Debunking the Impact of City Heat on Global Warming

It's no surprise that cities get a lot hotter than rural areas. Metro areas have more roads and taller buildings than the countryside, the better to collect sunlight by day and prevent the release of warmth by night. These distinguishing elements can cause city temperatures to reach greater relative heights — a phenomenon known as the urban "heat island" effect. That's certainly been the case in Tokyo, where temperatures have risen much more quickly compared to surrounding rural areas of Japan over the years. Here's a look at Tokyo temps against the global average since 1900:

Some climate change skeptics have wondered if urban heat islands may be contaminating global warming data. Does the existence of hot urban islands like Tokyo make it look like the whole world is getting warmer? After all, cities appear to be overrepresented when it comes to temperature measuring stations; although urban regions make up just about 1 percent of the Earth's land, roughly 27 percent of collection sites are located in areas with a population above 50,000 people.