All Parties’ emissions in 2017 were below their base-year level, which in many cases also means that they have already achieved their 2020 targets. However, for a number of Parties whose emissions in 2017 were between their base-year level and targeted emission level for 2020, the emission reductions achieved by 2017 are not commensurate with the targeted reductions by 2020, in terms of either emission level or emission budget, as relevant. Those Parties are expected to make further efforts to meet their 2020 targets by strengthening implementation of existing PaMs, and some Parties have already indicated their intention to use units from MBMs and, if applicable, the contribution of LULUCF towards achieving their 2020 targets.

The overall decline in GHG emissions since 1990 reflects primarily the impact of the economic transformation of EIT Parties in the 1990s and the strengthening of climate change mitigation actions by almost all Parties in the second half of the 2000s and after 2010, including those promoting increased use of less carbon-intensive fuels and renewable energy in the electricity mix and improvement of energy end-use efficiency, as well as other PaMs in the agriculture and waste sectors. Those measures have been accompanied by modernizing and enhancing the efficiency of industrial processes and reducing livestock population. The slight growth in emissions observed since 2016 may be attributed to the increase in industrial production, continuous increase in fuel consumption for road transportation and higher demand for heating due to colder winters. 

Most Parties view their 2020 targets as a waypoint on the trajectory towards their midterm and long-term targets under the Paris Agreement. They are capitalizing on their experience in implementing PaMs by tailoring their portfolios to target the key emitting sectors and where PaMs are cost-efficient and can bring multiple benefits, such as health benefits and job creation, in addition to emission reductions. NDCs containing midterm targets and long-term low-emission development strategies, which in many cases contain long-term goals or targets (e.g. carbon neutrality or net zero emissions by 2050), feature prominently in Parties’ reporting. Many Parties described their plans to transition to low-emission economies and societies, with newly reported PaMs being part of their strategies for achieving their 2030 and 2050 targets.

Long-term low-emission development strategies focus primarily on the energy and transport sectors. Key long-term policy objectives in these sectors include renewables becoming the main source of electricity while phasing out coal, and the electrification of building heating and road transport. Parties reported on new near-term actions needed to meet these goals, such as building infrastructure for electric transportation and scheduling retirement of coal power plants. A majority of Parties are or envisage using carbon pricing approaches in some form. Prominent examples of trading systems are the EU ETS, New Zealand Emissions Trading Scheme and Canada’s new Output-Based Pricing System. Many Parties reported on combining carbon pricing approaches in the form of levies or taxes and trading systems. 

In their BR4s Parties reported a total of 2,624 PaMs, with impacts reported for 37.7 per cent of them, totalling emission reductions of 3,811.47 Mt CO2 eq. A trend of measures moving through a ‘life cycle’ is evident throughout the four biennial reporting cycles as successful actions are replicated and expanded, imperfect policies are reformulated and strengthened, and ineffective policies are discontinued. This is manifested in a higher share of planned and adopted, but not yet implemented, measures being reported in the BR4s compared with in previous BRs, and indicates that Parties have started planning actions towards achieving their post-2020 targets. For example, the EU ETS has been substantially revised for its fourth phase (2021–2030). Planning for achieving post-2020 targets also includes strengthening institutional structures and processes, for example with regard to mitigation planning, tracking progress against targets and evaluating the effectiveness of implemented PaMs. 

Projections made in 2017 (the most recent reported year in GHG emission inventories) show a 10.1 per cent decrease in total GHG emissions excluding LULUCF by 2020 compared with the 1990 level and a 1.5 per cent increase compared with the 2017 level under the WEM scenario, which takes into account implemented and adopted PaMs. Despite the increased scope and strengthening of mitigation actions for beyond 2020, total emissions under the WEM scenario are projected to decline by only 2.2 per cent between 2020 and 2030. This suggests that planned mitigation actions may not be sufficient to completely offset the impact of the underlying emission drivers, such as economic and population growth, and to drive emissions down. It may also suggest that the impacts of the planned mitigation actions have not been fully accounted for because such impacts will depend on the exact form of the legislation and regulations supporting implementation of such measures, which has yet to be finalized. 

