Evidence that CO2 emissions are the cause of global warming is very robust. Scientists have known since the early 1800s that greenhouse gases in the atmosphere trap heat.

Global CO2 emissions from human activity have increased by over 400% since 1950. As a result, the concentration of CO2 in the air has reached more than 400 parts per million by volume (ppm), compared to about 280ppm in 1750 (around the start of the Industrial Revolution).

From: https://www.theccc.org.uk/tackling-climate-change/the-science-of-climate-change/climate-variations-natural-and-human-factors/