The bottom line when it comes to climate change is that carbon dioxide—CO2— traps heat; and that carbon dioxide concentrations are getting higher and higher.
It doesn’t matter that climate deniers say it’s more complicated than that.
My relationship with my wife is complicated but the bottom line is simple; we’re married, we’ve been a couple for 30 years and will stay married.
The link between CO2 and temperature is far more robust than that. It’s based on the laws of physics and was first established as fact in 1824 by Joseph Fourier.
Here’s a graph of the last century of global temperature and CO2 levels.
Of course the earth’s climate system is complicated, there are plenty of fine details to work out, but the basic relationship is simple and rock solid.