Climate change is bringing heavier downpours. Are cities ready?

Tourists wearing raincoats make their way along a street in Haeundae District, Busan, July 1, as the monsoon season begins. Yonhap

"Will it rain every day throughout July?"

A rumor spread online recently suggesting that it would rain continuously for an entire month starting in July. Korea's weather agency quickly debunked the claim, pointing to a post back in April explaining that the rainy season is identified only after it has passed through observational data analysis.

While the so-called "monsoon rumor" turned out to be false, there is little room for complacency as the rainy season approaches. Climate change is making heavier rainfall an unavoidable reality, not only in Korea but around the world.

So how exactly is rainfall changing and what must cities do to prepare?

People walk through the rain along 5th Avenue in Manhattan in New York City, June 22. The region was put on alert for flash floods as heavy downpours moved through the area. AFP-Yonhap

More frequent cloudbursts driven by climate change

According to the Korea Meteorological Administration's 113-Year Climate Change Analysis Report, released in December and covering the period from 1912 to 2024, Korea's annual precipitation has increased by an average of 17.83 millimeters per decade.

The report also found clear increases in rainfall intensity, the number of heavy rain days and the frequency of hourly rainfall exceeding 50 millimeters, showing that short but intense downpours are becoming increasingly common.

The trend has become even more pronounced in recent years. The report noted that rainfall exceeding 100 millimeters per hour was recorded at 16 locations in 2024 and 15 locations in 2025. Last summer, although total seasonal rainfall and the number of rainy days were below average, localized cloudbursts repeatedly drenched small areas in short periods of time.

Record-breaking rainfall struck several regions between July and September, including Gapyeong in Gyeonggi Province, Seosan in South Chungcheong Province, Hampyeong in South Jeolla Province and Gunsan in North Jeolla Province.

Researchers say climate change is the underlying cause.

A 2023 study published by the Korean Society of Climate Change Research, which analyzed changes in Korea's rainfall patterns over the past 30 to 50 years, found that extreme rainfall events have become more frequent across the country, although the pace of change varies by region.

The researchers concluded that rising temperatures associated with climate change are likely contributing to more storms capable of producing intense rainfall over short periods.

Locals wearing raincoats sell their produce during a heavy downpour in Accra, Ghana, June 26. Ghana's National Disaster Management Organisation (NADMO) issued an alert as parts of Accra and Tema experienced flooding, while the country's meteorological agency forecast heavier rainfall. EPA-Yonhap

Cities look for ways to better absorb rain

Climate-driven increases in heavy rainfall can have devastating consequences if cities are unprepared.

Northern Pakistan offers a stark example. Following repeated surges in rainfall during the 2025 monsoon season, catastrophic flooding struck the region in August. Maximum rainfall there has increased by roughly 22 percent, a change researchers attribute largely to long-term global warming driven by fossil fuel use and deforestation.

According to Pakistan's National Disaster Management Authority, the floods killed at least 1,000 people and damaged about 1,600 homes.

The disaster also highlighted how climate risks disproportionately affect vulnerable communities.

About half of those who died were children. Many fatalities were linked to the collapse of homes built in flood-prone areas, particularly near rivers and drainage channels or constructed without adequate structural safety. The tragedy underscored how climate disasters often hit the poorest and least protected populations first.

Beyond storm drains: Rethinking urban design

Korea is strengthening its short-term flood response.

Last month, the Ministry of the Interior and Safety and the Ministry of Climate and Environment established a task force to improve maintenance of storm drains and other rainwater drainage facilities. Authorities also plan to expand inspections to include underground drainage pipes and manhole safety barriers, while publicly disclosing maintenance progress every two weeks.

However, experts warn that better drainage systems alone will not be enough, as extreme rainfall continues to intensify over the long term.

Kim Gwang-yong, head of the Disaster and Safety Management Division at the Ministry of the Interior and Safety, inspects the progress of disaster recovery work, including embankments and bridges, during a visit to Gipeunsol Stream, a small local stream in Gapyeong County, Gyeonggi Province, June 19. Yonhap

The Korean Society of Climate Change Research warned that increasing short-duration, high-intensity rainfall will continue to raise the risk of disasters such as the deadly Osong underpass flooding, which claimed 14 lives in 2023. The researchers stressed the need for more advanced forecasting technologies based on a deeper understanding of changing rainfall patterns.

One approach attracting growing attention is the "sponge city" model, designed to help cities absorb and retain water rather than channeling it away as quickly as possible.

Under the concept, parks, rain gardens and other green spaces are expanded to soak up rainfall. Roads and parking lots are paved with permeable materials that allow water to infiltrate the ground. Large underground storage tunnels can also capture excess rainwater, reducing flood risks while providing reserves during droughts.

First introduced in China in the early 2000s, sponge city projects have since been adopted or tested in cities including New York and Copenhagen.

The approach is not without challenges. Creating more green space and building the infrastructure requires significant investment, while successful implementation depends on cooperation among governments, communities and developers.

Employees of the Suwon Urban Development Corp. inspect drainage equipment at Suwon Sports Complex in Jangan-gu, Suwon, Gyeonggi Province, June 29, to help prevent damage from heavy rainfall during the monsoon season. Yonhap

Still, experts argue that the era of climate change demands a fundamental shift in how cities manage water.

"The traditional urban drainage model focused on moving rainwater out of cities as quickly as possible," said Jang Dong-woo, a professor of urban and environmental engineering at Incheon National University. "In the era of the climate crisis, we need a fundamentally different approach that stores, infiltrates and reuses rainwater within cities to strengthen urban resilience."

This article from the Hankook Ilbo, the sister publication of The Korea Times, is translated by a generative AI system and edited by The Korea Times.