We should all take a moment and appreciate that plants are pegged to (IIRC) 10-15% theoretical max efficiency, and that's just in photocapture, it's even worse when you factor in chemical inefficies in storage and conversion of sugars back to usable atp (which it must do to use the energy)
> plants are pegged to (IIRC) 10-15% theoretical max efficiency...
OTOH, plants (i.e. trees) can live for hundreds of years, they are self-replicating, they extract their own minerals from the ground, require very little energy input to put in place, play an crucial role in the water cycle [1], reduce the albedo effect [2], cool the air [3], provide a habitat for a multitude of species, and bring joy to our hearts.
Oh, I almost forgot, they also fix carbon! And they do all this for free, the only thing you have to do is, you know, not cut them down.
> plants are pegged to (IIRC) 10-15% theoretical max efficiency
I suspect this is soon to change.... With CO2 levels around 280 ppm, the biggest challenge for many plants is finding a carbon atom - in fact, many plants grow just as fast under just 10% brightness sunlight.
Now that CO2 is up at 420 ppm, it's far easier to find carbon, so now the evolutionary race will be on to collect more sunlight and grow faster. And plants have done this before, ~20 million years ago, so somewhere there are probably some recessive genes just waiting for their moment to shine again, and natural selection will make them spread like wildfire.
If it was just CO2 levels going up then maybe. The problem is that temperatures are going up too, so gas solubility is going down. This means that C4 or CAM photosynthesis plants might get an edge over C3 on a larger area.
Do you have a source on that? We have been in an ice age for roughly the past million years. Pretty sure it was warmer in almost every other era prior.
> > 20mln years ago the sun was around 0,2% colder
> Do you have a source on that?
It's not solar radiation forcing that has made things relatively cooler, but it is cooler than 20M years ago. Of course, we could actually reach those temperatures again soon.
It's complicated! My bet would be less on individual species slowly adapting, and more on mass extinction and re-specialization.
When there's a big shock, specialists have a harder time, and generalist species have an edge. So, when an ecosystem is destabilized or totally transformed, generalists tend to take over. The thing about generalists is that they adapt to new environments quickly. Once they live stably in a new environment long enough, they begin to adapt to it more stably, and specialize, leading to new speciation.
Songbirds are a great example of this; they exploded out of Australia some 40 million years ago, spread everywhere, and then specialized like crazy into their new environments. They likely out-competed a lot of pre-existing local species as they spread out. Humans are also a great example - we spread everywhere as successful generalists, and started the process of biologically specializing in our new environments without fully speciating. In the case of humans, we know pretty precisely about the wave of megafauna extinctions that accompanied our spread.
The Younger Dryas megafauna extinctions cannot necessarily be attributed to humans. Humans spread tens of thousands of years ago. And numerous megafauna still exist in Africa, the likely birth place of humanity.
Well... lots more here. My impression was that African mammals survived in part because they co-evolved with humanity, and didn't get quite the shock as other places where humans showed up fully formed.
Wild mammal biomass is estimated to be about 83% lower due to humans. Reduction in biomass isn't exactly synonymous with extinction, but they aren't totally unrelated either.
There aren't any unless you're an incredibly fringe academic or using dumb terminology to avoid admitting that strong multiregionalism is entirely dead. Human evolution didn't stop there and there are unresolved questions about where within Africa different phases of the process occurred, of course, but the continent as a whole is undoubtedly where anatomically modern humans emerged.
Yep. I remember being blown away when I learned that most early trees fossilized because there was nothing yet to break them down. Not fungi, not bacteria, not insects.
This was the Carboniferous age when oxygen levels are thought to have been up to 35% as opposed to 21% now.
Most trees probably grew in swampy areas and the water they fell into would have been lower in oxygen. The material would have built up in the water and mud.
Atmospheric CO2 levels in the pre-tree era 400 Myears ago was something like above 6000ppm, compared to 280ppm in the pre-industrial era. Even burning coal formed during this time like mad, 90% of the atmospheric CO2 is still just gone.
Could mean a long time, or could not. There have been new bacteria/fungi discovered around chernobyl which subsist on gamma radiation. It's not like evolution of new processes are guaranteed to happen slowly, it just seems unlikely to happen quickly.
Many of the photosynthesizing algae can complete a lifecycle in 8 hours. They should be able to evolve pretty quick to new conditions, especially across the huge volume of ocean water.
10% is the theoretical quantum efficiency of the chlorophyll complex. Ps I/II use all sorts of tricks to squeeze electrons out of light, it's hard to imagine it getting better.
Remember that photosynthesis is a two stroke process. Fixing carbon tends to happen at night, so both sides are subject to optimization, and the day side has way more variation (seasonal etc) so you can't just say "RuBisCo sucks so PSI/II must be very suboptimal".
This Friday there was severe thunder and rain around here while the forecast said no rain at all. The reason was, they had 3 different models running and all of them gave the whole week different results (basically no overlap), so they just took the most probable, which was totally wrong.
