The likelihood and level of the threat
How do we made a decision on risk?
To make a decision on a threat, and what the response should be, is always a judgement. It is usually a decision made by those in authority based on the evidence of experts.
In the climate debate, we are often distracted, generally by those resisting action, by arguments over the level of certainty. The argument is: “We can’t be sure - so we should not act, or at least we should act cautiously, because action is expensive and disruptive”.
History tells us however, that leaders almost never make decisions based on certainty, even if it appears so in hindsight.
For example, there was enormous controversy in the United Kingdom before WWII about how serious the threat was, and what the response should be. Many people, including highly informed experts and leaders, argued about:
The level of threat – was it really that significant?
The cost and consequences of acting on the risk – can we afford the required response? and
The possibility of adapting to the impacts – instead of confronting the cause.
We see much the same debates today on climate.
This is normal human behaviour. As it was before WWII, there is natural resistance to facing an unpleasant reality. War is not something to enter lightly. However, nobody argued in hindsight that the response to the threat was overblown. So we need to acknowledge the natural tendency to understate the risk, especially when addressing it is going to be disruptive to the status quo or the advocates’ self-interest.
This means that, in making a decision on the risk of climate change, we should carefully and impartially examine the evidence, while remaining aware of the natural human resistance to unpleasant reality.
What does the evidence tell us about the level of threat?
First it should be noted that it is not the purpose of ClimateEmergency.com to present the science in comprehensive detail, as this has been done elsewhere. It will be summarised here with extensive references for those who wish to examine it further.
In considering the level of risk, we can draw from an enormous body of strong, peer reviewed science and the analysis of its conclusions by countless credible global bodies and experts in science, economics and politics.
Collectively, this body of work means the world’s most qualified people on the topic [FN1] conclude that:
The threat is here now - climate change is already dangerous today;
The threat is rapidly accelerating - and ahead of earlier predictions; and
The system on which our economy and population relies, is at risk of major global instability.
In terms of outcomes and likelihood, they conclude that we face:
Widespread negative and potentially catastrophic economic, social and environmental impacts that could last for hundreds of years, affecting all countries and many billions of people. This is close to certain.
A further level of existential risk of global economic and social collapse and the descent into chaos and conflict, lasting for centuries. This could result in the collapse of organised global society.
The question on the latter and more serious risk is not whether this outcome is certain on our current path. It is not. The question is whether there is a reasonable likelihood [FN2] of such an outcome, for which there is.
What does the science tell us about the path we are on today?
It is difficult to comprehend a threat at the scale of the climate crisis, let alone a civilisation-wide collapse. And it is very hard to model the consequences or accurately predict the likelihood. But those who have tried to do so, provide a credible and useful reference point for the type and scale of risks involved on the path we are currently on. This work is directionally very important to judging how large the risk is, and how much disruptive action we are prepared to take to reduce the risk.
For context, today, carbon dioxide and methane levels have reached historic highs. This represents our current state of response to the risk. There has been no reduction in the emissions which are creating the risk, some 30 years after it was known climate change was a threat, despite widespread global acceptance of the urgency. We should not confuse high awareness, global treaties and debate with any effective action to alleviate the threat.
Scientist warn that even if the Paris targets were met [FN3], temperatures would surpass 1.5°C warming (the target agreed to in Paris [FN4]), and then increase by 3 to 5°C by 2100 - with additional warming beyond.
The last time the world was 3-5 degrees hotter was 15 million years ago in the Miocene. At this temperature, all of nature will be affected – all coral reefs would have disappeared decades earlier and MIT’s Lorenz Centre predicts that 2100 will ‘herald the beginning of the Earth’s sixth mass extinction event’.
Seas could rise by more than 2 meters (and greater beyond 2100). Between two thirds and all of the glaciers that feed Asia and South America’s most important rivers will likely disappear. A combination of high temperature and humidity levels along the equatorial belt could see tropical regions in Asia, Africa, Australia and the America’s “largely uninhabitable for much of the year”. A large proportion of humanity, including an estimated 2 billion refugees , will need to relocate – many to areas of higher latitude or the lower southern hemisphere where agriculture will still be possible and temperatures tolerable. The global population is over 7 billion today and by 2100 it is likely to grow to 9-11 billion, all of whom will need food, water, power and somewhere to live. It seems unlikely that billions of people relocating would be a smooth or ordered process.
The IPCC reports the cost of just a 1.5° increase in temperature in 2100 at $54 trillion. This is the cost of controlled climate change – something we are not yet achieving.
The cost of the lower end of uncontrolled climate change – the path we are on today - for 3.7° warming is estimated at $550 trillion. This is more than all the wealth currently existing in the world [FN5].
Of course, such analyses are inherently complex and can only give us a directional indication, not accurate forecasts. After all, how do you value the costs of global collapse? Furthermore, there are countless unknowns in the climate system as well as the economic and biophysical responses to it. Therefore, the question is not whether these scenarios are certain on our current path. They are not. The question is whether there is a reasonable likelihood of such an outcome.
In considering that, we should remember our natural human tendency to err on assuming the more positive outcomes we hope for.
Critically, we should also note that the unknowns go in both directions – it may not be as bad as such scenarios suggest. Or it could be much, much worse.
What matters in all of the above, is that any calm and measured review of the evidence of the work of the world’s very best experts in science, economics, risk and all other fields lead us to a simple conclusion.
The threat we are facing presents a high likelihood– close to certainty - of catastrophic impacts lasting centuries and making life on earth very difficult. There is on top of that, a reasonable risk of the collapse of civilisation.
