In artifical conditions in laboratory there is a significant effect, up to 20% when doubling pre-industrial CO2 concentration.
But, in practice for wild plants nitrogen quickly becomes the bottleneck, so the real gains are much smaller.
And even for farming plants (which have fertilizer providing additional nitrogen) the real gains diminish, and are more in 5-10% range. For some crops CO2 has very little effect at all (for example corn).
Additionally - crops grew with raised CO2 levels have less proteins and useful nutrients.
And then you have to factor in the harmful effects from global warming on crops (heat damage, dry soil, less farmland available) and the overall effect is likely negative.
Edit funny the downvotes. I’m on your team guys! Just think we can’t ignore counter facts.
I don't think there is any risk of areas reaching temperatures too hot for any plants?
> which will reduce the length of growing season
Corn, for instance, can't grow when the temp is over 104 or so (depending on cultivar) and dies when exposed to temps over 110 or so. It maximizes its growth rate at around 86 degrees.
So: if you have a summer month when temps are regularly over 104, that's not really a growing season for corn. Thus you have to try to plant earlier and harvest earlier, and the window when you can do that successfully may be considerable shorter than it would if the temp stayed below 104 during the summer.
So then you try to go closer to the poles. But -- depending on temperatures and a lot of other factors -- that may not be a totally satisfying solution either. Corn needs specific amounts of rain, which may or may not coincide with periods when the temperatures are good. It also needs large amounts of soil nitrogen, which may or may not be present in arctic soils, and if the plant doesn't have it growth is slowed. Corn also needs the soil temperature to be relatively high to germinate (above 50 degrees, again depending somewhat on cultivar). In arctic soils, it may take a while for the soil to warm up that much in the spring, and that may reduce your growing season. So how all the factors play out, and whether those factors result in a longer or shorter growing season, are intimately connected to exactly how the climate changes.
I've used corn as an example, but of course other crops and wild plants all rely on complicated, interconnected conditions to thrive. The specifics are a bit different for every plant.
It all depends. There are a lot of factors that we won't really know until people start trying to do it.
How much is enough to matter? Will the net effect be more or less than change from CO2 or temperature? You tell me. We seem to have a lot of unknowns.
"Global warming" would be better named "wilder temperature swings" (which is why we hear the phrase "global climate change"). Larger temperature swings (colder winters, hotter summers, no real spring or fall seasons) are not good for growing crops.
It's splitting a hair, to be sure, but developing root nodules for hosting a nitrogen-fixer species is a lot easier than evolving all the biochemical precursors from scratch. Nitrogen fixation symbiosis may have evolved independently in plants at least three times. It would have been a big advantage from 460 to 380 Mya and then again, to a far lesser extent, from 240 to 160 Mya. Teredo shipworms also employ nitrogen-fixing symbionts, in their gill structures, as well as some termites, in their guts, but the latter only derive benefit in an extremely low-nitrogen environment.
Since atmospheric CO2 has dropped after the last peaks, some plant species failed to preserve that symbiosis. They would have an easier time getting it back, now that CO2 partial pressure is rising back to levels experienced in prior geological eras.
The ultimate bottleneck is likely to be iron or magnesium.
So you could spray ammonia everywhere to promote growth, but it's not clear that you'll offset the carbon emissions from making so much ammonia in the first place.
nitrogen fixing cover crops is the way in agriculture I guess
That's something the geeks have still a hard time to understand. They won't convince anybody by being right. That's not how public opinion work.
It's very small effect that would take enormous spans of time to make any significant difference. Also in order for those plants to grow faster and make a difference, there needs to be a significant amount of plants. So it's a marginal issue. If plants grow at (made up number) 2% faster due to higher CO2 concentrations, that doesn't help much if we've wiped out 90% of the plant biomass.
CO2 concentrations are growing at <1% pa (year on year - there are large variations between northern hemisphere summer/winter), so an additional 2% absorbing effect from an increasing number of plants is not insignificant.
Conditions might be rarer, but the steps aren't solely reliant on the absence of microbes which now exist.
As per https://www.politico.com/agenda/story/2017/09/13/food-nutrie...
> As best scientists can tell, this is what happens: Rising CO2 revs up photosynthesis, the process that helps plants transform sunlight to food. This makes plants grow, but it also leads them to pack in more carbohydrates like glucose at the expense of other nutrients that we depend on, like protein, iron and zinc.
Unless you think that the only thing that's "good for plants" is their suitability for being eaten by humans this seems like an unrelated issue.
The vast majority of the Earth's plant biomass isn't going to be eaten by humans. You're not going to nibble on the oak tree in your back yard, but increased CO^2 in the air will make it more efficient at sequestering carbon.
It's not going to be some amazing increase in perceived growth rate. The CO^2 level indoors is often 2-3x what it is outside, and people already grow plants in those conditions.
And while more plants is certainly a nice thing, there's more to having a healthy planet than just having more plants, especially when it comes at the cost of melting ice caps and changing weather patterns, possibly leading to desertification and less plants in other places.
Although according to the article, this particular increase in greenery is mostly due to projects to plant more trees in Indian and China, and investments into agriculture. All of them good things that don't really need more CO2 in the atmosphere.
Any time a group starts altering the facts like this, it just shows that they value their 'message' above the truth, and they lose all credibility.
Edit: Downvote = disagree, or people genuinely believe it's OK to lie to further your cause, I'm not sure what's more disturbing.
