No climate wars AND they’d be localized and easily defused.

While the concern for the effects of global warming is new, the underlying argument about armed conflict and other social consequences bears extensive similarities to the traditional neoMalthusian argument. Indeed, as Meierding (2013: 186) points out, ‘quantitative climate change–conflict researchers usually import arguments from earlier environmental conflict studies or from the civil wars literature’ and the same would seem to apply to the non-quantitative literature as well. Once again, even though climate change is not a traditional pollution issue, the fear of developing scarcities is at the core. The IPCC reports that a warmer climate will lead to more drought and be detrimental to agriculture, particularly rain-fed agriculture in Africa and the Middle East. Excessive temperatures may drive people away from their traditional homelands and force them to become migrants, leading to competition for scarce resources in their countries of arrival. Other parts of the world may be more affected by excessive rainfall, leading to floods that will negatively affect human habitation and livelihoods. More generally, a warmer climate will increase the probability of natural disasters such as storms and hurricanes. Rising sea levels will threaten low-lying areas as well as coastal cities and may make small low-altitude islands uninhabitable. The warming of the oceans will also impact the world’s fisheries, with possible consequences for another important component of food security (IPCC, 2019b).

The first reports from the IPCC paid little direct attention to armed conflict. The Third Assessment Report (IPCC, 2001) made a few references to the potential for climate change-induced conflict, mainly water wars, conflicts generated by migration, and resource wars. The report had a weak basis in peer-reviewed literature. The Fourth Assessment Report (IPCC, 2007) contained even fewer references to armed conflict. The Fifth Assessment Report (AR5) included a chapter on human security with a 4.5-page section on conflict, which noted that ‘collectively the research does not conclude that there is a strong positive relationship between warming and armed conflict’ (IPCC, 2014: 772). The report also noted ‘high agreement’ that ‘in the specific circumstances where other risk factors are extremely low […], the impact of changes in climate on armed conflict is negligible.’ The Africa chapter noted the possibility of water conflict. A chapter labeled ‘Detection and attribution’, devoted to assessing the robustness of relationships reported in other chapters, dismissed the link from climate change to violence out of hand. More recent reports from IPCC do not deal extensively with armed conflict, although it is briefly mentioned in the special reports on the impact of 1.5° global warming (IPCC, 2019a: 245), on the oceans (2019b: 30), and on land use (2019c: 23, 25), and neither will AR6 (IPCC, 2021).

While there is wide agreement that climate change poses large challenges to human security in a broad sense (IPCC, 2014, WG II: Ch. 12), the academic literature on climate change and armed conflict remains divided (Koubi, 2019; Mach et al., 2019). A common feature in most of the relevant research is that hypotheses about increasing scarcities provide the starting point regardless of whether the authors conclude in favor of a positive relationship or not. Key scarcities are reductions in arable land and a declining supply of food, fresh water, and the yield of fisheries. Important mechanisms assumed to generate increased scarcity from climate change are cross-border migration, domestic rural-to-urban migration, rising inequalities, interethnic tensions, climate changes that affect different groups unequally, pre-existing competition for scarce goods, competing claims to resources, and the response or lack of response of national and international authorities.

In this special issue, Mach & Kraan (2021) focus on interactions between science and policy. All the other articles feature emerging or increasing scarcities (mostly within but also between nations) as key mechanisms in translating climate change into violence and armed conflict, frequently through involuntary migration. Other links could of course have been hypothesized. If climate change were to lead to greater abundance in some areas (despite an overall decline), groups could have been assumed to fight over increased spoils, as in models of conflict driven by opportunity rather than grievance (Collier & Hoeffler, 2004). Alternatively, the link between climate change and violence could have been derived from the literature on heat and aggression (Anderson, 2012), which suggests that higher temperatures will lead to physical violence at the level of individuals and groups. But in fact, the academic work reported in this special issue is framed within a grievance model of conflict, with scarcity as the main source of grievance, as in the IPCC reports and in the earlier literature on environmental change and conflict more generally. This also applies to articles that study wider forms of human insecurity resulting from climate change (such as Adger et al., 2021). That said, these articles do not always take a neoMalthusian starting point, nor do they find unqualified support for the scarcity model – but the hypotheses tested are generally about scarcities.

