Desperate U.K. Turns to Shale Gas

[NickB79]

10. Mauna Loa is recording rapidly rising methane levels

http://www.theguardian.com/environment/2008/nov/10/network-climate-change

Your link isn't discussing just the overall levels of methane, but also the growth rate by which methane levels have been rising. They've seen no drop in the overall concentrations, just a short-term slowing in the rate at which they were rising. They were never falling, and are now shooting upwards again.

Their study focused on the period from the late 80's to early 2000's when methane growth leveled off. Their conclusion was that better control of fugitive methane from conventional natural gas wells was the cause.

HOWEVER, since that time we've begun fracking for gas on a massive scale, and the previous practices the natural gas industry employed to prevent methane losses doesn't appear to work with fracked wells nearly as effectively: http://www.csmonitor.com/Environment/Energy-Voices/2013/0623/Methane-leaks-of-shale-gas-may-undermine-its-climate-benefits