A century and a half of thermometers
Scientists have tracked Earth's average temperature since the 1880s. Single years jump up and down. The long-term pattern is what matters, and it points one way: up.
How to read it. Tap or drag along the line to see each year. Blue years are cooler than average, orange years are warmer. Every decade since the 1970s is warmer than the one before.
Why more CO₂ means more heat
Sunlight passes through the air and warms the ground. The ground gives that energy back as infrared heat. CO₂ lets sunlight in but catches infrared heat on its way out and sends some of it back down. More CO₂ means more heat sent back.
How to use it. Slide the CO₂ level and watch the arrows. Yellow arrows are sunlight coming in. Orange arrows are heat going out, and some get turned back down. The arrow counts are a simple picture, not exact numbers.
Why emitting less is not the same as cooling down
Think of the atmosphere as a bathtub. Our emissions are the tap. Oceans and forests are the drain, and they remove about 20 billion tonnes of CO₂ a year. The water level only drops when the tap runs slower than the drain.
How to use it. Move the slider or pick a preset. The line shows how much CO₂ is in the air out to 2100. Try 20 Gt a year, which is half of today. The line stops rising but does not fall. CO₂ only drops when we emit less than nature removes.
The Keeling Curve
Since 1958, a station on Mauna Loa in Hawaii has measured CO₂ in the air directly. Zoomed out, the line climbs steadily. Zoomed in, it zigzags every year as northern forests grow leaves in spring and drop them in fall.
How to read it. Switch between the two views. The long climb comes from burning fossil fuels. The yearly zigzag is the planet breathing.
What this looks like where you live
Global averages can feel far away. Pick your city or town anywhere in Canada and see how its climate is projected to change. This is your winters, your growing season, your lake ice and your smoke days.
Illustrative estimates for teaching, built from the regional warming patterns published in the Climate Atlas of Canada (higher-emissions pathway; “today” means the 1976–2005 average). For a specific address, look up exact figures at climateatlas.ca.
Every tenth of a degree is still up to us
Code red is not “game over”. It is the signal that waiting is the most expensive choice. The gap between the do-nothing path and the net-zero path is worth several degrees in Canada by the time today’s students are grandparents. Here is where a class can push.
Tell the people who decide
Emissions are set mostly by laws, budgets and building codes, not by individuals. Elected officials count letters, and a class of thirty is a stack.
- Find your Member of Parliament and your MPP (or provincial representative).
- Ask your city council one question: what is our climate plan, and is it on track?
- Use the letter starter below. It already contains your local numbers.
Make it a group, not a worry
Nobody fixes a planetary problem alone, and nobody should have to carry it alone either. Organized students have changed school boards, cities and countries.
- Start or join a school climate club; certify your school with EcoSchools Canada.
- Connect with youth movements such as Fridays for Future.
- Run this page at a school assembly or parent night with your town selected.
Change the big things first
Personal choices matter most when they are the big ones and when they are visible, because they make climate action normal in your community.
- How you get around: walking, cycling, transit, carpooling and electric vehicles.
- How your home is heated and how much energy it wastes. Ask about heat pumps and insulation.
- What you eat and throw away; how often you fly.
Your letter starter
Generated from your location and the numbers on this page. Edit it, sign it, and send it to the person who represents you.
Common questions and misconceptions
If it's freezing cold today, doesn't that disprove global warming?
No. Weather is what happens over hours and days in one place; climate is the pattern over decades across the whole planet. A record cold snap in Thunder Bay and a warming planet can absolutely be true in the same week. Chapter 01 shows individual years bouncing up and down inside a clear rising trend.
Hasn't the climate always changed on its own?
Yes, and that's part of how we know this change is different. Past shifts were driven by things like orbital cycles and volcanic activity over thousands of years. The current rise is happening in about 150 years, lines up with the growth of fossil-fuel use, and matches the physics of CO₂ absorbing infrared energy, which is exactly the mechanism shown in Chapter 02.
If we stopped emitting today, would the planet cool right back down?
Not right away. Chapter 03 is the reason: CO₂ already in the atmosphere stays there for a long time, and natural sinks only remove roughly 20 billion tonnes a year. Stopping emissions stops making the problem worse, which matters enormously, but the level comes down slowly.
Isn't CO₂ just plant food? More should be good, right?
Plants do use CO₂, and the Keeling Curve's annual zigzag is literally the biosphere breathing. But plants also need water, stable temperatures, nutrients, and pollinators. Extra CO₂ with more heat waves, droughts, and pests generally hurts crops more than it helps, which is why Chapter 05 shows both a longer growing season and more heat stress for the same place.
Isn't it too late anyway? Why bother?
No, and the numbers at the top of this page are the reason. Damage rises with every tenth of a degree, so the difference between the do-nothing path and the net-zero path is not “saved or doomed”, it is a heat wave that happens twice a decade versus every summer, or Canada ending the century around +3.5 °C instead of near +7 °C. Under a net-zero path, Canada’s temperature is projected to stop climbing after about 2050. Late is not the same as too late.
How can scientists predict 2080 when they can't predict next weekend?
They're different kinds of questions. Nobody can say whether it will rain in Sudbury three Saturdays from now, but we can say confidently that Sudbury's summers will average warmer over 60 years, the same way you can't predict one coin flip but can predict roughly 500 heads in 1,000 flips.