After much anticipation, the Trump administration has recently unveiled its replacement for the Obama-era Clean Power Plan. The CPP, which was the subject of legal challenges and many dire economic warnings before the election of Donald Trump finally put it out of its misery, would have required a 32 percent reduction in greenhouse gas emissions from the American power section by 2030. The new replacement rule, called the Affordable Clean Energy rule, has been widely decried by the left as being too weak.

And yet, even as the CPP itself is buried, the goals of the plan are proceeding apace. Emissions in the United States have already fallen 27 percent relative to the CPP’s baseline and are projected to further decline over the next decade. In fact, by 2030, emissions will have fallen by more than the CPP’s 32 percent target.

These numbers — driven largely by market forces rather than federal action — raise some interesting questions. To begin: If we are going to meet the CPP’s emissions targets without the CPP, what was the point of having a CPP in the first place?

There are several possible answers to this question. Defenders of the CPP would likely note that even if we meet the overall emissions targets, individual states may not meet their own state emissions reduction targets. A legally binding rule like the CPP could also prevent backsliding should the emissions trend reverse. On the other hand, it’s plausible that emissions will fall even faster than currently projected as the price of renewable energy continues to decline and new technologies like batteries and carbon capture and storage become more marketable.

A more cynical observer might note that the existence of a federal program like the CPP would have given politicians the opportunity to take credit for the fall in emissions — even if it would have happened without government action.

On the flip side, the natural decline in emissions also raises the question of whether reducing emissions further would be as costly as is often predicted. If emissions are falling already, imagine how much more quickly they might fall with an efficient mechanism like a carbon price to spur change.

While the market-driven fall in emissions over the last two decades is impressive, in the absence of a price on carbon, there is nothing inherent in the market that will make emissions continually fall. Market innovation has led to falling prices of low- and lower-carbon energy sources — first natural gas via fracking and now renewables. That’s great, but in theory, there could just as well be an innovation tomorrow that drastically decreases the price of coal.

America’s emissions decline demonstrates the power of markets. But they need to be properly harnessed if they are to continue to deliver the emissions reductions we need.