How Does Our Climate Compare To The Past?

Written By Teacher: Elaine Makarevich

Elaine is a New Jersey educator with 30 years of teaching experience in grades K-6. The earth and the natural world have always been a focus of her life and throughout her career as her students learned critical lessons about their planet when visiting her indoor or outdoor classrooms.

Earth’s climate has always changed, but today’s warming is happening much faster than in the past. Ice ages and warmer periods used to unfold over thousands or even millions of years, driven by natural forces like volcanic eruptions and changes in Earth’s orbit. Now, human activities—especially burning fossil fuels—are causing temperatures to rise at an unprecedented rate. This difference is key for students to understand: while climate change isn’t new, the speed and cause of today’s changes make it a serious challenge.

The Rising Temperatures Data Analysis Lesson gives students a hands-on way to explore temperature trends. Using real data, they can compare past and present climate shifts and see how human activities are accelerating global warming.

By looking at both natural and human-driven climate changes, students can develop a clearer understanding of why today’s warming is different—and why it matters.

Written By: MIT Environmental Solutions Initiative

The MIT Climate Change Engagement Program, a part of MIT Climate HQ, provides the public with nonpartisan, easy-to-understand, and scientifically-grounded information on climate change and its solutions.

For hundreds of thousands of years, the Earth has gone through repeated cycles of warming and cooling. Roughly every hundred thousand years, there has been an ice age, driven by changes in the planet’s tilt and orbit that allowed less sunlight to reach the Arctic. Between these ice ages have been periods of warming. 

The last ice age peaked around 21,000 years ago. This was followed by 10,000 years of warming that brought us to the climate we know now, says David McGee, an associate professor in the MIT Department of Earth, Atmospheric and Planetary Sciences. During that time, global temperatures rose by about 6° Celsius (around 11° Fahrenheit). The amount of carbon dioxide (CO2) in the atmosphere—the main planet-warming greenhouse gas responsible for today’s climate change—rose too, by nearly 50%.

“There's a lot of similarities there, of course, with our situation with modern global warming,” says McGee.

Ice sheets melted and seas rose, just as they are now. Driven by changing temperatures and rain and snow patterns, entire habitats like deciduous forests moved towards the poles, while the places those forests left behind began to look more like warmer locales. Some species migrated, or went extinct. These trends, too, are being echoed today.

But there are also key differences between the last significant period of warming and the modern day. First, today’s warming breaks from the historical cycle. In fact, before human-caused warming began, scientists believe the Earth was roughly due to enter a cooling cycle (although research to confirm this is ongoing).