Most of the discussion involves capturing and storing CO2. A different proposal that I heard years ago was to develop crops (specifically corn) with brighter-colored leaves - to reflect sunlight back out into space rather than adsorbing it and converting to heat. Acres and acres of cropland reflecting sunlight. (Oddly, there was no mention of brighter grasses for suburban areas.)
(Not the same, but there was some investigation about using light-colored gravel on top of buildings that have those flat tarred roofs. That was to reduce the A/C load in the summer.)
It seems like it’s even more economical to use those low population areas like deserts to grow algae to harvest the oil. Oil stores and transports far easier than hydrogen, and while algae isn’t as efficient at turning sunlight into energy as a good photocell, it’s a whole lot cheaper.
Electrification of transportation will only go so far. There are applications that without more than a magnitude increase in battery storage, electrics won’t work. Growing algae and squeezing it also seems to require far less infrastructure than turning CO2 into liquid fuels using the Fischer Tropsch process.
Definitely deserves research dollars. The lack of water has not stopped Lithium mining and it shouldn’t stop this technology either. But bottomline : it’s a research project
Let’s look at Hydrogen by electrolysis of water at small scale from renewable energy : this is usually PEM Electrolyzers which have been around since submarines have been around. Submarines make their oxygen by electrolyzing water. Crisco / hydrogenated vegetable oil is also made by electrolysis hydrogen (purity), so is parts of the impossible burger and many semiconductors around you.
Bottomline : Hydrogen through electrolysis is a mature technology at small scale and a Bank will provide guarantees paving the path for new projects.
Hydrogen electrolysis at large scale : The green revolution was ushered into the world when we started making Ammonia (Haber’s process) by reacting Nitrogen from air with Hydrogen. The hydrogen in initial projects came from large scale water electrolysis from Hydroelectric plants. It’s called the Alkaline electrolysis process and is again a very mature technology
Please Google “Neom Project” it’s a joint work by many chemical companies : Air Products, Thyssen Krupp, etc in Saudi Arabia.
Solar power in the Giga Watt range is made in the desert, then water is electrolysed to make hydrogen. Hydrogen is next converted to ammonia for use in transportation.
Photosynthesis may slow down in old trees, but it doesn’t stop. Plus, older trees are larger with more leaves, so while they may sequester less carbon per unit area of tree, they must still be sequestering significant amounts of carbon.
But there’s more going on in mature forests than just trees photosynthesizing. Trees die and rot. Forest fires, even if they never crown, burn up undergrowth and tree detritus. Unless the forest has a place to sequester the carbon away from the atmosphere (i.e. under water), in the long run, an undisturbed (by humans) forest will be carbon neutral.
Yeah, the simple way to look at it is, where is the carbon going? In a young forest (one that’s still growing and on its way to becoming old-growth), the carbon is being turned into wood, in more and/or larger trees. But an old-growth forest has as much wood as it’s going to have. Carbon dioxide is continually being turned into new plant material, but at the same time, old plant material is being eaten, or rotting, or burning, which return the carbon to carbon dioxide.
Afforestation in CONUS has potential to sequester about 3% of annual US carbon emissions, per study discussed here:
A paper from a few years back listed the global potential as an additional 0.9 billion hectares (an increase of 25%) storing a total of ~200 gigatonnes at maturity. But people threw a shitstorm about the authors’ math/assumptions and I haven’t dug into it since then. They did end up publishing an erratum.
Sure, but whether they’re storing carbon in wood or in soil, it’s the same issue either way. They’re not building up an entire mountain underneath themselves: At some point, the creation of new solid carboniferous mass is balanced by the removal of carboniferous mass, and an old-growth forest is, by definition, at that equilibrium point.
We humans can, of course, change that equilibrium in various ways. For instance, we can cut down trees, and do something with the wood that won’t release the carbon back into the atmosphere for a long time (whether by burying it, or by using it to make useful things like buildings), and then grow new trees. The details on that can vary: Do you use fast-growing trees and cut them all down after only a few years and replant all of them at the same time, or do you take a few large trees here and there out of an existing forest, but either way, the basic principle is the same. That can continually sequester carbon. But that’s not a natural old-growth forest, either way.
The above is inconsistent with recent literature. Even recent criticism of some the higher estimates from the late '00s are estimating continued accumulation in soil organic matter, e.g.: https://www.nature.com/articles/s41586-021-03266-z
You really can’t talk about carbon without talking about nitrogen, we seldom hear those words used in the same sentence. Nitrogen has been a big polluter for some time, but it also holds the key to increasing the biomass significantly. Right now, the carbon nitrogen cycle is a little bit out of wack, the carbon acts as a fertilizer and uses up it’s nitrogen a little faster than it should. I would be curious as to how soil nitrogen levels are responding to higher carbon levels. I wonder how long it will take for them to get back in balanced with one another. There is a lot of science going on studying nitrogen fixing bacteria, I can see this becoming a key player in managing the biomass. Another question I would like to see answered, what could be considered optimum co2 levels? I like the idea of seperate sciences studying different aspects independently of one another. Mitigation, conservation and alternative fuel sources are all major topics on their own.
I am also very curious as to how trees and other plant life will evolve under different atmospheric conditions. There is about 50% of all the co2 that humans have put in the atmosphere that we can’t account for… That is a very serious number that we need to learn more about.
The amount of increase in CO2 over the past decades is an exact match for an accounting of the CO2 we’ve produced. I don’t know where you’re getting numbers that say otherwise.
And here, it’s really not clear what you’re talking about. Nitrogen is 3/4 of the atmosphere; it can’t really be considered a polluter. Compounds of nitrogen might be, but then it depends on what compounds you’re talking about, and in what context.
The elephant in the room is coal.
Any effort made to address CO2 that isn’t reducing coal use is wasting time. Even replacing coal with methane is a significant net win. Anything else you do that involves energy production is likely best spent on replacing coal. Worrying about stuff on the edges is wasting time.
Get rid of coal and the problem is near solved.
Make steel with hydrogen (already a thing). Stop building coal fired power. Actively replace coal wherever you can. Messing about with anything else is a waste of breath.
True, but there’s also a hippo in the room. If we could phase out petroleum usage, especially for vehicles, that would make a big difference, too. And in fact, despite coal being worse than oil, if you could replace all petrofuel vehicles with electric vehicles powered by coal plants, that’d be a net win, too, because power plants are so much more efficient than car engines (though of course it’d be even better to power those vehicles with anything but coal).
While it’s true that powering electric cars from coal-fired power plants is still better than petroleum-fueled cars and trucks, coal is such a horrendously dirty fuel (and a horrific source of local regional pollution and health risks) that there’s just no excuse for it in this day and age. If Ontario could get rid of all its coal-fired power plants, so can anyone else. The biggest problem is special interests finding excuses to reject the alternatives – nuclear, hydro, wind, and solar all have their enemies. The most practical option in the US so far seems to have been conversion of some coal-fired plants to natural gas, which is only a stop-gap measure, and was motivated by cost savings, not climate considerations.