NETs range from afforestation to bioenergy with carbon capture and storage. They are seen by many as instrumental in achieving the mitigation objectives of the Paris Agreement. However, uncertainty remains regarding the technical, economic, and political feasibility of the large-scale deployment of NETs. The focus in this chapter is on whether a state may lawfully presume, for instance in the course of determining its long-term low-greenhouse-gas-emission development pathway under Article 4(19) of the Paris Agreement, that a future large-scale deployment of NETs will be realized. Gareth Davies maintains that that makes perfect sense, not least because conventional mitigation methods are in the same boat (of uncertainty), and that in other respects as well conventional methods are on a continuum with NETs. By contrast, Duncan McLaren and Wil Burns argue that any heavy reliance now on a presumed large-scale availability of NETs in the future would be irresponsible, unethical, and unlawful.

An increasing number of jurisdictions are using environmental impact assessment as a tool for climate change mitigation (in brief, ‘Climate Assessment’, or CA). This chapter debates whether this is a legal obligation, or whether this even makes sense. Benoit Mayer argues that CA is emerging as a rule of customary international law, and that, moreover, it is a potentially useful mitigation tool. Alexander Zahar, by contrast, questions the meaningfulness of CA, arguing that it is impossible to determine what constitutes a significant, excessive, or disproportionate emission of greenhouse gases in the case of a proposed activity subject to CA, or at all.

This chapter debates the appropriateness of the Paris Agreement’s ‘compliance’ system. The treaty’s Article 15 establishes ‘a mechanism to facilitate implementation of and promote compliance with the provisions of this Agreement’. Views differ radically on the legal mandate of this mechanism and its capacity to ensure that states comply with their treaty obligations. Meinhard Doelle praises the mechanism’s ability to sensitively inform domestic political and legal processes and, thus, to increase the likelihood of an effective implementation of states’ obligations. Anna Huggins develops the argument that an effective compliance system comprises both facilitation and enforcement elements, yet the Paris mechanism limits itself to facilitation. Moreover, in its facilitative role, the mechanism is duplicative of other facilitative elements of the Agreement.

This chapter debates whether litigation is a meaningful way to attack the problem of climate change mitigation. For the proponents of climate litigation, who side is taken by Cinnamon Piñon Carlarne, their action has the potential to ensure that states take more ambitious action than they would have taken otherwise. But the argument developed on this side is even stronger, namely that the courts have a positive duty to take decisions in support of mitigation of emissions. Guy Dwyer, for the sceptics, contends that litigation is the least promising way to go about addressing climate change mitigation because several unavoidable hurdles that face pro-climate litigants all but guarantee their defeat. Indeed, Dwyer argues, the number of cases that might have caused emissions to be reduced can be counted on half of one hand.

This chapter debates the displacement impacts of climate change. Is there a need for some sort of law on ‘climate migration’? Above all, does it make sense to talk about climate migration as a discrete phenomenon? Ingrid Boas argues that ‘climate mobility’ is real and observable and takes many forms (hence climate mobilities), including that of immobility (the decision to stay put despite the pressures to move). She makes the case for this phenomenon being a proper subject of research and governance. Calum Nicholson, by contrast, argues that climate migration researchers literally have no idea what they are talking about. These scholars, he claims, have made a virtue of imprecision in order to keep attracting research grants to study the individual experiences of those allegedly affected by the impacts of climate change, from which no generalizations could possibly be drawn.

This chapter debates historical responsibility for climate change. The argument from historical responsibility has a legal dimension, as it is often used to assert the heightened mitigation and compensation obligations of some states. The debate here begins with the question of whether certain historically high-emitting states are legally bound to provide some sort of compensation for past levels of greenhouse gas emissions. Sarah Mason-Case and Julia Dehm answer this question in the affirmative, arguing that international law, but also notions of justice, provide bases for recognizing historical responsibility and for claiming reparation for the wrongs inflicted. Alexander Zahar, on the negative side, attacks the assumption that historical emissions and their growth rate since Industrialization are known accurately enough, such as to allow for blame to be pinned on certain countries and not others.

