Updated: Nov 6
On land, plants (particularly trees) are our most precious carbon sink, actively taking CO2 out of the air and producing O2. They offer much needed shade in extreme weather, mitigate flooding by storing water in their roots, trunks and leaves, keep waterways clean by filtering the water that runs past them, and are an important food source and habitat for many insects, animals, fungi, and some other plants.
We are only just beginning to understand how complex and amazing trees are. We know they communicate with each other using gases (e.g. ethylene), and mycorrhizal fungi that connect their root systems underground. We know that 'mother trees' look after their young, and they are capable of recognising members of their own species.
Without trees we can kiss goodbye to nature; bees rely on trees (and their 1000s of flowers) more than they do flowering plants. Birds spend most of their lives sheltering and raising their young in trees, many insects and small mammals depend on them, and they're vital for maintaining soil integrity by preventing erosion and flooding.
So knowing all this, can planting trees and restoring nature be a key way to reduce climate change impacts and improve biodiversity? What about planting trees vs other alternatives such as carbon capture utilisation and storage (CCUS) technologies?
Well let's see.
Before human civilization, there were an estimated 6 trillion trees
And far less carbon in the atmosphere. We now have 54% of tree cover left, and ideally we'd replace all we've cut down. But obviously that's not possible with a large portion of our land being taken up with farming, housing and industry. It's estimated that 1.2 trillion trees is the maximum number we can replace, given the available space we have, and that number would capture up to a quarter of human carbon emissions.
And it's interesting to note that not all forests are equal. For example, forests around the equator grow faster than those in colder regions, meaning they capture CO2 quicker, so ideally these would be the areas to focus on first in terms of rewilding. But at present, trees are still our cheapest and easiest way to capture and store CO2 from the atmosphere (1/2 the dry weight of a tree is carbon), and they are hands down more efficient than any of the technologies (such as CCUS) we've created so far.
Plus, as mentioned, trees have the added benefit of increasing biodiversity, mitigating flooding, offering shelter and shade (the temperature under a tree can be as much as 12 degrees Celcius lower on a hot day), and improving our mental health.
I'm all in for this!
But, given that we can't restore all we've cut down, climate scientists suggest we must start looking after what we have left (including other carbon sinks such as wetlands, peat bogs and seagrass), replant where we can, and change our diets to become more plant-based. This way more land will be available for crop growing (which uses less space and water than animal agriculture), and rewilding.
To stabilise the climate, we need global CO2 emissions to halve by 2030, a goal that's looking less and less likely as we draw nearer. So let's all make changes where we can, and let's get planting trees!