Trees — a climate solution

Worried we'll never solve climate change? One solution is not too far away, maybe in your yard, growing on the side of the road, or a nearby park.

It's trees.

Trees breathe in CO2 and use photosynthesis to break down the CO2 into carbon and oxygen. The oxygen we breathe, while the carbon is stored away in the tree's roots.

With an estimated 3 trillion trees covering most parts of the world, trees make a natural way to bring down CO2 levels in the atmosphere. There are now 3.04 trillion trees on earth — ScienceNordic

Room for a trillion trees

A recent study by Dr Tom Crowther, senior scientist and founder of the Crowther Lab at ETH Zurich, and colleagues, found that the earth could be home to even more trees. Using satellite images, the scientists identified available, disused land where trees could be grown.

These extra trees "could store 205 gigatonnes of carbon", said the scientists. The global tree restoration potential — research article To store that much carbon, the trees need to breathe in a lot of CO2 — about 3.67 times as much. Comparing CO2 emissions to CO2 levels — Skeptical Science This means that the additional trees could remove about 750 gigatonnes of CO2 from the atmosphere.

If true, this figure means an enormous reduction in the amount of CO2 in the atmosphere, and would take us a long way to bringing CO2 levels back down to the safer levels we enjoyed a century ago.

In practical terms it means planting a trillion trees, according to Dr Crowther. Backing the trillion tree campaign to combat climate crisis —The Guardian The figure has captured imaginations. The Trillion Tree Campaign was announced just this year (2020) by world leaders at the World Economic Forum. Trillion Tree Campaign To carry out this mission, the youthful Plant for the Planet announced their goal to plant a trillion trees. They have already planted 13.6 billion trees. Plant for the Planet — aims and vision

Scientists disagree

Unfortunately, many scientists disagree with Dr Crowther's findings. In fact, 49 scientists felt strongly enough to write an article criticising Dr Crowther's figures. Their final figure for the carbon removed was much lower, at 42 gigatonnes. Comment on “The global tree restoration potential” — Science Magazine

But whatever figure the scientists end up agreeing on, it seems apparent trees can store massive amounts of carbon — whether it's 42 gigatonnes or 205 gigatonnes of carbon, it's going to make a dent in climate change.

The race for trees

While scientists debate, forests and jungles are disappearing. Since 2000, the Amazon has shrunk by 8%, an area the size of Spain lost. Deforestation razed eight percent of Amazon in 18 years: Study — Al Jazeera In 2021, forest fires across the great Siberian taiga burnt an area the size of Greece. Wildfires in Siberia have burned down an area larger than Greece — CBC This is on top of the damage from wildfires of previous years.

Wildfires are threatening forests around the globe. Because of climate change, the trees are becoming drier, temperatures higher, and there's more lightening too, making perfect conditions for extreme forest fires, or "megafires". The age of megafires: The world hits a climate tipping point — Yale Environment 360

Forests are also under threat from land-clearing by local farmers and loggers. It's driven by the world demand for beef, soybeans, palm oil and wood. What's driving deforestation? — Union of Concerned Scientists With a growing world population, this demand is likely to increase, unless alternatives to these products can be found.

But treeplanting is also making a huge difference. Between 1982 and 2016, an area equal to Texas and Alaska was replanted with trees. While some of replanting was to create plantations for timber or palm oil, a lot of it is due to treeplanting projects. Earth has more trees than it did 35 years ago — but there’s a huge catch — World Economic Forum

So treeplanters have a chance. But to win this race against climate change and deforestation, they need to pull a few more tricks out of their sleeves. A variety of trees need to be planted which suit local conditions, similar to an actual forest. Planting a forest with just one species ends up in an area without natural life, dead soil, and no extra carbon storage. How to design a forest fit to heal the planet — The Conversation

It may even be cheaper and more effective just to let forests regenerate on their own. On farms, this is called agroforestry, and it could be a way to cover much more land in trees than through treeplanting projects. Farmers can look after the trees for the long-term, and local communities may also begin to see their benefit. Can we restore 350 million hectares by 2030? — WRI

It's a good reason to plant more trees.

Planting trees in New York City. Tishman Center, CC BY 2.0