In particular there's a faction of people who use "CO2 is plant food" to argue that it cannot be harmful, that reduction efforts would be wrong, etc.
And also, the whole discussion branch nearby on the greening effect of small increases in CO2 is really missing the point, and is completely ungrounded in any science. There is a whole literature out there on how significant this effect is relative to other effects of rising CO2! (Spoiler: it is not that significant.)
So you disagree with the grandparent post's statement that "But it seems this fact is usually omitted so as not to complicate the intended message."?
There are plenty of large, prominent climate activist groups making prominent public statements. I've never heard a single one of them discuss this aspect. (Contrast with scientific papers, many of which do mention it and which are not what we were talking about).
The key phrase you're looking for is: CO2 fertilization.
That sounds a lot like intentionally misleading people.
> The greening in China is from forests (42%) and croplands (32%), but in India is mostly from croplands (82%) with minor contribution from forests (4.4%).
I can't comment on the sequestration effects of farms, though, beyond my ken.
That global warming may induce more agriculture, and forest growth, in the global North is something I'd like to learn more about. Anyone have any further reading to recommend?
It is well known that CO2 improves plants growth. It is also well known that plants grow better within a narrow band of temperatures.
Increasing both the CO2 contents of the atmosphere and Earth's temperature will have some complex results where on the places within that temperature band, plants grow slightly faster, on places that cross from too cold into the band plants grow much faster, and on places that cross from that band into too hot plants will grow much slower.
Also, solar incidence has a much larger effect than CO2 concentration, so the places with best growth rate can only cross into the too hot region, and polar places crossing into the good temperatures can't really compensate (besides, there isn't much area at the polar regions, unless you are talking about the hole Antarctic getting green).
And, anyway, water availability has a much larger effect than solar incidence, and this one is completely chaotic. So, good luck getting any conclusion.
The specifics of how trees react to increase CO2 concentration varies from one species to the other. AFAIK, only a few species have been measured, thus the increase on rate of growth on that component is quite uncertain. That can be improved by empirical tests, that many specializations of science are currently working into. Of course, the big elephant in the room here is ocean plankton, that has a two sided relation with CO2, because it both participates on photosynthesis and increases ocean acidity. AFAIK, there is little known on how those react.
Solar incidence is completely predictable, and doesn't tell a good story for global warming.
And for humidity, I don't think there is any reliable model out there. None of those are my specialization, so I may be wrong, but I don't think we have anything nearly viable for predicting this one.
There was a 200 page report on global warming from the 1980s on HN a few days ago which had several sections on this as upsides to global warming. I only read 50 pages of it, but it is a remarkably clear and level headed document.
The increase in CO2 strongly disfavors slow-growing old groth and established ecosystems, and favors fast growing plants, which are typically invasive species that take over and destroy established ecosystems, and reduce biodiversity.
Per usual, the devil is in the details.
In particular I'm interested agricultural and dense growth projections in the North (and South?). The above stuff covers this only in passing to my recollection.
However that's not how the planet works. If you put more CO2 in the atmosphere you'll have for example rising sealevels and larger deserts (and probably more effects that diminish food production). You can't just pick a single effect of increased CO2 in isolation. (Except of course that's what the CO2 coalition does, because they chose to believe fairytales instead of science on climate change.)
This is just the obvious flaw in that argument. If you want the details and all the science there's a chapter on food security in the IPCC report:
It discusses potential yields as well.
As it happens, seawater is denser than pure water, with a density averaging 1.088 g/mL, so if we were just talking about floating ice, 1 kg of floating ice would displace 1 kg of seawater, with a volume of 0.919 L, when the ice (mostly-pure water) melts, it supplies additional volume of 1 L, an increase of 8.8% over the submerged volume of the ice. This mixes with the saltwater to reduce salinity and lower the density, but the overall effect is a slight rise in water level.
Now forget about floating ice. Some ice is not floating. It rests upon surface rock. When it melts, 100% of its volume (eventually) flows down into the ocean. When land-ice melts, it has a far greater impact on sea level. But we only need to worry about land ice that rarely melts due to seasonal variation: ice found mainly in the glaciers and icepack on Greenland and Antarctica. Due to albedo and insulation effects, it is more difficult to melt land-ice than sea-ice, but it is indeed melting at rates unprecedented within the relatively short span of human observations.
(If a land-ice glacier calves an iceberg into the ocean, the immediate effect is to raise sea level by about 86% of the volume of the ice, with additional rise occurring as the ice melts.)
There's Greenland in north.
> But then, shouldn't northern cap melting cancel out melting of the south one?
Cancel out? Melting can't decrease water level, so I don't see how canceling out is possible.
If a person or group consistently advances bullshit, it eventually becomes a useful heuristic to dismiss that person's or group's ideas without consideration.
It takes more energy to argue against the bullshit than it does to advance it in the first place, so insisting on that argument hurts dialogue more than it helps.
CO2 is a gaseous fertilizer, providing carbon to plants. But anyone that has ever kept a garden, or even a potted plant, knows that plants also need water, plus nitrogen, phosphorous, and potassium (N-P-K). Hydroponics growers can add to that list [Mg++], [Ca++], [SO4--], [Fe++], [Mn++], [Zn++], [Cu++], [BO3---], [MoO4--], and [Cl-] ions, usually present in the soil that is not used in a hydroponics system.
