Global Warming Causes Northern Kyushu to Fall — American Cockroaches Rapidly Expanding Their Territory | WPN World People News

Due to climate change, global warming has led to a surge of American cockroaches in Fukuoka, Japan, in recent years. In the past, these cockroaches—about 3 to 4 centimeters long, originally from Africa, and unable to tolerate cold—arrived via cargo ships and could barely survive in warm boiler rooms or on street corners where heating leaked out. Now, however, they have almost completely settled across northern Kyushu.

According to data from the Fukuoka Meteorological Observatory, the city’s average minimum temperature in February has risen from **1.24°C (1921–1925)** to **4.92°C (2021–2025)**. Although American cockroaches still cannot survive entirely outdoors, their habitats—such as commercial buildings and restaurants—have expanded, allowing them to endure the winter more easily. Persistently high temperatures have also extended their outdoor activity and breeding periods. Associate Professor **Munetoshi Maruyama** of Kyushu University’s Museum of Natural History noted that “the number of American cockroaches has been increasing rapidly in northern Kyushu over the past two or three years.”

Now, in this comfortable new habitat, the population of American cockroaches is approaching that of Japan’s common smoky-brown cockroach and the smaller German cockroach. Particularly in sewers—where food is abundant and the environment is warm and humid—they thrive as if in paradise. Like German cockroaches, American cockroaches are sensitive to cold, meaning that in the future, they will likely be seen even more frequently in restaurants and commercial buildings.