Page 86 - Science Course 2 (Book 2)

Mo10-L2a: What is the Carbon Cycle?

Carbon is in reservoirs, or storage places, within all CO2 is a greenhouse gas. Greenhouse gases are
Earth systems. gases in the atmosphere that absorb and re-radiate
thermal energy from the Sun.
Carbon Reservoirs
When levels of atmospheric CO2 increase, Earth’s
Carbon average temperature increases.
Carbon
Reservoirs (billions of Form
tons)

Atmosphere 750 CO2 gas

organic
Biosphere 3,000
molecules
dissolved
Hydrosphere 40,000
CO2 gas
Geosphere minerals and
(crust and 750,000
upper mantle) rocks

Geosphere minerals and
(lower mantle) 750,000+ rocks

On Earth, most carbon is
combined with other
elements in compounds. 6

Carbon in the biosphere is C This phenomenon is known as global warming.
stored in organisms.

In both the atmosphere
and the hydrosphere, SUMMARY
carbon exists as gaseous What are Natural Resources?
CO2.
Earth systems include the atmosphere, the
hydrosphere, the biosphere, and the
geosphere.
Some changes in levels of atmospheric CO2 are
caused by human activities, such as the burning of Examples of interactions among Earth
fossil fuels. systems include the water cycle, the rock
cycle, the carbon cycle, and the
phosphorus cycle.

Human activities disturb natural cycles.

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