cities. LSEG estimates that the bloc will surpass its 1.5°C aligned emissions budget by 2035. 

Capitalising on Europe’s wind power potential is identified as a strong way to improve its energy outlook. 

Meanwhile, London and Manchester are in the spotlight in the UK. The capital is currently deemed low-risk for major physical hazards, but is set to experience a 22 per cent rise in water stress by mid-century. London’s extreme heat will more than double from 11 to 25 days each year. 

Remaining low-risk overall, Manchester will nonetheless experience climate change with a 93 per cent increase in heatwaves and a 45 per cent rise in water stress, according to the study.

How can major cities increase their climate resilience?

“As we approach COP29, G20 countries need to urgently reduce emissions to prevent climate hazards from rapidly escalating,” says Kooroshy.

“The next wave of national climate commitments will be critical for this. Nonetheless, even if the worst impacts of climate change can be prevented, significant investment will be required to adapt cities to new climate extremes.”

LSEG has outlined a range of adaptation strategies that cities can deploy, from life-saving early-warning systems and fortifications to ‘nature-based solutions’.

For example, structures such as sea walls, flood barriers, and drainage systems can cushion storm surges, allowing cities such as Amsterdam to thrive for centuries despite its extreme flood risk.

Similarly, cities are increasingly realising the value of green infrastructure in green parks, green corridors, and wetlands as these help manage floods and reduce the urban heat island effect. The LSEG report points to successful experiments, including creating a ‘sponge city’ in Shanghai, and ‘cool islands’ in Paris.