This chapter debates the displacement impacts of climate change. Is there a need for some sort of law on ‘climate migration’? Above all, does it make sense to talk about climate migration as a discrete phenomenon? Ingrid Boas argues that ‘climate mobility’ is real and observable and takes many forms (hence climate mobilities), including that of immobility (the decision to stay put despite the pressures to move). She makes the case for this phenomenon being a proper subject of research and governance. Calum Nicholson, by contrast, argues that climate migration researchers literally have no idea what they are talking about. These scholars, he claims, have made a virtue of imprecision in order to keep attracting research grants to study the individual experiences of those allegedly affected by the impacts of climate change, from which no generalizations could possibly be drawn.

This chapter debates whether litigation is a meaningful way to attack the problem of climate change mitigation. For the proponents of climate litigation, who side is taken by Cinnamon Piñon Carlarne, their action has the potential to ensure that states take more ambitious action than they would have taken otherwise. But the argument developed on this side is even stronger, namely that the courts have a positive duty to take decisions in support of mitigation of emissions. Guy Dwyer, for the sceptics, contends that litigation is the least promising way to go about addressing climate change mitigation because several unavoidable hurdles that face pro-climate litigants all but guarantee their defeat. Indeed, Dwyer argues, the number of cases that might have caused emissions to be reduced can be counted on half of one hand.

This chapter discusses the main debates surrounding climate adaptation law. Adaptation to climate change is often presented as a subfield of climate law, alongside that of mitigation. Article 7 of the Paris Agreement establishes ‘the global goal on adaptation’ and links it with the Article 2 mitigation goal, thus lending support for the idea that an adaptation law might develop under the influence of the Paris Agreement, at least at the domestic level. Nevertheless, many in the field are sceptical: adaptation efforts often consist in the implementation of pre-existing developmental, environmental, or human-rights policies that are highly localized in their outlook. This chapter reviews the wealth of views on whether ‘adaptation law’ has emerged or should be recognized as a legal field, creating new, legally enforceable rights and obligations.

This chapter debates the significance of the principle of common but differentiated responsibilities and respective capabilities in the light of different national circumstances (CBDR-RC+). A top-down determination of state responsibility based on an objective assessment, as in the case of the Kyoto Protocol, which created two main categories of states, has proved controversial, due to the existence of alternative theories of differentiation. All of them seem to have been mashed up together in CBDR-RC+. Thomas Leclerc develops the argument that the principle has now become legally meaningless, as it does no more than invite each state to determine its own contribution to climate action, entirely free from external review, which is something we hardly need a new principle for. But there is also the argument, articulated by Daria Shapovalova, that CBDR-RC+ remains central to the UNFCCC regime, and can influence the direction of the negotiations, as well as litigation outcomes.

This chapter reviews the debates relating to the interface of climate change law and aesthetics. Global warming alters the aesthetic properties of nature, and additional aesthetic changes are precipitated by the mitigation and adaptation responses of impacted societies. Domestic legal systems already have a leading role in governing certain disputes that involve strong aesthetic elements, such as the location of wind turbines or seawall defences. The international legal system has established some regimes that explicitly engage with aesthetic values, such as the World Heritage Convention. Ben Richardson maps the views expressed in the growing scholarship on climate law’s encounters with aesthetics. The chapter also weighs different views on why aesthetic experiences might be important to better understanding the dangers of climate change, which mostly lie in the future and thus out of sight and out of mind.

NETs range from afforestation to bioenergy with carbon capture and storage. They are seen by many as instrumental in achieving the mitigation objectives of the Paris Agreement. However, uncertainty remains regarding the technical, economic, and political feasibility of the large-scale deployment of NETs. The focus in this chapter is on whether a state may lawfully presume, for instance in the course of determining its long-term low-greenhouse-gas-emission development pathway under Article 4(19) of the Paris Agreement, that a future large-scale deployment of NETs will be realized. Gareth Davies maintains that that makes perfect sense, not least because conventional mitigation methods are in the same boat (of uncertainty), and that in other respects as well conventional methods are on a continuum with NETs. By contrast, Duncan McLaren and Wil Burns argue that any heavy reliance now on a presumed large-scale availability of NETs in the future would be irresponsible, unethical, and unlawful.

