Question

How are forests moderators of the climate?

Answer 1

A moderate climate is one near the median of the coldest and hottest climates on verifiable historical records. That would place our current climate as of two years ago as moderate but a little cool. As we are approximately 2C cooler than the Medieval, Roman and Holocene optimums and approximately 1.5C warmer than the coldest period of the little ice age thus we are just slightly cooler than what could be considered moderate.

Answer 2

Deforestation, and especially the destruction of rainforests, is a hugely significant contributor to climate change. Scientists estimate that forest loss and other changes to the use of land account for around 23% of current man-made CO2 emissions – which equates to 17% of the 100-year warming impact of all current greenhouse-gas emissions.

As children are taught at school, trees and other plants absorb CO2 from the air as they grow. Using energy from the sun, they turn the carbon captured from the CO2 molecules into building blocks for their trunks, branches and foliage. This is all part of the carbon cycle.

A mature forest doesn't necessarily absorb much more CO2 that it releases, however, because when each tree dies and either rots down or is burned, much of its stored carbon is released once again. In other words, in the context of climate change, the most important thing about mature forests is not that they reduce the amount of CO2 in the air but that they are huge reservoirs of stored carbon. If such a forest is burned or cleared then much of that carbon is released back into the atmosphere, adding to atmospheric CO2 levels.