Annual increase of whole-atmosphere mean concentration of carbon dioxide in 2024 was the largest in the past 14 years

The Secretary-General of the United Nations António Guterres stated in 2023, “The era of global warming has ended; the era of global boiling has arrived.” His remarks reflect the fact that climate change is an issue of great concern to all humankind and has become increasingly serious in recent years. The World Meteorological Organization (WMO) has confirmed that the global annual average temperature has increased since the 1970s and reached a new record high in 2024, when it rose to 1.5℃ above the pre-industrial level and therefore exceeded the goal of the Paris Agreement. Because the temperature rise fluctuates from year to year, medium–to–long-term trends should be confirmed. It is therefore unclear whether the temperature will continue to exceed the goal of the Paris Agreement, but last year’s rise should be regarded with a sense of urgency. The deviation of Japan’s average temperature in 2024 from the baseline (the 30-year average from 1991 to 2020) was +1.48℃, the warmest since records began to be kept in 1898. It will therefore be necessary to improve the monitoring of climate change in the future.

Press release by the WMO:

https://wmo.int/news/media-centre/wmo-confirms-2024-warmest-year-record-about-155degc-above-pre-industrial-level

Japan’s annual average temperature by the Japan Meteorological Agency (JMA):

https://www.data.jma.go.jp/cpdinfo/temp/an_jpn.html [Japanese only]

The National Institute for Environmental Studies (NIES), the Ministry of the Environment of Japan (MOE), and the Japan Aerospace Exploration Agency (JAXA) have been jointly promoting the development and operation of the Greenhouse gases Observing SATellite Series (GOSAT Series) to monitor the concentrations of greenhouse gases in the atmosphere, especially carbon dioxide and methane. Increases of the concentrations of those gases have been primarily responsible for global warming. The observations by “IBUKI” (GOSAT), the first satellite in the GOSAT Series, have revealed that the annual increase of the whole-atmosphere mean concentration of carbon dioxide (i.e., the average concentration throughout Earth’s atmosphere) from 2023 to 2024 was 3.5 ppm, the largest annual increase since 2011, when it first became possible to calculate the annual increase based on GOSAT observations.

Figure 1 shows the trends in the whole-atmosphere annual mean concentration of carbon dioxide from 2010 to 2024 and the annual increase from 2011 to 2024 based on GOSAT observations. Although the whole-atmosphere mean concentration of carbon dioxide was 388 ppm in 2010, it has increased gradually since then and exceeded 421 ppm in 2024. The average annual increase over the past 14 years was 2.4 ppm per year, but it peaked at 3.5 ppm per year in 2024. That increase exceeded the previous largest annual increase of 3.1 ppm in 2016.

The conditions that caused the increase from 2023 to 2024 to exceed all of the annual increases during the previous 14 years may have included the following: high temperatures and droughts caused by the El Niño of 2023–2024; increased emissions of carbon dioxide and decreased areas of terrestrial vegetation and rates of photosynthesis due to forest fires; and increased anthropogenic emissions of carbon dioxide. To clarify the causes of the increase, a detailed analysis will be conducted based on not only the GOSAT data obtained during 2024 but also the entire GOSAT Series data.

El Niño Monitoring and Outlook by JMA:

https://ds.data.jma.go.jp/tcc/tcc/products/elnino/elmonout.html

Main Message of “Global Carbon (Carbon Dioxide) Budget 2024” by the Global Carbon Project, Tsukuba International Office:

https://cger.nies.go.jp/gcp/pdf/20241113/GCB%202024%20press%20release_FINAL.pdf

NIES, MOE, and JAXA will continue to monitor climate change by utilizing the GOSAT Series dataset and will disseminate the information to the international community.