(Art direction and design: Jean-Dominique Lavoix-Carli)

“Climate breakdown has begun” warned UN Secretary-General António Guterres in a statement released on 6 September 2023.

Globally, throughout the 2023 Summer, the world has lived through the beginning of the turmoil and havoc that climate change and related temperature rise bring. Repeated heatwaves, related air pollution “with knock-on effects on human health, ecosystems, agriculture and indeed our daily lives,” as stated by WMO Secretary-General Prof. Petteri Taalas, drought, mega wildfires, medicanes (Mediterranean hurricanes), climate-driven storms, hurricanes, devastating floods, have globally scarred the Summer (UN News, “‘Climate breakdown’ alert as air quality dips during heatwaves: UN chief” 6 September 2023).

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If climate breakdown has commenced and if its start entails so many disasters, then we must imperatively begin proactive planning to protect us from havoc. Especially, we need to have a better idea of what is more likely to happen among the various scenarios and hypotheses identified and studied by the Intergovernmental Panel on Climate Change (IPCC). This will enable us to outline potential trends that will constrain our lives, governance, and geopolitics. In other words, we shall make a draft of the structure of the world and its polities, under likely conditions of climate change.

Thus, first, we shall stress where we stand exactly in terms of temperature rise caused by climate change. Then, using the March 2023 synthesis of the Sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC), we shall look at the climate change scenarios for the future, notably through the perspective of carbon budgets. We shall explore what that means at both the global level and individual countries’ level, with a focus on the largest emitters. Building upon this last point, we shall deduce future consequences. We shall notably wonder if, in the future, some states could try to force others to reduce their emissions rather than seek to cooperate.

Where we stand in 2023

In a nutshell, we have been living between 2011 and 2020 at 1.1°C  above the levels of temperature that existed between 1850 and 1900, which are considered as the healthy norm. In 2022, the average global temperature was about 1.15°C in excess  (UN News, “2022 confirmed as one of warmest years on record: WMO“, 12 Jan 23).

Earth had the hottest three-month period on record, with unprecedented sea surface temperatures and extreme weather.

🗣️: #StateOfClimate
🔗: https://t.co/Mnt7t1g2VU
📷: @CopernicusECMWF pic.twitter.com/Chje3zZ4A0

— World Meteorological Organization (@WMO) September 6, 2023

The Summer (June-July-August) of 2023 was the hottest on record globally “by a large margin, with an average temperature of 16.77°C, 0.66°C above average” (Copernicus Climate Change Service, “Summer 2023: the hottest on record“, 5 Sept 23). August 23 was the warmest August on record, and its temperatures second only to July 23 (ibid.). It is estimated to be around 1.5°C warmer than the healthy norm (ibid.).

Hence what was lived over the last years and more particularly over the Summer 23  represents the start of a very concrete experience of what we can expect next.

The near-future reality will probably be worse than what we experienced over the Summer.

Indeed, some harmful effects of rising temperatures may still remain to be discovered. For example, scientists seem to start agreeing on the possibility that the poles’ melting ice may trigger earthquakes, as well as tsunamis. Yet those would be limited to certain regions, close to the poles, and take place only in thousands of years (Anthony Kaczmarek, “Le réchauffement climatique peut-il provoquer davantage de séismes ?“, tameteo.com, 11 April 2023). Research and development of models are ongoing (Rebekka Steffen et al., “Early Holocene Greenland-ice mass loss likely triggered earthquakes and tsunami“, Earth and Planetary Science Letters, Volume 546, 2020; Rebekka Steffen, “Un lien entre changement climatique et séismes à l’origine de tsunamis inattendus ?“, Axa fund for research, 25 June 2018).

Other impacts are known, but can be insidious and will skyrocket. For example, houses so far perfectly fine, suddenly start showing cracks because of drought. This stems from the shrink-swell capacity or shrinkage and swelling of clayey soils (retrait-gonflement des argiles – RGA), one of the consequences of drought – as a consequence of heatwave – and floods on expansive soils (e.g. Géorisques). It hits all countries with such soils and dwellings built upon them are at risks. For example, in France, the government estimated in June 2021 that “10.4 million individual houses [were] potentially very exposed to the phenomenon” up from 4,27 million in 2017 (Cerema, “Phenomenon of shrinkage and swelling of clayey soils (RGA): definitions, impacts on structures and people and solutions for adaptation to climate change,” 14 April 2022). 84% of French communes have more than 50% of their houses exposed with a risk ranging from low to high (MNR, Reference systems for the resilience of buildings to natural hazards, July 2023).