So increasing CO2 has diminishing returns, until further increase results in no further plant growth.
Edit: I know it shows the % increase in greenary. What I meant is the "greenary" shown in the map actually has almost no correlation with the greenery in the real world. Looking the map and expecting Rajastan to be a green area would be a bad idea.
"Despite global greening, carbon dioxide levels have climbed over the past two centuries to levels not seen on Earth for millions of years. And the carbon dioxide we’ve injected into the atmosphere is already having major impacts across the planet."
The "global greening" effect, to the amount it can manifest itself, existed since the CO2 started to increase but we still see that the problems from higher CO2 increase and will get always bigger.
It won't save us from any problems made by global warming.
So predicting future tree ring growth based on climate changes, when we estimate the historical climate based on tree ring growth, means we can make up any relationship we want.
But we don't configure the current modeling systems at all using the "prehistoric" reconstructions, the models and the currently measured values are much more precise. The "prehistoric" reconstructions only give you something to compare the orders of magnitudes.
And comparing that, the warming is unprecedented. Which is not surprising giving that the humanity managed to extract and burn more then the half of all readily available oil from the Earth's crust in just 100 years.
That very oil in the crust is however a result of more than 4 billion of years of the Earth's existence.
If you’re reading this in some country like US, given that the average US car weights around 2 tonnes, your existence alone is probably responsible for the CO2 mass equivalent to the weight of 7–10 cars every year, and to the volume of CO2 which corresponds to the volume of more than 3000 cars.
And the CO2, even if it's invisible for us, is actually "black" for something important: it's blocking the part of the spectrum that would allow the Earth surface to cool off. That's how small concentrations of it, compared to some other stuff in the air, produce such a big effect.
The physics is simple and undeniable, and it's known that there will be always more problems caused by the growth of CO2 in the atmosphere which increases the surface temperature of the Earth.
> The physics is simple and undeniable, and it's known that there will be always more problems caused by the growth of CO2 in the atmosphere which increases the surface temperature of the Earth.
Take a look at this graph of co2 vs temperature over a geological timescale: http://www.biocab.org/Geological_Timescale_op_712x534.jpg (from http://www.biocab.org/carbon_dioxide_geological_timescale.ht...)
From this, there doesn't seem to be any relationship at all and the co2 has been much higher during much of the history of earth. At the very least, you can't say that the relationship is simple.
Not a scientist.
Now... anybody who is really interested in the real geological history knows that even the continents "weren't there" where they are now, when we look long enough in the past. Not to mention that, for the old enough times, not even plants existed on the land!
In that context:
"However, until recently, CO2 levels during the late Ordovician were thought to be much greater than 3000 ppm which was problematic as the Earth experienced glacial conditions at this time. The CO2 data covering the late Ordovician is sparse with one data point in the CO2 proxy record close to this period - it has a value of 5600 ppm. Given that solar output was around 4% lower than current levels, CO2 would need to fall to 3000 ppm to permit glacial conditions."
"(Young 2009). Rock weathering removes CO2 from the atmosphere. The process also produces a particular isotope of strontium, washed down to the oceans via rivers. The ratio of strontium isotopes in sediment layers can be used to construct a proxy record of continental weathering activity. The strontium record shows that around the middle Ordovician, weatherability increased leading to an increased consumption of CO2. However, this was balanced by increased volcanic outgassing adding CO2 to the atmosphere. Around 446 million years ago, volcanic activity dropped while rock weathering remained high. This caused CO2 levels to fall below 3000 ppm, initiating cooling. It turns out falling CO2 levels was the cause of late Ordovician glaciation."
"So we see that comparisons of present day climate to periods 500 million years ago need to take into account that the sun was less active than now. What about times closer to home? The last time CO2 was similar to current levels was around 3 million years ago, during the Pliocene. Back then, CO2 levels remained at around 365 to 410 ppm for thousands of years. Arctic temperatures were 11 to 16°C warmer (Csank 2011). Global temperatures over this period is estimated to be 3 to 4°C warmer than pre-industrial temperatures. Sea levels were around 25 metres higher than current sea level (Dwyer 2008)."
You have to understand geology to be able to compare. If you don't, people with agenda will easily sell you worthless graphs. Worthless as in "CO2 was higher when there were no plants and animals on the land at all, just the naked rocks." Nice target you have.
However, the rebuttal surprisingly leaves out a graph that directly shows temperature against glaciation, solar output and co2, but rather just talks about the comparison, without showing it. I don't find that particularly convincing of anything. Just because
> "Around 446 million years ago, volcanic activity dropped while rock weathering remained high."
it doesn't follow that
> "This caused CO2 levels to fall below 3000 ppm, initiating cooling. It turns out falling CO2 levels was the cause of late Ordovician glaciation.",
especially given that this simple graph of all 3 influences mentioned (sun output, glaciation, and co2 levels) against temperature isn't included. Do you know of a source that shows this?
> "So we see that comparisons of present day climate to periods 500 million years ago need to take into account that the sun was less active than now. What about times closer to home? The last time CO2 was similar to current levels was around 3 million years ago, during the Pliocene. Back then, CO2 levels remained at around 365 to 410 ppm for thousands of years. Arctic temperatures were 11 to 16°C warmer (Csank 2011). Global temperatures over this period is estimated to be 3 to 4°C warmer than pre-industrial temperatures. Sea levels were around 25 metres higher than current sea level (Dwyer 2008)."
