Anyone who has followed the climate change issue in the last 30 years knows that official forecasts provided by the Intergovernmental Panel on Climate Change (IPCC) are quickly upended by developments and have often been obsolete before they were issued.

The latest report from the IPCC is the first, however, to abandon the measured tone of its previous ones and foretell what it considers a climate catastrophe for human civilization unless the world makes an abrupt U-turn and begins dramatic reductions in greenhouse gas emissions almost immediately.

And yet, even this forecast is probably too conservative in its pronouncements. That’s according to Michael Mann, a climate researcher whose famous “hockey stick” graph has been central to understanding the rise in global temperatures and has been replicated again and again using other measures of historical worldwide temperatures.

What is little understood by the public is that humans have been underestimating the pace and impact of climate change since Swedish chemist Svante Arrhenius first suggested in 1896 that the globe was warming due to emissions of carbon dioxide.

Which brings me to a broader point: The public tends to hear most often about the median values or middle-of-the road scenarios in any forecast, sometimes called the reference case. (Very little emphasis is put on the range of possibilities. For example, the IPCC in 2000 forecast that global average temperature could be 1.4 to 5.8 degrees Centigrade higher than the 1990 level by 2100.)

Today, we find ourselves fretting that going beyond a 1.5-degree increase from pre-industrial times will spell catastrophe involving global agriculture, severe weather, sea-level rise, and disease epidemics. Previously, 2 degrees was thought to be the threshold for severe irretrievable consequences resulting from climate change.

We’ve been surprised by the speed with which climate change is proceeding (because we tend to think of climate change as progressing in a gradual straight line). And, we’ve been surprised by the effects so far. Ice sheets are melting faster, the rate of carbon buildup in the atmosphere is accelerating, and the observed rise in sea level continues to accelerate. But, the public has not even begun to grasp what 4 or 5 degrees of warming would mean.

There is a double conundrum: What is the extent of warming likely to be over time and how severe will the effects be of each level of warming? These are difficult questions to answer since truly accurate answers lie in the future. But the whole point of a forecast is not to forecast an exact trajectory but to create scenarios for evaluating risk. That is why most bona fide forecasts contain ranges (sometimes referred to as “error bars”) for numbers and for various scenarios of effects. The IPCC has been faithful in providing these.

But we as a society have not done what good risk analysis suggests, namely, take the worst case scenario and ask whether human civilization as it is currently constituted could survive that scenario intact. The answer is probably not and has been for a while.

We thought we had plenty of time to deal with climate change 30 years ago. Its effects and dangers were still many decades away. As those 30 years have passed, the old extreme scenarios have become the consensus scenarios and the new extreme scenarios have gone beyond catastrophic. Our previous benign or not-too-serious climate change scenarios soothed our emotions, but they failed to prepare us for serious challenges to the stability of our modern civilization.We failed to understand that the most severe end of the range of possibilities is what we should have been preparing for—precisely because such an outcome is likely to be too severe for our civilization as currently organized to survive.

Speeding up deployment of renewable energy while ramping down carbon emissions, reducing meat consumption, and reversing deforestation were considered costly and possibly growth-destroying for the economy. But the ravages of climate change will almost certainly outweigh all of those costs many fold. In fact, if we take as our assumption that the destabilization of society followed by rapid depopulation is simply unacceptable, then we will realize that cost/benefit analysis is simply unacceptable, even insane, when it comes to climate change.

As famed student of risk Nassim Nicholas Taleb wrote in his book Fooled by Randomness, “It does not matter how frequently something succeeds if failure is too costly to bear.” Industrial civilization continues to mount new records of production and wealth. And yet, if its current path results in societal collapse, that path can hardly be counted as a benefit.

I would be remiss if I did not mention here that in another important area, energy supplies, the public and policymakers have been inflicted with the same emphasis on the median forecast. Forecasts for the supply of our major energy source, oil, continue to be sanguine. But these long-term forecasts often lack ranges for us to contemplate.

We assume wrongly that the forecasters must “know” what is going to occur in the oilfields in the future. But a chart prepared by a U.S. Energy Information Administration staff member demonstrates how little we know about future oil supplies. The chart is somewhat dated now, but it makes an important point that is still valid  today. Most of the new supply we expect worldwide is based on faith and nothing else. We’re saying to ourselves, “We’ve always grown supplies in the past, so we will in the future.”

Let us return to Taleb and repeat his warning: “It does not matter how frequently something succeeds if failure is too costly to bear.” If oil supplies begin to decline in earnest unexpectedly and we are not prepared, then global society will experience serious hardship and possible destabilization. We are faced with the same problem as in climate change. We aren’t ready for this event because we have been told that everything will go exactly right for the median forecast of oil supplies through 2040 or 2050 to come true.

A friend of mine, Dick Vodra, calls this “Yhprum’s Law.” He wrote me recently that this law “assumes that everything will happen on time, within budget, and work as well as planned the first time. Yhprum is Murphy spelled backwards.” (Readers will recall that Murphy’s Law says more or less the opposite: “If anything can go wrong, it will.” Don’t ask me how to pronounce “Yhprum.”)

Yhprum’s Law is the benign assumption our global society has been living out in its daily life with regard to climate change, namely, that we will somehow solve it easily and with time to spare. It is also the assumption behind our sluggish effort to transition away from fossil fuels, particularly oil.

Usually, it is technology that is said to be the solution to these twin problems. But if we humans were as clever as the techno-utopians tell us, it is puzzling that we are not well on our wall to solving both climate change and oil depletion. Perhaps these are not technical problems. Perhaps technology is the cause and not strictly speaking the solution to these problems. Perhaps these problems are political and social in their essence. All that is for another essay.

For now, try to remember than the median is not the message. It is just one among many messages. The most important message comes from the range of possibilities we face, especially those that threaten to bring down our entire system.

Image: A schematic showing the regions where natural disasters will occur due to climate change.  Key: Areas exposed to:

  • Pink: hurricanes
  • Yellow: desertification or drought
  • Blue: small islands and deltas subjected to extreme weather or greater surf; some islands will be completely submerged

The schematic was based on the Environmentally Induced Migration map from GRID Arendal. Via Wikimedia Commons.
[Of course there are many more effects not shown on the map, such as agricultural production affected by changes in temperatures and growing seasons; the enlargement of areas affected by parasites and pests; changes in rainfall and snowpack causing floods and reduction in water available; numbers of refugees (difficult to predict). -BA]