Even if you planted every single place on Earth that could accept a tree, you would not double Earth's biomass. If you did this and then somehow managed all those trees from dying, the only thing you would achieve is you would delay the entire proces by roughly 7 to 8 years. And if you can't prevent trees from dying or getting burned, you only get about 5 years.
From my point of view, planting trees is a huge distraction. There is absolutely no way planting trees will get us out of our problems, it is much better to start thinking about something actually productive.
Trees are a great co2 sink and large reforesting would result in a lot of runway, on the order of hundreds of years of runway, for technological co2 sequestration to develop further.
You are misusing this word, by suggesting that planted tree is a sequestered form of CO2. That's not the reality, in reality trees die or burn.
Your logic is faulty.
You see, you can bind all CO2 we emit per year with 1.6 trillion trees. True. But you can only do this ONCE, and it takes many years.
And then you are left with the Earth's landmasses all covered with trees that need to be actually sequestered (like buried deep underwater) to create space for a new batch of trees that have to be planted all over again.
From a climate concern point of view, trees as carbon sinks work.
- global amount of co2 emissions per year
https://www.statista.com/statistics/276629/global-co2-emissi....
- average co2 sequestered per tree - 25-45 kg depending on species (google for estimates)
https://www.usda.gov/media/blog/2015/03/17/power-one-tree-ve...
37 billion metric tons / 25 kg = ~1.48 trillion
Amount of land available for reforestation as of 2019 is enough for 1.2 trillion native saplings.
If you start with completely empty land, at first you will have increase in biomass, but after some time for new trees to grow you will need to have some other ones to die. The trees might keep exchanging CO2 to O2, but you will also get steady increase in emitted CO2 either through forest fires or microorganisms or animals eating and decomposing and literally breathing the CO2 back to atmosphere.
When things are in balance, forests do not actually remove any CO2 because any CO2 removed is balanced out by new CO2 emitted. Only planting a new forest on a new land binds some new CO2, and that only temporarily until the forest matures.
That's why "invest on renewables" was right next to it on the OP. I'd invert the order, and invest on artificial capture too. But the comment is quite right.
Where do you find the space for that, and the labour?!
https://www.science.org/doi/10.1126/science.aax0848
We could also set aside more land for reforestation as well.
Finding labor is easy.
This is an easy problem to solve, we just need to build up the knowledge that it is possible and then execute on it. Right now most people have never even considered things this way because they’re only exposed to doomer talk whenever climate change gets discussed. :(
It would probably use land that's currently in use for agriculture, in a time when huge areas of old growth rain forest are cleared to make more space for agriculture. One country deciding to turn pasture into forest would probably cause more forest to be lost in Brazil, of a type that stores _way_ more CO2 per hectare.
I think we should start with getting better at preventing and fighting huge forest fires, and to stop considering wood pellet burning as "renewable energy".
Any further focus on planting trees only distracts from real solutions, imo.
That's absolutely false. Most of the world's biomass is stored in peatlands and burning that much peat in 10 years would increase the atmospheric CO2 by hundreds of ppm very quickly - significantly more CO2 than humans have produced in our entire history combined.
Why is this important is that living things form a carbon cycle of which our atmosphere is a part. Peat is sequestered for an unknown amount of time and is at the very least temporarily removed from the cycle.