Again, it's hard for me to take this seriously without seeing the comparison between the different forces that are identified against each other and temperature. It's like someone was peering at something through binoculars and said they saw an elephant. They offer as proof by stating, "I see a trunk, and a tail, and its tusks..", but they won't let you look through the binoculars yourself. (Also the Csank 2011 link gives a 404)
The best I could find was https://www.co2levels.org/, which if you click the buttons in the top left, can be massaged in displaying co2 vs temperature for the last 800k years. And even in this period there are a few the temperature decouples from the co2 levels and mostly the temperature rise precedes the rise in co2, which makes one think that co2 entering the atmosphere is a effect of climate rather than a cause.
> You have to understand geology to be able to compare. If you don't, people with agenda will easily sell you worthless graphs. Worthless as in "CO2 was higher when there were no plants and animals on the land at all, just the naked rocks." Nice target you have.
I'm not saying the earth was the same as before. Just that the idea is that co2 is causing irreversible warming and that's that, isn't supported very well by the evidence I've seen. At best what you have given me shows that the co2 causing warming isn't entirely disprovable.
I guess what I'm worried about is that the news often simplifies complex topics to, "it's a disaster!", or alternatively, "it's a hoax!" I don't think things are that simple, yet I haven't heard from anyone, scientist or no, that things are not either a "disaster" or a "hoax".
But it is, it’s the topic of physics, not history. The historical remains are by nature very incomplete and geology is extremely relevant when you try to interpret the historical proxies, but all that doesn’t matter if you want to understand how warming works: physics is undeniable, and all effects are known and are part of the models:
Once again: it doesn’t help to say “it was warmer n millions years ago” if the continents weren’t the same and there were no humans. Our civilisation depends on many very fine tuned balances.
There are no sources in this link. There is nothing about physics in this link. It simply describes a bunch of other forces and declares they are not applicable, therefore co2 is the only thing left and it must be the culprit. Forgive me, but science isn't a game of "Clue". Putting up a bunch of straw men and tearing them down doesn't mean that "the butler must have done it with the wrench", or in this case, co2 must have increased the temperature.
And wasn't your link from the your last post primarily referring to the history of the earth as evidence of co2 production? So which is it? The case for undeniable physics, which you have not provided a link for, or from the evidence from geologic history, which you have abandoned.
In the same spirit as your link, here is Leonard Nimoy talking about Global Cooling from the 1970's: https://www.youtube.com/watch?v=ei-_SXLMMfo . It has about the same amount of evidence. You can also check out https://en.wikipedia.org/wiki/Global_cooling to see the history of this.
> Once again: it doesn’t help to say “it was warmer n millions years ago” if the continents weren’t the same and there were no humans. Our civilisation depends on many very fine tuned balances.
Where did I say that "it was warmer n millions years ago" proves that increased co2 is not going to increase the temperature? I'm just saying you haven't shown it will. You are vehemently asserting, times were different then, so all I can conjecture is that you mean that we can throw that data out. I don't necessarily think so, but I also don't think that doing so proves your point. I can't prove co2 hasn't increased the temperature, but it's difficult to prove a negative. To wit, maybe an extreme example, but I can't prove the earth wasn't created 4000 years ago as per the Christian Bible, yet that doesn't mean it's true.
I'm am saying that what you've shown doesn't prove that increased co2 is going to warm the earth to a significant degree, and the current situation isn't caused by other factors.
To that point, it shares all the hallmarks of mass hysteria. A single central idea is put into the public consciousness, and each and every event is then linked to that event.
I also ask you to respond point to point to what I've written rather than simply try and attack a single statement. I wish you'd have responded to what I wrote concerning the lack of transparency of your link from skepticalscience.com or the graph from co2levels.org. Why won't you address this?
Of course there is, in the very page:
“Researchers who study the Earth's climate create models to test their assumptions about the causes and trajectory of global warming. Around the world there are 28 or so research groups in more than a dozen countries who have written 61 climate models. Each takes a slightly different approach to the elements of the climate system, such as ice, oceans, or atmospheric chemistry.
The computer model that generated the results for this graphic is called "ModelE2," and was created by NASA's Goddard Institute for Space Studies (GISS), which has been a leader in climate projections for a generation. ModelE2 contains something on the order of 500,000 lines of code, and is run on a supercomputer at the NASA Center for Climate Simulation in Greenbelt, Maryland.”
“GISS produced the results shown here in 2012, as part of its contribution to an international climate-science research initiative called the Coupled Model Intercomparison Project Phase Five. Let's just call it "Phase-5."
Phase-5 is designed both to see how well models replicate known climate history and to make projections about where the world’s temperature is headed. Initial results from Phase-5 were used in the 2013 scientific tome published by the Intergovernmental Panel on Climate Change.”
> The case for undeniable physics, which you have not provided a link for, or from the evidence from geologic history, which you have abandoned.
The link is the summary of what calculating which physical formulas gives, as I've quoted. It's you who "doubt" in the "tree rings" and I've given you the context: tree rings are just a small piece of he whole picture, and what we know, including the levels of confidence from that part of science is still good enough to have a good picture of what is happening and what has happened before. But once again: not any single historical proxy is directly used when the physical formulas are applied.
