Tokyo's concrete traps enough heat to bloom flowers early

While modern satellites track the changing seasons, we know exactly how much the city has warmed thanks to court diaries dating back to 794 AD. Since the Heian era, Japanese officials have logged the first blush of pink on the cherry trees, creating a 1,300-year record of the climate. These logs show that the bloom has advanced by roughly five days every century. Today, Tokyo sits under a heat dome that remains nearly 2 degrees Celsius warmer than the surrounding countryside.