Weather events are becoming increasingly unpredictable, intense, and damaging, note JLL experts. Today's cities face huge challenges in both preparing for and recovering from the growing impact of extreme weather events.

Devastating Effects

From extreme heat in southern Europe to the heaviest rainfall recorded in Shenzhen and Hong Kong, to floods in Brazil and cyclones devastating parts of South Africa, cities are confronting unprecedented physical risks.

Four out of five cities worldwide now face significant climate hazards such as heatwaves, floods, and droughts, according to the non-profit CDP, which surveyed 998 cities. Much of this extreme weather is due to climate change, coupled with the cyclical effects of El Niño in the latter part of 2023.

"Many cities are facing multiple threats due to extreme weather," says Jeremy Kelly, Global Director of Research in Cities at JLL. "While currently establishing long-term resilience plans, they must also deal with the immediate consequences of costly and unprecedented weather events."

Changing weather patterns have huge implications for real estate and the people living in cities. For nearly a third of the cities surveyed by CDP, climate-related hazards pose a threat to at least 70% of their population.

Over 90% of the world's largest companies will have at least one asset—offices, factories, warehouses, or data centers—financially exposed to climate risks such as water stress, wildfires, or floods by 2050, according to S&P Global.

Standing up to Heat

Rising temperatures have broken records for longer and more intense heatwaves in several urban areas in recent years. In response, cities are implementing a range of policies and measures to cool their streets.

City-appointed chief heat officers are increasingly taking the lead in combating rising temperatures and keeping local populations safe. Sierra Leone's capital, Freetown, recently appointed Africa's first heat director, a role that cities like Miami, Melbourne, and Monterrey in Mexico have also invested in.

"It's essential to be prepared. Heatwaves are a growing problem for cities, often putting pressure on outdated energy infrastructure to keep buildings cool through air conditioning," says Kelly. "In turn, this adds to carbon emissions (unless energy comes from renewable sources), fueling long-term global warming. In contrast, nature-based solutions can help cool urban areas in a more environmentally friendly way."

A Model

The city of Medellin in Colombia reduced the effects of the urban heat island by 2 ℃ in three years by creating 30 green corridors. Shaded tree routes, with tens of thousands of indigenous trees and tropical plants, include new bike paths and walkways throughout the city.

It's not just about planting trees; it's also about keeping them alive in a changing climate. As part of Paris's plans to plant 170,000 trees by 2026, it is growing a variety of heat-resistant species in different locations, depending on their water and sunlight needs.

Traditional city infrastructure is also being rethought. South Korea's capital, Seoul, removed a major elevated artery through its center, opening access to the river and reducing urban heat by at least half a degree Celsius. Vienna in Austria has developed its "cool streets" initiative with four permanent streets and 18 pop-up streets featuring a mix of open-surface road restrictions, "fog showers" on hot days, water elements, and tree cover.

Roofs are also coming into focus. Many cities have introduced legislation requiring green roofs on new buildings and sometimes on existing ones. Some cities provide financial incentives for installing green infrastructure. Hamburg in Germany subsidizes green roof measures with grants of up to €100,000, while New York has renewed its tax abatement program for green roofs.

As a different tactic, cities like New York and Los Angeles are painting rooftops white to reflect sunlight.

"Resilience measures need to be more explicitly incorporated into existing building codes and city-level regulations," says Kelly. "Take Japan, for example, where they have very rigorous building codes regarding earthquakes and are ahead of the curve on cyclones. We need to extend this thinking around broader resilience into city regulations. Many buildings are not prepared for the climate risks they now face, and owners don't understand the impact until it's too late."

Turning the Tide on Floods

Heavy rains are a critical threat faced by many of today's cities. Research conducted by C40, which analyzes nearly 100 member cities, found that floods could cause $64 billion in damages in urban areas each year by 2050, even with current flood protection levels.

Meanwhile, the non-profit First Street Foundation and engineering firm Arup have identified 730,000 retail, office, and multi-unit residential properties at retail risk of flooding in the US, costing over $16.9 billion annually by 2025.

Some cities, especially those in coastal areas, are already taking preventive measures. Shanghai, New York, and Cardiff are enhancing their "sponginess" by implementing inner-city gardens, improved river drainage, and more vegetation.

After a storm in 2011 that cost around $1 billion in damages, Copenhagen built Enghaveparken. Located at the foot of a hill, it contains numerous chambers to safely store and manage heavy rainfall. Rotterdam's Watersquare Benthemplein equally transforms from a submerged public square and basketball court into a major rainwater basin during heavy rains.

Thinking Boldly

Storms that often bring heavy rains also disrupt infrastructure and operations as usual. They prompt some cities to invest in microgrids, self-sufficient energy systems that can generate and store their own energy and distribute it locally to connected buildings.

In Columbus, Ohio, a severe storm in 2022 left hundreds of thousands without power for almost a week. The city recently installed the first of five planned microgrids with 100 kW of on-site solar generation and 440 kWh of battery energy storage.

San Diego is also investing in eight microgrids to support both short-term resilience and the long-term goal of being powered 100% by renewable sources by 2035.

"Today's cities need to be willing to think boldly about potential resilience measures and collaborate on a large scale to share knowledge about what works," says Kelly.

"Cities like Melbourne, Sydney, Amsterdam, and Paris have been pioneers in developing climate resilience strategies, but as climate risks continue to grow, even they will need to evolve. No city can afford to be complacent about what increasingly extreme weather means for their buildings or their people."