I know these models are not that mich related, but when we can't look at the wheather of tomorrow, I question the precision of a model looking 1000 years into the future a bit. It will get warmer, for sure. But _how much_ is IMHO subject to interpretation.
> I know these models are not that mich related, but when we can't look at the wheather of tomorrow, I question the precision of a model looking 1000 years into the future a bit. It will get warmer, for sure. But _how much_ is IMHO subject to interpretation.
You say you know these models aren't that much related, but you still question the precision based on weather models. So do you, or do you not think they are much related?
If you throw a marble into a pit I can't easily predict which path it will take, but I can tell you where it will end up with which likelihood.
Evolution takes a lot longer than 1000 years to affect fundamental processes like photosynthesis, which is an ancient biological chemical reaction. Plants experienced thousands of ppm of CO2 and warmer temperatures for most of Earth's 1 billion plus year history. The fossil fuels that are being burned, the carbon that is being burned, is dead plant matter from millions of years ago, when CO2 was thousands of ppm.
This isn't new knowledge. We've known this for over 100 years.
"An increase in ambient CO2 to 800-1000 ppm can increase yield of C3 plants up to 40 to 100 percent and C4 plants by 10 to 25 percent while keeping other inputs at an optimum level."
It's mostly a joke on that basis, but I am a little skeptical that the well-known CO2 experiments will apply on average across the globe without being counteracted in part or whole by the temperature & growing season impacts.
In our current breadbaskets plants are going to be losing a chunk of the day in the middle of the growing season when it is too hot to photosynthesize on a regular basis, and the tradeoffs of what land is desertified and what land is defrosted is unlikely to be a net gain. The gains from increased CO2 are starting from in a hole and I'm not expecting to break even, let alone see faster or greater biomass on average, let alone at the rate we see in experiments using our current climate and future CO2 levels.
We have two main types of human corn here (Quebec). Yellow corn, and bi-colour corn.
Yellow corn literally does not come to full harvest if there are too many cloudy days. This happens once a decade maybe. It needs a growing season longer, and with more light than we have here.
Just 300km further south, in Ontario, this is not a problem.
(Bear in mind that the days shorten fast as fall approaches here)
Bi-colour corn can get two crops.
My point is, we already... without genetic engineering, just by selective breeding, get wild variations in growth rate, and yields, and harvest times... with just a decade or two of selective breeding work!
And my second point is, the most fertile land is going to become usable, if temps continue to rise. All that bog in Northern Canada.
We just need crops suited to shorter growing seasons, and very long days at equinox.
Canada is already mostly farmland. It will be interesting to see where this goes.
Re: selective breeding and genetic engineering, that's going to happen regardless of the atmospheric carbon levels.
Also, while I did bring up agriculture and it's fair to point out that it's going to get better over the next thousand years, agriculture is only about 2% of the Earth's plant biomass. While the rest of the biomass will be affected by the heat and benefit from the CO2, unless we start engineering the phytoplankton and the forests and all the other plants around us, it's not going to benefit from it.
Re: Canada's gain, there is a lot of land between 50 and 70 degrees north. The questions are (a) how much land in the north are we trading for how much land in the south? and (b) how does the productivity of the northern land compare to the productivity lost in the southern land?
Re: selective breeding and genetic engineering, that's going to happen regardless of the atmospheric carbon levels
But not to tailor crops, for areas that are currently permafrost.
There are billions of acres of permafrost bogs/peat in Northern Canada. They are even a concern, for as they thaw, they offgas.
Think of these areas as you would think of coal, in terms of CO2 being released.
But! That peat and bog is immensely fertile. If, outside of the growing season length issues, warmer temperatures come, then that is very, very rich, fertile farmland.
But we need specially tailored crops, which would never be created otherwise.
Err, "the data" [1] doesn't talk about increases | decreases in total land area with vegetation, the data talks about increases in green leaf area within already established areas of vegetation.
ie. Your data and the prior comment aren't necc. in conflict.
We show a persistent and widespread increase of growing season integrated LAI (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing LAI (browning).
The global vegetated area is [2]:
About 85 percent of Earth’s ice-free lands is covered by vegetation. The area covered by all the green leaves on Earth is equal to, on average, 32 percent of Earth’s total surface area - oceans, lands and permanent ice sheets combined.
If you're trying to tell me about the existence of the law of conservation of mass, I'm not sure what to tell you other than 'duh'
The point I was making is that cash crop farming is not a self-contained system even if the earth as a whole mostly is. (Much) more carbon goes into its production than comes out in the crop. Most of that takes the form of operating machinery, but there's also the production of fertilizers, and also the incremental loss of carbon in topsoil through tillage and erosion.
I am singling out maize (and, well, soy) because the scale of it is absolutely crazy; also on the whole most of the product isn't for direct human consumption (animal feed and ethanol). (Also BTW I work on software for running machinery which operates in those fields.)
Anyways, this is intrinsic to farming, which is an extractive process. The question is how to more smartly manage it in the long run.
>The use of those inputs isn't creating carbon, just transforming it
It is though. Or if you like, it's transforming carbon from "in the ground" to "not in the ground", which is fundamentally the only thing that matters, since you're adding to a closed system.
