Mosquitoes have finally invaded one of the world's last mosquito-free countries

For as long as anyone can remember, Iceland was one of the only places on earth where you could sit outside at dusk and not get eaten alive by mosquitoes. No buzzing, no swatting, and no itchy welts the next day. Tourists loved it. Scientists were fascinated by it. The reason was simple: Icelandic winters were too tough. A short hot spell would get the mosquito larvae moving, and then a cold snap would kill them off before they could mature. Nature had its own built-in bug killer.

That streak officially came to an end in October 2025.

Three bugs changed everything
A biologist, Björn Hjaltason, had installed a moth trap on a farm in western Iceland. Instead, he caught a wild mosquito, the first ever to be recorded in the country. Then another. Then a third one. He sent them to the Natural Science Institute of Iceland, where entomologist Matthías Alfreðsson confirmed what scientists had long suspected: Iceland had its first wild mosquito residents.


The species was Culiseta annulata, a large, cold-hardy mosquito common across Europe. The really clever bit is how it survives the winter. It just waits in basements, barns, and outbuildings, hunkering down, not needing the stable temperatures most species require. No freeze-thaw cycle can affect it.

This discovery makes Antarctica the only landmass on Earth without mosquitoes.

This isn't just an Iceland problem
This is where it becomes relevant to Americans. The forces that are pushing mosquitoes to Iceland are reshaping the map for mosquitoes everywhere, including in the U.S. A study in PNAS found that mosquitoes aren't just moving into cooler areas; they are actually evolving to keep up with rising temperatures. UC Berkeley researchers found that mosquitoes have a lot of genetic variation in their ability to tolerate heat, meaning they can evolve as fast as climate change. “We may be underestimating future disease risk,” said lead author Lisa Couper.

The Arctic is warming faster than almost anywhere else on Earth, roughly four times the global average. A Dartmouth College study found that a 2°C increase in Arctic temperatures could boost the odds that mosquitoes in the region survive to adulthood by more than 50 percent. Warmer springs mean earlier emergence, faster development, a compounding effect that helps the bugs and no one else.

Should Americans worry about disease?
Culiseta annulata itself is not a major disease carrier; it bites, but it doesn't carry dengue or Zika. So Iceland is not in a public health crisis, but the big picture is what researchers lose sleep over.

The US is already seeing a longer mosquito season. The CDC has reported expanding ranges of Aedes aegypti and Aedes albopictus, the two species that carry dengue, chikungunya, and Zika. That means out earlier in the year and in the fall in Florida, Texas, and parts of the Southeast. Climate scientists say that by 2050, almost half of the world’s population may be newly exposed to these disease-carrying species.

The big picture: nature’s boundaries are shifting
Iceland’s story is a neat, crisp example of something global and messy. Species that couldn’t survive in certain climates are finding workarounds, whether through evolution, dumb luck, or a cargo ship. The reason? The world’s natural barriers are being quietly renegotiated.

The history of Iceland is a helpful reality check for Americans accustomed to thinking of mosquitoes as a summer backyard pest. Climate change is more than hotter summers and rising seas. It’s about getting around, it’s about who lives where, and what they bring with them.

Iceland had a pretty good thing going. It took one season, and climate change to kill it off.