How do we know climate change is caused by humans?She says this info is hard to find, but I found the same info as the first link from a search, a 2009 artucke:
In this video I summarize the main pieces of evidence that we have which show that climate change is caused by humans. This is most important that we know in which frequency range carbon dioxide absorbs light, we know that the carbon dioxide ratio in the atmosphere has been increasing, we know that the Ph-value of the oceans has been decreasing, the ratio of carbon isotopes in the atmosphere has been changing, and the stratosphere has been cooling, which was one of the key predictions of climate models from the 1960s.
How Do We Know that Humans Are the Major Cause of Global Warming?YouTube also slaps an obnoxious "context" link on the video, with some info. You also get the same info from ChatGPT.
The evidence is that humans burning fossil fuels emit CO2, and the increases in atmospheric CO2 have caused warming. Probably most of the warming observed in recent decades.
My quibble is when they leap from this to saying that humans cause most of the climate change. The climate is changing a lot of different ways, in different places. I do not see anyone even trying to quantify climate change. Just CO2 and temperature.