> In the same spirit as your link, here is Leonard Nimoy talking about Global Cooling
That's a joke, right? I'm presenting you the results of the NASA's best computer models, and you are giving me a link to... what actually? Since when are TV shows a proof for anything?
> I'm am saying that what you've shown doesn't prove that increased co2 is going to warm the earth to a significant degree, and the current situation isn't caused by other factors.
And what you are saying is simply untrue. What I've given you is the result of a lot of precise calculations using the physical formulas and the values obtained by all the scientific work we have. And nobody ever has found any meaningful error in the physics we use.
If you don't understand physics, I can imagine that it's hard to you to believe in something you simply don't understand, and I don't know your background to help you. What I can give you is a personal page maintained by one English PhD in Chemistry, Dr Jack Barrett, which was known as the "global warming skeptic" in the 90ties (you can Google his name, at the time the other person mentioned on his page was also active in "denying", this other guy was a reasonably famous face in Britain, but also uninformed at then). But then Barrett tried to learn the physical processes, relevant for climate, which he missed while pursuing his career in chemistry. And if you read his newer material, he is now completely convinced that the physics is absolutely valid and confirming the warming:
Everybody who has enough knowledge to be able to check the formulas and who has enough integrity to admit what he didn't know, and who doesn't have some hidden agenda would have to come to the same conclusion. Read the pages on his site. It's the most honest outcome of a former "doubter" I know of. There are still some "old" page from the time when he "was not convinced" but if you are really interested in the formulas and science behind all this, you will find enough there, I believe he updated most of his site to that what he knows and understands now (edit: I've checked, he still just updates the "news" pages, i.e: http://www.barrettbellamyclimate.com/page4.htm and http://www.barrettbellamyclimate.com/page5.htm )
It's about the formulas and measurements. Note: I'm not saying "take that guy as a reference." I'm saying: he's the guy who didn't know enough but was willing to learn and made enough notes, so if you are actually interested in some formulas "for beginners" you can find them there. If you'd want something even "more serious"... you'd need at last university level material, which of course exists too...
Those aren't sources.
>“Researchers who study the Earth's climate create models to test their assumptions about the causes and trajectory of global warming. Around the world there are 28 or so research groups in more than a dozen countries who have written 61 climate models. Each takes a slightly different approach to the elements of the climate system, such as ice, oceans, or atmospheric chemistry.
This isn't a source. You need to provide the actual studies, and point out where it proves that global warming is caused by co2, and have a coherent argument. Right now seem to be throwing everything but the kitchen sink at me in an attempt to win the argument.
> The computer model that generated the results for this graphic is called "ModelE2," and was created by NASA's Goddard Institute for Space Studies (GISS), which has been a leader in climate projections for a generation. ModelE2 contains something on the order of 500,000 lines of code, and is run on a supercomputer at the NASA Center for Climate Simulation in Greenbelt, Maryland.”
500,000 lines of code? Oh wow, then, must be accurate! NASA did it, must be correct, right? That's how you prove things, you get NASA to sign off on them.
> The link is the summary of what calculating which physical formulas gives, as I've quoted. It's you who "doubt" in the "tree rings" and I've given you the context: tree rings are just a small piece of he whole picture, and what we know, including the levels of confidence from that part of science is still good enough to have a good picture of what is happening and what has happened before. But once again: not any single historical proxy is directly used when the physical formulas are applied.
When did I ever say I doubted tree rings? All I'm saying is that I'm not sure that co2 is a significant cause of global warming.
> > In the same spirit as your link, here is Leonard Nimoy talking about Global Cooling
> That's a joke, right? I'm presenting you the results of the NASA's best computer models, and you are giving me a link to... what actually? Since when are TV shows a proof for anything?
Actually, you're right, it was a joke, but you missed the punchline. You give me a link of a news reporter trying to interpret and regurgitate what scientists say now, and I give you an actor doing the same for what scientists said in the 1970's. You don't see the similarities?
> If you don't understand physics, I can imagine that it's hard to you to believe in something you simply don't understand, and I don't know your background to help you.
I do understand some physics. And what I don't I'm willing to learn. Do you? Why is it that all you do is regurgitate quotes from websites, or give arguments of authority?
> It's about the formulas and measurements. Note: I'm not saying "take that guy as a reference." I'm saying: he's the guy who didn't know enough but was willing to learn and made enough notes, so if you are actually interested in some formulas "for beginners" you can find them there. If you'd want something even "more serious"... you'd need at last university level material, which of course exists too...
You still haven't addressed my concerns the lack of transparency of your link from skepticalscience.com. You also didn't address the graph from co2levels.org. I was hoping you knew or would be able to say why temperature increase precedes co2 rising in the graph from co2levels.org. I was hoping you'd be able to show the sun output, the glaciation, the co2 levels against temperature, so I can see the relationship between them. At this point, though, it seems you're not interested.
I thought I was talking to someone who knew what they were saying. You're telling me to read this guys entire website, but I know all I'll be left with a bunch of conflicting data and further questions, and probably still not have my questions answered.
The reason I was talking to you in the first place was that I thought you had some understanding. But by now, I'm pretty convinced, you don't.
Believe it or not, I'm on the fence about whether co2 is the primary cause of global warming or not. I simply was refuting the original poster's assertion that co2 being the primary cause of warming was basic physics and the relationship is undeniable. Talking to you, it seems that you don't know much about the topic, but instead believe that arguments from authority are good enough. You can't find information that directly answers my questions, but instead point to just reams and reams of data that has nothing to do with what I asked, along with snide comments (ex. me "doubting tree rings", although I never brought this up).
