En-en adult card 11 concentration of co2

Card #11: Concentration of CO₂

About half of CO₂ emissions are captured by natural carbon sinks. The other half remains in the atmosphere. The concentration of CO₂ in the air has increased from 280 to 415 ppm (parts per million) over the past 150 years. This is higher than at any point over the last three million years.

Explanation

CO₂ measurements have been taken since 1958 in Hawaii, on Big Island, on the flanks of the Mauna Loa volcano. They were initiated by Charles Keeling. In the blue scenario (2°C) they increase until 2040-2050, then they decrease because emissions will have been reduced so much that natural sinks no longer absorb them.

Correction

Causes

• Carbon Sinks

Consequences

• Additional Greenhouse Effect

Wrong links

Wrong consequences

• Carbon sinks It can be argued that CO₂ emissions take place before reaching carbon sinks. But the opposite link has our preference.
• Ocean acidification Players often identify CO₂ concentration as a cause for ocean acidification. But it is more logical to link back to carbon sinks.

To go further

CO₂ elimination

The surplus CO₂ is permanently stored in the atmosphere (no chemical degradation process). There are only 2 physical processes: dissolution of CO₂ in the oceans, and synthesis of O₂ via photosynthesis (in the presence of photons).

Therefore:

• in 100 years' time, 40% of the surplus CO₂ released today will still remain in the atmosphere
• in 1000 years' time, 20% of the surplus CO₂ emitted today will still remain in the atmosphere
• in 10,000 years' time, 10% of the surplus CO₂ emitted today will still remain in the atmosphere.

It is an almost irreversible process.

French emission factors

In France, the main cause of CO₂ emissions has shifted from industry to transportation in 150 years.