Densely populated cities could face growing risks from changing global climate patterns, with Tokyo's Ueno Park facing mounting threats from rising temperatures, extreme rainfall and shifting weather conditions, according to a new physical climate risk assessment by HDI Risk Consulting (HRC), a subsidiary of insurer HDI Global.
The study found that temperatures in Tokyo have been rising faster than the global average, with heatwaves projected to last more than three weeks annually by 2050 under a business-as-usual scenario, compared with fewer than seven days in 1970. The report also warned that increasingly frequent “guerrilla rainstorms” could overwhelm drainage systems, disrupt transport networks, interrupt supply chains and force temporary business closures across the Japanese capital.
HRC said climate change could also affect Ueno Park’s famous cherry blossom season, one of Japan’s biggest tourist attractions that draws around two million visitors each year and generates billions of dollars in economic activity. Longer periods of extreme heat and changes in flowering patterns could reduce visitor numbers, shorten the time tourists spend outdoors and negatively affect nearby restaurants and businesses.
“Our goal is to identify climate risks with precise spatial accuracy,” said HDI Risk Consulting Head of Resilience Services Lars Regner.
“Ueno Park shows that local changes are part of broader climatic developments affecting entire cities.”
To minimise the impact, the report recommended measures including micro-heat zoning, expanded cooling corridors, sponge city infrastructure and stronger protection for underground transport and utility systems.
HDI Risk Consulting Risk Analyst for Natural Hazards Johanna Rohrer said the urban heat island effect is becoming a systemic economic risk by reducing worker productivity, increasing energy demand for cooling and placing greater pressure on infrastructure, supply chains and insurers.
HDI Global said Tokyo has already introduced several adaptation measures, including its G-Cans underground flood protection system and around 190 kilometres of heat-reducing “Cool Pavements”.
However, HDI Global Japan Managing Director Hiro Yamasaki said forward-looking climate risk analysis remains essential to help businesses and public authorities protect investments, maintain business continuity and preserve culturally significant landmarks such as Ueno Park and its iconic cherry blossom season.