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This article builds on the suggestion that objects should be thought of not as bounded entities but as sites of flow, mixture and mutation. In arguing that processes of thermal exchange are outcomes and expressions of socio-material organization, the authors demonstrate the potential for linking concepts from physics and social science. Drawing on a recent study of air conditioning in the UK, they show that increasingly standardised notions of room temperature have implications for product and building design, and for how energy circulates through the many components and bodies involved. In describing indoor climates in these terms, they develop a social analysis of thermal exchange that is relevant at the molecular level and for long-term trends in energy demand and climate change.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

In less than a generation, air conditioning has spread around the world, increasing energy consumption and producing demand where none existed before. How has this come about? This article asks whether transition theories (and the multilevel perspective as an exemplar) are of value in addressing this question and what other approaches might be developed. It is concluded that what seems to be the transnational diffusion of mechanical cooling is best understood as an outcome of multisited processes in which air conditioning is integrated into practices like those of office work, nursing, taking a luxury break or simply living at home. Rather than mapping diffusion across a stable terrain, this perspective argues for a more sophisticated interpretation of how mechanical cooling remakes practices and the places in which they are reproduced. This conclusion has implications for efforts to stem air conditioning and the energy demand associated with it.

Our 12th annual horizon scan identified 15 emerging issues of concern for global biodiversity conservation.A panel of 25 scientists and practitioners submitted a total of 97 topics that were ranked using a Delphi-style technique according to novelty and likelihood of impact on biodiversity conservation.The top 38 issues were discussed at an online meeting held in September 2020 during which issues were ranked according to the same criteria.Six of the 15 issues primarily affect marine or coastal ecosystems and seven are related to human and ecosystem-level responses to anthropogenic climate change.Other emerging issues include complete coverage of Indian states for sustainable farming and the potential for use of selfhealing building materials.

Bacteria can be highly social, controlling collective behaviors via cell-cell communication mechanisms known as quorum sensing (QS). QS is now a large research field, yet a basic question remains unanswered: what is the environmental resolution of QS? The notion of a threshold, or “quorum,” separating coordinated ON and OFF states is a central dogma in QS, but recent studies have shown heterogeneous responses at a single cell scale.

A tragedy of the commons occurs when individuals take actions to maximize their payoffs even as their combined payoff is less than the global maximum had the players coordinated. The originating example is that of over-grazing of common pasture lands. In game theoretic treatments of this example there is rarely consideration of how individual behavior subsequently modifies the commons and associated payoffs. Here, we generalize evolutionary game theory by proposing a class of replicator dynamics with feedback-evolving games in which environment-dependent payoffs and strategies coevolve. We initially apply our formulation to a system in which the payoffs favor unilateral defection and cooperation, given replete and depleted environments respectively. Using this approach we identify and characterize a new class of dynamics: an oscillatory tragedy of the commons in which the system cycles between deplete and replete environmental states and cooperation and defection behavior states. We generalize the approach to consider outcomes given all possible rational choices of individual behavior in the depleted state when defection is favored in the replete state. In so doing we find that incentivizing cooperation when others defect in the depleted state is necessary to avert the tragedy of the commons. In closing, we propose new directions for the study of control and influence in games in which individual actions exert a substantive effect on the environmental state.Game theory is based on the principle that individuals make rational decisions regarding their choice of actions given suitable incentives [1, 2]. In practice, the incentives are represented as strategy-dependent payoffs. Evolutionary game theory extends game theoretic principles to model dynamic changes in the frequency of strategists [3]. Replicator dynamics is one commonly used framework for such models. In replicator dynamics, the frequencies of strategies change as a function of the social makeup of the community [4][5][6]. For example in a snowdrift game (also known as a hawk-dove game), individuals defect when cooperators are common but cooperate when cooperators are rare [2]. As a result, cooperation is predicted to be maintained amongst a fraction of the community [4, 6]. Whereas, in the prisoner's dilemma individuals are incentivized to defect irrespective of the fraction of cooperators. This leads to domination by defectors [6, 7].Here, we are interested in a different kind of evolutionary game in which individual action modifies both the social makeup and environmental context for subsequent actions. Strategy-dependent feedback occurs across scales from microbes to humans in public good games and in commons' dilemmas [8][9][10][11]. Amongst microbes, feedback may arise due to fixation of inorganic nutrients given depleted organic nutrient availability [12, 13], the production of extracellular nutrientscavenging enzymes like siderophores [14][15][16] or enzymes like invertase that hydrolyze diffusible products [17], and * Electronic address: jsweit...

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