June 2025 Atmospheric CO2 Content 429.61 ppm; June 2024 426.91 ppm; June 2023 423.68 ppm

[OKIsItJustMe]

3. Climate impact of increasing atmospheric carbon dioxide. - Hansen et al. 1981

Summary. The global temperature rose by 0.2°C between the middle 1960's and 1980, yielding a warming of 0.4°C in the past century. This temperature increase is consistent with the calculated greenhouse effect due to measured increases of atmospheric carbon dioxide. Variations of volcanic aerosols and possibly solar luminosity appear to be primary causes of observed fluctuations about the mean trend of increasing temperature. It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980's. Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.

Hansen et al. 1981
Hansen, J., D. Johnson, A. Lacis, S. Lebedeff, P. Lee, D. Rind, and G. Russell, 1981: Climate impact of increasing atmospheric carbon dioxide. Science, 213, 957-966, doi:10.1126/science.213.4511.957.
https://www.giss.nasa.gov/pubs/docs/1981/1981_Hansen_ha04600x.pdf

His appearance on Capitol Hill served notice that “anthropogenic carbon dioxide warming (had) emerge(d) from the noise level of natural climate variability.”