As a result, direct costs in terms of reinforcement of houses or even relocation of dwellers will be high (Ibid.). Worse still, the capacity to carry out the work will need to be available in the proper timeframe, which may lead to local challenges and tensions. Furthermore indirect costs such as psychological impacts start being estimated as being far from being negligible (Ibid.) Meanwhile, roads may also be impacted, which will likely increase the challenge faced (ibid.).

The global impacts of the Summer 2023 on individual dwellings and roads are still to be evaluated.

As the Intergovernmental Panel on Climate Change (IPCC) assesses with high confidence:

“Every increment of global warming will intensify multiple and concurrent hazards”.

Climate Change 2023, Synthesis Report – Summary for Policymakers, 20 March 2023, p.12

Meanwhile, cascading effects are almost certain.

Where we could stand in the future: the IPCC scenarios and carbon budgets

On 20 March 2023, the IPCC released the synthesis of its Sixth Assessment Report (AR6). The latter highlights possible scenarios for climate change and temperature rise, each with varying likelihoods, according to what is potentially done in terms of emissions of carbon dioxyde (CO2) and more generally Greenhouse Gas (GHG).

Looking at climate change through carbon budgets

Carbon budgets

The simplest way to look at the problem of climate change and GHG emissions is to think in terms of carbon budget.

Imagine the planet endowed with the capability to store a certain amount of carbon dioxyde or greenhouse gas. Because it can store these gas, and as long as it can do so, then it can safely emit these gases in the atmosphere. Below a given amount of gas, which corresponds to the capacity of storage or carbon budget, despite emissions, the temperature of the planet does not change and remains within healthy norms. Once the storage has reached full capacity, then the carbon budget is spent, further emissions cannot be stored anymore and the temperature starts rising with its corollary of adverse and deleterious impacts. Hence, using this principle, for each level of temperature in excess, a remaining carbon budget, compared to what has been spent so far, is approximately calculated.

What must be understood is that the carbon budget of the planet is for ever. It cannot be exceeded without consequences in terms of temperature change. If we want to emit CO2 and other GHG again, without consequences, then the amount of GHG in the atmosphere must first be lowered, which would mean decarbonisation.

For example, if we want the temperatures to remain at 1.5°C in excess, with little or no overshoot (i.e. up to about 0.1°C above the scenario level for up to several decades), and with a 50% likelihood, then scientists best estimates tell us that starting in 2020 we had 500 GtCO2 left (AR6). If we limit in the meantime other GHG emissions, then the budget for CO2 can become 600 GtCO2 (AR6). Inversely if we emit a lot of other GHG then the budget for CO2 may become only 300 GtCO2 (AR6).

If we wanted to increase the probability to see the temperature in excess remaining within the bounds of 1.5°C, for example to 83%, then the remaining global budget would become 300 GtCO2 (Patrik Erdes, Carbon Budget Calculator).

This implies that all countries must reach at one stage net zero emissions.

What are the consequences in terms of way of life and governance?

The new art of governance for a country will thus be to integrate at all levels, in all policies and actions, a balance between the level of one’s GHG emissions with direct consequences in terms of way of life, on the one hand, and, on the other, the impact of contributing to the global overspending of the carbon budget, i.e. consequences in terms of temperature excess, climate change and then cascading and self-reinforcing effects. And that, of course, without forgetting any of the principles that historically and fundamentally rule the art of governing, such as legitimacy and providing security to citizens.

However difficult, the new art of governance under conditions of climate change, furthermore, to be efficient, demands that all countries act similarly in a considerate and responsible way.

Scenarios of temperature rise and global carbon budgets

Now, we have seen the general principles, more concretely, what are the remaining global carbon budgets for the various possible temperature increases highlighted in the AR6 until reaching net zero emissions (5 scenarios of emissions and 3 sub-scenarios) ?

What does that let us expect globally ?

In 2019, global CO2 emissions from fossile fuel combustion and cement production stood at at 35,3 Gt, in 2020, because of the Covid 19, at 33,4 Gt, in 2021 at 35,5 Gt and finally in 2022, they reached 36,1 Gt ((Liu, Z., Deng, Z., Davis, S. et al., “Monitoring global carbon emissions in 2022“, Nat Rev Earth Environ 4, 205–206, 2023). 

Thus, not only we do not decrease our global CO2 emissions, but we increase them, which is exactly opposite to what should be done. In two years, we have used almost 14% of the remaining budget to have a temperature increase of 1.5°C.

The United Nations highlights the current “Climate Emergency” in their Emissions Gap Reports (link to the 2022 edition). Considering current policies, we are on track for probably worse than the 2.8°C temperature rise by the end of the century estimated by the UN (Ibid).

