17 June 2019

Is humanity dying?

The recent release of the Breakthrough National Centre for Climate Restoration policy paper on "Existential climate-related security risk" attracted a lot of media coverage: from the Guardian, Independent, New Scientist and Al-Jazeera to CNN,  CNS and ABC in the USA, amongst others. And there was a lot of coverage in northern Europe, especially Germany, from where this story comes. It was one of the most thoughtful pieces of journalism on the report. It appeared in KlimaReporter as Stirbt die Menschheit aus? Translation thanks to Dr Google.

Download the policy paper
Is humanity dying?
by  Christian Mihatsch, Climate reporter, 9 June 2019

The climate crisis is becoming increasingly apocalyptic. It is unlikely that our civilization will end soon — but possible. And this possibility is still receiving too little attention.

The perception of the climate problem is currently changing rapidly. The term "climate change" is increasingly being replaced by "climate crisis", and instead of "warming", what will probably prevail is "climate overheating" or a similar term. But is it appropriate to speak of the end of our civilization or even the extinction of humanity?

Some of the most important climate movements are doing just that. Extinction Rebellion is already carrying extinction in its name and the movement's first call is: Tell the truth and explain the state of emergency.

Fridays for Future's Greta Thunberg also clearly states what options humanity has: "Either we choose to preserve our civilization or we do not." And addressing world leaders, Thunberg says: "I want you to panic."

But is there really a reason to panic? The IPCC says that overheating can theoretically be stopped at 1.5 degrees. The IPCC reports are considered the "gold standard" of climate science because they summarize the findings of thousands of studies.

But the reports are also criticized, for example, because of their language. Prof. Hans Joachim Schellnhuber, ex-head of the Potsdam Institute for Climate Impact Research and an IPCC author, says that among IPCC authors a trend has developed "to err on the side of  least drama". So you may present a better situation than exists in order not to sound alarmist.

The “probability obsession" of the IPCC

In addition, the IPCC assumes that warming will continue in a linear fashion. However, many climate models  show that warming is accelerating. The difference: Instead of 2040, the 1.5-degree threshold will be reached in 2030 (see diagram).

In addition, the IPCC does not take into account feedback processes such as permafrost thawing, which may cause climate overheating to increase.

According to Schellnhuber, however, the biggest drawback is the IPCC's "probability obsession" because it means not enough attention is paid to the most dangerous developments: "Calculating probabilities has little meaning in the most critical areas, such as the thawing of permafrost or the possible collapse of entire states."

In addition, the damage of, for example, the collapse of our civilization cannot be quantified. A recent study by the Australian think tank Breakthrough states: "A risk is usually calculated by multiplying the probability of an event by the expected damage, but if the damage can no longer be quantified, this method breaks down."

But even in the quantifiable realm, one underestimates the risk by focusing on relatively probable warming and masking worst-case scenarios. For these damages increase exponentially (see chart below).

Unlikely, but catastrophic

Schellnhuber calls for less attention be paid to "probabilities" and more to "possibilities". "This corresponds to the scenario planning in the economy, where the consequences of possible developments are examined, which seem unlikely, but have far-reaching consequences."

That's exactly what the authors of the Breakthrough study, David Spratt and Ian Dunlop, have done, developing a scenario that will raise the climate by three degrees by 2050. That's not extreme. For the 30 years to the middle of the century, there is a five percent chance that the climate will warm up by 3.5 to 4 degrees.

How sensitive is the climate to the warming of the atmosphere
(climate sensitivity) and what are the consequences?
The probability (likelihood) multiplied by the damage (impact)
gives the risk (risk). The light blue bar shows that very
unlikely developments are the biggest risk.
(Graphic from the study).
To show how this can happen, Spratt and Dunlop tell a "story": In the coming decade, the climate crisis is still receiving too little attention, and emissions will continue to rise until 2030, only to decline thereafter. Then it is already too late and the climate warms by 2050 by three degrees.

In retrospect, scientists then find that several tipping points have been reached, such as the thawing of permafrost and droughts in the Amazon rainforest. One-third of the earth is now too hot for at least 20 days a year to allow people to survive outdoors. Food production is no longer enough to feed all people, and there are more than a billion climate refugees.

As I said: The probability of this development is around five percent.

Extinction Rebellion and Greta Thunberg invoke such scenarios with their apocalyptic language. Still, it is more likely that our civilization will not end and humanity will not die out. Nevertheless, it is possible if our protection from climate change continues to be only half-hearted.

These "possibilities" must be given more attention, says Schellnhuber: "This is especially true when it comes to the survival of our civilization."