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Why is Earth warm enough to live on, and why is it getting warmer? Puff explains the invisible blanket in the sky.
Moogi: Puff, why is the world so warm and cosy? Isn't space super cold?
Puff: Freezing! But the Earth wears an invisible blanket.
Moogi: A blanket? Where? I can't see it.
Puff: It's made of gases mixed into the air, like carbon dioxide and water vapour. We call them greenhouse gases.
Puff: Here's the trick. Sunlight shines down and warms up the ground.
Puff: Then the warm ground sends heat back up toward space.
Puff: Greenhouse gases catch some of that heat and send it back down. Just like a blanket keeps you warm in bed.
Puff: Try it yourself! Make the blanket thin, then make it thick.
Build the blanket: play it in the world above!
Moogi: With no blanket, everything froze!
Puff: Without any greenhouse gases, Earth would be about −18°C on average. With them, it's about 15°C. Just right for flowers, and for us.
Greenhouse gases trap some of the heat the Earth gives off. A little of that trapped heat keeps our planet warm enough for life.
Moogi: But when I made the blanket thicker, it kept getting warmer...
Puff: That's what's happening right now. Burning coal, oil and gas puts extra carbon dioxide into the air.
Puff: The blanket gets thicker, more heat gets trapped, and the whole planet warms up. That changes the weather everywhere.
Burning fossil fuels adds extra greenhouse gases. A thicker blanket traps more heat and the planet warms. That's climate change.
Moogi: So we need the blanket, just not too thick.
Puff: Exactly! Clean energy from the sun and wind doesn't thicken the blanket.
Moogi: Goodnight, just-right Earth!