* greenhouse gases: water vapor, **carbon dioxide**, methane
* **natural process, accelerated by humankind** (emit greenhouse gases)
* **gases in Earth’s atmosphere trap heat from the sun that would otherwise escape back into space => heats up the Earth's atmosphere** and keeps the planet warm
* without greenhouse effect, Earth would be too cold to support life as we know it
* human activities, such as burning fossil fuels & deforestation, have increased the concentration of greenhouse gases in the atmosphere, causing the Earth's temperature to rise => **anthropogenic climate change**
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