What this lesson teaches
I can judge how well mitigation strategies, such as cutting emissions and storing carbon, build community resilience.
Syllabus K226, Topic 3.3, Key Question 3. How effective are mitigation strategies in building a community's resilience to climate change?
Make a guess
A company plants a forest of seedlings. Does that cancel out the fuel it burned this year?
- No, because trees release the carbon again each night.
- No. Seedlings take years to absorb that much carbon.
- Yes, as soon as the seedlings are in the ground.
- Yes, because a forest absorbs the carbon from nearby air.
Show the answer
No. Seedlings take years to absorb that much carbon.
Regrowth removes carbon slowly and can be undone by fire, drought or clearing. So it must go with fast cuts in emissions.
Protecting forests and oceans stops stored carbon escaping, and regrowing forests removes more, but this takes time and can be undone.
A carbon store holds carbon. A carbon sink takes in more carbon than it releases over a period. Growing forests absorb carbon dioxide through photosynthesis and store carbon in trees and soil. A big store is not always absorbing much now: how much is stored and how fast it takes in more are different things.
Protecting forests avoids the emissions from clearing and disturbed soil, and keeps them absorbing carbon and providing other services. This needs planning, enforcement and other ways for local people to earn a living. If clearing just moves to another forest, little is gained.
Regeneration helps forests and ecosystems recover on suitable land. Natural regrowth or well-planned planting can store carbon, support wildlife and help regulate water. The choice of species, land rights, fire risk and upkeep all matter. The wrong plantation in the wrong place can damage an existing ecosystem or take land needed for food.
Oceans also absorb carbon dioxide, through physical and biological processes. Protecting mangroves, seagrass and their carbon-rich mud keeps carbon stored. Cutting pollution and habitat loss helps marine life. But ocean capacity has limits, and dissolved carbon dioxide also makes the ocean more acidic.
Removal takes time. Fire, drought or new clearing can release the carbon again, and land and nature limit how much can be stored. So protecting and restoring sinks must go together with fast emission cuts. Monitor how much extra carbon is removed and whether it stays stored.
- Carbon store
- Holds carbon, like a forest or peat.
- Carbon sink
- Takes in more carbon than it releases.
- Permanence
- Stored carbon can be released by fire or clearing.
Step by step
Protect stores
Stop clearing that releases carbon.
Restore uptake
Regrowth absorbs more carbon over time.
Keep it stored
Watch for fire, drought and new clearing.
Real examples to use
Amazon rainforest
Clearing the Amazon for farming releases stored carbon and weakens one of the world's largest carbon sinks.
OneMillionTrees, Singapore
Singapore aims to plant a million more trees between 2020 and 2030 to cool the city and store carbon.
Worked example: Mangroves do several jobs
Protecting mangroves keeps carbon in their trees and mud, saves habitat and can calm waves on some coasts. But a thin strip of mangroves cannot protect every coast from every flood.
Watch out for this
Planting a seedling cancels out burning fossil fuel straight away.
Trees take in carbon slowly, may die, and can release it again. Timing, amount and permanence all matter.
Check your understanding
Why combine forest regrowth with cutting emissions?
- Regrowth is slow, limited and can be undone.
- Planted trees remove greenhouse gases for good.
- Plants absorb too little carbon.
Show the answer
Regrowth is slow, limited and can be undone.
Yes. Sinks cannot replace fast emission cuts.