What is the Yearly Atmospheric CO₂ Increase?

This is the difference in the atmospheric CO₂ of a given year compared to the previous year. We call this an ‘increase’ rather than a ‘change’ because in recent history, every year has had more CO₂ in the atmosphere than the previous year. However, in the past there was sometimes a decrease, for example in the 1850s, which is why those values are negative. The yearly CO₂ increase depends on the processes that emit CO₂ into the atmosphere and absorb CO₂ out of the atmosphere. The average lifetime of CO₂ in the atmosphere is just over 400 years.

The Yearly Atmospheric CO₂ Increase is critical because as long as it increases, the warming effect due to CO₂ is also increasing.

Units and measures

The primary unit here is parts per million (ppm), which describes the increase in the concentration of atmospheric CO₂ per year. The secondary unit here is gigatonnes, which describes the weight of the increase in atmospheric CO₂ per year. We show this to be able to relate to emissions, which are commonly expressed in gigatonnes.

Insights from this chart

Not only is atmospheric CO₂ increasing every year, the rate is also growing. There are large yearly fluctuations that are mostly due to the changes in CO₂ absorbed by the Earth’s land mass. You can read about in the Yearly Absorption of Human-Induced CO₂ Emissions.

In the chart you can see a smooth line before the late 1950s and a fluctuating line thereafter. In reality, there were fluctuations before the 1950s too, but there are not enough measurements to confidently calculate the yearly fluctuations and that is why there is a smooth line highlighting the trend. In 1958 the direct continuous measurements of atmospheric CO₂ started at Mauna Loa under Charles Keeling, after whom the Keeling Curve is named.

About the data

The data since 1958 is from NOAA’s Global Monitoring Laboratory, which has a global network of air sampling sites to measure CO₂. The atmospheric CO₂ increase is calculated by taking the difference between consecutive deseasonalized December-January averages. For recent years where only parts of the months are available, the increase is calculated as the difference between the average of the available months compared to that same period of the previous year. If monthly data is not yet available, the daily estimate data is used to compare the available days with the same days of the previous year.

The values from 1850 to 1959 are taken from the Global Carbon Budget 2023.

Data sources

Globally averaged marine surface annual mean growth rates data NOAA's Global Monitoring Laboratory
Credits: Ed Dlugokencky and Pieter Tans, NOAA/GML (gml.noaa.gov/ccgg/trends/)Update cycle: monthlyDelay: ~ 3 months

Globally averaged marine surface monthly mean data NOAA's Global Monitoring Laboratory
Credits: Ed Dlugokencky and Pieter Tans, NOAA/GML (gml.noaa.gov/ccgg/trends/)Update cycle: dailyDelay: ~ 2 days

Global Carbon Budget 2023 Global Carbon Budget
Credits: Friedlingstein et al., 2023b, ESSD, full reference below **Update cycle: yearlyDelay: ~ 10 months after end of a year. Current year values estimates published in November.Reference: ** Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Bakker, D. C. E., Hauck, J., Landschützer, P., Le Quéré, C., Luijkx, I. T., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Anthoni, P., Barbero, L., Bates, N. R., Becker, M., Bellouin, N., Decharme, B., Bopp, L., Brasika, I. B. M., Cadule, P., Chamberlain, M. A., Chandra, N., Chau, T.-T.-T., Chevallier, F., Chini, L. P., Cronin, M., Dou, X., Enyo, K., Evans, W., Falk, S., Feely, R. A., Feng, L., Ford, D. J., Gasser, T., Ghattas, J., Gkritzalis, T., Grassi, G., Gregor, L., Gruber, N., Gürses, Ö., Harris, I., Hefner, M., Heinke, J., Houghton, R. A., Hurtt, G. C., Iida, Y., Ilyina, T., Jacobson, A. R., Jain, A., Jarníková, T., Jersild, A., Jiang, F., Jin, Z., Joos, F., Kato, E., Keeling, R. F., Kennedy, D., Klein Goldewijk, K., Knauer, J., Korsbakken, J. I., Körtzinger, A., Lan, X., Lefèvre, N., Li, H., Liu, J., Liu, Z., Ma, L., Marland, G., Mayot, N., McGuire, P. C., McKinley, G. A., Meyer, G., Morgan, E. J., Munro, D. R., Nakaoka, S.-I., Niwa, Y., O'Brien, K. M., Olsen, A., Omar, A. M., Ono, T., Paulsen, M., Pierrot, D., Pocock, K., Poulter, B., Powis, C. M., Rehder, G., Resplandy, L., Robertson, E., Rödenbeck, C., Rosan, T. M., Schwinger, J., Séférian, R., Smallman, T. L., Smith, S. M., Sospedra-Alfonso, R., Sun, Q., Sutton, A. J., Sweeney, C., Takao, S., Tans, P. P., Tian, H., Tilbrook, B., Tsujino, H., Tubiello, F., van der Werf, G. R., van Ooijen, E., Wanninkhof, R., Watanabe, M., Wimart-Rousseau, C., Yang, D., Yang, X., Yuan, W., Yue, X., Zaehle, S., Zeng, J., and Zheng, B.: Global Carbon Budget 2023, Earth Syst. Sci. Data, 15, 5301–5369, https://doi.org/10.5194/essd-15-5301-2023, 2023.