Planting a tree reverses some of the damage done by deforestation. Bt reforesting the earth would not restore things to how they were. As the OP said, that only happens if the excess CO2 is stored below the ground, too.
Planting trees is good, but only part of the full sequestration needed.
So carbon offsets by planting tree is a scam, and we need better than that.
You do realize that carbon sequestrated in a forest 100ks of years is prevented from contributed to global warming during all that time period, right?
> Not consuming fossil carbon means it will stay in the earth mantle for a geological time.
Nobody's arguing against that. But it's silly to argue that not consuming fossil fuels is a better solution than carbon sequestration. We urgently need to do BOTH. When your house is burning, you don't choose between calling the firemen and using the extinguisher - you do both.
> So carbon offsets by planting tree is a scam, and we need better than that.
That's naive and simplistic. If carbon offsetting was widely adopted, it would 1) be a fast way to start our transition towards a sustainable economy and 2) encourage reducing fossil fuel consumptions as it gets more and more expensive (as it will inevitably).
When it comes to fighting climate change, what matters is results, not this sort of uninformed rethoric.
We need to do something right now, carbon sequestration fits there.
We also need to change our ideology, and our energy resources, if we stick a plaster (ie bandaid) of carbon sequestration on it now and assume that is going to fix it, that's where we going to get to the point where land usage is going to go up against that. We can't simply go on using carbon based fuels and just "plant trees" forever unless we also create a reducing global population ...
Sequestration needs to be at greater levels than current use, we shouldn't allow rich people to go on 'using' by only sequestering to counter current usage.
Increasing the biomass of trees (e.g, growing a new forest) does reduce the CO2 levels; true, each tree in this forest will at some point die and re-release its carbon, but another will grow in its place; therefore, if the forest has grown and stays there forever the the result will be a net negative contribution to CO2 levels forever as well.
That of course does not change the fact that carbon offsetting alone is NOT a sufficient way to tackle climate change. Please do reduce your carbon footprint people, and encourage others to do so. Of course, there's nothing wrong with planting trees in addition (not instead of) reducing your emissions - you can think of it as charity for the planet; if you're interested in donating money so that forests get protected / grown, I recommend Stand For Trees: https://standfortrees.org/en/#protect-a-forest (I'm not affiliated with them).
Please people, be careful about what you write on these topics. We really need a high bar on scientific rigour on these topics if we are to act effectively.