The Verdict

Last Friday the Intergovernmental Panel on Climate Change (IPCC) concluded its meeting in Paris with the release of the Summary of its Fourth Assessment Report (4AR.) There's not much I can add here to what is being reported about the significance of its findings on the connection between greenhouse gases and climate change, and of the likely course of the latter over the rest of the century. I think I contribute more in two areas that haven't gotten a lot of attention in the media blitz over the 4AR: the value of the engineering approach for problems at this stage, and how best to regard the remaining climate skeptics.

Even though I haven't done much actual engineering in the last 25 years, my engineering training provided a framework for problem-solving that informs everything I do. Engineering is all about turning the results of science into practical things in the real world, and that is increasingly relevant to the problem of climate change. With the release of the full 4AR over the next several months--last week's output was just the executive summary of the first of the three main Working Groups--we're reaching the point at which the main focus must shift to action, rather than more analysis. That doesn't mean the scientific investigation of climate change should stop, or that we know everything we need to know about climate change; rather, in the manner of the solution to Zeno's Paradox, we know enough to get started. It's time to turn the engineers loose on this problem and move the scientific debate off to the side.

Making our energy systems more climate-friendly will be the centerpiece of that work. There are many competing blueprints for how to do that, and another one was also released last week by the American Solar Energy Society, with some impressive institutions and individuals behind it. Although I wonder how rapidly their proposed solutions could actually be ramped up, the report provides a good picture of the magnitude of response necessary to avert the consequences that the 4AR describes. (The IPCC will apparently contribute its own thoughts along these lines in the upcoming reports of the second and third Working Groups.) And we shouldn't limit ourselves to devising new ways of generating electricity or making cars more efficient. It may turn out that the only means of arresting the uncontrolled science experiment we've been running for the last century is with some truly large-scale engineering, and we ought to have options for that in our back pocket, in case we encounter a "runaway greenhouse" effect. I recognize that some will find that idea nearly as worrying as the climate problem itself.

Now to the skeptics. Although the strengthened scientific consensus of the 4AR will change the landscape for them, no one should expect the skeptics to disappear, nor would that be desirable--and here I draw an important distinction between genuine skepticism and self-interested obstructionism. That doesn't mean the skeptics should be driving the agenda, but having to answer their hard questions will clarify our thinking. Fundamentally, if they are going to challenge the IPCC view, they must do so in the only way that has worked throughout the history of science: by creating a better hypothesis that can be demonstrated to fit more of the available data and observations. Until that should happen, we must assume that man-made greenhouse gases are warming our planet, and act accordingly.

Life is going to get progressively harder for the skeptics. Their sources of funding will start drying up, and they may find themselves persona non grata, even among those whose support they could count on in the past. With the future of the planet increasingly seen to be on the line--and the fate of our descendants with it--the non-scientists' view of climate science is taking on attributes of religious dogma, and skeptics are being cast as heretics. That isn't healthy, but it's understandable. We need to preserve a level of continued funding and access to the mainstream of science for skeptical scientists, on the off chance that the consensus might prove to be wrong in some important way. If it turned out that the main driver of climate change were something other than man-made greenhouse gases--be it the cosmic ray/cloud hypothesis or something else--it would be nice to know that before we've spent trillions of dollars on a crash effort to decarbonize our energy systems and transform the global economy.

As the 4AR has made quite clear, waiting for the last lingering doubts about climate change to be resolved is a losing game that risks highly detrimental, potentially irreversible changes in our environment. Now we must see what the scientists can convince the policy makers to engage the engineers and financiers to do. I don't think we're going to have to wait long to find out.