Sir David Attenborough summarised the situation very clearly, in his address to the UN Climate Summit, Katowice, Poland:
“Right now we are facing a man-made disaster of global scale, our greatest threat in thousands of years: climate change…”
“If we don’t take action, the collapse of our civilisations and the extinction of much of the natural world is on the horizon.”
The scale, duration and predictability of the threat
Of particular significance to the question of whether this threat justifies an emergency response are:
The scale of the threat – which is global and negative to all countries and all people [FN6];
The length of time over which the threat will impact society – certainly many hundreds of years, possibly thousands; and
The potential for rapid and unpredictable acceleration of the threat through system feedbacks which could eliminate our ability to influence or control outcomes.
As discussed, this is not a question of certainty. The system is far too complex for that. The question is whether there is a material risk of global chaos and a further risk of collapse. On that, the science and the world’s best experts are strongly and clearly aligned that there is such a material risk.
The scale, duration and unpredictable nature of the threat does not however, by itself, justify a conclusion that this is an emergency.
An emergency response requires two things to both be true:
1. That the threat is real, there is a reasonable likelihood of it occurring and it will have a large and unacceptable impact; and
2. That the response necessary to address and reduce the risk requires an abnormal level of urgency, mobilization and action. In other words, a solution cannot be delivered through normal processes of policy and market economics.
Concluding on the level of threat
Given what’s at stake is global civilization’s capacity to develop, and possibly to survive, this is quite simply the most serious risk humankind has ever faced, certainly for many thousands of years and possibly ever.
Therefore, the likelihood doesn’t need to be high to justify an emergency scale of response, no matter how disruptive that response would be. But analysis of the science by world leading experts on risk suggests the likelihood of climate change having at least very serious impacts, is in fact very high.
While the IPCC and other experts cover the likelihood of risk in some detail from a scientific view, the World Economic Forum’s annual risk report give us a perspective from experts in the world of economics and risk. The WEF 2019 Global Risk Report, draws on various experts including the Institute of Risk Management to describe changes in the global risk landscape.
In the 2019 report ‘Extreme weather events’ and ‘Failure of climate change mitigation and adaptation’ were identified as the two most likely global risks from a total of 30 risks. In addition, ‘Failure of climate mitigation and adaptation’ and ‘Extreme weather events’, were included in the top three risks that have the highest global impact while climate-related risks were recognised as having the strongest influence (highest number and strength of connections) on other risks, particularly social and geopolitical.
Thus, we have a very large threat and high likelihood (together being materiality) supporting a conclusion that an emergency response is the only rational response to the science, but still only if urgency is also present.
footnotes
[FN1] For example:
-IPCC: IPCC Press Release (8 October 2018)Summary for Policymakers of IPCC Special Report on Global Warming of 1.5ºC approved by governments. https://www.ipcc.ch/site/assets/uploads/2018/11/pr_181008_P48_spm_en.pdf
-World Economic Forum: World Economic Forum (2019) The Global Risk Report 2019 14th Edition. Prepared in Partnership with Marsh & McLennan Companies and Zurich Insurance Group. http://www3.weforum.org/docs/WEF_Global_Risks_Report_2019.pdf
-World Meteorological Organization (WMO): WMO Press Release (20 November 2018). Greenhouse gas levels in atmosphere reach new record. https://public.wmo.int/en/media/press-release/greenhouse-gas-levels-atmosphere-reach-new-record
-World Bank: World Bank Climate Change Overview website (last accesses 26 June 2019). https://www.worldbank.org/en/topic/climatechange/overview
-Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IBPES): IBPES Report Release (6 May 2019) UN Report: Nature’s Dangerous Decline ‘Unprecedented’; Species Extinction Rates ‘Accelerating’.https://www.un.org/sustainabledevelopment/blog/2019/05/nature-decline-unprecedented-report/
-UN Secretary General: Secretary-General's remarks on Climate Change [as delivered] (10 September 2018). https://www.un.org/sg/en/content/sg/statement/2018-09-10/secretary-generals-remarks-climate-change-delivered
-Letter from 15,364 top scientist from 184 countries (13 November 2017). World Scientists’ Warning to Humanity: A Second Notice. https://academic.oup.com/bioscience/article/67/12/1026/4605229#105092270
[FN2] For example, a massive meteor strike is an existential risk to civilisation, but it is very unlikely in the next few thousand years.
[FN3] We should not confuse high awareness, global treaties and debate with any action to alleviate the risk. 30 years after the issue first emerged and risk become clear, we are at our highest ever levels of the greenhouse gases which cause heating.
[FN4] The agreement states to hold average global temperature increases to “well below 2°C above preindustrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels”.
[FN5] Information on 4-5 degree warmer future taken from: Vince, G (published 19 May 2019 in the Guardian) The heat is on over the climate crisis. Only radical measures will work. Citing: Johan Rockström, director of the Potsdam Institute for Climate Impact Research; Richard Betts, head of climate impacts at the Met Office Hadley Centre; Daniel Rothman, co-director of MIT’s Lorenz Centre, Geisler & Currens (2017) and Warren, R. et al.(2018). https://www.theguardian.com/environment/2019/may/18/climate-crisis-heat-is-on-global-heating-four-degrees-2100-change-way-we-live?CMP=share_btn_fb&fbclid=IwAR0SWuOBsh3KtyI8KVQ_61rX-nVLwRDn00tXoRN_GXlyIS6wTnTZouJHqYY
[FN6] Some countries and analysts argue some benefit from very marginal economic issues like increased crop yields. Some argue the rich will not suffer and can protect themselves. Both of these ignore the macro-economic global impacts which will cause loss to all countries and people along with the high likelihood of major security and conflict which will cause social and military instability.