Since the relationship between CO2 and forcing is logarithmic, an increase from 400 to 600 ppm would result in about 1 degree extra warming. We have doubled the concentration from 200 ppm to 400 ppm since the begining of the industrial revolution and we are on track to increase temperatures by about 1.8 C. We need to go to 800 ppm for another 1.8 C in warming.
You can wave your hands about the effects of feedbacks, but the truth of the matter is, we really don't understand climate dynamics well enough to predict. I am not a climate scientist, but I can produce dozens of graphs which have already overestimated the warming effect of CO2.
Given that the doubling of CO2 increases temps by about 1 degree by itself and incorporating a doubling of the effect caused by positive feedbacks, I would guess it would be about 1.17 degrees warmer, the seas would rise by about 4 mm/year and we would see the arctic ice-free during the summer.
This would cause some slight changes in microclimates at various locations. The effect of these changes would balance out, but the changes themselves would cost money in adapting to the changes. Positive results would be farming in more northernly locations and at high elevations. Fruther, the increase in CO2 concentration would increase plant life. Given there woudl be time to adapt to the changes, the overall effect of all the changes would be negative, but nothing one would consider catastrophic. And argument could be made for it being catastrophic, however, if you ONLY considered the negative aspects of the changes and did not consider the positve aspects.
This is my guess, based upon my research. I do not and cannot know the future or the effect of hypothetical scenario.
Anarticice,
I do not ignore the evaporation issue. BUT, as you warmers keep saying, that leads to more floods and more droughts. I don't think it does lead to either as I have seen no evidence of an increase in either. BUT, by saying such a thing, you tacitly acknowledge, that more evaporation does not necessarily lead to an overall decrease in rainfall. Further, the advantages to crop of having more ready access to CO2 is not only growth but since they can close their stomata more because they don't need to pull in as much air to get the required CO2, the amount of water needed by the plants is reduced. So even assuming a small change in overall precipitation, there may be no effect seen.
BUT, I have to give you props for actually correcting a clearly false alarming view of 15 years to hit 600 ppm.
Of course you nearly used up all the credit when referring to Russian roulette. THE FACTS are that the amount of food produced yearly over the amount of people on the planet has been increasing for some time now. With the UN prediction of hitting our maximum Earth population by 2050, and our current direction in technological improvement in farming becoming mroe readily availabel to the rest of the world, I would say your russian roulette is a rather extreme exaggeration.
In fact, I don't hesitate to say that IF we got rid of that stupid ethanol requirement, we could keep the earth's farming constant for the next 100 years and still be able to feed everyone. Right now we can easily feed everyone were it not for the dictators and distribution issues.
So perhaps you can tell me how your AGW catastrophe is going to so limit crop production that it will not only kill the gains of the northern and higher elevations, but kill any technological gains as well.
We are pretty much @400ppm, Larry is a little off in his 15 year estimate as the current rate of rise is ~2ppm per year, if that maintained we may be ~600ppm by the end of the century.
Current estimate range on what that may be like, but the lower end estimates at least 3c rise in temperature (global average) linked to a sea level rise of ~1m
Plants do grow better in a richer CO2 environment (as denier continually try to remind us) of course in a warmer world you also have changes in precipitation and an increase in evaporation, but denier try to ignore that part (as can be seen in their answers)
We grow a lot of food in reclaimed semi-arid zones, this has been made possible by building dams and concentrating water supplies, but such systems would fail if there was even a small change in precipitation , even if you have a large dam, some rain is still needed to keep it topped up, some areas will indeed get more rain but other will not and we have know way of knowing which these will be. So we are playing Russian roulette with our food supply, a supply that fluctuates in price on even small changes like the Ethanol issue denier where so keen to remind us of.
If seas level is held to just 1m that will still have a major effect on the worlds coastlines and cities around the world, this is maxies "greener world"
WHEN atmospheric co2 levels reach 0.06% (600 ppm) the earth will be considerably greener & areas that are now barren or marginal may become more productive & more amenable to all forms of life.
http://www.scientificamerican.com/articl...
http://onlinelibrary.wiley.com/doi/10.10...
http://www.sciencedaily.com/releases/201...
http://notalotofpeopleknowthat.wordpress...
The charts in this link indicate indicate co2 effects on the growth of several types of plants.
http://notrickszone.com/2013/05/17/atmos...
the 'climate' inside a greenhouse does not produce extremes of weather and people do no live inside greenhouses- it would be too hot most of the time.. Some deniers will even claim that the Earth had over 2000PPM in the past and fail to mention that the Sun was cooler 500 million of years ago.
At 600PPM, you can expect more parts of the planet to be deserts, coast lines to be changed due to sea levels changed and general weirdness of the weather.
Greener. Green houses have raised their CO2 lever to over 1900 ppm with beneficial results in production.
We'll find out in about 15 years at the rate we're going.
Greener probably. We would have higher food production too. But that's about all.
CO2 is not responsible for any significant warming, no matter how much propaganda says it is.
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Same as 400 nothing
I'm with "MIKE L", I don't think you would notice any difference.
What would Earth be like?
