Methane, a greenhouse gas

Why isn’t anyone talking about this?  From the article:

Sometimes called the “other greenhouse gas,” methane is responsible for 75% as much warming as carbon dioxide measured over any given 20 years. Unlike carbon dioxide, which remains in the atmosphere for hundreds of years, methane lasts only a decade but packs a powerful punch while it’s there.

Methane’s short life makes it especially interesting in the short run, given the pace of climate change. If we need to suppress temperature quickly in order to preserve glaciers, reducing methane can make an immediate impact. Compared to the massive requirements necessary to reduce CO2, cutting methane requires only modest investment. Where we stop methane emissions, cooling follows within a decade, not centuries.

Regardless of where you stand on climate change, I think it is remarkable that this isn’t common knowledge.  While I am theoretically for a global cap-and-trade regime (although in practice, I am not, because I don’t trust governments to implement it effectively), why is cap-and-trade always talked about in terms of CO2 emissions?  Instead, both cap-and-trade (and carbon taxes, for that matter) ought to be talked about in terms of emissions of greenhouse gases, measured in terms of their expected warming effect, at least if there is a reasonable consensus as to what that expected warming effct actually is.