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Does More Carbon Dioxide Mean Increased Crop Water Productivity? (arstechnica.com)
An anonymous reader points us to an Ars Technica report: For the most part, we think of rising levels of carbon dioxide as an environmental problem. But atmospheric CO2 can also boost agricultural productivity by helping plants grow. How do these potential issues balance out? In an investigation recently published in Nature Climate Change, scientists have looked into the global implications of carbon dioxide's ability to enhance agricultural productivity. Increased levels of CO2 can enhance photosynthesis and reduce leaf-level transpiration, the process by which some of the water that plants draw from the ground gets released back into the atmosphere. These changes can reduce growing seasons and water loss. The result could be an increase in what's called "crop water productivity," i.e. the amount of food produced for each unit of water expended. If elevated CO2 levels increase crop yield and reduce water consumption at large scales, this could help ensure water and food security despite the climate disruptions. By combining data from a massive network of field experiments and global crop models, the scientists claimed that depending on the crop type, global crop water productivity will increase by 10 to 27 percent by the 2080s. Arid regions exhibited large increases that were based on crop type.
It sounds good that crops will be more productive. So will other things, though. There was an experiment in which poison ivy was grown in higher CO2 conditions. It grew better and produced more urushiol (the stuff that causes you to have an allergic reaction). Crops may grow better, but so will weeds. It wouldn't surprise me if that included some invasive weeds like kudzu. If it stays warmer, pests might not die off in the cold; the mountain pine beetle is an example. Furthermore, there's not only increased temperatures and longer growing seasons; rainfall patterns will shift, too. Areas that currently grow crops might become arid and either have to grow different crops or not be productive at all. Other areas, such as the northern US, are likely to become wetter. Maybe you have longer growing seasons in some areas, but I'm not sure how much of a real gain there will be if the rainfall moves poleward with the warm temperatures.
Correct. Much as higher CO2 levels and temperatures dominated during the Carboniferous period, spurring massive plant growth and laying down many of the geographic strata that turned into the massive coal fields we mine today, we will likely see greatly increased plant growth which is yet another of the negative feedback mechanisms that keeps the global climate catastrophe from happening the way the alarmists want you to believe.
I've got a planted freshwater aquarium. In addition to good lighting and appropriate fertilization, people who like to keep this kind of aquarium tend to inject carbon dioxide to keep the plants growing well. The difference in plant performance in the aquarium with and without CO2 injection is substantial.
-- "Oh. This guy again."
Off the top of my head, I'd imagine they mean fresh water scarcity, as higher ocean levels could overrun natural fresh/salt transition zones and contaminate fresh water supplies.
Well, we can't be having any of this shit. These guys need to be black balled and the editors at Nature Climate Change need to be fired.
The warmer the climate is (WAY beyond any projected increase) the wider the area of land is that you can grow productively on.
From just the north to the south of the U.S. is an average temperature differential of nearly 10 degrees celsius. The South is of course more productive crop wise; as you grow closer to the equator it gets hotter and plats grow even more vigorously.
So even the worst case (and totally contrived) 4c increase in average temperatures means the united states (and Canda) become even more the gardens than they are today. It means massive increase in agricultural output across the entire globe, not just here... most of Europe (on average colder than the U.S.) benefits similarly.
The only danger there ever was from global warming was a runaway warming effect, which was supposed to be do to CO2. But CO2 levels skyrocketed without any kind of correlation to actual temperature increases, so we KNOW that there will be no runaway effect. The REAL danger lies in when the next ice age starts - we can only pray we have warmed the earth enough to avoid the next ice age but if you look at historical data you'll realize that is sadly just a fantasy.
It's really sad how the warring Alarmists such as yourself can't even use the common sense of remembering that jungles are hot before you write up long screeds about how energy is actually a detriment to the expansion of a system...
"There is more worth loving than we have strength to love." - Brian Jay Stanley
The problem probably isn't about the total amount of water, but rather, the distribution of it. Areas that have shortages of water would have more severe shortages.
As for why it would be a net bad thing, it would be that the changes happen faster than evolution can keep up. That might also include humans, or a large portion of our population.
This is my signature. There are many like it, but this one is mine.
Most of the pine beetles were killed off in a heavy freeze a few years ago.
The reason why your example is bad is that even a rise of a few degrees C in temperature ON AVERAGE, does not mean you will not continue to have heavy cold snaps in areas like the mountains - and it only takes one such to kill back a large number of beetles.
Also trees getting more CO2 and warmer temperatures grow better and thus resist insects better also.
It's absurd to claim the offset in the ability to grow ANYTHING is offset entirely by a possibly increase in weeds and insects... come on.
I notice you post AC when spreading your warming alarmism, it speaks heavily to how much stock we should put in your claims.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
will this reduce the need for fresh water by the same amount lost to salt water inundation from global warming?
“Common sense is not so common.” — Voltaire
Globally, water will not become more scarce unless we boil some past the Van Allen belts (not sure how hot it would have to be for that) or launch it to Mars. The point of concern that is often portrayed as "water scarcity" is "potable water scarcity," the reduction in available drinking water as some of the normal sources fade. Many clean rivers start from mountain meltwater that is restocked with snow each winter. If the winters are insufficient to create such a bank of snow on the mountains (too rainy or too dry), the familiar availability of water decreases (even if the annual precipitation does not change at all).
Similarly, subterranean aquifers are a point of concern. Some are restocked by rain, but not always as quickly as they are drained by human use. The recent California drought (like all the ones before it) put a strain on the water supply from the aquifers they have tapped.
