Also, it is difficult to plant trees in a desert. Also, algae blooms are dangerous for other life forms.
However, there are some startups working with super-fast-growing (ugly) trees that are then used as construction material, which would be a longer-term-functioning sink. Not very clear whether that scales.
The trees grow. We cut them down. We make houses out of them, which are wrapped to prevent deterioration. The sunk carbon becomes our buildings.
Other uses of the wood are also usually carbon sinks. Paper either gets recycled (the carbon is preserved) or it gets buried in a sealed landfill where is takes decades or longer to break down.
It'd be cool to calculate how much carbon Weyerhaeuser sucks out of the atmosphere each year.
A 25 year old maple will sequester 400 pounds of co2 in it's lifetime. An average commuter car will emit that in 2 weeks. Hauling all that carbon out of the forest will likely emit far more than that.
If we're building the buildings anyway, we have to compare with alternative building materials. That is, how much more would transporting that lumber emit, compared to transporting for instance brick?
But since CO2 is easier to measure than biomass and ecosystem complexity, everyone is focused on sucking carbon out of the air when we need to be restoring grasslands, forests, and coral reefs.
Source: Charles Eisenstein's "Climate: A New Story"
[1]https://www.oecd.org/env/cc/Outlook%20to%202050_Climate%20Ch... [2]https://www.acer-acre.ca/resources/climate-change-in-context... [3]https://www.businessinsider.com/carbon-dioxide-indoors-could...
That might be slightly more tricky (and less efficient) than you seem to imagine.
Also, the prize is not exclusively for "chemical" carbon extraction, if you can find a way to scale algae bloom to be a long term carbon sink without ruining the environment in other ways you are eligible:
> Any carbon negative solution is eligible: nature-based, direct air capture, oceans, mineralization, or anything else that achieves net negative emissions, sequesters CO2 durably, and show a sustainable path to achieving low cost at gigatonne scale.
TL; DW: planting 20 million trees would equal roughly the CO2 emissions of the USA for half a day.
1. Trees will eventually die and release their CO2 through rot or burning
2. Consequences of changing the ecosystem so rapidly
"Surely the net biomass stored in fossil fuels could be completely resuscitated, so to speak." - that's a strong no - fossil fuels have accumulated over millions of years, having all that carbon become biomass all at once would not be returning to something that existed earlier but something completely unprecedented, it would require many times more biomass than the Earth has now or has had at any particular moment of history.
I was surprised that Sahara has been green cyclically.
https://en.wikipedia.org/wiki/Sahara#Desertification_and_pre...
'What the heroin industry can teach us about solar power' - https://www.bbc.co.uk/news/science-environment-53450688
The satellite images show the green areas over the desert increasing.
They're pumping water from underground to irrigate the poppies using electric pumps and solar panels.
I wonder how quickly the water table will be depleted though.
Algae can be >100 times as efficient at that than terrestrial plants, so there might be a there there, but even still, fracking basalt probably beats that by a couple of orders of magnitude.
> Certain species of bamboo can grow 910 mm (36 in) within a 24-hour period, at a rate of almost 40 mm (11⁄2 in) an hour (a growth around 1 mm every 90 seconds, or 1 inch {2.54 centimeters} every 40 minutes).
At least it's better than no trees at all.
As long as we don't end up with monocultures (also bad for the environment) they should be part of the solution!
We could plant fast growing bamboo and turn it into biochar/bio-oil? Or use it for sustainable housing?
Sadly, the natural kelp forests are in really bad shape. I haven't seen the stats on giant kelp, but the bull kelp forests have been practically been wiped off the map by sea urchins and warming waters over the past decade or two. The natural kelp forests probably didn't provide much in terms of CO2 absorption, as dead plant matter would decay quickly in the ocean, but it's been a huge loss for aquatic wildlife.
1) Reduce emissions to zero (will take some time).
2) Use more natural solutions (trees, algae, kelp etc. - will also take time).
3) Enhance natural solutions with tech (enhanced weathering).
4) Develop carbon capture tech to reverse the damage done by the fossil-fuel burning tech.
Why do you prefer "freeing up carbon from the ground" ? Usually that's just a sideeffect that happens only because we want some other thing e.g. extract energy from oil or manufacture cement by calcinating limestone; and if we want a stable atmosphere then we can't be freeing up carbon from the ground without putting it back.
How many centuries is it going to take to reduce global emissions to... Half of their current levels?
But this depends on global willingness to do so by choosing (more expensive) sustainable products and voting for politicians who want to enforce/encourage carbon reductions
The New Soviet Man was an experiment only 70 years in the making, and it was in no way a successful one.
2. Let's suppose that actually happens. Let's suppose we get to 50% of current emissions in... 50 years.
We currently increase CO2 concentrations by 2.5 ppm/year. This would put us at over 500 PPM in my expected lifetime... In one of the more optimistic interpretations of your predictions.
For bonus points, even if we hit 50% reduction in 50 years, that would way overachieve what the Paris Accord set out. We are currently not on track to hit any of the targets in the Paris Accord.