The Sun keeps on expanding by nuclear fusion due to large amount of hydrogen fuels:
{}^{2}_{1}\text{H} + {}^{3}_{1}\text{H} \rightarrow {}^{4}_{2}\text{He} + {}^{1}_{0}\text{n} + \text{Energy}
The volume of Helium atom is much larger than Hydrogen atoms, so the size of the Sun is getting bigger and bigger.
Formerly, Venus was like the Earth, and human civilization had once fourished. Now, the temperature of the atmosphere of Venus is over 498K, which is unsuitable for living to all aerobic organisms. Water inside Venus has completely evaporated, and with UV light supply form the enlarged Sun, water molecules decompose like electrolysis:
2H_2O(g) + UV \to 2H_2(g) + O_2(g)
High temperature fosters combustion, and the light Hydrogen gases escape from Venus. So the sole chemical existing in Venus air is a greenhouse gas CO_2.
Another common cause is nuclear power plants. With AI industry prospering, the demand for electricity surges, and nuclear fission is the only means to deal with such a energy hunger.
The problem is, such a power supply requires a lot of water as a coolant. Since steam itself is a profound greenhouse gas, it absorbs a lot of latent heat and ejects such energy to the sea with lots of hot effluents.
As a result, CAT5 Hurricanes become the norm to coastal areas, and the Antarctica now has temperature over 273K all the time.
Infrastructures and mining (for starting materials of making motherfucking AI chips) also allow a powerful, colourless and odorless greenhouse gas, methane, to escape from rocks and soils.
By the way, some methyl compounds from ores will react with Mercury to form a toxin commonly found in Sushis. Our next generations are embracing skyrocketing certifications of Autism.
The final cause is lack of contraception of the third worlds such that human overpopulation is the leitmotif of high power usage.
Men respire more intensely than women do, and the former always declare wars all the time. Use a napalm and the target will burn like shitholes.
So, douchebags from world politics are the culprit of global warming.