Science Direct Paris Agreement

To this end, we integrate BHM`s estimates into one of the largest AMI14,15,16, DICE-201316. Thanks to its simplicity, DICE makes it possible to evaluate the cost-benefit optimality in a scientifically very transparent and controlled way. According to its original version, which was also used to advise U.S. climate policy,17,18,19, achieving the 2°C target would result in significantly higher mitigation costs than the resulting avoided harm.16,20,21 This result is largely due to a loss function that does not take into account the latest estimates of economic impact13,22,23. Here we update this function according to BHM8 estimates. As DICE seeks the economic growth trajectory that maximizes global prosperity, growth estimates cannot be implemented directly. To solve this problem, we are developing a new process that retains the characteristic of the growth model. We iteratively adjust the damage function to reproduce the temperature-induced growth relationship estimated in DICE-2013. For reasons of consistency with BHM`s estimates, we design a scenario that mimics a future world in which the most important conditions are similar to those of the past, i.e. the absence of climate policy. In the following, we subject our results to extensive robustness tests.

First, we complete the climate sensitivity analysis of the main text by considering an integer probability density function for ECS values. Second, we look at the impact of uncertainty in BHM`s estimates. In this regard, we take into account alternative estimates of β1 and β2 on the one hand and different model specifications on the other. This analysis is followed by a comparison with WCO estimates. Third, we examine the impact of uncertainty on the socio-economic future by recalibrating the DICE model according to a select group of SSPs. As a by-product of this calibration, we receive mitigation cost functions that emulate the costs of a detailed process model and thus represent further development of the DICE model. Deriving these functions allows us to test the sensitivity of our results to these alternative emission reduction costs. We complete this section by giving more information about the robustness test in relation to the preference parameters indicated in the main text.

This background information informs our systematic map of the Paris Agreement literature – a descriptive overview of the types of studies in this field, their main areas of investigation, joint journals, etc. We obtain the metadata directly from the Web of Science and Scopus platforms. We grouped the mechanisms used to inform our search query (Table 1) and then classified each document by group of mechanisms it examines. We have added a «general» category for relevant documents that do not explicitly examine any of the groups of mechanisms, but cover more than one mechanism or the PA in general.4 Finally, we rank the literature according to its overall assessment of the Paris Agreement, distinguishing between documents that the PA generally considers to be a positive development, negative, or neither positive nor negative (mixed). We add an N/A category. for documents that are not subject to a PA assessment. In our analysis, the possibility of achieving the 2°C target is considerably limited by excluding negative emissions during this century. Nevertheless, we show that if future damage follows the same temperature dependence as historically observed, the total cost of the damage will reach a level that makes the cost-benefit ratio of 2°C optimal. This result is a direct consequence of the recently presented empirical evidence, which shows a significant marginal increase in damage at higher temperatures, and the universal functional behaviour of reduction costs in the vicinity of current temperatures (see Fig.

1). To ensure the relevance of the literature identified by our search, we review all documents identified by our search chain at the title and abstract level using strict inclusion and exclusion criteria. We include all documents explicitly examining the Palestinian Authority or any of its mechanisms (as described in Section 2), as well as analyses of similar mechanisms with explicit reference to the Palestinian Authority and analyses of the UNFCCC negotiations that explicitly refer to a PA mechanism. We exclude studies that focus on national/regional case studies without explicit reference to the broader function of the mechanism they are studying. These cases are often limited to their context and do not provide comparable information on the functioning of the PA in general (i.e., case studies of individual GCF projects). We also exclude all studies on climate impacts, as they may relate to PA but are not directly related to its function. Finally, we exclude ex ante models of emissions or GDP scenarios, unless they explicitly refer to a function of a PA mechanism (i.e. the implementation of the global balance sheet).

This also excludes models of the likely warming effect of submitted NDCs. Although these models technically examine the effectiveness of PA, they are considered sufficiently synthesized in the annual emission gap reports (United Nations Environment Programme 2019) or similar assessments. For example, the latest emissions gap report shows that, based on current NDCs, we are on track to reach 56 Gt of CO2 equivalent in emissions by 2030, more than double the threshold of 25 Gt of CO2 equivalent called limiting global warming to 1.5°C (United Nations Environment Programme 2019). In order to avoid the replication of such an existing synthesis, we omit these studies from our research. We also exclude conference proceedings and book reviews. We test the consistency and clarity of these criteria by reviewing the samples with multiple reviewers and then discussing the resulting ambiguities. This comparison provides warming at the end of the century, which is associated with the lowest total cost of damage and mitigation as used in the IAM used (Fig. 1). Cost-benefit-optimal heating is therefore determined by the shape of the two cost curves.

Mitigation cost curves are characterized by two universal properties. First, they diverge from today`s warming, especially when negative-emission technologies are not available. Second, the costs of mitigating a warming scenario without mitigation efforts fall to zero. The combined ratio, on the other hand, is known to be zero without warming and increases with rising temperatures. The extent to which damage increases without mitigation shall be investigated […].