Tokyo is becoming more of a jungle every year -- meteorologically speaking. As metropolitan temperatures continue to climb annually, there are signs that temperate Tokyo is becoming more tropical.
Tokyo's average temperature has jumped 2.9 over the past century -- outpacing global warming by about a factor of five, experts say. Meanwhile, the number of "tropical nights," during which the temperature fails to slip below 25, has climbed steadily and the number of hours the city bakes in 30-degree heat or more each summer has doubled in less than 20 years.
But this is old hat. The heat island phenomenon has been understood for more than a century and at least one paper was written about it by a researcher in Tokyo as early as 1930. What is new is that Tokyo has gotten so hot that it creates its own weather, hosts subtropical flora and fauna, and -- some say -- poses a threat to the health of Tokyo residents as well as Tokyo Bay.