This chapter debates the consistency of the deployment of Solar Radiation Management (SRM) with international law. SRM might help to counter global warming at relatively low cost, but it could also have substantial negative environmental impacts. Jesse Reynolds, reviewing all the relevant international treaties, as well as customary international law, argues that solar geoengineering could be consistent with international law. There is even some evidence, he argues, that solar geoengineering may be required by international law. Kerryn Brent reaches the exact opposite conclusion. She argues that solar geoengineering at scale would violate the no-harm rule and is prohibited by the UNFCCC and other treaties.

This chapter reviews the legal debates surrounding climate finance. The UNFCCC and the Paris Agreement both declare that developed states ‘shall’ provide financial support to promote adaptation and mitigation in developing countries, but neither treaty specifies the form, or the amount, of such support. This chapter discusses various views on whether there is a legal obligation resting on certain states, or perhaps on a collective of states, to provide financial support to developing countries—and, if there is, what it might consist in and which legal principle it might be founded on.

This chapter debates the appropriateness of the Paris Agreement’s ‘compliance’ system. The treaty’s Article 15 establishes ‘a mechanism to facilitate implementation of and promote compliance with the provisions of this Agreement’. Views differ radically on the legal mandate of this mechanism and its capacity to ensure that states comply with their treaty obligations. Meinhard Doelle praises the mechanism’s ability to sensitively inform domestic political and legal processes and, thus, to increase the likelihood of an effective implementation of states’ obligations. Anna Huggins develops the argument that an effective compliance system comprises both facilitation and enforcement elements, yet the Paris mechanism limits itself to facilitation. Moreover, in its facilitative role, the mechanism is duplicative of other facilitative elements of the Agreement.

An increasing number of jurisdictions are using environmental impact assessment as a tool for climate change mitigation (in brief, ‘Climate Assessment’, or CA). This chapter debates whether this is a legal obligation, or whether this even makes sense. Benoit Mayer argues that CA is emerging as a rule of customary international law, and that, moreover, it is a potentially useful mitigation tool. Alexander Zahar, by contrast, questions the meaningfulness of CA, arguing that it is impossible to determine what constitutes a significant, excessive, or disproportionate emission of greenhouse gases in the case of a proposed activity subject to CA, or at all.

This conclusion highlights the key themes developed throughout the book. It identifies three main questions to which climate law scholarship seeks to respond: What are states’ obligations? What are the foundations of climate law? How does climate change transform the law?

This chapter captures the controversy on ‘state extinction’ through climate change. Sea-level rise and changing weather patterns, among other impacts of climate change, are likely to cause some low-lying Small-Island Developing States (SIDS) to be uninhabitable in the coming decades, even before SIDS territory ‘sinks’ out of sight. Academic debates have offered various proposals on what might happen to the remnants of the states concerned, if they continue to exist at all, and the rights of these territorially orphaned entities under various regimes. Sharon concludes that there is one and only one legal avenue for the—very slight—possibility that statehood would continue after the land is gone.

This chapter debates the significance of the principle of common but differentiated responsibilities and respective capabilities in the light of different national circumstances (CBDR-RC+). A top-down determination of state responsibility based on an objective assessment, as in the case of the Kyoto Protocol, which created two main categories of states, has proved controversial, due to the existence of alternative theories of differentiation. All of them seem to have been mashed up together in CBDR-RC+. Thomas Leclerc develops the argument that the principle has now become legally meaningless, as it does no more than invite each state to determine its own contribution to climate action, entirely free from external review, which is something we hardly need a new principle for. But there is also the argument, articulated by Daria Shapovalova, that CBDR-RC+ remains central to the UNFCCC regime, and can influence the direction of the negotiations, as well as litigation outcomes.

Climate law has often been framed as a component of environmental law. Under this conception, environmental law and climate law are mutually supportive endeavours towards sustainable development. Yet, in a growing number of instances, climate action has been shown to undermine the protection of other environmental values, or even the enjoyment of human rights. For instance, hydroelectricity, often embraced as pro-climate, has been promoted as a source of (relatively) clean energy, but hydroelectric dams often have a significant negative impact on human settlements and river ecosystems. In other cases, the UNFCCC regime may be read as ‘giving up’ on some impacts of climate change, possibly in contradiction to certain states obligations on environmental protection. The author asks whether climate law is inevitably on a collision course with environmental law, or whether there exist credible ways to reconcile the objectives and operation of these two regimes.