A review of emission metrics GWP and GTP

doi:10.12006/j.issn.1673-1719.2024.167

Abstract

Abstract:

There are usually two kinds of metrics being used to measure emissions, including Global Warming Potential (GWP) and Global Temperature Change Potential (GTP). These metrics are scientific basis for making emission policies and thus have important reference for policy makers in manufacturing and related economic fields. Meanwhile, it is significant to quantitatively understand the effects of emission and its reduction on the past and future climate change. How to accurately calculate and reasonably apply GWP and GTP to assess the impact of emission on global warming is an important scientific issue and a hot topic in climate change. Therefore, it has received extensive attention from the scientific community and related fields. IPCC AR5 and AR6 have set up special chapters for GWP and GTP to summarize and discuss the content of calculation methods and their application development. Based on the discussion of GWP and GTP in IPCC AR5 and AR6, this paper firstly summarizes the basic conceptions of emission metrics and their development in the past 30 years, then introduces the algorithms of common emission metrics of GWP and GTP in detail, finally gives the differences and applicability of the two metrics systematically. GTP is more closely related to global mean surface air temperature change, so it has potential advantages compared with GWP in evaluating the impact of greenhouse gases on surface air temperature. However, GTP also has some uncertainties, such as the influence of climate sensitivity factors, the heat exchange in the Earth system, and the selection of target time points. Then, the values of key emission indicators are summarized in the table for reference, including CO₂, CH₄, N₂O, HFC, CFC, PFC and aerosols. In addition, this paper also introduces some emerging emission metrics, such as Combined-GTP (CGTP) and GWP*. These new metrics are more precise, and more suitable for short-lived greenhouse gases.

Key words: Emission metric, Global warming potential (GWP), Global temperature change potential (GTP)

CHEN Qi, ZHANG Hua, LIU Li-Ting, WANG Qiu-Yan, ZHOU Xi-Xun, XIE Bing. A review of emission metrics GWP and GTP[J]. Climate Change Research, 2025, 21(1): 69-77.

Figures/Tables 4

Fig. 1 The variation of methane GWP with integration time

Table 1 Emission metrics of greenhouse gases

Table 2 Emission metrics of carbon aerosol

Fig. 2 Explores how cumulative carbon dioxide equivalent emissions estimated for methane vary under different emissions metric choices and how estimates of the global surface air temperature (GSAT) change deduced from these cumulative emissions compare to the actual temperature response computed with the two-layer emulator

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