What does that mean for individual states?

Let us now look at the situation for some of the largest emitters, taking into account their population to estimate their specific carbon budget, using Patrik Erdes’ convenient Country Carbon Budgets Calculator (2019 population estimates).

If countries do absolutely nothing, apart from India, it appears obvious that the largest emitters, even considering a carbon budget allowance related to their population, will all soon have spent their budget for a 1.5°C temperature increase. Furthermore, by 2030, if the U.S. does not reduce its emissions below the 2019 level, then it will also have spent its carbon budget for a rise in temperature limited to 2°C. 

If an effort is done towards reducing emissions regularly to reach net zero, then the U.S. still runs out of carbon budget in 2027 for the 1.5°C scenario, and thus is on a course for more than 2°C globally.

The disparities in time to net zero emissions and efforts to reach this state in a context of national interest, competition for power, ideology demanding an ever-lasting growth, let us expect that, most probably, most states will not willingly make the necessary effort to reduce their GHG emissions.

Possible future consequences

Thus, we need to get ready to live in a planet that knows at least a 2°C rise in temperature, which will certainly mean radical changes in our ways of life. We must prepare to adapt to live in extreme environments, as soon as possible (e.g. Extreme Environments Security; Helene Lavoix, “The Ultimate Key Technologies of the Future (3) – Extreme Environments“, RTAS, 21 June 2021).

Meanwhile, as we have seen above with the carbon budget, the new governance in a warmer world becomes more complex, with, as a result, more room for a host of tensions and challenges. 

Furthermore, countries, their citizens and governments will have to bear the brunt, in terms of survival and legitimacy, of others’ actions in terms notably of GHG emissions. 

As a result of these two nexusses, one direction that could be taken is a mammoth effort towards decarbonisation. The way the latter is endeavoured, its timeline, who is carrying it out and how, may create very different paths forward. 

Conversely, in the absence of relatively rapid and consistent global decarbonisation, with States facing duress within their borders, given the repeated failure to cooperate effectively on the issue of GHG emissions, can we imagine a future where some States try to force others to reduce their emissions? This would mean war.

Scenarios considering this possibility should be envisioned, even though they may be perceived initially as unlikely.

In examining such cases, we would also have, for example, to take into account the very cost of a war in terms of GHG emission.

One such study focuses, for instance, on the first seven months of the war in Ukraine (Lennard de Klerk et al., Climate Damage Caused by Russia’s War in Ukraine, Initiative on GHG accounting of war, 1 Nov 2022). It estimates that the cost “totals at least 100 million tCO2.”

However large, this amount only represents 1.58% of the 2018 yearly GHG emissions of the United States and 0,72% of the 2018 yearly emissions of China.

However, the study does account neither for the diminution of emissions in Ukraine – if any – resulting from industrial and agricultural destructions, nor for the increase in GHG emissions stemming from changes in patterns of international flows, new production of armaments, or destruction of carbon sinks, etc.

Yet, for our purpose, to get a real idea of the cost of the war in Ukraine in terms of GHG emissions we would also need to consider the destruction of industrial activity and food production.

For example, and to give an order of magnitude, the collapse of the Soviet Union led to a fall of approximately 40% of GHG emissions (Jean-Michel Valantin, Menace Climatique sur l’Ordre Mondial, 2005). Indeed, considering the economic collapse of the countries of the former Communist bloc, in 2007 the emissions of these states “were still about 37 percent below 1990 levels” (Bill Chameides, “Did the Kyoto Protocol Miss the Target?“, The Green Grok – Archive, 12 Oct 2009). As far as agricultural activities and food production are concerned, we now know more precisely,  that following the collapse of the Soviet Union we had a cumulative net reduction of 7.61 Gt CO2 from 1992 to 2011 in GHG emissions (Florian Schierhorn, “Large greenhouse gas savings due to changes in the post-Soviet food systems“, Environ. Res. Lett. 14 065009, 2019)

Thus, if we consider on the one hand the order of magnitude estimated by the study of the increase of GHG emissions linked to the war in Ukraine, and on the other hand possible drop in emissions over many years consecutive to a collapse, then some countries could consider that the cost in GHG emissions of a war are worth destroying industrial, energetic and agricultural activity of other large emitters. This would, of course, mean they have such states have the power to destroy the activity of others.

Specific and detailed scenarios must be created to account for the possibility to see war used as a way to reduce the GHG emissions of others. 

Climate change will bring numerous unsettling novelties, many of which will be dire. Only by lucidly anticipating and planning for these changes can we hope to survive and eventually reconstruct a more promising world.