What might cause major changes in earths climate?

Weather might change it

After enough storms the weather has been with hotter air causing mor and more storms which means Heatwaves are stronger. Storm surges rise higher and higher. Blizzards bring more  and more snowfall. The number of natural disasters has doubled in the past few decades – 90 percent of them are weather related due to earthquakes hurricanes tornado's tsunami's and more!  MARK ME AS THE BRAINLIEST :)

The size of a population would be low or would decline if there were more deaths than births so A I think.