I'm on the side of "Question authority" and you seem to be on the side of "Accept authority". That's fine, but I'm not interested in taking conclusions as gospel simply because NASA says so, no matter how many models nor lines of code were used.
I never said that. What I've said was:
> Everybody who has enough knowledge to be able to check the formulas and who has enough integrity to admit what he didn't know, and who doesn't have some hidden agenda would have to come to the same conclusion. Read the pages on his site.
So no, it's not easy. If you are able to check the formulas, you can see they are right. If you aren't, you can claim that "it's not enough" and it will of course never be enough because it demands certain capabilities of the reader. You have to go slowly, formula after formula, and do simplified calculations, for which you don't need a supercomputer.
Once you understand formulas, and you understand that they are right, you could say "OK but I'd like to know what the more precise calculations would bring, if I'd apply these formulas separately on every small point of the earth, and then see how the parameters dynamically change through the time." Note: You don't need that to verify the validity of the warming physics, you need that "only" to know how your part of the Earth would typically behave through the time, including all the oscillations, ups and downs.
Then you would have either to write one another model, just like 63 models written by the scientists worldwide. Or you'd simply understand "from the inside" how the existing models work, and be able to accept that what is presented on the Bloomberg page I've linked is real (because once you have enough knowledge of what is in the program you don't have to repeat every step to see that the results do follow from the calculations).
The scientific paper about the computing model used on the Bloomberg page was also linked on that same page:
as well as the measurements:
So you surely had enough references even before.
Like I've said, the physics is real and there are no errors. If you can't understand the physics, then you are unable to be able to "check" anybody. And the physics is not simple as pre-school math:
If you can't understand this:
just don't ask me anymore for the proofs, because you are either incapable or unwilling to work it through. You have to do a lot of work, if you haven't before, and based on what you answered up to now, it's effectively sure you haven't, otherwise you'd ask about some detail in some formula, if you missed only that.
That is if you want to work through the formulas. If you don't but you want to see everything worked through, the shortest version is the Bloomberg article I've given you, and the longest the IPCC (The Intergovernmental Panel on Climate Change) report:
(all from: https://archive.ipcc.ch/report/ar5/ )
In the IPCC is effectively the summary of everything all the world scientists know about the topics, together, the result of the consensus of all the world scientists qualified enough to be able to work on the topics. It's long and complex, and long exactly because it addresses many different details.
And all that is full of references (which aren't lacking on the pages of the former skeptic too). So you can work through it as much as you want. Don't trust, check the formulas, really go through them yourself. The former skeptic did it too (he had the background in spectroscopy, luckily for him) . I've done it, I've did go through the points for which I didn't accept "it is said it's so" (and I, luckily for me, have enough background in physics). Every student of these sciences does it, every year the new ones. It is doable.
> I never said that.
You did quote bloomberg "ModelE2 contains something on the order of 500,000 lines of code, and is run on a supercomputer at the NASA Center for Climate Simulation in Greenbelt, Maryland." that line. If you don't think it was important, why quote it to me? Maybe I was misinterpreting you, but..
> What I've said was:
>> Everybody who has enough knowledge to be able to check the formulas and who has enough integrity to admit what he didn't know, and who doesn't have some hidden agenda would have to come to the same conclusion. Read the pages on his site.
Everybody with enough knowledge has to come to the same conclusion, huh? That's a lot of hubris.
> If you can't understand this:
> http://www.barrettbellamyclimate.com/page20.htm http://www.barrettbellamyclimate.com/page21.htm
> and this:
> just don't ask me anymore for the proofs,
I read through these, and I do understand them.
Basically "http://www.barrettbellamyclimate.com/page8.htm" is modeling a outside radiation source penetrating an outer atmosphere layer which allows 100% of it go through it. Then the earth radiates back to the layer which absorbs and reemits it, half back to earth, and half into space. The forces have to be in balance for the temperature average to stay in equilibrium. The conclusion is that the absorption/emission of the atmosphere at 0% would mean the earth would be a lot cooler 253K, and at 100% would be a lot hotter, 302K, so it must be somewhere inbetween. Therefore there is a greenhouse effect.
I never argued against the fact that there is a greenhouse effect, so although interesting, I don't see how it affects anything at all.
I looked at the other two links from that site, and see that co2 blocks a certain wavenumber band. Fine.
Lets take a look at page 28, however: http://www.barrettbellamyclimate.com/page28.htm
"The intention is to show the logarithmic nature of the relationship between CO2 and surface temperature, i.e., the temperature rises non-linearly with every successive addition of CO2 causing smaller effects. "
So here is the answer to something I suspected. The amount of co2 in the air becomes saturated at greater amounts. If you look at the graph, from 400ppm today, it will take up to 1000 ppm of co2 to increase the temperature effect as from 200ppm to 400ppm. So for we're only talking about a degree or two.
