With enough trees …

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There was this fascinating recent article in the Guardian which laid out in very plain terms what we know already.  The best way to start addressing climate change and to start to absorb carbon dioxide while we work out how we are going to wean ourselves off petroleum and air travel is to plant trees, lots and lots and lots of trees.

From the article:

Planting billions of trees across the world is by far the biggest and cheapest way to tackle the climate crisis, according to scientists, who have made the first calculation of how many more trees could be planted without encroaching on crop land or urban areas.

As trees grow, they absorb and store the carbon dioxide emissions that are driving global heating. New research estimates that a worldwide planting programme could remove two-thirds of all the emissions that have been pumped into the atmosphere by human activities, a figure the scientists describe as “mind-blowing”.

The analysis found there are 1.7bn hectares of treeless land on which 1.2tn native tree saplings would naturally grow. That area is about 11% of all land and equivalent to the size of the US and China combined. Tropical areas could have 100% tree cover, while others would be more sparsely covered, meaning that on average about half the area would be under tree canopy.

The scientists specifically excluded all fields used to grow crops and urban areas from their analysis. But they did include grazing land, on which the researchers say a few trees can also benefit sheep and cattle.

“This new quantitative evaluation shows [forest] restoration isn’t just one of our climate change solutions, it is overwhelmingly the top one,” said Prof Tom Crowther at the Swiss university ETH Zürich, who led the research. “What blows my mind is the scale. I thought restoration would be in the top 10, but it is overwhelmingly more powerful than all of the other climate change solutions proposed.”

A trillion trees, it sounds like a lot.

We have had Phil Goff’s million trees project for Auckland Council and Shane Jones’ billion tree project for the Government.

Both are positive.  Jones’s proposal is not so great because it is mostly planting Pine for harvesting in the not too distant future.  To really make a dent in our carbon budget deficit we need to have long term sustainable forests grow, and Kauri are especially good at carbon sequestration.

But a billion trees is about 200 per kiwi.  A trillion trees is about 125 per person on the planet.

Of course the proposal needs to address the supply side of the equation as well as the demand side.  We need to urgently reduce the amount of CO2 we are pumping into the atmosphere as well as increasing the amount of CO2 we are sequestering.  And sorry meat lovers but we need to cut back on red meat consumption.

And we need to stop cutting down existing trees, particularly the large ones that have sequestered lots of carbon.  And there needs to be strong disincentives to dissuade Indonesia and Brazil from clearfelling their forests.

And this particular solution will take years to start having an effect.

But the message is clear.  Time to start planting.

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