Blind, starving cheetahs: the new symbol of climate change? | Adam Welz | Environment | guardian.co.uk
Savanna ecosystems, such as those that cover much of Africa, can be seen as battlegrounds between trees and grasses, each trying to take territory from the other. The outcomes of these battles are determined by many factors including periodic fire, an integral part of African savannas.
In simple terms, fire kills small trees and therefore helps fire-resilient grasses occupy territory. Trees have to have a long-enough break from fire to grow to
a sufficient size — about four metres high — to be fireproof and establish themselves in the landscape. The faster trees grow, the more likely they are to reach four metres before the next fire.
Lab research shows that many savanna trees grow significantly faster as atmospheric CO2 rises, and a new analysis of satellite images indicates that so-called 'CO2 fertilisation' has caused a large increase in plant growth in warm, arid areas worldwide.
Although poor land management is undoubtedly partly to blame for bush encroachment, increased atmospheric CO2 seems to be upsetting many savanna ecosystems' vegetal balance of power in favour of trees and shrubs.