31% of the globe’s land surface is forest. By 2015-16 the world’s forest area was estimated at close to 4 billion ha.
Increasing forest area through reforestation is an efficient way of absorbing back CO2 that has been released into the air.
It was some years ago that we were informed that unfortunately reforestation could not sequester enough carbon to match the release of CO2 from for example the coal burning into the atmosphere. The plantation area would have to be enormous, and there is simply not enough land to create plantations that could neutralise – and much less bring down – the CO2-growth.
Many forest plantations are established, that is a fact. China is an example of a country that has expanded its forest area. But globally the trend is negative – the forest area is shrinking. In a report called Living Forests WWF predicts that between now and 2030 another 170 million ha of forest may be lost unless firm measures are taken. This means two things:
on top of all other sources of CO2 release into the atmosphere, additional CO2 will be released when those forests are converted; and
the total area of forest land that can serve as a carbon sink and absorb CO2 will be reduced. So forests cannot be expected to change the trend of increased CO2 levels.
Now there is more news. A report in Science 28 Sept 2017 finds that the tropical forests, often referred to as the lungs of the earth, are by now a net contributor to CO2 emissions, due to clearing and conversion to other land uses.
From that follows necessarily that since absorption by forests cannot be increased, then emission will have to decrease to keep us below the temperature rise of 2 degrees as stipulated in the 2016 Paris agreement. This will require inventiveness!!! We are not expecting people to assume an ascetic life style. And while we are talking the world population keeps on growing, with raising expectations. How to do more with less?