Only new forests sequester. Old forests are in approximate CO2 balance: rotting trees and the consumption of green mass by wildlife emit CO2 at approximately the same rate as it is absorbed. Since we have a limited area to plant new forests this is only a temporary solution.

But it's important, since it could buy us a few more years to implement more permanent solutions.

>Only new forests sequester

*Younger forests pull the most out over a given period of time. The bulk of the carbon stays locked up as long as the wood doesn't decay/isn't burned. It's one reason some architects are starting to look at structural wood for larger buildings again, as long as the building stands you keep the carbon locked up in the framing. If we had a magic wand we could create a few super-fast growing species and plant massive amounts of forest of complimentary species that provide the soil with nearly everything needed to grow one another and simply harvest the lumber, drag it out to anoxic depths at sea and sink it not unlike the commonly accepted theory of the azolla event doing similar with aquatic ferns in our planet's past.

The best trees can manage about 48lbs of CO2 per year, that's 46 trees per metric tonne and healthy forest is 40-60 trees per acre. Just to go carbon neutral last year that would mean you would have needed at LEAST 53 million square miles of optimal forest. For reference, there are 196.9 million square miles of land on earth, effectively 1/4 of the land mass on earth would need to be 100% optimized decade or two old forest.

Roughly 31% of the earth is forest, however it's far from the above optimal conditions. In reality we'd need probably 50% (if not more) of the earth to be forest to manage what we did last year.

Coincidentally, pre-industrial era the earth was about 48% forest and current estimates are we lose something like 28,125 square miles annually to human operations. We're producing more and more while reducing the planet's ability to sequester.

Sadly planting more trees isn't even going to equate to a bandaid, it's going to be like loosing a limb to a wood chipper and gently blowing on the wound. It's purely a "this makes me feel good" thing.

> Don't plants require carbon dioxide to grow?

Yes, but they also require other things to grow, so the scaling of their growth with rapidly increasing atmospheric CO2 concentration isn't as impressive as some people imagine, and it's only been empirically demonstrated in the short term. As far as I've read, the main uncertainty as to what happens in the medium-long term relates to how much nitrogen is available in the soil, and how the nitrogen-fixing topsoil ecosystem adapts. If it can thrive in such a way as to fix more nitrogen, that could lead to further plant growth. But it's also plausible that the rapid shift in the environment disrupts that system and leads to a regression in plant growth rates.

And all of that assumes that unseasonably warm/cold temperatures from changing weather patterns, drought or flooding from changing weather patterns, increased wildfires from changing weather patterns etc doesn't kill off many species in an area.

That is like arguing against drowning because you require water. The dose and application make the "poison".

It is even true that the CO2 was at this point before. If it had shifted at geological timescales even if it was from human activity it would be more or less fine as the ecosystem could adapt to it like previous epoches. Certainly there would be extinctions but would give time to adapt and speciate.

Tree planting helps some but it isn't comparable at scale at all - as in running out of available landmass bad.

Tree planting would help the ultrapoor if they maintained it locally given things like impact on soil erosion and rainfall but those are only localized effects

> Don't plants require carbon dioxide to grow

Of course. Nobody is saying there should be no CO2. But if your implication is that higher CO2 means better growth, it is generally wrong. Some plants do grow better, some don't, in a higher CO2 environment. But more importantly, it isn't as if CO2 is an independent variable. Along with it comes significant changes that plants are not adapted to -- higher average and peak temperatures, more or less rainfall (depending where in the world it is). Yes, given enough time, the plants that make it through the stresses of climate change will adapt and thrive, but in the near term (a few generations of humans) it will cause problems.

> I am not sure it was immediately obvious to people 120 years ago that CO2 was such a "dangerous" thing.

https://en.wikipedia.org/wiki/Greenhouse_effect

In short: Joseph Fourier (of the Fourier transform) advocated for the idea of atmospheric gasses causing a greenhouse effect. It was advanced along the years, in 1896 Arrhenius even calculated the effect on the climate due to a doubling of CO2. There were scientific papers published in the 50s using the terms "climate change" in the 50s, well before the Mariner 2 spacecraft.

Not all energy sources generate significant CO2 or even cost more than those that do. It’s vastly more efficient to make the least economically expensive changes early than to wait and be forced to use more drastic approaches.

Long term carbon sequestration via forests is extremely expensive as you can’t then use the land for anything else. Not extracting carbon is by far the cheapest option for long term sequestration.

PS: Sequestration of biomass underground is a viable long term option, but it’s again expensive.

Forested land has tons of economic uses, and in many cases it improves the productivity of the other activities that are done within the land. Most human dwellings do better when they are surrounded by trees (lowers cooling/heating costs and improves the sanity of the occupants). Most livestock can be raised in orchards, along with quite a few consumable plants (coffee, cows, mushrooms, etc.). Also the trees themselves can be converted to charcoal through gasification, which provides a carbon feedstock for graphite, activated charcoal, or biochar, all of which lock away the carbon. The gasification process produces syngas/woodgas/producers gas which is a viable fuel source. Lastly the wood can be used itself for building structures and furniture which locks away the carbon for the life of the item.

