Trump backs one trillion trees initiative. But what is it?
The trillion trees initiative is based on a study that says that planting 1.2 trillion trees could "cancel out" the last decade of the world's carbon emissions.
On Tuesday, while speaking at the World Economic Forum meeting at Davos, US President Donald Trump said that his country will join an initiative to plant a trillion trees.
The commitment by the head of the world's second-largest CO2 emitting country came at a time when climate change was the talk of the town at the annual assembly of the world's richest and most influential people.
"We're committed to conserving the majesty of God's creation and the natural beauty of our world. Today, I'm pleased to announce the United States will join one trillion trees initiative being launched here at the World Economic Forum. One trillion trees," Trump said. A sceptic of climate change, he did not mention anything about how the initiative will help cut carbon emissions.
But teenage climate activist Greta Thunberg, a speaker at the event, said that simply planting trees isn't enough to combat climate change.
"Planting trees is good of course, but it is nowhere near enough of what is needed, and it cannot replace real mitigation and rewilding nature."
So, whose idea is this?
The idea of planting a trillion trees came from ecologist and ETH Zurich professor Dr Thomas Crowther, who says trees are “our most powerful weapon in the fight against climate change."
He and his team at Crowther Lab have estimated that there are 3 billion trees on the planet and planting another 1.2 trillion trees will help neutralize CO2 emissions made during the last 10 years. The findings were presented at the AAAS Annual Meeting in Washington, D.C. on February last year.
“There’s 400 gigatons [of CO2] now in the 3 trillion trees, and if you were to scale that up by another trillion trees that’s in the order of hundreds of gigatons captured from the atmosphere – at least 10 years of anthropogenic emissions completely wiped out,” Crowther said, as per a report on The Independent.
But where do we plant these trees?
Crowther doesn't want to make use of any of the areas where people are living. “We are not targeting urban or agricultural area, just degraded or abandoned lands," he says. His team has identified 1.7bn hectares of treeless land, where trees can be planted. Equivalent to the size of the US and China combined, this land area is more than one-tenth of the total land area on earth.
According to him, the drive will help address both climate change and biodiversity loss.
How long will it take to plant trillion trees?
Many years. Probably several decades, unless all 7.53 billion people on earth planted 159 trees each. The scientist estimates 50-100 years of tree plantation is needed if we need to remove 200bn tonnes of carbon from the atmosphere.
Do all scientists agree with the plan?
No. Several scientists have pointed out that the plan fails to answer several questions. These include,
- What happens to the carbon absorbed by the oceans? (Estimates say 55% of all historical carbon emissions get dissolved in oceans)
- Won't planting trees in areas where they were never present increase global warming, as the trees could reduce planetary albedo (reflection from the ground) in several areas?
- How does it account for ecosystems where a large amount of carbon have already been sequestered?
The researchers at Crowther Lab had only this to say:
“We intended to highlight that we are aware of no other viable climate change solution that is quantitatively as large in terms of carbon drawdown. We did not suggest that tree restoration should be considered as a unique solution to climate change.
When his study was published, Crowther had told The Guardian that tree planting is “a climate change solution that doesn’t require President Trump to immediately start believing in climate change, or scientists to come up with technological solutions to draw carbon dioxide out of the atmosphere”.