They say humans are changing the climate. This is completely and unequivocally false and can easily be demonstrated via a very simple and rudimentary understanding of basic physics and chemistry.
"Carbon dioxide warms the planet!" The classic "greenhouse effect theory". Yes, greenhouse gases are real and they do drive climate dynamics during interglacial periods during which greenhouse gases (most notably water, the most potent and abundant greenhouse gas in the atmosphere) accumulate in the atmosphere, blocking the radiation of thermal energy into outer space.
However, the amounts of carbon dioxide in the atmosphere are incredibly tiny in comparison to the amounts of water, and more importantly, the specific heat capacity of water is many times that of CO2. This means that atmospheric water vapor traps and contains heat much more efficiently and for longer periods than carbon dioxide ever will. There is also the matter of absorption spectra. Water absorbs thermal energy at the same wavelengths as CO2 and CH4 and the overall absorption spectrum is wider in water as well.
The glacial-interglacial state cycle switching is ultimately driven by the biphasic stability variation of the thermohaline circulation (THC) in the surface ocean of our planet. The THC transports massive amounts of thermal energy from tropical, equatorial areas into higher planetary latitudes, effectively equalizing the thermal distribution of energy received from the sun, making the planet as a whole warmer.