Carbon Sequestration (HL IB Biology)

• Scientists believe that global warming can be slowed by increasing carbon sequestration
  • Carbon sequestration can be defined as

The process of capturing and storing carbon dioxide from the atmosphere

• This can be accomplished by increasing the removal of carbon from the atmosphere into natural carbon sinks
  • It is hoped that artificial carbon storage may become viable at some point, but this is still at the research stage
• Natural carbon sequestration can be increased by:
  • Forest regeneration and afforestation
    • Forest regeneration, or reforestation, involves planting new trees in deforested areas, while afforestation is the creation of new forests
    • If trees are allowed to grow to maturity, they can store huge amounts of carbon in their biomass
      • Some countries around the world have shown that it is possible to restore lost areas of forest by carrying out reforestation, e.g. Costa Rica now plants seven times more trees than it cuts down
      • This kind of achievement requires huge government inputs in the form of benefits to landowners
  • Peat bog restoration
    • Peat bogs form when plant matter cannot decompose fully due to waterlogged (anaerobic) and acidic conditions; the carbon stored in the partially decomposed plant matter means that peat bogs are an essential carbon sink
      • Peatlands form in boreal and temperate ecosystems, and can form rapidly in tropical ecosystems
    • Human activities include the harvesting of peat for fuel and the draining of peat bogs to clear land for development and agriculture; these activities release carbon back into the atmosphere by combustion or decomposition
      • Peat bogs are drained by digging drainage ditches to allow the land to dry out
      • The activity of decay organisms increases as the peat dries out
    • Filling in drainage ditches and regulating peat harvesting can allow peat bogs to recover and to continue growing in depth; this restoration of peat bogs increases their ability to sequester carbon

CC BY-SA 2.0, via Geograph

CC BY-SA 2.0, via Geograph

Reforestation (left) and the blocking of drainage ditches on peat bogs (right) can increase carbon sequestration by naturally occurring ecosystem processes

NOS: There is active scientific debate over whether plantations of non-native tree species or rewilding with native species offer the best approach to carbon sequestration

• Scientists do not always agree on the best approaches to a process, and different approaches may bring different benefits and problems
• There are differences of opinion among scientists around the best way to approach carbon sequestration by planting trees
  • Some think that planting non-native trees which grow quickly and sequester the maximum mass of carbon in the shortest time is the best approach
  • Other scientists prefer a rewilding approach, which involves encouraging the growth of native species and so restores naturally occurring ecosystems; this would sequester carbon more slowly, but could be more beneficial for biodiversity