Existential climate-related security risk: A scenario approach (David Spratt)

Spratt, D., Dunlop, I., Existential climate-related security risk: A scenario approach, Breakthrough – National Centre for Climate Restoration (NCCR), Melbourne, Australia, policy paper, 2019, pp. 11

Abstract
•    Analysis of climate-related security threats depends significantly on understanding the strengths and limitations of climate science projections. Much scientific knowledge produced for climate policy-making is conservative and reticent.
•    Climate change now represents a near- to mid-term existential threat to human civilization. But this is not inevitable. A new approach to climate-related security risk-management is thus required, giving particular attention to the high-end and difficult-to-quantify “fat-tail” possibilities, in order to avoid such an outcome.
•    This may be most effectively explored by scenario analysis. A 2050 scenario of the high-end risks is outlined, where accelerating climate-change impacts pose big negative consequences to humanity which might not be undone for centuries.
•    To reduce or avoid such risks and to sustain human civilization, it is essential to build a zero-emissions industrial system very quickly. This requires the global mobilization of resources on an emergency basis, akin to a wartime level of response.

2. Scientific reticence
Climate scientists may err on the side of “least drama”, whose causes may include adherence to the scientific norms of restraint, objectivity and skepticism, and may under-predict or down-play future climate changes [8]. In 2007, security analysts warned that, in the two previous decades, climate-change scientific predictions had consistently underestimated the severity of what actually transpired [9]. This problem persists, notably in work of the IPCC, whose Assessment Reports exhibit a one-sided reliance on general climate models, which incorporate important climate processes, but do not include all of the processes that can contribute to system feedbacks, compound extreme events, and abrupt and/or irreversible changes [10]. Other forms of knowledge are downplayed, including paleoclimatology, expert advice, and semi-empirical models. IPCC reports present detailed, quantified, complex modelling results, but then briefly note more severe, non- linear, system-change possibilities in a descriptive, non-quantified form. Because policymakers and the media are often drawn to headline numbers, this approach results in less attention being given to the most devastating, difficult-to-quantify outcomes. In one example, the IPCC’s Fifth Assessment Report in 2014 projected a sea-level rise of 0.55-0.82 m by 2100, but said “levels above the likely range cannot be reliably evaluated”. By way of comparison, the higher of two US Department of Defence scenarios is a 2-m rise by 2100, and the “extreme” scenario developed by a number of US government agencies is 2.5 m by 2100 [11]. Another example is the recent IPCC 1.5°C report, which projected that warming would continue at the current rate of ~0.2°C per decade and reach the 1.5°C mark around 2040. However, the 1.5°C boundary is likely to be passed in half that time, around 2030, and the 2°C boundary around 2045, due to accelerating anthropogenic emissions, decreased aerosol loading and changing ocean circulation conditions [12–14]. 

3. Existential risk
An existential risk to civilisation is one posing permanent large negative consequences to humanity which may never be undone, either annihilating intelligent life or permanently and drastically curtailing its potential. With the commitments by nations to the 2015 Paris Agreement, the current path of warming is 3°C or more by 2100. But this does not include “long-term” carbon-cycle feedbacks, which are materially relevant now and in the near future due to the unprecedented rate at which human activity is perturbing the climate system. Considering these, the Paris path would lead to ≈5°C of warming by 2100. Scientists warn that warming of 4°C is incompatible with an organised global community, is devastating to the majority of ecosystems, and has a high probability of not being stable. The World Bank says it may be “beyond adaptation”. But existential threats may also exist for many peoples and regions at a significantly lower level of warming. In 2017, 3°C of warming was categorised as “catastrophic” with a warning that, on a path of unchecked emissions, low-probability, high-impact warming could be catastrophic by 2050.
Prof. Hans Joachim Schellnhuber warns that “climate change is now reaching the end-game, where very soon humanity must choose between taking unprecedented action, or accepting that it has been left too late and bear the consequences.” He says that if we continue down the present path “there is a very big risk that we will just end our civilisation. The human species will survive somehow but we will destroy almost everything we have built up over the last two thousand years.”
Unfortunately, conventional risk and probability analysis becomes useless in these circumstances because it excludes the full implications of outlier events and possibilities lurking at the fringes.
Prudent risk-management means an objective look at real risks to which we are exposed, especially at those “fat-tail” events, which may have consequences that are damaging beyond quantification, and threaten the survival of human civilisation. Global warming projections display a “fat-tailed” distribution with a greater likelihood of warming that is well in excess of the average amount of warming predicted by climate models, and are of higher probability than would be expected under typical statistical assumptions. The risk lies disproportionately in the “fat-tail” outcomes (see Fig. 1).

 

 

5. Discussion
This scenario provides a glimpse into a world of “outright chaos” on a path to the end of human civilisation and modern society as we have known it, in which the challenges to global security are simply overwhelming and political panic becomes the norm. Yet the world is currently completely unprepared to envisage, and even less deal with, the consequences of catastrophic climate change. What can be done to avoid such a probable but catastrophic future? It is clear from our preliminary scenario that dramatic action is required this decade if the “hothouse Earth” scenario is to be avoided. To reduce this risk and protect human civilisation, a massive global mobilisation of resources is needed in the coming decade to build a zero-emissions industrial system and set in train the restoration of a safe climate. This would be akin in scale to the World War II emergency mobilisation. There is an increasing awareness that such a response is now necessary. Prof. Kevin Anderson makes the case for a Marshall Plan-style construction of zero-carbon-dioxide energy supply and major electrification to build a zero-carbon industrial strategy by “a shift in productive capacity of society akin to that in WW II”. Others have warned that “only a drastic, economy-wide makeover within the next decade, consistent with limiting warming to 1.5°C”, would avoid the transition of the Earth System to the Pliocene-like conditions that prevailed 3-3.3 million years ago, when temperatures were ~3°C and sea levels 25 m higher. It should be noted here that the 1.5° goal is not safe for a number of Earth System elements, including Arctic sea-ice, West Antarctica and coral reefs. The national security sector has unrivalled experience and capacity in such mobilisation, and can play a unique role in its development and implementation, as well as educating policymakers of the existential security risks in failing to do so.

5. Conclusions
•    Recognize limitations of policy-relevant climate change research (it may show scientific reticence).
•    Adopt a scenario approach giving attention to high-end warming possibilities in understanding mid-range (mid-century) climate and security risks, particularly due to the existential implications.
•    Give analytical focus to the role of near-term action as a determinant in preventing planetary and human systems reaching a “point of no return” by mid-century, in which the prospect of a largely uninhabitable Earth leads to the breakdown of nations and the international order.
•    Urgently examine the role that the national security sector can play in providing leadership and capacity for a near-term, society-wide, emergency mobilization of labor and resources, of a scale unprecedented in peacetime, to build a zero-emissions industrial system and draw down carbon to protect human civilization.