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While that is an interesting study, please explain exactly how it relates to the question I asked:
" I wonder what the cutoff point is where the CO2 level gets low enough that crops don't grow well enough to feed the billions of people on this ball of dirt?"
One also has to wonder if the conditions worldwide will EVER equal those of the study, since it measures not only high CO2 levels, but other factors also. The study admits that high CO2 levels DO improve plant growth!
"Most studies have looked at the effects of CO2 on plants in pots or on very simple ecosystems and concluded that plants are going to grow faster in the future," said Field, co-author of the Science study. "We got exactly the same results when we applied CO2 alone, but when we factored in realistic treatments -- warming, changes in nitrogen deposition, changes in precipitation -- growth was actually suppressed."
Also worthy of note:
" ...the novel experiment was designed to simulate environmental conditions that climate experts predict may exist 100 years from now: a doubling of atmospheric CO2; a temperature rise of 2 degrees Fahrenheit; a 50 percent increase in precipitation; and increased nitrogen deposition..."
Yeah, right; "...climate experts predict..." We all know how accurate their predictions have been since the 1970s...
Way to read selectively.... While treatments involving increased temperature, nitrogen deposition or precipitation -- alone or in combination -- promoted plant growth, the addition of elevated CO2 consistently dampened those increases.
CO2 is CO2 - whether it comes from humans or atmospheric "waste". Plants absorb CO2 and release CO.
Now if they want to say it's other atmospheric waste - OK.
From the paper...
The biggest surprise from the study was the discovery that elevated carbon dioxide only stimulated plant growth when nitrogen, water and temperature were kept at normal levels.
...
But results from the third year of the experiment revealed a more complex scenario. While treatments involving increased temperature, nitrogen deposition or precipitation -- alone or in combination -- promoted plant growth, the addition of elevated CO2 consistently dampened those increases.
"The three-factor combination of increased temperature, precipitation and nitrogen deposition produced the largest stimulation [an 84 percent increase], but adding CO2 reduced this to 40 percent," Shaw and her colleagues wrote.
From the last paragraph... plants still grow, but at a slower rate.
But you have to look at this carefully. INCREASING CO2 with normal levels of water, nitrogen, and temperature stimulated growth.
INCREASING water, temperature and nitrogen FIRST increased growth... THEN when CO2 is added, the growth slows. MAYBE the increased nitrogen is the problem. Did they study that?
In other words increasing CO2 was fine when other factors were untouched. But increasing everything, including the nitrogen and the CO2 - that retarded the growth.
CO2 is CO2 - whether it comes from humans or atmospheric "waste". Plants absorb CO2 and release CO.
Now if they want to say it's other atmospheric waste - OK.
From the paper...
The biggest surprise from the study was the discovery that elevated carbon dioxide only stimulated plant growth when nitrogen, water and temperature were kept at normal levels.
...
But results from the third year of the experiment revealed a more complex scenario. While treatments involving increased temperature, nitrogen deposition or precipitation -- alone or in combination -- promoted plant growth, the addition of elevated CO2 consistently dampened those increases.
"The three-factor combination of increased temperature, precipitation and nitrogen deposition produced the largest stimulation [an 84 percent increase], but adding CO2 reduced this to 40 percent," Shaw and her colleagues wrote.
From the last paragraph... plants still grow, but at a slower rate.
But you have to look at this carefully. INCREASING CO2 with normal levels of water, nitrogen, and temperature stimulated growth.
INCREASING water, temperature and nitrogen FIRST increased growth... THEN when CO2 is added, the growth slows. MAYBE the increased nitrogen is the problem. Did they study that?
In other words increasing CO2 was fine when other factors were untouched. But increasing everything, including the nitrogen and the CO2 - that retarded the growth.
Shoddy conclusions based on the research...
Shoddy conclusions made by you based on your bias....
