Last year was the hottest year on record and the ten hottest years on record have in fact been the last ten years. Ocean heat reached a record high last year and, along with it, global sea levels. Those are rising twice as fast as they did in the 1990s.
The World Meteorological Organization reports that the global atmospheric concentration of carbon dioxide reached a new observed high in 2023, which is the latest year for which global annual figures are available. The level was 420 ppm, which is the highest level it has been in 800,000 years.
The increase in carbon dioxide levels was the fourth largest one-year change since modern measurement began in the 1950s. The rate of growth is typically higher in El Niño years because of increases from fire emissions and reduced terrestrial carbon sinks.
Concentrations of methane and nitrous oxide – which are two other key greenhouse gases – also reached record high observed levels in 2023. Levels of both of these gases have also continued to increase in 2024.
The annually averaged global mean near-surface temperature in 2024 was 1.55 degrees Celsius above the 1850-1900 average. Apart from being the warmest year in the 175 years records have been kept, it is also above the 1.5-degree limit set as the goal of the Paris Climate Agreement. While a single year above 1.5 degrees of warming does not mean that the efforts to limit global warming have failed, it is a strong warning that the risks to human lives, economies, and the planet are increasing.
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Carbon Dioxide Levels Highest in 800,000 Years
Photo, posted January 30, 2018, courtesy of Johannes Grim via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio