Yes, the climate does change. It’s gone through some wild shifts over the Earth’s 4.5-billion-year history.

Sometimes it got warmer. Sometimes it froze. Natural forces like volcanoes, changes to the sun’s energy, and even the wobble of the Earth’s orbit all played a role. 

Ancient volcanoes released gas over millions of years, slowly warming the planet. Small changes in the Earth’s orbit triggered Ice Ages that took tens of thousands of years to build up and melt away.

The climate changes we’re seeing today are very different.

Earth that is cracked and dry from drought in Canada. © Greenpeace / Thomas Porter

Today’s warming is fast and furious

Natural climate shifts normally take a long time – thousands or even millions of years. The warming we’re seeing now is moving much more quickly. It’s happening over decades.

The Earth is heating up about 10 times faster than it does after an Ice Age. In just the last 200 years, average temperatures have climbed by 1.1 °C, and they’re still rising.

Humans lit the match

Scientist Jason Box, from Byrd Polar Research Centre at Ohio State University, holds an ice core sample taken after drilling a long hole in the ice in Greenland. Core samples like these are used to understand how the climate has changed over many years. © Greenpeace / Nick Cobbing

99% of climate scientists around the world agree. Today’s climate change isn’t part of any natural cycle. It’s caused by humans.

The problems started during the Industrial Revolution, which lasted from around 1760 to 1890. That’s when humans began burning fossil fuels to power factories, trains, and later, cars and homes. Burning these fuels releases greenhouse gases that trap heat from the sun inside of them and warm the planet.

Carbon dioxide is one of the main greenhouse gases. Today, human activities pump out about 100 times more carbon dioxide each year than all the world’s volcanoes combined.

Scientists have dug deep to understand this. Literally! By studying layers of ice, mud, and sand, as well as tree rings, they’ve tracked greenhouse gas levels over millions of years. What they’ve found is alarming. 

Carbon dioxide levels are now the highest they’ve been in at least 2 million years. Methane and nitrous oxide – two other powerful greenhouse gases – are also at their highest in 800,000 years.

We’ve changed the chemistry of the atmosphere in a couple of centuries. In response, the planet is heating up fast.

What’s the big deal?

Activists and cyclists on the “Ride for Renewables” in 2010. They were demanding that the Ontario government start using more renewable energy sources. © Greenpeace / Eric Coomes

For the past 10,000 years or so, the climate was pretty stable. That stability gave humans the chance to farm, build cities, and create the world we live in today.

But now the climate is changing so quickly that it’s hard for nature and animals (including us humans!) to keep up. Seas are rising, swallowing up coastlines and islands where people live. Floods and wildfires are destroying the homes of people and animals more often. Heatwaves and droughts are putting our health at risk and making it harder to grow food. And scientists are warning that one million species are at risk of extinction. 

It’s hard to accept that we’ve caused such a serious problem, but it’s also in our power to change course. We can demand stronger climate laws, support Indigenous land and water protectors, and push governments to shift from fossil fuels to clean energy, like wind and solar. The science is clear, and the moment to act is now.