Isn’t the climate always changing?
Yes. There is natural variability in Earth’s climate but the current climate change is very unusual as it is not exclusively part of a natural cycle. Natural factors include volcanic eruptions, aerosols and phenomena such as El Niño and La Niña (which cause warming and cooling of the Pacific Ocean surface). Natural climate variations can lead to periods with little or no warming, both globally and regionally, and other periods with very rapid warming. However, there is an underlying trend of warming that is almost certainly caused by man’s activities.
