Question

volcanoes cycle carbon from below the earths surface back into the atmosphere. volcanoes emit co₂, ash, and other gases. over billions of years, volcanoes have added a significant amount of co₂ to the atmosphere.

however, the amount of co₂ that volcanoes contribute each year is small compared to other carbon sources. for example, the eruption of mount st. helens in washington emitted 10 million tons of co₂ into the atmosphere over 9 hours. by comparison, human activities release the same amount of co₂ in about 2.5 hours.

how do volcanoes affect the carbon cycle? select the true statements.

• volcanic activity is a carbon sink.
• volcanoes emit more co₂ per year than human activities.
• volcanic eruptions move carbon from below earth’s surface to the atmosphere.
• volcanoes have added co₂ to the atmosphere over billions of years.

Explanation:

• A carbon sink absorbs carbon. Volcanoes emit \(CO_2\), so they are not a carbon sink.
• The text states that volcanoes emit less \(CO_2\) per year than human activities.
• The first sentence says "Volcanoes cycle carbon from below the Earth's surface back into the atmosphere".
• The text mentions "Over billions of years, volcanoes have added a significant amount of \(CO_2\) to the atmosphere".

Answer:

• Volcanic eruptions move carbon from below Earth's surface to the atmosphere.
• Volcanoes have added \(CO_2\) to the atmosphere over billions of years.