I think that scientists have made a lot of progress modeling the atmosphere because its so simple but the rest of the earth is much more complex and their models are, to put it bluntly, crap. The author agrees with me:
From http://www.barrettbellamyclimate.com/page48.htm :
"There is an absence of nits to pick in the physics of the greenhouse effect, but there are many incorporated in the various models. The fact that the twenty or so models all claiming to incorporate the same physics produce different results for temperature changes, cloud cover and rainfall indicates that something is wrong. These are early days in the development of climate models and it is expected that they will become more believable in the future. "
So what seems to be happening is that because they have this small effect from co2 modeled pretty well, and since it's not enough to explain the larger fluctuations of temperature through earths history, they try and find a way to make it seem as a lever to affect a larger change. I think they are subconsciously doing this... since it is the path of least resistance to finding an interesting, measurable formula by incorporating another rock solid one into it.
I also found an answer to my same question on that page about why temperature seems to precede co2 increases, not the other way around for the last 800k years at least, from co2levels.org . You've been ignoring me on this point for 3 replies now, so I doubt you'll respond, but just to let you know:
"Our comment: There is considerable misunderstanding of the ice-core records that do show that ~800 years after a temperature rise following an ice-age the concentration of CO2 increases. Not even the possibly exaggerated general circulation models can explain the ending of an ice-age by the appearance of large amounts of CO2. They end by various possible mechanisms. A change in the Earth’s orbital characteristics might increase the value of solar input to the Earth. Volcanic activity could deposit material on the snow/ice coverage that alters the planet’s albedo; the fraction of solar radiation reflected by the system. If this is the case the planet would warm up and this would have the consequence of releasing CO2 from the oceans and increasing the amount of water vapour in the lower atmosphere. This would, in consequence warm the system by the greenhouse effect and release more CO2 and water vapour… "
So the author explains it away with volcanos, sun spots and earths distance from the sun. Hmm... sounds a little vague for such large fluctuations, don't you think? Could it possibly be, that even with their complex and conflicting models, scientists don't actually know what caused these fluctuations back then? And further, that a small change in temperature due to co2 does not have a lever effect causing the larger change needed for these disastrous predictions? I suppose it so.
Now, couple that with all the "adjustments" to historical temperature data. Yes, they have excuses, measurements being taken at different times of day from before, older inaccurate equipment, change of environment, etc. I'd accept that if they changed it a couple of times, but they seem to have done it a lot. And there are a lot of other suspicious stuff going on. Why is there a temperature station now between the runways of a heavy trafficked airport (see the first link)?
Call me a conspiracy theorist if you like, but the temptation is there. Along with the general attitude of trying to suppress skeptics by the liberal media, liberal college bias and liberal institutions.
Anyway, barretbellamyclimate.com is a lot better than I first thought. So thank you for that.
I don't know why you think I need to understand the models that are not predictive in order to form an opinion. I will go through the rest of that site, but I don't think I need to delve deeper into theory that creates models that conflict with each other in order to form opinion on the predictions of the scientists who use those models as their basis.
So you do understand some physics at least. Then...
Buy his book, and try to find any error: he confirms there that IPCC is right:
It's less than 200 pages, much less than IPCC report, and also concluded without the use of the supercomputers. Human released CO2 is what is warming the Earth right now, at least at the speed as calculated by Intergovernmental Panel on Climate Change. Exactly what I've told you that anybody who honestly approaches the topic should do.
Prove yourself that you don't listen to authority, especially not Watts authority who is effectively a liar and the authority only to those who want to delude themselves or the others and who you obviously read.
You saw yourself what was Barrett's starting point on the pages that you like. You delightfully quote what he wrote before he checked everything himself. Then see how he was able to come to the conclusion that IPCC is actually right. There's no error: he was just able to repeat what the whole world can repeat and repeats everywhere every day... except the people who read Watts and such, which blocks them to see for themselves that IPCC is indeed right.
I already understood it is against your political sympathies to say that IPCC calculations is right. Well... it's time to prove that you don't listen to "authorities." You can confirm yourself and still have the political sympathies that you have. I definitely do not consider any of the two big parties or their voters even behaving consistently sane, but believe that in some topics one are right, in some topic another, and in some topics even neither. You are allowed to do that too. That can be a better chance for a real change, different than the pre-election slogan pseudo-change.
Don't support scientific illiteracy.
And most important: don't run searching for the false instant excuses by watts et al, search for the real sources yourself, check yourself what is real. Then once you are yourself sure compare what you've learned with what watts writes... and it will finally click how he distorts the truth. I don't care what his motivation is, his goals don't justify his means.
If this statement is untrue, in any way, then please correct me, because yes, I've misunderstood how past climates are scientifically reconstructed. But I'm going to need you to explain what data is used during their reconstruction (and not some hand-wavy "it's very difficult and not for non-climate-scientists to understand").
The limitations of it are known, and you won't find that the results of it are used for false claims by the real scientists:
What I'm posting above is the real report by the The Intergovernmental Panel on Climate Change. If you look in the context, tree rings are just one piece of the big and complex picture. See my other comment for an example how those who just try to confuse simply ignore (and don't even care for) geological facts when they try to push their agenda. The same happens with those who try to sell you the doubt and false claims about the state of climate research. The scientifically known uncertainties in using the tree rings as proxies aren't changing any facts about the reality of global warming.
It's undeniable basic physics. CO2 makes the Earth surface warmer because it blocks the part of the spectrum that would otherwise allow it to cool off. The part of the spectrum of the Sun that warms the surface up is however not blocked by the CO2. So the Earth gets the same effect that you have when you cover yourself with a blanket. It's warmer under it. It's undeniable and we are observing the effects every day:
If we don't do anything the expected sea rise on US shores is estimated up to 2.5 m higher (8 feet) in 2100. The non-red lines in the graphs are for the scenarios if the humanity actually stops pushing CO2 in the atmosphere very soon. We're already not following the "blue" strategies.
We've been hearing this Peak Oil crap for years. Maybe eventually it will be true...
If the world was in fact getting less green, and this was presented as bad news, would you hold the reporters to the same high standard of including all relevant silver linings?
A greener Earth is not a good sign. It's a swan song :'(
See e.g. page 3 of https://www.pnas.org/content/pnas/115/33/8252.full.pdf on biogeophysical feedback.
I am afraid the warming rate anticipated currently is at least an order of magnitude higher than any climate changes the earth faced before.
A slightly more nuanced discussion upthread here: https://news.ycombinator.com/item?id=19263836
here is a discussion of a neat study in 2016 that showed this effect: https://www.pnas.org/content/113/21/5768
the already warm tropics are expected to get even warmer, which likely isn't great for the forests there.
So is the resolution high or moderate?
I have always supposed that they wanted to leave the door open for actual high (spatial) resolution observations in the future. The driving design requirement was for global coverage every two days, so this meant a wide field of view of the downward-looking optics (2200 km wide FOV) which in turn meant "moderate" spatial resolution.
It was designed in the early 1990s. If you look at the original MODIS design papers (e.g., The Moderate Resolution Imaging Spectrometer (MODIS) Science and Data System Requirements, IEEE TGARS, Jan. 1991), you read the design was inspired by instruments like AVHRR and HIRS. The "VHR" in AVHRR stands for "Very High Resolution" and it was 1km! And the H in HIRS stands for High-resolution and it was > 1km, as much as 10km (!!). So calling it "Moderate" seems like a corrective message to the community.
Why would you need more? Many of the MODIS products are 1000m X 1000m, which is too coarse for many "field-scale" applications, where you want to get down to the health of individual fields of crops, or mixed suburban/rural areas, or biomes where vegetation types are mixed at local scales.
For instance, transpiration from broad-leafed trees is very different from grasses, and "mixed pixels" of these two types can confuse models. Or scattered parking lots at the fringe of suburban areas impinging on vegetation.
The number of trees needed (1.2T) is pretty close to the estimation of the accepted answer in your link (1.5T). The difference is, the up-to-date study has found that there is enough space for the trees. Now we just need to plant them :)
So is it a net gain or not?
In Brazil there's a biome called cerrado, characterized by low trees and shrubs, from the sky might seem brown but there's a lot of biodiversity and flora. Replacing it with soy fields should not be a net gain in my book.
0 - https://en.wikipedia.org/wiki/Cerrado
Geoff Lawton's permaculture work on 'Greening the Desert" is well worth a watch e.g. https://www.youtube.com/watch?v=yI9wMtTvWps
(plenty more videos around if you search)
2.If the water table is too deep, trees will need artificial irrigation, forever.
3.It seems easy to create a single-point of failure : monoculture of "best-performing" tree species which would succumb easily to specialized insects or fungus.
2. Tree raise the water table under them, by providing shade (so water on the ground doesn't evaporate as quickly and gets a chance to soak into the ground). They also prevent water tables from surfacing (by drawing the water up from their root systems). In other words, a mature forest will manage the water table, rather than being managed by the water table. You get water table problems if you cut down too many trees. Growing more will solve that.
3. this is true. There are lots of ways around it, though, if your goal is to green the desert rather than creating lots of cheap timber quickly.
Pretty big if.
And second, the Earth might get greener as a result of climate change, and that those changes might not necessarily be what is best for Humanity.
The effect that this "practice" has had on the environment is irreversible at this point.
But to each his own. Any positive news regarding the environment are always welcome.
>I suspect they are compensating for not being "allowed" to call their own president what they really want to.
If there's one country where you're free to say whatever you want about the president, it's the USA.
But the person you're replying to was clearly using quotes to put emphasis on the fact that they are in fact allowed to do that, but there are social/political consequences for it. (And they're right. Look no farther than HN: During the election and much after it, there was a clear movement to "treat both sides equally".)
I only care about ecologically minded governments and I don’t care about left or right. It’s the only important issue at this point.
I don't think you have a handle on the right's agenda in the United States, nor how the left can create a majority. Conceding the issues that you describe here would take the United States further away from dealing with our climate emergency.
To be clear: Trump is a corrupt person so there probably is lots of corruption to report. We all hung our hats on a particular flavor of corruption that involved him working with the Kremlin to get elected, which did not happen.
This is a rather strong statement given that it comes right after a recognition that fascist governments have historically had some ecologically friendly ideals. Are we talking about accepting literal genocide? Like, if we don't take care of the environment then everybody dies, so a fascist dictator who systematically wipes out an ethnic minority but also drastically cuts carbon emissions and restores a rainforest is a net-win? I'm not trying to put words in your mouth, I'm genuinely curious if that's what you're talking about, or if I'm parsing unintended meaning in your comment. I could see it either way.
Another note: Anti-Malthusians (including a few prominent HN posters who might show up in this thread when they wake up this morning), are always quick to gleefully point out that we haven't run out of food in no small part thanks to the development of synthetic fertilizer. What they loath to mention is the ecological impact of massive population growth, and the fact that humanity has already surpassed ecosystem's carrying capacity when you consider ecological impact.