China, Hong Kong's Yearly Greenhouse Gas Emissions in CO₂ Equivalent
Key Insights
A Long, Fossil-Heavy Legacy
Hong Kong's historic greenhouse gas profile is dominated by fossil CO2, roughly three-quarters of its total temperature contribution. Land-use CO2 is not shown in this record. Most of the remaining share comes from methane, with relatively small contributions from nitrous oxide and fluorinated gases.
Rapid Rise, Then Retrenchment
From the late 1960s to early 2000s, fossil CO2 climbed rapidly from the single digits to the low 40s of megatonnes, hovered near the mid-40s into the mid-2010s, then fell. Since around 2016, totals have declined to roughly 30 megatonnes. Coal-about half of fossil CO2-surged from the 1980s to a mid-2010s peak near 25 megatonnes before dropping to the low teens. Oil rose through the 1970s, dipped, and has been broadly steady around 10 megatonnes since the late 2000s. Gas, once minor, has risen recently toward around 10 megatonnes.
Methane And Other Gases
Methane increased through the post-war era and has edged up slowly since the mid-1990s to around 5 megatonnes today, largely from waste. As emissions stabilized, the warming impact from methane has eased compared with earlier decades of rapid growth. Nitrous oxide rose to the early 1990s, then trended down and remains well under 1 megatonne. Fluorinated gases have climbed since the late 1990s to around 2 megatonnes-small but gradually rising.
What Matters Going Forward
The current trajectory features falling coal emissions, steady oil, rising gas, and slowly increasing methane from waste. Sustaining and deepening the coal decline, preventing oil from rebounding, curbing growth in gas, and tackling waste methane would reinforce the recent drop in total emissions and accelerate Hong Kong's progress.
Background
Greenhouse gas emissions from human activities are the main drivers of human-induced warming. In the scientific literature, human-induced emissions are often referred to as anthropogenic emissions.
- CO2 Fossil Fuels and Industry (CO2 FFI)
- CO2 Land-Use, Land-Use Change and Forestry (CO2 LULUCF)
- Methane (CH4)
- Nitrous oxide (N2O)
- Fluorinated gases (F-gases)
Emissions from all different gases are expressed in CO2-equivalent units to make it possible to compare the relative emissions from these different gases. CO2-equivalents are calculated using the global warming potentials of the respective gases, in this case using a 100-year time horizon.
Wikipedia: Global Warming PotentialTotal Historic Share
Emissions from all different gases are expressed in CO2-equivalent units to make it possible to compare the relative emissions from these different gases. CO2-equivalents are calculated using the global warming potentials of the respective gases, in this case using a 100-year time horizon.
CO2 From Fossil Fuels and Industry
The sources are mostly fossil-fuel combustion emissions from coal, oil, and gas, as well as emissions from industrial processes such as cement production. Cement also absorbs CO2 out of the atmosphere through carbonation, which reduces emissions by about 0.8 Gt per year and is included here.
CO2 From Land-Use, Land-Use Change, and Forestry
The main driver of these emissions is deforestation, which includes logging and forest degradation, as well as other land-use change activities. The emissions also take into account the absorption of CO2 by processes that remove CO2 from the atmosphere, such as afforestation and reforestation. It is the net effect that is indicated here.
Methane (CH4)
Methane emissions are caused by human activities such as rearing livestock, agricultural practices, and fugitive fossil fuel emissions.
Nitrous Oxide (N2O)
Common sources of these emissions are fossil fuel emissions and the agricultural use of synthetic fertilizer and manure.
Fluorinated Gases (F-gases)
Fluorinated gases are a group of gases defined by UNFCCC: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3). Fluorinated gases are also known as halogenated gases.
Wikipedia: Greenhouse Gas EmissionsIPCC: Annual Report 6, 5.2.1 5.2 Historical Trends, Variability and Budgets of CO2, CH4 and N2O
Units and Measures
CO2-equivalent emissions are expressed in the total weight in megatonnes per year. 1 Megatonne is equal to 1 million tonnes.
Wikipedia: MegatonneWikipedia: Global warming potential
About the Data
The last available year in all the emission datasets is 2023. CO2 emissions data is from the Global Carbon Project. It contains national CO2 emissions from fossil sources and land-use change. Emissions from CH4, N2O and F-gases come from the PRIMAP-Hist dataset. It is a rich dataset that combines several published sources to create a historical emissions time series for various greenhouse gases.
The Key Insights paragraph was created using a large language model (LLM) in combination with our data, historic events, and a structured approach for best accuracy by separating the context generation from the interpretation and narrative.
Data Sources
Global Carbon Budget 2024 Global Carbon Budget
Update cycle: yearlyDelay: ~ 10 months after the end of the year. Current year values are estimated and published in November.Credits: Friedlingstein et al., 2024, ESSD. Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Hauck, J., Landschützer, P., Le Quéré, C., Li, H., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Arneth, A., Arora, V., Bates, N. R., Becker, M., Bellouin, N., Berghoff, C. F., Bittig, H. C., Bopp, L., Cadule, P., Campbell, K., Chamberlain, M. A., Chandra, N., Chevallier, F., Chini, L. P., Colligan, T., Decayeux, J., Djeutchouang, L., Dou, X., Duran Rojas, C., Enyo, K., Evans, W., Fay, A., Feely, R. A., Ford, D. J., Foster, A., Gasser, T., Gehlen, M., Gkritzalis, T., Grassi, G., Gregor, L., Gruber, N., Gürses, Ö., Harris, I., Hefner, M., Heinke, J., Hurtt, G. C., Iida, Y., Ilyina, T., Jacobson, A. R., Jain, A., Jarníková, T., Jersild, A., Jiang, F., Jin, Z., Kato, E., Keeling, R. F., Klein Goldewijk, K., Knauer, J., Korsbakken, J. I., Lauvset, S. K., Lefèvre, N., Liu, Z., Liu, J., Ma, L., Maksyutov, S., Marland, G., Mayot, N., McGuire, P., Metzl, N., Monacci, N. M., Morgan, E. J., Nakaoka, S.-I., Neill, C., Niwa, Y., Nützel, T., Olivier, L., Ono, T., Palmer, P. I., Pierrot, D., Qin, Z., Resplandy, L., Roobaert, A., Rosan, T. M., Rödenbeck, C., Schwinger, J., Smallman, T. L., Smith, S., Sospedra-Alfonso, R., Steinhoff, T., Sun, Q., Sutton, A. J., Séférian, R., Takao, S., Tatebe, H., Tian, H., Tilbrook, B., Torres, O., Tourigny, E., Tsujino, H., Tubiello, F., van der Werf, G., Wanninkhof, R., Wang, X., Yang, D., Yang, X., Yu, Z., Yuan, W., Yue, X., Zaehle, S., Zeng, N., and Zeng, J.: Global Carbon Budget 2024, Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2024-519, in review, 2024.
PRIMAP-hist The PRIMAP-hist national historical emissions time series (1750-2023)
Update cycle: Every few monthsDelay: Less than 1 yearCredits: Gütschow, Johannes; Busch, Daniel; Pflüger, Mika (2024): The PRIMAP-hist national historical emissions time series (1750-2023) v2.6. Zenodo.