I can't tell if your comment is a false flag operation. I actually tried to find it any oil executives, lobbyists, or republican said something about big greening but couldn't.
There were a lot of advertisements about " they call it pollution, we call it life" about 15-20 years ago, and I still see some billboards to that extent in PA, funded by groups like CEI:
Oh man you've never cared for trees/plants have you. Some of em (most often the ones you "want") are total crybabies over those "trace elements".
You can't have DNA without phosphorus, for example, and many plants can't make nitrogen from air. Don't get me started on magnesium (needed for chlorophyll)
Corn tissue...with a very instructive caveat emptor:
> Be aware that elemental concentrations in plant tissue can vary widely for a given crop depending on the stage of growth and environmental conditions and for different crops, yet plants can still appear normal and healthy. For some elements the range of sufficiency is wide and for others the range is narrow. A good deal of caution needs to be exercised in diagnosing mineral deficiencies based only on plant tissue analysis.
That quote is talking about the way nutrients move around a plant I think, and how that introduces measurement issues depending on where and when you sample. Whereas I think this comment thread is just talking about overall composition. As in when the nutrients move from the stem to the head of a crop, if you sample the stem you would see a nutrient deficit, but actually the nutrients are still there, in the head.
That's important for farming, not that important when discussing the makeup of plants overall.
Useful sampling for crops is usually done post harvest, since that's the output and what we actually care about. Even after harvest, crops will change depending on the conditions endured during processing and shipment.
No idea what gives an arbitrary vegetable "flavor" relative to another in the same genus. Given how much of the industry is trial-and-error breeding to objectively target certain characteristics, it's unclear that practicing experts do either.
Fascinating - that's lower than I would have guessed. It seems ocean water is 2.5% salts, which, yeah, is pretty damned salty compared to anything I cook...
I want to suggest re-reading their comment. “mostly they make themselves from air” and “dirt has necessary trace elements” are both 100% factually correct. The word “necessary” covers what you are saying in your comment. There’s no need to suggest they haven’t raised plants when what they said is literally correct.
I understand what you mean but the vast majority of their structure is carbon based and that comes from gaseous CO2. Can’t survive without the dirt but can’t get big without CO2
It’s been a thing for hundreds of years. That’s why agriculture traditionally rotated crops and planted beans every 3rd season or so. I’m not sure what if anything is deferent about this species of corn, except perhaps that it is itself a desirable crop with more market value.
We stopped doing this and moved to artificial fertilizers in the 20th century because it vastly improved crop yields, and is cheaper.
> I’m not sure what if anything is deferent about this species of corn
This species of corn has weird roots halfway up which drip goop down on the ground. The goop contains nitrogen fixing bacteria from the soil which pull nitrogen out of the air to fertilize the soil.
It is massively different from what you say. It would vastly reduce farm runoff while increasing yields. All facts contained within the article.
Beans have been used for thousands of years without fertilizer. They restore the nutrients in the ground by exactly the same process as this maize, because it is the exact same nitrogen-fixing bacteria at work.
I'm pooh-pooh'ing the idea because this isn't any more practical than rotating beans to restore a field was. These microbes don't fix nitrogen anywhere fast enough to supply acceptable yields. You end up with fields giving out 3-4x less end product with this strategy vs. using artificial fertilizer. You're not going to feed the worlds population with replenishing crops.
that's strictly nitrogen, which comes from the atmosphere. There are many plants that host nitrogen-fixing bacteria. Corn is not one of them. You cannot make other elements out of whole cloth unless they discover how to do transmutation in vivo. Not saying it's impossible, but we are far from there yet.
It's kinda surprising that plant efficiency is so low, considering the absolutely massive number of plants and the hundreds of millions of years of competitive evolution to collect as much energy from sunlight as possible.
If you can collect more carbon, you can grow faster, letting you put big leaves to collect more light and overshadow and kill all the plants below you.
Being a plant is, locally, a winner-takes-all market.
So there is a very strong incentive for carbon-efficiency.
Hmmm, I don’t think that's accurate. To label plant ecosystems as 'winner-takes-all' really misses the forest for the trees (sorry..!). It's not all about sun-hogging; different species have unique needs and abilities, thrive in symbiotic relationships, and flourish under different conditions. For instance, take the relationship between certain fungi and tree roots, where the fungi provide the trees with hard-to-reach nutrients and, in turn, the trees supply sugars to the fungi. It's not a simple competition, it's a world full of complex interactions, adaptations and interdependencies. That's generally why we refer to these as 'ecosystems', no?
I read somewhere they don't opt for maximum efficiency turns out when it's most efficient it becomes too varied for efficient consistent atp or something, amazing stuff
This is fascinating. I assumed plants were far more efficient at extracting energy from sunlight but I had no reason to believe that. What is the source of this claim? Is it efficiency of a leaf in direct sunlight? Or of the entire plant with leaves wherever they may be?
Theoretical max efficiency on one particular step of the process. If you include such things as "rebuilding after a severe hailstorm" I think plants may still be impressively competitive.
