How long do we have to address this risk?
Having concluded the risk is very high - both the size of threat and the likelihood - our next question is whether the response to the risk requires an abnormal level of mobilization and action (i.e. an emergency response), or whether it could be dealt with through the normal reform processes of policy and markets, as we are currently doing.
This is a question of both:
Scale: how broad is the change required; and
Speed: how fast do we need that change to have an impact.
The science - and the analysis of this science by other experts - give us clear information on both these issues.
For example, the IPCC’s 1.5°C report in 2018 had a headline conclusion that we need to first cut CO2 emissions by 45% by 2030 (from 2010 levels) then reduce them to zero by 2050. This compares to the globally agreed Paris climate targets which involve not a 45% reduction but an increase in emissions by 2030 [FN7].
To turn the situation around in just a decade - from an increase to a massive decrease - would require a broad and transformational change in the direction and structure of the economy. This is sufficient by itself to justify an emergency response – an abnormal level of mobilisation – when added to the scale of risk and impacts described above. Only an emergency mobilisation could possibly achieve such a result in such a short time.
However, if we examine the actual science and work of the IPCC we can conclude it is highly probable that this level of action considerably understates the scale and speed of change required.
JUST HOW URGENT IS THIS? HOW SHOULD WE JUDGE THAT?
There are three issues to consider in regard to the urgency of action, remembering this all involves judgement, based on evidence:
How conservative are the scientific models’ predictions of impacts?
How conservative is our interpretation of them?
What level of risk are we prepared to take, given what’s at stake?
How conservative are the forecasts of impacts?
There is growing evidence that, while the modelled pathways of warming rates have been broadly accurate, the IPCC have consistently underestimated the speed and scale of the climate impacts in turn caused by this warming [FN8].
This is understandable given the incredible complexity of the climate system and its influence on other natural systems, the variability and limitations of models’ data and the requirement for consensus among reviewers which tend to result in understatement of the severity of impacts. This all reinforces the natural tendency of science to be conservative.
However the consequences of this can be quite serious, as was argued in a recent report from the Breakthrough Climate Centre,, “What Lies Beneath”. In a summary of the report, the author said:
“..IPCC reports also tend toward reticence and caution, downplaying the more extreme and damaging outcomes...This is of particular concern with potential climatic ‘tipping points’- passing of critical thresholds which result in step changes in the climate system…Under-reporting on these issues is irresponsible, contributing to the failure of imagination in our understanding of, and response to, climate change”…If climate policy making is to be soundly based, “a reframing of scientific research within an existential risk-management framework is urgently required, both in the work of the IPCC and in UN climate negotiations.Current processes will not deliver either the speed or the scale of change required”.
How conservative is our interpretation of the forecasts?
How we interpret the science is a separate issue from the science itself. In this interpretation we face a further problem, particularly given the context that facing up to risks and threats at this scale is unprecedented and very difficult to do.
We should be aware of just how challenging it is for people to incorporate a threat of this nature fully into their thinking. As academic experts in how we do so concluded:“even for an honest, truth-seeking, and well-intentioned investigator it is difficult to think and act rationally in regard to… existential risks”
Prof. Hans Joachim Schellnhuber is one of the world’s leading scientists in climate impact research. He heads the Potsdam Institute for Climate Impact and has acted as senior advisor to Pope Francis, German Chancellor Angela Merkel and the European Union. He understands the scientific process as well as anyone in the world, but is also close to political and other leaders and observes them then interpret the science.
He points out that the current climate is a “a unique situation with no precise historic analogue”in which “the level of greenhouse gases in the atmosphere is now greater, and the Earth warmer, than human beings have ever experienced”. What’s at stake “is the very survival of our civilisation, where conventional means of analysis may become useless”. (Emphasis added).
With respect to the science, Schellnhuber argues: “One should not be overly critical of the IPCC, since the scientists involved are doing what scientists are expected to do, to the very best of their ability in difficult circumstances. But 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.”
Thus we can conclude the issue is not primarily how the science is done. The problem is how we respond to it. However, even if it is understandable, the consistent pattern of underestimating impacts, leaves policymakers and all who follow the issue with an incorrect impression of the scale of the problem and the urgency of the required action.
This is because, firstly, the science is naturally conservative on the level of risk. Then, secondly, as discussed in the previous section, we default to further understating the risk because the implications of accepting and therefore addressing it are disruptive, frightening or just uncomfortable.
While we cannot have certainty, we can reasonably assume, given the above, that the risk is significantly higher than is generally recognised, while noting that the generally recognised level of risk is already very high.
