The new research, looking into the feasibility of growing trees on large plantations to off-set climate change, comes from the Potsdam Institute for Climate Impact Research. The research organization calculates that the necessary size and number of plantations would need to be so large, they would eliminate most natural ecosystems or reduce food production.
The argument for growing more trees runs that more plants allows the carbon dioxide they have taken up from the atmosphere to be stored (through photosynthesis trees absorb carbon dioxide to produce oxygen and wood). This means, in theory, that the greenhouse gas is not released into the atmosphere at the same quantity. This is a type of carbon offset scheme.
The researchers state that attempting to build a big plantation in an area already subject to high levels of fossil fuel emissions (a so-called ‘late regret option’) simply won’t work due to the size of plantation needed. Here they calculate that even if carbon dioxide emissions are reduced in line with current national pledges under the Paris Climate Agreement, biomass plantations would still need to be enormous, on a scale that would been unsustainable.
However, growing biomass quickly in well-selected places with increased irrigation or fertilization can have a benefit. However, this needed to be supported by a range of other measures. As it stands other carbon offset schemes are likely to be more effective, such as distributing efficient cooking stoves through to capturing methane gas at landfill sites, or simply going to the source and reducing the burning of fossil fuels substantially.
The new study is published in the journal Earth’s Future, under the heading “The limits to global-warming mitigation by terrestrial carbon removal.”
