Scientists Track Carbon Footprint of Major Cities: Los Angeles and Paris

Major cities can have a lot in common. They're usually culturally diverse, filled with people and, unsurprisingly, produce a lot of carbon dioxide. Now, scientists from across the globe are finding out exactly how much of this greenhouse gas these cities produce. They've joined forces to track the carbon footprints of some of the world's largest cities.

How do they do this? Researchers have planted devices in cities that possess more than 10 million residents, such as Paris and Los Angeles. There, these devices record exactly how much carbon dioxide is present in the air. This gives scientists a better understanding of how seasons and development can affect the greenhouse gas.

The study couldn't have come at a more timely moment. Researchers from the Keeling Lab in Hawaii recently announced that for the first time in human history, the concentration of climate-warming carbon dioxide in the atmosphere has passed the milestone level of 400 parts per million (ppm). The only time these levels have been higher was when the Arctic was ice-free about 3.6 million years ago. That said, researchers recently downgraded the amount to 399.89 ppm, which is still a cause for concern.

This latest initiative to monitor carbon dioxide is currently only implemented in a few locations. Yet there are plans to expand the network, according to the AP. This summer, technicians will install commercial gas analyzers at a dozen more rooftops around the great Los Angeles region, which will allow them to better monitor the total area. In addition, other scientists in places such as Boston and Indianapolis are working to decipher the carbon footprint in these smaller cities.

So how much carbon dioxide are these cities producing? Overall, California released about 408 million tons of carbon dioxide into the air in 2010. That's greater than all but 20 countries, and is just ahead of Spain's emissions.

Currently, the researchers are continuing to monitor these major cities as they try to find the best strategies to calculate the amount of carbon dioxide being produced. As greenhouse gas emissions rise, though, it's more important than ever to understand exactly how cities are contributing to this increase.