Predicting the world's overall changes in food production in response to elevated CO2 is virtually impossible. Global production is expected to rise until the increase in local average temperatures exceeds 3°C, but then start to fall. In tropical and dry regions increases of just 1 to 2°C are expected to lead to falls in production. In marginal lands where water is the greatest constraint, which includes much of the developing world but also regions such as the western US, the losses may greatly exceed the gains. Climate myths: Higher CO2 levels will boost plant growth and food production - environment - 16 May 2007 - New Scientist
2. Back in the 1970s, I was highly interested in Meteorology (along with Geology, Seismology and Astronomy) and I checked out many books from libraries in that subject.
If we put any more SUVs on the road, I will have to buy a boat because the sea level rising will mean we will live in a world of water and disappearing land
I want to see more electric cars and more bicycles, if we do this, then temperatures won't be so hot anymore and we can finally not have to worry about vacuuming out tons of water and launching it into space to save the planet from global warming waters. We can keep the ice caps colder if we could elect more House Democrats in November 2014 election coming up to take back the House
Conservative Republicans are so worried about other countries getting nukes and building a nuclear arsenal to bomb Iran when they don't have to because global warming will take EVERYBODY'S land away
Dear Worry Wart,
Go get yourself a dose of Reality.
Consider:
If we're under imminant threat of being flooded why is no one building levies around our cities to protecrt them? I mean, stop and think about it: When people inland hear their town is about to be flooded they go down to the river and start throwing up sandbags. So why are there no calls for that around the WORLD'S major port cities? You don't think the seas will rise ONLY around America, do you? Won't sea levels rise the same amount all over the world? There are also environmental groups in Europe, Asia, Australia, and everywhere else. You'd think SOMEBODY somewhere in the world would be calling for levies to be built. Why aren't they? What's wrong with this picture? We're in dire danger of being flooded yet no one is taking the most elementry measure everyone all over the world universally takes when they learn they're about to be flooded. They're acting exactly like they would if the whole thing was just a lying crock of bull. Forget what they're saying; take a look at what they're actually DOING.
Now this Global Warming supposedly began in the 1840s with all the coal being burnt. If the ice caps have been melting at the rate claimed then by 1900 it would be noticed that shipping channels no longer needed to be dredged as often as in the past. Men who made their living on the docks would notice the ships seemed to be riding a bit higher at the piers and the gangways weren't falling quite where they had several years ago. By the 1920s it would have become a topic of conversation in newspapers and magazines and on the radio. It would have affected wartime planning by all sides in the 1940s. By the 1960s there would be serious need to rebuild harbors all over the world. Why haven't these things happenned?
Green plants take in carbon dioxide and give off oxygen--so why is no one planting trees in parking lots and vines on skyscrapers to absorb carbon dioxide at its source?
When you look at what they're doing rather than what they're saying Global Warming is a con job and you're the sucker. Check the sea level in 20 years, you'll see what we mean.
If we put any more SUVs on the road, I will have to buy a boat because the sea level rising will mean we will live in a world of water and disappearing land
I want to see more electric cars and more bicycles, if we do this, then temperatures won't be so hot anymore and we can finally not have to worry about vacuuming out tons of water and launching it into space to save the planet from global warming waters. We can keep the ice caps colder if we could elect more House Democrats in November 2014 election coming up to take back the House
Conservative Republicans are so worried about other countries getting nukes and building a nuclear arsenal to bomb Iran when they don't have to because global warming will take EVERYBODY'S land away
Since every human emits about 2.3 lbs of co2 per day, you could begin helping the situation by not breathing.
Also we had hot weather during the Bush and Cheney years and then it got much cooler out in the Obama years like the 2010 blizzard was Obama-Biden driven
2012 was a warm snowless winter because Obama temporarily laxed up on green policies to help get centrist votes for the 2012 election which Obama won. After that the polar vortex thing happened more because Obama green policies helped reduce global warming
I want the polar vortex colder air to keep at it and not be destroyed by a Republican Anti-green pro-oil change of pace
You are a complete idiot.
Obama hasn't even claimed credit for cooler temps!
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