I often get asked this question on social media, so I decided to provide the answer as a simple primer.

1. The Basics: Climate Does Change

First, let’s be clear — climate change is real in the literal sense. The Earth’s climate has been changing for billions of years. We have geological records showing periods that were much warmer (like the Eocene, with crocodiles in the Arctic), and much colder (like the Ice Ages that covered North America in glaciers).

Even more recently, we have the Holocene Climate Optimum, significantly warmer than present day: