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Comment by boringg | Hacker News Reader

The key line for those who don't read the article: "Scientists say that global greening since the early 1980s may have reduced global warming by as much as 0.2° to 0.25° Celsius (0.36° to 0.45° Fahrenheit). In other words, the world would be even warmer than it is if not for the surge in plant growth."

The surge in plant growth is a result of increased amount of CO2 in the air as a result of anthropogenic activity. Quirky systems we have on the planet.

Other key piece of the pie - we need to reduce CO2e emissions to ensure habitability of the planet. I.e. our effects >> global greening effects.

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They mention growing season. I wonder if growing seasons have been extended too.

> I wonder if growing seasons have been extended too.

You are correct. This has been known already 24 years ago:

https://www.nature.com/articles/386698a0

I should have worded it better. I mean in regards to this study. The graphic is for "more green" and I was wondering if they have another one for the "longer green" part.

> The surge in plant growth is a result of increased amount of CO2 in the air as a result of anthropogenic activity. Quirky systems we have on the planet.

That's not quirky, it's why global warming is less of a risk than people care to admit. If CO2 is the primary cause of global warming then organisms that need / utilize CO2 will flourish. A byproduct of this is often oxygen, so it'll likely stabilize itself given enough time.

This is like saying "my car burns gasoline, so more gasoline in the engine is better".

There's only so much CO2 organisms can absorb, and they all buffer it - not consume it. Meanwhile, we're still adding CO2 at an exponential rate.

I don't think your car engine can grow to consume gas at a faster rate or spawn other engines that consume gas. I don't think the OP or this article is saying it will completely eliminate global warming, but a new equilibrium where co2 consumption by plants pushes back and holds the line at some point seems plausible (hopefully before we reach something like this before we turn into a venus).

I'm looking forward to the return of megaflora. Too bad I won't be here to see it.

Plant life grows exponentially and can catch up to our additions of carbon.

If it was that easy, we would never have switched from charcoal to coal.

Every exponential has a limit, and in the case of plants the old limit might the pre-industrial or possibly pre-agricultural equilibrium. How much can grow now depends on not just the atmospheric CO2, but also plants and animals we have selectively bread, the canals we’ve built, the the phosphate we’ve mined, the mountain tops we’ve removed to make mining easier, the glaciers we’ve melted, the storms whose frequency we’ve changed, the aquifers we’ve emptied, the lowlands which have become salty from the sea level rises, and almost certainly a lot more besides. (Edit: and if the zooplankton which human activities ultimately encourage produce waste which floats or sinks, the latter being a way to remove carbon from the system, the former puts it back in the air).

Some of that pushes the equilibrium up, some down.

Not if it runs out of nitrogen in the soil - and we're already supplementing that for our crops. Then there are also limits on water, sunlight and space.

Sure, life will adapt and overcome - over time. But evolution won't save us here, as we're altering the climate orders of magnitude faster than natural selection runs its OODA loop.

> it'll likely stabilize itself given enough time.

Is there more to this argument? Because it could well stabilize at "palm trees at the poles". Or it might never stabilize because of ever-increasing CO2 production (compared to sequestration).

"There could be an equilibrium" really isn't an argument imo.

If that were the only factor, sure. But there's also drought, heat stress, invasive insects migrating to higher latitudes, and topsoil loss. Forests in the western US, for example, are not benefiting from climate change.

Prior to humans industrializing the Sahara desert was green, 11,000 - 5,000 years ago.

https://www.nature.com/scitable/knowledge/library/green-saha...

The world regularly adjusts, California has had more fires historically (and less).

https://www.pnas.org/content/early/2012/02/09/1112839109

I agree things are changing, but it's not clear who or what is causing it. That's really my only thoughts on the subject. Seems CO2 has a smaller impact than what ever has caused the Sahara to turn into a desert.

Here's a to-scale visual timeline of the earth's temperature change over the last 20,000 years. See if you can find anything anomalous ;)

https://xkcd.com/1732/

Classic XKCD: an incredibly tall image that ends in the Hockey Stick. The winky face is what really settles it, though. QED. ;)

As far as I know this is calculated into climate change models.

So I'm curious based on what study you assume plants will flourish unlimited to compensate all additional CO2.

The IPCC report analysis increase risks with more CO2. Shouldn't the risk go down if plants would just compensate it?

And apparently the Amazonas as a whole org is now no longer consuming CO2 and is a net negative.

You seem to have a lot of confidence that you are the only person to think of this.

There are actually indications that even though some plants may grow faster, their evapotranspiration is decreased[1] and the plants grow fewer valuable nutrients[2].

[1] https://www.sciencedirect.com/science/article/abs/pii/S13695... [2] https://cfaes.osu.edu/news/articles/higher-carbon-dioxide-le...

> That's not quirky, it's why global warming is less of a risk than people care to admit.

The consensus of climate scientists is wrong, everyone! The consensus of economists is wrong, everyone! We all just overlooked this one simple fact.

A few more plants will grow... and then we'll still see the ecological collapse that is the true fear. And those plants are going to de-acidify the ocean anytime soon.

Your true fear is that they are wrong (just like the contemporary authorities have been wrong about major things throughout history, like heliocentrism and hand-washing). Because if they are, then we don't know as much as we think we do, and we aren't as powerful as we'd like to be, and we really are helplessly spinning through the universe on this tiny blue ball. It's too much to handle, so we close our eyes and cover our ears and hope that the people in the lab coats are right this time. But in the end, they're still human beings, just like the rest of us, just like the robed figures of old.

For some things we have a process now that helps us discover truth about tangible things. But since we don't have a control planet, we abstract that problem to man-made oracles (i.e. black-box models), which is not much better than ancients who sacrificed to the rain gods--it might even be worse, because we think the models are accurate, whereas no one today would believe in rain gods.

> Your true fear is that they are wrong

Ah yes, the crippling terror that everything will be fine. How foolish we would appear, to have spent trillions on mitigation efforts, with nothing to show for it except sustainable jobs, technological research and development, cleaner air, quieter streets, reduced dependence on unsavoury oil-producing nations, less incentive to wage war in the middle east. What a catastrophe that would be...

> Your true fear is that they are wrong

Your certainty belies your arrogance. Nothing would make me happier than the doomsday predictions being wrong.

>increased amount of CO2 in the air as a result of anthropogenic activity

Couple of questions because I'm curious...

What percentage of the 0.04% CO2 in Earth's atmosphere do humans contribute?

Has it yet been absolutely proven 100% that a gas comprising 0.04% of Earth's atmosphere is the main culprit/control knob which controls climate(s) around the Earth?

> Has it yet been absolutely proven 100% that a gas comprising 0.04% of Earth's atmosphere is the main culprit/control knob which controls climate(s) around the Earth?

Yes and no. It has been proven (for more than 200 years) that CO2 increases heat retention, even when present in small amounts.

It has also been proven that CO2 is not the only one doing that (methane has an effect even far greater than CO2, for the same amount).

> Has it yet been absolutely proven 100% that a gas comprising 0.04% of Earth's atmosphere is the main culprit/control knob which controls climate(s) around the Earth?

Could you share some scientific facts that you believe to be 100% proven?

Would help to determine what your yard stick is here...

I somehow don't think this person is a Popperian!

The IPCC reports describe the answers to those questions very thoroughly, no point in rehashing that here.

> What percentage of the 0.04% CO2 in Earth's atmosphere do humans contribute?

Since CO2 ppm nearly doubled since pre-industrial times then humans are responsible for nearly half of the CO2 in the atmosphere.

> Has it yet been absolutely proven 100% that a gas comprising 0.04% of Earth's atmosphere is the main culprit/control knob which controls climate(s) around the Earth?

Yes, for reasonable definitions of "proven 100%".

The papers accepted by the IPCC put the confidence between 95-100%, or what they label was "Extremely likely", for Humanity's contribution to CO2 being the dominate driver of climate change.

"Carbon emissions" is a collection of gasses, one of which is CO2. It's pretty common to equate the damage different gases do to CO2 and refer to it as "Carbon", which then get's messy when people paraphrase and leave out some context. For example Methane does something like 80x more damage than CO2 by weight, so it said a ton of Methane is "80 tons of carbon"

And Science doesn't work by "Absolutely 100% proving" anything. Bayesian statistics which underpins almost all of modern science lets us take highly educated guesses with communicable confidence in that guess. So stop looking for "100% absolute proof" to be convinced, you won't get it.

> Has it yet been absolutely proven 100% that a gas comprising 0.04% of Earth's atmosphere is the main culprit/control knob which controls climate(s) around the Earth?

Aside from the hyperbole, pretty much yeah.

Oxygen and Nitrogen aren't important when considering the greenhouse effect since they're diatomic molecules with tighter absorption bands and don't have the broad bands in the IR so that 99.96% of the atmosphere just doesn't matter (Argon is monoatomic which is even more dismissable. H2O matters but gas-vs-droplets is complicated and took decades to sort out).

It is all the rest of it that matters. And for example, satellite measurements of the absorption bands in the atmosphere show that CO2 absorption has been widening which explains the satellite observed reduction in IR emission from the Earth which explains warming as an imbalance in the heat budget of the entire planet.

The increase in CO2 coming from humans is also established via analysing the isotopes of carbon in the CO2 in the atmosphere and we can see that it is coming from carbon that we dig up out of the ground (protected from cosmic ray radiation) vs. the CO2 that was in the atmosphere. We can also measure that only about half the carbon we emit stays in the atmosphere, while the other half does get captured by the natural carbon cycle. But that's enough to disturb the balance. Small deviations in the budget add up over time.

And these questions are very, very basic. We wouldn't be discussing climate change if scientists didn't have the answers more or less nailed down.

More information and a massive amount of references can be found at skepticalscience.com

I'd also recommend Ruddiman's undergraduate text on climate:

https://www.amazon.com/William-F-Ruddiman-Earths-Climate/dp/...

Although for $287 for the paperback, maybe rip it off on libgen. I think back when I bought the first edition it was $80 which seemed steep. Fuck science publishers, seriously.

I think it was around 1 gigaton of CO2 caused by humans for every 40 gigatons of CO2 caused naturally, which is about 2.5% of total CO2 emissions every year.

Thanks, so that's 2.5% of 0.04%, right?

Has it been proven that a gas comprising 0.04% of Earth's atmosphere is the main factor which affects Earth's climate(s)?

I'm asking, because 0.04% of something seems like a particularly small fraction to have such a dramatic effect on a whole planet's weather and climate. Especially in a non-linear dynamic and chaotic - hence very difficult to predict - system like Earth's weather and climate system.

In my opinion it is important to ask these questions because some extremely huge decisions ride on them.

The fact that a small proportion of the atmosphere causes the greenhouse effect makes it more likely that the amount of CO2 we are adding is affecting the planet. It's easier to make a significant change in a smaller quantity.

If you have doubts about the scientific understanding of the greenhouse effect, study up on that. But continually bringing up that 0.04% makes it sound like you are clinging to that fact as a "gotcha" and avoiding learning anything more.

>If you have doubts about the scientific understanding of the greenhouse effect, study up on that. But continually bringing up that 0.04% makes it sound like you are clinging to that fact as a "gotcha" and avoiding learning anything more.

After having spent decades debating "climate change deniers", I came to to the realization that the greenhouse effect as thought in schools is vastly oversimplified, and essentially no lay person understands it.

This is not to say that climate change isn't real, but most people don't have the technical background to educate each other, and attempt to do so based on inaccurate models.

Having read hundreds of articles, I still don't understand how to reconcile the greenhouse model with the fact that infrared radiation only travels ~10m in the atmosphere in the bandwidth absorbed by CO2.

> Especially in a non-linear dynamic and chaotic - hence very difficult to predict - system like Earth's weather and climate system.

It's because it's a highly non-linear and chaotic system.

If earth's climate was a linear system, then indeed your gut feeling that 0.04% change is small would be warranted.

Natural emissions are balanced by natural sinks, so that the balance is close to zero, while human emissions are not balanced by anything. The actual variation of CO2 levels in the atmosphere is almost exclusively due to human emissions tipping the equilibrium.

The effect of CO2 on the climate is old science, it goes back to the 19th century, it seems a little bit insincere to ask this kind of question, if you had actual interest you would have found the answer very easily already.