As noted by Busby (2021), climate change has become a prominent policy concern for the international community. President Barack Obama, several Secretaries-General of the UN, and other prominent figures have argued that climate change is likely to increase the risk of violent conflict, and similar concerns are widely voiced by the environmental movement. The Extinction Rebellion lists sea-level rise, desertification, water shortage, and crop failure as unprecedented effects of the present climate and ecological disruptions.5 The environmental activist Greta Thunberg claimed, in a dramatic speech to the UN General Assembly, that because of climate change, ‘People are suffering. People are dying.’6 Public support can be found even for quite extreme views. For instance, a YouGov poll in July 2019 found that a majority in the USA and nine European countries thought that it was likely (‘quite likely’ or ‘very likely’) that climate change would cause small wars, around one-third thought that it would cause a new world war, and about as many that it would result in the ‘extinction of the human race’.7 In ten countries in Asia, the pessimism was even more pronounced.8 David Wallace-Wells (2019), in a book tellingly titled The Uninhabitable Earth, attempts to demolish the line between alarmism and realism. And because the effects of human-induced climate change are quite unprecedented, there may be a limit to what can be learned by looking to earlier environmental debates (Meierding, 2013: 200).

The optimists’ responses to climate change

The most extreme contrarian position is, of course, to deny one or both key conclusions of the IPCC: the reality of global warming or the human contribution to it. However, most environmental optimists accept these two key conclusions but raise other problems with the panel’s discussion of the social effects of climate change and even more so with popular interpretations of the panel reports. For instance, Hausfather & Peters (2020), by no means ‘climate deniers’, decry the common use of choosing the high-risk RCP8.59 to illustrate ‘business as usual’ as misleading.

The causal chains from climate change to the proposed effects on human beings are long and complex, and the uncertainty increases every step of the way. In the literature on the social effects of climate change, including the IPCC reports, statements abound that something ‘may’ lead to something else, or that a variable ‘is sensitive to’ another, without any guidelines for how to translate this into probabilities (Gleditsch & Nordås, 2014: 87f). Uncritical use of the precautionary principle, where any remotely possible calamity unwittingly becomes a probable event, is not helpful.

Gleditsch & Nordås (2014: 85) note that while AR5 (IPCC, 2014) did not find strong evidence for a direct link between climate change and conflict, it argued that climate change is likely to impact known conflict-inducing factors like poverty and inconsistent political institutions and therefore might have an indirect effect on conflict. But this assumes that correlations are transitive, which is not generally the case. If A correlates with B and B with C, we know nothing about how A relates to C unless both correlations are extremely high. The strongest case for the climate–conflict link is the effect of interaction between climate change and factors like poverty, state failure, or ethnic polarization. It may be more cost-effective to try to deal with these other risk factors than with global warming itself if the goal is to reduce the ‘risk multiplier’ effect of climate change on armed conflict.

The articles in this special issue do not generally see scarcity by itself as necessarily resulting in strongly negative outcomes. Factors like development, state failure, and previous overload on ecosystems continue to play an important role in that they interact with climate change to produce conflict and other social outcomes. For instance, Ide, Kristensen & Bartuseviĉius (2021) conclude that the impact of floods on political conflict are contingent on other factors such as population size and regime type. Moreover, most of the articles do not assume that scarcities are likely to arise at the global level. They may be regional (mostly in Africa), national, or local. Urban and rural areas may be affected by different scarcities. Climate change may also affect particularly strongly groups that are already at an economic or political disadvantage. The effects can be alleviated and adaptations constructed at these levels.

The argument about how climate change may indirectly impact conflict leans heavily on the negative economic consequences of climate change, but with little or no reference to the research that explicitly deals with this topic. In fact, the relevant chapter in AR5 concluded that for most sectors of the economy, the impact of climate change was likely to be dwarfed by other factors. Tol (2018) finds that the long-term global economic effects are likely to be negative, but that a century of climate change will have about the same impact on the economy as the loss of one year of economic growth. Other economists are more cautious, but the dean of climate change economics, William Nordhaus (2018: 345, 359), estimates that ‘damages are 2.1 percent of global income at 3°C warming and 8.5 percent of income at 6°C’, while also warning that the longer the delay in taking decisive action, the harsher the necessary countermeasures. Stern (2006) is more pessimistic, based mainly on a lower discount rate (the interest rate used to calculate the present value of future cash flows) as are Wagner & Weitzman (2015). Heal (2017) argues that the Integrated Assessment Models generally used in the assessment of the economics of climate change are not accurate enough to provide quantitative insights and should not be taken as serious forecasts. Yet, all these economists take the basically optimistic view that climate change is manageable with appropriate policies for raising the price on the emission of greenhouse gases. With a chapter heading from Wagner & Weitzman (2015: 17): ‘We can do this’.