Rat population in Amsterdam will keep growing due to climate change
While climate change and the resulting rising temperatures are threatening animal populations worldwide, rats are actually thriving, especially in densely populated cities like Amsterdam. Such cities will see their rat populations continue to grow as temperatures rise, according to an international study published in the Science Advances journal.
The researchers investigated rat reports in 16 cities, including Amsterdam, over an average period of 12 years. They also looked at the development of greenery, construction, and population growth in the cities in that period.
They concluded that densely built-up cities like Amsterdam, New York, Chicago, and Los Angeles saw the number of rat reports increase as they became warmer and more densely populated. And that will only get worse as climate change continues to increase temperatures and populations continue to grow.
Dutch researcher Jan Buijs of the GGD Amsterdam, who was involved in the study, was not surprised by the results. “The more people live in the city, the more food is available,” he told Parool.
Densely built cities heat also up faster than the countryside as they consist more of concrete than greenery, which makes them an attractive place to live for rats. The winters are less severe, so rats are more likely to survive and reproduce. “A rat lives mainly outside and is therefore dependent on the outside temperature,” Buijs said. “If a city is warmer, rats have to spend less energy on surviving and finding food.”
The researchers also found that sprawling cities with lots of greenery are less affected by a growing rat population. Tokyo, for example, has relatively little food for rats and has focused on retaining its greenery in recent years. “More greenery leads to a cooler city and more space between buildings, which has a positive effect on the rat population because they prefer to breed in warmer places,” Buijs said.
He acknowledged that it would be a challenge for Amsterdam to create enough greenery to affect the rat population. Due to urban expansion and more housing construction, the green areas in the city have decreased significantly in recent years. But he stressed that it was worth the effort. “It is important to create sufficient greenery between the buildings and, as a resident of the city, to ensure that you do not leave unnecessary food waste lying around,” he said to the newspaper.
