One place in the United States is making it harder for the world to lower ethane levels.

For the last five or six years, there’s been a big mystery in climate science: What’s behind the sudden rise in global ethane gas emissions?

Ethane is a hydrocarbon (a gas made of hydrogen and carbon) and is the second most common one in the atmosphere.

A simulation showing surface ozone levels over the U.S. GIF via Michigan Engineering/YouTube.

One of the main sources of ethane is the process of drilling for fossil fuels. When ethane enters the atmosphere, it can react with sunlight and other molecules to form ozone, which is a greenhouse gas.

Ethane emissions were steadily decreasing until about 2009, when they started to crawl back up again and no one could really explain why.

Scientists had their suspicions, though: One thing that seemed to coincide with the rise in ethane emissions was a rise in shale oil and gas production in the U.S. using a process called hydraulic fracturing.

Read more: http://www.upworthy.com/one-place-in-the-united-states-is-making-it-harder-for-the-world-to-lower-ethane-levels?c=tpstream