Not sure how any of that is expensive, as it fulfills our requirements for food, housing, and luxury goods.

The issue with this line of thinking is we are not talking about a single forest or some minor changes to urban settings, but a massive change to the number of forests. The scale is vastly beyond adding more trees near buildings or a few more orchids. Ideally you want massive trees that live a long time and spend as much energy as possible growing larger not making fruit.

This land is not already being used for forests because other uses are simply more useful or less costly. The net loss of utility then needs to continue for as long as the carbon is sequestered.

Finally, if you want to sequester carbon somewhere else you need to collect and transport it which adds more costs. Further, if that’s the goal forests are simply slow carbon sinks in comparison to other plants.

Sequestered carbon just goes into the ground. You need not transport it anywhere. It improves the health of the soil. There is equipment that will take dead standing wood and gasify it into biochar which is stable in the soil for theoretically 10k years. These systems also produce a net positive energy (electricity and heat). Source: I wrote the firmware that runs All Power Lab's Power pallet, which does just this. It fits on a 4' pallet and can be taken to a fuel source (woodchips, corn cobs, walnut shells, grass pellets, etc.).

You still need to either move the equipment to the plant matter, or the plant matter to the equipment.

I'm having a hard time understanding the fundamental problem that you are bringing up. Sure, machinery doesn't just magically transport itself, same goes for the plant matter. But these machines produce fuel/electricity, so they can be used to power chippers, tractors, or whatever machinery you need to run your orchard, timber mills, or office park cleanup activities. This is the point I'm making, there is free fuel that can be used from growing plants (of a variety of sizes and uses). Just as we use lawn mowers and wood chippers to clean up our yards, we should also be using the resulting material to fulfill our energy needs and produce biochar to lock away carbon back into the soil.

You're correct, nothing comes for free, but the alternative is to leave this dead standing wood on forest floors to be later fuel wild fires. Or in the case of agricultural waste, to be composted or burned directly. Seems like a waste, as composting produces methane and CO2, which unless captured in an anaerobic digester just goes into the atmosphere and contributes to global warming, and burning does similar harm.

Small scale gasification reactors can run equipment, and are easily transported on trailers to the site of waste if it is not already easily centralized (in which case a dedicated cogeneration plant is usually a better option). A 20kW reactor can produce enough electricity to run 16 US homes, so situating one on every block is also a viable option that we should be considering.

> I personally find ideas such as these are far better for world's ultra-poor then raising the price of energy thru carbon taxes, as pretty much the only way people can move into a significantly better living situation is thru the use of energy.

"Carbon tax hurts the poor" is oil industry propaganda. The poor use less carbon than average -- especially the "ultra poor" -- but everyone receives the same dividend. It's a net transfer to the poor.

On top of that, the underlying cost (after accounting for tax, subsidies and regulations) for oil in poorer countries is higher than in richer countries because they have worse infrastructure for delivering fuel. You can put solar panels and batteries on a shack in the middle of a field and have electricity for decades. To do that with a gas generator you need gas stations, vehicles to deliver it, roads to drive them on etc. They don't have those things, and won't get them overnight, but meanwhile you can give them electricity today and they immediately get running water and electric light and wireless telecommunications etc. So oil is garbage for them and they're better off never burning a drop of it while the people who do are paying a carbon tax that funds a dividend they can use to buy solar panels.

It is true but not on individual level, on country level. There are countries that generate > 80% of their energy from fossil fuels and do not have enough money to invest at scale in nuclear, or wind, or solar. Rich Western countries on the other hand invested in clean energy first, and now that they have significant advantage in that area they are trying to impose arbitrary CO2 limits, which is kind of pulling up the ladder behind them - now the poor countries not only have to find money to invest in clean energy, but also twice the amount, to pay penalties for exceeding those limits.

> It is true but not on individual level, on country level.

It's true all over the place.

Suppose you live in a country which gets 80% of its energy from fossil fuels. Well, that sucks, so now your average energy costs go up by $1000 a year. You can't afford that! Only you get it all back. You get a $1000 dividend, use it to pay for the same energy you did before, and nothing changes.

Except for one thing. When your country continues its path to industrialization, nobody is ever going to build a new coal fired power plant again. All the new capacity will be non-fossil fuels, because now they're much cheaper relative to coal -- no carbon tax.

The only cost you're really paying is the relative price difference between fossil fuels and alternatives. But that's already close to zero and has non-cost benefits for your country like air quality and energy independence.

Moreover, the idea that this is some cost for developing countries that developed countries didn't have to pay is also a lie. The cost of renewables is driving the cost of fossil fuels down through competition. The carbon tax is only needed to prevent that -- to keep their price back up around their traditional cost, which makes them uncompetitive with the falling price of renewables, so that they die out instead of the lower demand causing their price to fall to the point that they still end up as 20-50% of generation capacity.