As reported in the BR4s, total climate support reached an annual average of USD 48.7 billion in 2017–2018; on a comparable basis, this represents a 9.9 per cent increase over the previous biennium 2015–2016, on a comparable basis. Both Annex II Parties and Annex I Parties not included in Annex II provided quantitative or qualitative information on climate finance in their BR4s, on climate-specific support (funds targeted specifically at climate action) and core/general support (funds that are not specifically targeted at climate action). One third of the total support (an average of USD 16.4 billion per year over the biennium) was allocated through multilateral channels, with over half allocated to mitigation, followed by cross-cutting and adaptation. As previously, multilateral development banks represent the largest share of multilateral finance institutions for channelling climate finance. Multilateral climate finance funds, such as the Green Climate Fund, are now also attracting considerable funding, allowing them to channel expanded support for climate action in developing countries. 

The BR4s demonstrate some new developments, including expanded use of innovative financial instruments such as insurance, a move towards more detailed sectoral reporting, improved tracking of private sector finance and the introduction of voluntary reporting on issues such as gender. Additionally, more Annex I Parties not included in Annex II reported on climate support provided to non-Annex I Parties in the BR4s than in any previous BRs. Parties also demonstrated ongoing efforts to expand their tracking and reporting of private sector finance leveraged by public investments, thereby helping to clarify the bigger climate finance picture. 

In their BR4s Parties reported 391 activities relating to technological support (29 per cent more than in the BR3s), with more than half supporting mitigation (56 per cent), a quarter supporting adaptation (26 per cent) and the remaining supporting cross-cutting actions (a similar pattern to that presented in the BR3s). Annex II Parties highlighted their efforts to fully respond to developing country Parties’ needs as identified by 53 non-Annex I Parties in their technology needs assessments and contained in the fourth synthesis report on technology needs. Deploying mature technologies remained the predominant supported activity, while support for technology research and development and demonstration activities has increased since the BR3s, in line with the need to support research and development and facilitate access to technology highlighted in the Paris Agreement. Asia-Pacific continued to benefit most from the reported technology support, with 46 per cent of all reported technology support activities focusing on that region. 

In the BR4s, 686 capacity-building activities were reported, a significant increase (by 77.3 per cent) on the 387 activities reported in the BR3s. The reported capacity-building activities cover all 15 priority areas outlined in the framework for capacity-building in developing countries established under decision 2/CP.7. Continuing the trend observed from the BR3s, the most significant share of capacity-building was for adaptation (40 per cent) and was mostly focused on integrating climate resilience into existing and new infrastructure or on promoting green transformation in agriculture and forestry. Mitigation accounted for 28 per cent of capacity-building, primarily aimed at strengthening monitoring and evaluation. Geographically, a majority of the capacity-building support for adaptation was provided to the Asia-Pacific and African regions. Mitigation support was primarily provided for multiregional or global projects. 

These systems are supported by domestic institutional frameworks and international technical reviews under the UNFCCC, thereby laying the groundwork for a successful transition to the enhanced transparency framework under the Paris Agreement. In addition, Parties without reporting obligations under the current system have voluntarily reported on support (e.g. Annex I Parties not included in Annex II reporting on financial, technological and capacity-building support provided to developing country Parties), which has helped them to gain reporting experience and facilitated the development of reporting systems and approaches to help them prepare for the transition to the enhanced transparency framework. Developed countries have demonstrated a deeper understanding of how their climate policies are performing over time and how they affect emission levels. As well as contributing to the quality of reporting under the UNFCCC, the establishment of systems for ensuring transparency of climate action and support has facilitated domestic policymaking by providing policymakers with access to accurate, reliable and up-to-date information on emission levels, impacts of mitigation actions and support provided.