Dumb and Dumber

Foreign Affairs:

Global carbon emissions rose again in 2017, disappointing hopes that the previous three years of near zero growth marked an inflection point in the fight against climate change. Advocates of renewable energy had attributed flat emissions to the falling cost of solar panels. Energy efficiency devotees had seen in the pause proof that economic activity had been decoupled from energy consumption. Advocates of fossil fuel divestment had posited that the carbon bubble had finally burst.

Analysts who had attributed the pause to slower economic growth in a number of parts of the world, especially China, were closer to the truth. The underlying fundamentals of the energy economy, after all, remained mostly unchanged—there had been no step change in either the energy efficiency of the global economy or the share of energy production that clean energy accounted for. And sure enough, as growth picked up, emissions started to tick back up again as well.

Even during the pause, it was clear that the world wasn’t making much progress toward avoiding significant future climate change. To significantly alter the trajectory of sea level changes or most other climate impacts in this century or the next, emissions would not just have to peak; they would have to fall precipitously. Yet what progress the world has made to cut global emissions has been, under even the most generous assumptions, incremental.

But at the latest climate talks in Bonn last fall, diplomats once again ratified a long-standing international target of limiting warming to two degrees Celsius above preindustrial levels. This despite being unable to commit to much beyond what was already agreed at the Paris meeting two years ago, when negotiators reached a nominal agreement on nonbinding Intended Nationally Determined Contributions, which would result in temperatures surpassing three degrees above preindustrial levels before the end of this century.

Forty years after it was first proposed, the two-degree target continues to maintain a talismanic hold over global efforts to address climate change, despite the fact that virtually all sober analyses conclude that the target is now unobtainable. Some advocates still insist that with sufficient political will, the target can be met. Others recognize that although the goal is practically unachievable, it represents an aspiration that might motivate the world to reduce emissions further and faster than it would otherwise. For still others, the target remains within reach if everyone gets serious about removing carbon from the atmosphere or hacking the atmosphere in order to buy more time.

But it is worth considering the consequences of continuing to pursue a goal that is no longer obtainable. Some significant level of future climate impact is probably unavoidable. Sustaining the fiction that the two-degree target remains viable risks leaving the world ill prepared to mitigate or manage the consequences.

My uncle, the Yale University economist William Nordhaus, is widely credited with being the first person to propose that climate policy should strive to limit anthropogenic global warming to two degrees above preindustrial temperatures. He didn’t arrive at that conclusion through any sort of elaborate climate modeling or cost-benefit analysis. Rather, he considered the very limited evidence of long-term climate variance available at that time and concluded that a two-degree increase would take global temperatures outside the range experienced by human societies for the previous several thousand years and probably much longer. The standard was, by his own admission, arbitrary.

In the decades that followed, the international community formalized his target through a series of UN conferences, assessments, and negotiations. Climate researchers, meanwhile, have backfilled the target with science, some of it compelling. It does indeed appear that the earth is already hotter than it has been in the last several hundred thousand years, with temperatures likely to rise substantially more through this century and well beyond.

But limiting global temperatures below two degrees provides no guarantee that the world will avoid catastrophe, nor does exceeding that threshold assure it. No one knows with much precision what the relationship will be between global temperature and the impact of climate change at local and regional levels. Nor do we have a particularly good handle on the capability of human societies to adapt to those impacts.

Limiting global temperatures below two degrees provides no guarantee that the world will avoid catastrophe, nor does exceeding that threshold assure it.

In reality, most of the climate risks that we understand reasonably well are linear, meaning that lower emissions bring a lower global temperature increase, which in turn brings lower risk. That is the case for impacts such as sea level rise, agricultural yields, rainfall, and drought. Stabilizing emissions at 450 atmospheric parts per million brings less risk than stabilizing at 500, 500 brings less risk than 550, and so on. The world isn’t saved should we limit atmospheric concentrations to 450 parts per million, nor is it lost should concentrations surpass that threshold.

There are a range of potential nonlinear tipping points that could also bring catastrophic climate impacts. Many climate scientists and advocates argue that the risks associated with triggering these impacts are so great that it is better to take a strict precautionary approach to dramatically cut emissions. But there are enormous uncertainties about where those tipping points actually are. The precautionary principle holds equally well at one degree of warming, a threshold that we have already surpassed; one and a half degrees, which we will soon surpass; or, for that matter, three degrees.

Such calculations are further complicated by the substantial lag between when we emit carbon and when we experience the climate impacts of doing so: because of the time lag, and because of the substantial amount of carbon already emitted (atmospheric concentrations of carbon today stand at 407 parts per million, versus 275 prior to the start of the Industrial Revolution), even an extreme precautionary approach that ended all greenhouse gas emissions immediately would not much affect the trajectory of global temperatures or climate impacts until late in this century at the earliest.

Projections of sea level rise, for instance, don’t really diverge in high-emissions versus low-emissions scenarios until late in this century, and even then not by very much. It is not until modelers project into the twenty-second century that large differences begin to emerge. The same is true of most other climate impacts, at least as far as we understand them.

Many advocates for climate action suggest that we are already experiencing the impacts of anthropogenic climate change in the form of more extreme weather and natural disasters. Insofar as this is true—and the effect of climate change on present-day weather disasters is highly contested—there is not much we can do to mitigate it in the coming decades.

Over the last two decades, discussions of climate risk have been strongly influenced by concerns about moral hazard. The suggestion that human societies might successfully adapt to climate change, the argument goes, risks undermining commitments to cut emissions sufficiently to avoid those risks.

But moral hazard runs the other way as well. On a planet that is almost certainly going to be much hotter even if the world cuts emissions rapidly, the continuing insistence that human societies might cut emissions rapidly enough to avoid dangerous climate change risks undermining the urgency to adapt.

Adaptation brings difficult tradeoffs that many climate advocates would prefer to ignore. Individual and societal wealth, infrastructure, mobility, and economic integration are the primary determinants of how vulnerable human societies are to climate disasters. A natural disaster of the same magnitude will generally bring dramatically greater suffering in a poor country than in a rich one. For this reason, poor nations will bear the brunt of climate impacts. But by the same token, the faster those nations develop, the more resilient they will be to climate change. Development in most parts of the world, however, still entails burning more fossil fuels—in most cases, a lot more.

Most climate advocates have accepted that some form of adaptation will be a necessity for human societies over the course of this century. But many refuse to acknowledge that much of that adjustment will need to be powered by fossil fuels. Hard infrastructure—modern housing, transportation networks, and the like—is what makes people resilient to climate and other natural disasters. That sort of infrastructure requires steel and concrete. And there are presently few economically viable ways to produce steel or concrete without fossil fuels.

The two-degree threshold, and the various carbon budgets and emissions reduction targets that accompany it, has provided the justification for prohibitions at the World Bank and other international development institutions on finance for fossil fuel development. Given how much climate change is likely already built into our future owing to past emissions and how long it takes for emissions reductions to mitigate climate impacts, those sorts of policies will almost certainly increase exposure to climate hazards for many people in developing economies.

Religion is a wonderful thing. If you believe in the AGW religion, you know for sure that 1 bit of atmosphere out of 2500 makes the difference between glory and gloom. For a different perspective we offer professors Will Happer and Richard Lindzen.

One Response to “Dumb and Dumber”

  1. Bosun Says:

    These “Climate Bozos” do fit the profile of Eric Hoffer’s “True Believers” perfectly. That this silliness is considered science just shows how far the DUMBING DOWN has progressed. Cui Bono?

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