Temperature variations in ancient times are very unreliable, because they can only be inferred indirectly. The big giveaway for anthropogenic climate change is

Temperature variations in ancient times are very unreliable, because they can only be inferred indirectly. The big giveaway for anthropogenic climate change is co2 concentration, since we can directly measure its value hundreds of thousands of years in the past thanks to air bubbles enclosed deep in glaciers: https://climate.nasa.gov/climate_resources/24/graphic-the-relentless-rise-of-carbon-dioxide/ https://climate.nasa.gov/climate_resources/24/graphic-the-re... It clearly shows that the atmosphere never looked anything like this since humans climbed down from trees. Bonus fact: All mass extinctions happened when the co2 levels rose over a certain value (we're already at 419ppm, that 393ppm value in the article is from a few years ago): https://johnenglander.net/co2-levels-and-mass-extinction-events/ https://johnenglander.net/co2-levels-and-mass-extinction-eve... If they rise over 600ppm for example, the oceans will acidify and their ecosystems will collapse. Since most of our oxygen comes from oceanic plankton, we'll literally suffocate when that happens - and at the current trend it could happen before the century is over. The largest extinction event ever, the Permian-Triassic event (where 80% of marine life and 70% of terrestrial vertebrates died), is currently thought to have been caused by massive emissions of runaway greenhouse gases in the thawing Siberian tundra - similar to what we are seeing right now.