This problem can be countered with many known processes, but those all add cost to extract drinkable water from otherwise nonviable sources. (desalinization, transportation, distillation, a few other fun techniques I'm forgetting as I type)
As for the weather predictions, there are equally valid models that warming will lead to more hurricanes, less hurricanes, stronger hurricanes, weaker tropical storms, and a complete cessation of Atlantic currents. So far, with a statistically insignificant set of years since those predictions were first made, the "mostly weaker storms, few making landfall" model seems to fit better but this could be a few years of anomaly.
Some weeds grow faster as well, which might lead to more herbicides. Also, poison ivy grows better with increased CO2, which in my book is a bad thing.
What about the biomass decay from all that extra food we'll be throwing away? What's the point of growing more if we're just going to let it rot? We don't suffer from food shortages, we suffer from de facto food rationing. The CO2 thing? Replace the hydrocarbon fuels with something else. The only impediment there is the political corruption.
“He’s not deformed, he’s just drunk!”
"The Greenhouse Effect Theory"
I'd watch that.
Measurable nutrients from food has declined by up to 40% since the 1930s and by about 15% since 1950.
The water content of fruits has exploded (most fruits are basically packed nutrientless water and sugar).
Faster growing crops boosted by CO2 will have even less time to draw as many nutrients from the soil.
We really should measure a random sampling of end consumer food products for nutrients each year and then require current real values to be on the food labels. Monsanto, Conagra and others spend millions to prevent that kind of labeling however. And do everything they can to muddy what organic and natural means.
But you can't trust organic and natural either outside of constant testing. Farmers want to make money- they'll try something "organic" which is actually unsafe.
So send agents to stores to buy food and then measure it. Then post the results on the web and require each seller to use that nutritional data on labels for their food until the next test.
She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
There are diminishing return at some point, and other elements begins to be a limiting factor : nitrogen fixation and phosphorus for example. So it *may* produce some better plant growth some places, but for our agriculture it sounds doubtful.
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
The difference this time around is that Carboniferous period fungi were unable to break down lignin. Lignin adds rigidity to plant cell walls and was what plants needed to grow into tall trees with the capacity to bind trillions of tonnes of carbon into wood. For about 50 millions years, all the tree trunks that fell over from storms, disease, old age, insects, earthquakes, dinosours knocking them over, what have you, did not rot completely. Much of their carbon was sequestered underground and compressed into coal. The Caboniferous period ended as Fungi evolved the means to digest lignin and ended the massive carbon sequestration.
http://www.mining.com/coal-sto...
So yeah, plant growth will spike, but don't expect that to mean much for reducing global C02 levels.
Increased plant growth does not mean increased yield in food stapple, if we are still limited in Phosporus and nitrogen fixation. But even if it did, the water increase and climate chaotisation would far more offset that. What good is it that Florida could produce more orange, if it loses its coastal city and vast swath of the everglade, or land ? Or if the ocean pH changes destroy the food stapple (fishing) of many countries ? And that is only on top of my head. There are so many factor at play that your typical "AGW is not that bad" is sad.
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
There are many areas of the world that depend on glaciers to feed rivers in order to supply them with water during the dry season. For example India, Pakistan, and California (though this could just be snow packs and not glaciers). As the glaciers and snow cover has been shrinking there has been water shortages causing people to tap into underground aquifers at an unsustainable rate. Once the glaciers are gone the rivers will dry up except for the rainy season (the monsoon season in India which due to climate change is becoming unpredictable itself) and unless some way is found to capture a massive amount of water then there will be a great humanitarian crisis.
But it lowers nutrition of some food.
http://www.theguardian.com/env...
These guys need to be black balled and the editors at Nature Climate Change need to be fired.
Good news and reference to potential positive effects are not permitted. We can only have bad news, doom and gloom.
> Guess which are the key words in that sentence.
The words that you didn't include?
"So long and thanks for all the fish."
Free-Air Concentration Enrichment studies such as soyFACE artificially raise CO2 (among other variables) and monitor plant response. SoyFACE, as the name implies, is focused on soy, an important food crop. Imagine a crop field surrounded by CO2 sprayers and heaters to simulate elevated CO2 and its effects.
Findings from the experiment include that increased temperatures will likely reduce yields of soy, even at elevated CO2. Higher average temperatures also increased susceptibility to herbivory by the Japanese beetle.
A related meta including 228 experimental observations found that barley, rice, wheat, soybean, and potato all have lower protein content at elevated CO2.doi: 10.1111/j.1365-2486.2007.01511.x
14 years of publications can be found here: http://www.igb.illinois.edu/so...
In short: even if water use efficiency were to increase, that does not result in increased yield, or crop quality.
You know what? My doctor said years ago I'd get lung cancer from smoking. He kept saying, those things are going to kill you, you'll get lung cancer!
So now that it's years and years later, of course he's flip flopping and saying it's emphysema that's killing me. And before that, cigarettes are what the doctors said they ordered!!! This is all just to force their radical pro-lung agenda and so of course they have to make up this stuff as they go along!
[Pauses to light bong...]
Isn't the Sahara greening?
I come from a greenhouse family, and I remember using CO2 generators in the 90's briefly. I asked about this a few months ago and they quit because it prompted too much growth in some crops so they nixed the idea.
The reason I asked the question is I was coming back from a small class put on by MSU Extensions (Eric Runkle lead it) about LED lighting. He briefly touched on CO2 generation and it was basically a toss out of... "Yeah, we used to suggest that but ambient is now over 400ppm, so if you think you're low just crack a vent. I've seen some greenhouses down to 200ppm. Impressive they had it that sealed up, but just vent and you'll come back into the 400's." -- paraphrasing a lot there. I didn't take notes.