1.3 Local effects

These measures – effectiveness and speed – ignore something fundamental to human lives and ecosystems, that is: changes happening at a local level.

CDR methods, of course, ‘undo’ human CO₂ forcing and therefore would likely have an exactly opposite effect on local changes.

With SRM methods, it might be possible to ‘fine-tune’ global mean climate change, but it would not be possible to fine-tune climate change in every region. This is because forcings from CO₂ and the Sun act in different ways – they have different fingerprints on climate in space and time (Session 3).

In Session 6, you saw GeoMIP predictions for a scenario in which SRM balances a quadrupled CO₂ forcing. Even though the global average temperature was adjusted to be the same as the preindustrial climate, the models predicted many local areas would be warmer than preindustrial times.