That number sounds in line with other estimates I have heard, but of course those are just estimates. They are also estimating something which doesn't really exist, because certainly there ARE various feedbacks. The Clausius-Clapeyron equation tells us that each one degree C rise in temperature raises the saturation vapor pressure by about 6%, so we'll certainly have more water vapor in the atmosphere--how is there not going to be a feedback from that?
EDIT: I think you are confused about what you asked, which was "Does everyone agree...: ?" That is the question that I answered. And to say "...no estimates allowed..." is just silly--that's all anyone can give you. It's not like you're asking for the cube root of 27 or the capital of Bolivia--there are only estimates from models--no one can give can perform this experiment, and it's not like the answer can be derived from a set of fundamental postulates.
"He stated that a doubling of co2 from present levels would result in a 1,2 degree rise. Now note, this figure is before any feedback's (pos or neg) are added to the maths.
Do you agree with this figure?"
I don't think I do. I'd like to see how he calculated this (can anyone post a link?). I'd particularly like to see the assumptions made in the calculation.
If we look at how the earth is warmed at the most basic level, we know that our heat comes from the sun. Some is retained, and the balance is radiated to space. The 'blackbody' earth is warmed to an equilibrium temperature.
If adding more CO2 increased retained heat, then we would see outgoing longwave radiation reducing as CO2 concentration increases. This should be a direct and instantaneous relationship. We do not see this (chart below). Adding CO2 does not cause apparent corresponding observable OLR reduction. Adding more appears to make no difference to ORL.
http://farm9.staticflickr.com/8376/83960...
We know the physical properties of CO2 very precisely. We know the absorbtion bands, and we know that CO2 absorbs energy in a logarithmic relation to concentration. However we do not see absorbtion directly increasing with CO2 concentration. Something is happening (probably to do with cloud and/or water vapour?) to moderate this anticipated increase.
If posters are inclined to quote Griggs and Harris 2006 as evidence that absorbtion HAS increased with CO2 concentration, I'd encourage them to re-read the paper and check their conclusions first. The full paper is here
http://web.gps.caltech.edu/~mlau/Griggs-...
OLR data here. http://climexp.knmi.nl/select.cgi?id=som...
CO2 data here. ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/c...
Edit Big G. Re "The tipping point is 450ppm and anything approaching 600 would cause catastrophic results". Do you have a source for this please? I'd like to read it.
GN Plass, considering only the increase in carbon dioxide and with the other feedbacks and variables held constant, calculated that doubling the amount of carbon dioxide would increase to temperature of the Earth 3 to 4°C.
I think doubling current CO2 would result in at least a 5 deg C rise. You have to take into account that as the temperature rises, the oceans are going to sequester less carbon, there will be less trees to absorb CO2 and the ocean to CO2 positive feedback loop would be going wild. I think even 5 deg is a conservative estimate.
As a result, hundreds of millions could die of thirst and hunger. There would be more desert and less and less farm and grazing land. Lack of water would cause an untold number of cattle, hogs sheep and goats to die. Grain would be so costly only well to do nations could afford it.
It would be next to impossible to make a comeback even instantly stopping CO2 emissions.
The tipping point is 450ppm and anything approaching 600 would cause catastrophic results.
I believe that we are contributing (not the cause). We are over populating but we also have to survive.
The best we can do is manage with as little as possible without making life not worth living. We are not just doing it for global warming but also for our future generations. What irritates me is how many ppl literally stick 2 fingers up to our descendants by saying, it will be there problem not ours. I find that grossly unfair and totally disrespectful, after-all our ancestors fought for us to survive today didn't they?
It's a little high; my understanding is around 1.0C for a doubling of CO2. I assume we are talking Centigrade here, if not, then 1.8F/2xCO2.
For this question I think that is near enough, so put me down as agreeing.
The calculation without the feedbacks is worthless. But iirc that is about what I've previously seen.
It's kind of hard to produce a mathematical model that takes account of solar storm activity that is entirely unpredictable, yet can alter planetary temperature and weather events dramatically.
Also, did you factor in the huge amount of C02 released in dramatic forest fires in the States, EU and Australia?
Whatever C02 cutbacks were achieved in human activity in 2012, were more than discounted by the C02 fallout from these fires.
Let's face it, AGW was and is a discredited theory...
I was told it would be more like 3 degrees but I didn't think anyone thought global warming was fake, I just believe that it can't be mans fault due to how small our carbon footprint is in comparison to the natural emissions produced by animals, plus we're still leaving the ice age. Please please please best answer me and give a retort would like your opinion
Then what is there to agree on?
I recently followed a link to a video looking at some of the maths in agw theory. (yes it was a pro warming guy doing the maths if that makes a difference to some of you). He stated that a doubling of co2 from present levels would result in a 1,2 degree rise. Now note, this figure is before any feedback's (pos or neg) are added to the maths.
Do you agree with this figure? Now obviously there are many variables in a dynamic Earth but if we pretend for a moment that earth will react as though it's in a test tube do you agree with the previous statement and 1.2 degree figure?
Do we have a consensus on this point?
No, recent studies have indicated that what little effect CO2 has on the temperature, reaches its saturation point at around 400 ppm. Anything higher than that has little or no effect.
We all agree on AGW math myths?
disagree!
no
