the solar system
Venus
we can learn a lot about climate change from Venus, our sister planet. Venus currently has a surface temperature of 450℃ (the temperature of an oven’s self-cleaning cycle) and an atmosphere dominated by carbon dioxide (96 per cent) with a density 90 times that of Earth’s.
Venus is a very strange place, totally uninhabitable, except perhaps in the clouds some 60 kilometres up where the recent discovery of phosphine may suggest floating microbial life. But the surface is totally inhospitable.
Venus once likely had an Earth-like climate. According to recent climate modelling, for much of its history Venus had surface temperatures similar to present day Earth. It likely also had oceans, rain, perhaps snow, maybe continents and plate tectonics, and even more speculatively, perhaps even surface life.
Less than one billion years ago, the climate dramatically changed due to a runaway greenhouse effect. It can be speculated that an intensive period of volcanism pumped enough carbon dioxide into the atmosphere to cause this great climate change event that evaporated the oceans and caused the end of the water cycle.