# Explain why scientists are concerned about the increasing concentration of carbon dioxide in the atmosphere.

> Cambridge International IGCSE Chemistry (0620) — 10.3 Air quality and climate · Explain · 4 marks

> Carbon dioxide is released into the atmosphere from a number of human activities. Its concentration in the atmosphere has risen significantly since the beginning of industrialisation.

## Mark scheme (4 marks)

1. Carbon dioxide is a greenhouse gas (that absorbs/traps heat/infrared radiation)
2. Higher concentration of CO2 means more heat/infrared radiation is trapped/absorbed (enhanced greenhouse effect)
3. This causes the average temperature of the Earth to rise / global warming
4. This leads to a named consequence of climate change (e.g. rising sea levels / melting of polar ice / more frequent extreme weather events / changes in rainfall patterns)

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