This reinforces an urgency conclusion because:
It is already very urgent, using a conservative view of the risk; and
It is likely to be far more urgent than this conservative view suggests.
How much risk are we prepared to take?
A second key consideration for the level of urgency, is the judgement we make on what level of risk we are prepared to take. What is our goal in terms of the likelihood of success of our planned response?
In this regard and following on from the points made about conservatism on the nature and scale of the threat, it seems the public and policy makers then misinterpret even those conservative conclusions in a quite dangerous way. A way that increases the risk of the serious and uncontrollable catastrophe of runaway climate change.
For example, as discussed above, the IPCC report on 1.5 °was widely reported as concluding we needed to reduce CO2 emissions by 45% by 2030 (compared to 2010) and then to zero CO2 emissions by 2050, to keep warming below 1.5°C [FN9]. However, what the report actually says in the detail is that this is what is required if our goal is to have around a 50% likelihood of success [FN10].
Given the risk is to the future stability of global civilisation, this is clearly an illogical level of action for global leaders and the market to plan for. It means we are effectively choosing to ‘flip a coin’ on the future of civilisation.
It is also an approach to risk that is quite out of step with any other assessment of major risk that society undertakes. No security or defence strategy or indeed any strategy dealing with a catastrophic risk in business would accept a plan of action that the best experts considered had only around a 50% likelihood of success [FN11].
We don’t need to resolve these numbers in the short term, and precision is not possible anyway in such a complex system with current knowledge and computing capacity. We do need however to make an intelligent judgement based on available expert advice.
Based on that, it seems likely we are seriously underestimating both the level of risk we face, and the level of urgency required.
Footnotes
[FN7] Considering current global policies, emission projections are predicted to be ~ 57-60 GtCO2e pa by 2030, this is an increase of 4-7 GtCO2e pa on approximate current emissions (2019). According to the IPCC’s 1.5°C Report, if Paris pledges and targets are met, emissions are predicted to reach 54-57 GtCO2e pa by 2030, while this is lower than out current path, it is still an increase of 1-4 GtCO2e pa on today’s emissions. Data provided by Climate Action Tracker
[FN8] Observed impacts of warming on Arctic sea ice, Polar ice mass loss and sea levels are greater than IPCC models have projected. For further review see :
Steffen et al (2018) Trajectories of the Earth System in the Anthropocene (also referred to as Hot House Earth paper). PNAS Latest Articles. http://macroecointern.dk/pdf-reprints/Steffen_PNAS_2018.pdf
Spratt & Dunlop (2018). What Lies Beneath: The understatement of existential climate risk. Breakthrough National Centre for Climate Restoration. https://www.breakthroughonline.org.au/whatliesbeneath
[FN9] It is interesting to note that in AR5, the carbon budget for a 66% chance of limiting warming to 1.5°C, is 302 GtCO2 larger in SR15, as it assumes heavy reliance on achieving negative emissions in the future (e.g.: BECCS and reforestation), despite there being no scale programmes in place today to act on this .
[FN10] “This report defines a ‘1.5°C pathway’ as a pathway of emissions and associated possible temperature responses in which the majority of approaches using presently available information assign a probability of approximately one-in-two (50%) to two-in-three (66%) to warming remaining below 1.5°C or, in the case of an overshoot pathway, to warming returning to 1.5°C by around 2100 or earlier”. (IPCC 2018. SR15, Ch.1,pp 60). For a 50% likelihood of limiting warming to 1.5°C (based on a carbon budget of 580 GtCO2 from 2018 levels), emissions need to reach carbon neutrality in ~ 30 years (2050 – the target identified in the reports headline statement), to increase this likelihood to 66% however, carbon neutrality would need to be reached a decade earlier - 2040(based on a carbon budget of 420 GtCO2 from 2018). (IPCC 2018. SR15, Ch.2, pp 96).
[FN11] The IPCC 1.5°report’s assessment of mitigation pathway scenarios, found no pathways were available that achieved a greater than 66% probability of limiting warming below 1.5°C during the entire 21st century (IPCC 2018. SR15, Ch.2, Table 2.1, pp 100). As indicated in footnote 9, carbon budgets (albeit with high uncertainty range) were also developed for 1.5°C. For a 50% likelihood of limiting warming (580 GtCO2from 2018), emissions need to reach carbon neutrality in ~ 30 years (2050), but to achieve a 66% likelihood (420 GtCO2 from 2018), carbon neutrality would need to be reached a decade earlier (2040) (IPCC 2018, SR15, Ch.2, pp96).