Climate and climate change
Climate zones, the greenhouse effect, where the extra carbon dioxide comes from, and the evidence that the Earth is warming. With a model that shows which melting ice raises the sea level.
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Weather is the state of the air over hours or days. Climate is the average weather of a place, usually measured over 30 years: how warm, how wet, how often it is above 30 °C.[1][2]
The world has five main climate zones: tropical, dry, temperate, continental and polar. Which zone a place is in depends mostly on its latitude (how far it is from the equator), but also on how far it is from the sea and how high it is.[3]
The greenhouse effect: sunlight passes through the air and warms the ground. The ground gives off heat, and gases such as carbon dioxide, methane and water vapour trap some of it. This keeps the Earth warm enough for life.[4][5]
Burning coal, oil and gas (fossil fuels) adds carbon dioxide to the air, and so does clearing land. Since 1750 the amount of carbon dioxide in the air has gone up by nearly 50%.[5]
The Earth's average surface temperature has risen by about 1 °C since the late 1800s, and two-thirds of that warming has happened since 1975. 2024 was the hottest year since records began in 1880.[6][7]
Other evidence: the sea level rose about 20 cm in the last century, glaciers are shrinking almost everywhere, and Arctic sea ice has become smaller and thinner.[6]
Melting ice on land (glaciers and ice sheets) runs into the sea and raises the sea level. Ice that already floats on the sea does not raise the sea level when it melts.[10][11]
Scientists of the IPCC concluded that human activities, mainly by giving off greenhouse gases, have caused the warming, and that the choices made in this decade will matter for a very long time.[9]
Try it: Land ice or sea ice: which raises the sea?
You need
- 2 identical clear plastic containers
- Modelling clay or a stone to make 'land'
- 8 ice cubes, all the same size
- Water
- A marker pen or sticky labels
- A ruler
Safety
Wipe up spills at once so nobody slips. Use plastic containers, not glass.
What to do
- In container A, build a 'land' of clay or a stone at one side that sticks out above the water. Container B has no land.
- Pour the same amount of water into both containers.
- In A, put 4 ice cubes ON the land (land ice). In B, put 4 ice cubes floating in the water (sea ice).
- Mark the water level on both containers straight away.
- Wait until all the ice has melted. Mark the new water levels and measure how much each one changed in millimetres.
- Fair test: same containers, same amount of water, same number and size of ice cubes, same place.
Play: Weather or climate?
Is this about the weather (now, today, this week) or the climate (the average over many years)?
Your best score is kept only on this device. Nothing is sent anywhere.
Quiz
Other ages: Ages 6–7 · Ages 15–16