This Stunning Graphic Shows Earth’s Temperature Over 22,000 Years

Climate change is a touchy subject, and it’s something that we only approach with the utmost deliberation and care.

However, as simple or as light-hearted as it appears at first glance, today’s infographic actually provides an invaluable amount of context on a subject that is often mired in the ugly details of mathematical models, multipliers, and policy implications.

Earth’s Temperature Over 22,000 Years

Today’s infographic from XKCD shows the Earth’s temperature since the last ice age glaciation, which was 22,000 years ago. It was around this time that there were vast ice sheets covering North America, northern Europe, and Asia.

This infographic does two things very well.

First, it gives us an idea of temperature changes over time in a relatable fashion, but it also gives us a sense of time scale.

Temperature Changes in Context

Temperatures were cold at the end of the last glaciation, which was around 20,000 BCE – about 4°C cooler than they were during the modern era. Boston and New York would have been covered in thick ice at that time.

Fast-forward half of the span of the infographic, and temperatures have increased to near modern levels (the average between 1961-1990) in about 11,000 years. This would have been around 9,000 BCE, which is around the time the very first humans started farming way back in today’s Middle East region.

From there, temperatures continue to increase for another 4,000 years, peaking around the time that the wheel was invented. This was around 5,000 BCE, which is still considered to be the end of the Stone Age. This is an era still well before the Ancient Egyptians rose to prominence.

The Earth cools again. By the time of the birth of Jesus, temperatures are close again to to those in the modern era. It continues to cool until Shakespearian times, which were in the middle of what is called the “Little Ice Age”.

Finally, after the Industrial Revolution, temperatures spike at a rate not seen before. In the short span of just a century or so, temperatures are back at their previous peak that occurred when the wheel was invented – roughly 7,000 years ago.

Sources used: Shakun et al (2012), Marcott et al (2013), Annan and Hargreaves (2013), HadCRUT4, IPCC,