> main factor which affects Earth's climate

This is such a dubious statement you keep repeating. Is it the main one? No, probably not. If you took out all the Nitrogen, shit would break a lot faster than if you took out all the CO2. You could probably name a few others.

However it is proven that carbon emissions is the main thing affecting the the change we are observing in earth's climate. And I shouldn't have to, because you are who you are, I'm going to staple on "within reasonable amount of certainty"

Water vapor is the #1 greenhouse gas but that is a closed system. We aren’t making (much) more water.

Now, we could potentially make many more clouds. For instance, container ships could be required to have fuel additives or “salt lofters”that promote cloud seeding and marine cloud brightening.

We aren't directly putting more water vapor into the atmosphere, but a warmer atmosphere can hold more water and (I would think) would also increase the overall rate of evaporation.

Regarding the greenhouse effect of water vapor, I don't know whether what matters is the average relative humidity or the total amount of water vapor in the atmosphere. For our sake I hope it's the former.

Being 100% certain of anything is insanity; it implies that literally no amount of evidence could change your mind, while a rational mind is always open to revising its beliefs when new evidence becomes available. Religious faith and psychosis can "absolutely prove 100%". Science and reason can't.

1) 0.024%

2) 100% of what?

Uh oh, these questions smell like climate heresy

Edit: for those struggling with the irony, my comment is pro-questions and pro-heresy. Let's not attack people for asking questions

Doesn't matter which side of the fence you fall on, it's good practice to validate the conclusions--and to continue doing so regularly. Please don't discourage people from asking for the data and the facts, no matter what your perspective is.

Just curious, could somebody explain to me quickly here how computers work, starting from transistors? It seems implausible to me that tiny electrical circuits could be used to produce logical operations.

I'm really just asking an honest question, and it's always healthy to revisit the evidence especially when you're making a big claim like "sand does maths".

https://www.tindie.com/products/codecorrect/basic-logic-gate...

And then

https://www.nand2tetris.org/

What's heretical about asking honest straightforward questions?

The phrasing of the question is odd and hints at rhetoric instead of curiosity as intention.

What if it's only 99.99% sure that CO2 is the reason for climate change? What about 90%? No need to act until we bring that up to 100%?

What's with the fixation on 0.04% as a number? Things can't have huge impact unless numbers are also big? I don't want to offend, but that's honestly third grade mentality.

There's surprise about small things having little impact, and then there's denial hidden as feigned curiosity. Especially when the answers are directly available from much more credible sources than random internet posters.

Compare with:

"Has it yet been absolutely proven 100% that the lead comprising 0.03% [hypothetically - for reference, this is 100000x the FDA limit] of our food intake is the main culprit/control knob which controls brain development?"

No, it actually isn't the "main" control knob. And our bodies are also complex with many feedback loops. And no study will ever reach p = 0. And it's a really small number. And yet we have made "extremely huge decisions" regarding what fuels we allow, what tests food have to undergo etc...

The fixation on the 0.04% is particularly confusing, as the other 99.96% of the atmosphere is mostly completely transparent to the relevant frequencies. Going by volume or ppm is wrong when all we care about is the absorption factor. Greenhouse gases don't absorb less infrared radiation by adding transparent nitrogen, even though it would reduce the greenhouse gas concentration.

> What's heretical about asking honest straightforward questions?

This is a loaded question ( https://en.wikipedia.org/wiki/Loaded_question ), since it implies that this question-asking is honest and straightforward.

On the contrary, it seems like OP is "jaqing off" ( https://rationalwiki.org/wiki/Just_asking_questions ); unless, of course, they can absolutely prove 100% that they're acting in good faith.

Can you absolutely prove 100% that you're acting in good faith?

Nope, but that's no matter, since whether or not I am acting in good faith is logically independent of whether OP is jaqing off (see also https://en.wikipedia.org/wiki/Tu_quoque ).

In contrast, OP's hunch about the climate emergency either not existing because the concentration of anthropogenic CO2 in the atmosphere is "small" (according to some unspecified criteria), and/or fixing itself due to plant growth, run counter to the consensus position of the world scientific community, and hence the burden of proof is on OP https://en.wikipedia.org/wiki/Burden_of_proof_(philosophy)

It was their choice to raise that burden to the unachievable height of '100% absolute proof' :)

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