Answer:
approximately 2.3 parts per million (ppm) per year
Step-by-step explanation:
In 2019, the global amount of atmospheric carbon dioxide (CO2) has been estimated at approximately 410 parts per million (ppm). These levels are higher than at any time in the last 800,000 years, and it has been estimated that in 2025 the CO2 levels will be higher than at any time in the last 3.3 million years. In 2018, there has been an increase of approx. 2.5 ppm, the same increase observed between 2017 and 2018. Moreover, the average increase of the CO2 levels in the atmosphere between 2009 and 2018 was 2.3 ppm each year.