More than once I’ve berated clean energy "nay sayers" who argue that renewable energy can never meet our society’s needs. So I was interested to read an opposite argument over at Ensia, where Paul McDivitt makes a compelling case that clean energy advocates are harming the climate cause with their overly optimistic scenarios for renewable energy development.

Pointing to recent news stories about renewable energy capacity now beating out coal, McDivitt argues that such stories are creating a misleadingly optimistic impression because a) capacity does not equal production and b) renewable energy includes a hodgepodge of sources including hydropower, which hasn’t grown for years. Nevertheless, he says, the casual reader (and most readers are very casual) will infer that solar and wind are already taking over and their momentum is too much to be stopped. Indeed, argues McDivitt, most Americans vastly overestimate how much energy is coming to us from truly renewable sources.

It’s an important point that’s well worth considering. And I confess I may be guilty for spreading such optimism myself. From Tony Seba’s predictions of all vehicles being electric by 2030 to my enthusiastic reporting on countries kicking the coal habit, there’s a fine line to be had between celebrating progress and making a clean energy future sound inevitable. After all, for every news story about Finland banning coal, there’s another about Australia’s emissions creeping back up as it doubles down on coal. The truth is, no future is guaranteed. We’re going to have to pick a future we want and then work like hell to get there.

I would argue, however, that there’s an important distinction to be made between predicting a clean energy future as fate, and presenting it as an inspiring and achievable vision. From The Solution Project’s state-by-state roadmaps to developing 100% clean energy system to Governor Cuomo’s backing for an ambitious expansion of offshore wind energy, we need ambition and vision now more than ever. We just can’t afford to be complacent about getting there.

I think Alex Steffen puts it most succinctly when he points out that even if a clean energy transition is ultimately inevitable, the scale of the climate crisis means that the speed at which we get there is critical to "success" or too-hideous-to-imagine failure.

Every year we delay climate action, the speed of action needed becomes more rapid.

Curves grow steeper—what I mean by "steepening problems"

— Alex Steffen (@AlexSteffen) February 27, 2017

So yes, let’s keep celebrating successes and presenting grand visions. Let’s just not let those successes be an excuse for letting up the pressure.