It is true that the Earth has been much warmer in it’s billions year long lifetime. This factual, yet flawed, statement has been used to downplay the impact of human driven climate change as skeptics say that global warming is just part of a natural cycle.

Image/data credit: NOAA

If we go through the geologic record, dating back nearly half a billion years, we can identify periods of time where global temperatures rose as high as 90 degrees- much, much higher than our current average of around 58 degrees Fahrenheit! 

However, these hottest phases of our ancient climate happened long before humans ever walked the Earth with the most recent peak, the Paleocene-Eocene Thermal Maximum (PETM), occurring more than 50 million years ago- a time where you’d find palm trees and crocodiles above the ice-free Arctic Circle. 

An artist’s interpretation to what the late Paleocene looked on an Earth with no ice caps and an average global temperature as high as 73 degrees.
Image credit: USGS

Since the start of modern human civilization, roughly 10,000 years ago, global temperatures have remained relatively stable and cool compared to earlier times in our planet’s history. We’ve established our agriculture, civilizations, our general way of life in this climate- but now we’re facing the fact that this climate is changing as more greenhouse gases are released into the atmosphere. 

An increase in greenhouse gases, released by volcanic eruptions and other natural processes, likely also caused the rapid warming trend that peaked with the PETM. However, this warm up took roughly 20,000 years- today’s will only take 200. 

Global temperature trends since modern human civilization began roughly 10,000 years ago.
Image/data credit: NOAA

This astonishingly fast rate of warming can’t be attributed to the natural processes that have warmed the planet in the past, but instead has been “indisputably proven” to be a direct result of human actions that have left Earth warmer than it’s been in recorded human history. 

Storm Team 2 Meteorologist David Dickson