while market mechanisms like a carbon tax can definitely spur parallel innovation and direct economies toward desirable solutions, it's less clear that it's an

while market mechanisms like a carbon tax can definitely spur parallel innovation and direct economies toward desirable solutions, it's less clear that it's an obvious efficiency win (it's not even clear that optimal efficiency is the most desirable feature of a solution, since it trades away resiliency). what is often missing in the market efficiency argument is that the efficiency-killing waste is concentrated for government projects and distributed for markets. that makes it eaiser to "see" the government waste (especially if the government has transparency rules that don't apply to corporations), and makes the waste of market-based solutions less obvious (because it needs someone to aggregate it properly). in market-based economies, many companies will try and fail for a given opportunity (e.g., the thousands of instagram & facebooks that didn't make it), and that's "wasted" economic activity. and sometimes, it takes a market economy a few tries and many years to get something right (internet search as another example), which also lowers overall efficiency. markets work well in many cases, but they aren't a cut-and-dried answer to every economic challenge. when the risks are low, central planning can potentially "beat" a market-based approach. in any case, it's not an either-or choice--countries are continually experimenting to find the best blend of the two. (for the record, i'm all for pricing in externalities with mechanisms like a carbon tax)