Researchers in Japan say satellite data show that the concentration of carbon dioxide in the Earth's atmosphere in 2024 marked the largest year-on-year rise on record.

The Environment Ministry and the National Institute for Environmental Studies have been using the Japanese satellite Ibuki to observe the atmospheric density of greenhouse gases, including CO2 and methane. The data are used to help combat climate change.

The researchers say CO2 density last year stood on average at 421.3 ppm, the highest since record keeping began in 2010. They say it translated to an increase from the previous year of 3.5 ppm, also the most on record.

Ministry officials say the largest year-on-year growth may have partly stemmed from recent major wildfires in Canada and Brazil. They also cite as another possible reason increasing emissions from human activity, such as the use of fossil fuels.

Environment Minister Asao Keiichiro said at a news conference on Friday that he views the data with a sense of urgency, because increasing greenhouse gas density is a primary factor behind rising temperatures.

He added that Japan will continue to work with other countries and do everything it can to reduce greenhouse gas emissions.