A quantitative approach to evaluating the GWP timescale through implicit discount rates

The Social Costs of Hydrofluorocarbons and the Large Climate Benefits from their Expedited Phasedown

Hydrofluorocarbons are a potent greenhouse gas, yet there remains a lack of quantitative estimates of their social cost. The present study addresses this gap by directly calculating the social cost of hydrofluorocarbons (SC-HFCs) using perturbations of exogenous inputs to integrated assessment models. We first develop a set of direct estimates of the SC-HFCs using methods currently adopted by the United States Government, and then derive updated estimates that incorporate recent advances in climate science and economics. We compare our estimates with commonly used social cost approximations based on global warming potentials to show that the latter is a poor proxy for direct calculation of hydrofluorocarbon emissions impacts using IAMs. Applying our SC-HFCs to the Kigali Amendment, a global agreement to phase down HFCs, we estimate that it provides $37 trillion (2020USD) in climate benefits over its lifetime. Expediting the phasedown could increase the estimated climate benefits to $41 trillion (2020USD).

How necessary and feasible are reductions of methane emissions from livestock to support stringent temperature goals?

Agriculture is the largest single source of global anthropogenic methane (CH4) emissions, with ruminants the dominant contributor. Livestock CH4 emissions are projected to grow another 30% by 2050 under current policies, yet few countries have set targets or are implementing policies to reduce emissions in absolute terms. The reason for this limited ambition may be linked not only to the underpinning role of livestock for nutrition and livelihoods in many countries but also diverging perspectives on the importance of mitigating these emissions, given the short atmospheric lifetime of CH4. Here, we show that in mitigation pathways that limit warming to 1.5°C, which include cost-effective reductions from all emission sources, the contribution of future livestock CH4 emissions to global warming in 2050 is about one-third of that from future net carbon dioxide emissions. Future livestock CH4 emissions, therefore, significantly constrain the remaining carbon budget and the ability to meet stringent temperature limits. We review options to address livestock CH4 emissions through more efficient production, technological advances and demand-side changes, and their interactions with land-based carbon sequestration. We conclude that bringing livestock into mainstream mitigation policies, while recognizing their unique social, cultural and economic roles, would make an important contribution towards reaching the temperature goal of the Paris Agreement and is vital for a limit of 1.5°C. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 1)'.

Energy and Environmental Analysis of Single-Family Houses Located in Poland

This paper presents a comparative analysis of the carbon footprint, energy demand and life cycle costs of a model of a building located in the Central Europe climate zone. One specific example—the quantitative differences in global warming potential, life cycle costs and thermal comfort—has been shown, depending on the different construction (wood, brick) and heat sources used; traditional and energy-saving solutions have been considered. The research was carried out using the EnergyPlus simulation program for a multi-zone model of a naturally ventilated single-family house. Calculations were made for a 25-year life cycle using the standard climate data for Warsaw (Poland). The real occupancy schedule of the individual rooms was adopted and the instantaneous ventilation airflow was modeled, and its intensification due to the additional opening of windows was optimized. An estimated budget of the entire structure of the building and the heat sources was used for the cost analysis. The research has succeeded in developing some general conclusions and guidelines and recommendations for both the investors and designers of energy-saving and environmentally friendly houses. Considering the most economical an ecological solution, wooden houses are better than brick houses. In the wooden building, however, there are a larger number of thermal discomfort hours.