Comment history

Where We Are Going

Doug, I agree except for your last sentence (see below) and I am glad you now see the importance of the first 20 ppm of CO2 in producing that 80% or so of the GH effect. My quibble is that the sensitivity estimates are from models which don't model mesoscale weather. It doesn't mean they are wrong, but they are not well supported.

The ocean acidification doesn't accelerate with increasing atmospheric concentration of CO2 since it goes by Henry's law which is linear. Also the ocean acidification is another case where we are creating (probably irreversible) consequences but those consequences are down the road (decades or centuries). Currently ocean pH is lowest in upwelling areas because bottom water has the most CO2. In those cases and many others, atmospheric CO2 doesn't matter, it won't make the surface more acidic than the natural fluctuations. But we are sending lower pH water to the bottom with some unknown consequences and one known consequence: that it will come up eventually.

The deep ocean is essentially our dumping ground for both heat and excess CO2. It won't last forever, but it will last a while.

June 5, 2012 at 10:02 a.m. ( | suggest removal )

Where We Are Going

Doug, 80% is the hypothetical attributed greenhouse effect due to the freezing of water and lack of water vapor at low CO2 levels. 80% would only be true if all water vapor feedback (not forcing) were added to the CO2 forcing. As your link explains, the percentage of forcing of present day CO2 is 14 to 25% depending on how one does line by line models (removing water vapor vs removing CO2).

Here's a graph of the heating of CO2 from the first 20ppm versus each subsequent 20ppm http://wattsupwiththat.files.wordpres... Please don't conflate this forcing with water vapor feedback: the first 20 ppm of CO2 causes more than enough heating to get water vapor in the air and thus a huge amount of feedback (water vapor forcing). So the attribution of the total greenhouse effect to that first 20 ppm of CO2 is very large (probably something like your 80%)

June 5, 2012 at 4:13 a.m. ( | suggest removal )

Where We Are Going

If you want a current example, look at Germany. Despite an enormous welfare system they have increasingly large slums and income disparity (a shrinking middle class). They are still a powerhouse exporter with some of the best value created per unit of energy in the world. But the price is shrinking workforce in the less efficient industries which have been basically shipped to China. Germany employs far more Chinese in China than Germans. Germany also supplies the "clean coal" whitewash tech allowing the rapid rise of Chinese emissions.

If you want a state to try it on, California is an obvious choice. They already have huge slums and near slums that will turn into slums when the jobs disappear. The middle class will also get tired of supplying the dividend checks to the lower class just for the privilege of commuting to a job they like and keeping the house comfortable.

The upshot will be more, not less worldwide emissions since industry will move from relatively efficient California to inefficient second and third world countries.

June 4, 2012 at 8:18 p.m. ( | suggest removal )

Where We Are Going

I think we can handle our one inch of sea level rise per decade. There are arguments over whether that rate is accelerating, but if it is accelerating it is not accelerating rapidly.

June 4, 2012 at 8 p.m. ( | suggest removal )

Where We Are Going

No it is not relevant, and it is misleading. The reason is that the first 20 or so ppm of CO2 are what is necessary to melt the ice and get water vapor in the air in nontrivial quantities. Any CO2 beyond that is superfluous to getting over the 0C hurdle. If water didn't freeze at O there would be no issue at all.

At current levels of CO2 and current temperatures the role of CO2 is the 25% of greenhouse effect that it contributes. Even during the ice age the role of CO2 was not 80% (don't know that number off hand, but certainly larger than today's 25%.

BTW, realclimate says 14%:

June 4, 2012 at 7:54 p.m. ( | suggest removal )

Where We Are Going

The nonlinearity of water vapor can sort of justify a notion like "80%" But in a line by line model the CO2 is about 25% as they say in their article. That is the number that counts because as we add CO2 its contribution will turn 33 degrees of greenhouse into 34. Any further warming will be from water vapor feedback (an unknown amount). The 80% notion is irrelevant.

Water vapor warms by being evenly distributed. But if the weather distributes it unevenly then it will not warm as much. For example without land the world would be much warmer. Essentially land concentrates moisture, causes convection, and increases latent heat transfer from the surface to the upper atmosphere (more than a world without land). Weather is no different. The upper air and surface patterns determine the latent heat transfer and average amount of global warming or positive feedback from CO2 warming.

June 4, 2012 at 2:30 p.m. ( | suggest removal )

Where We Are Going

Solar forcing is at least two things, what your link depicted was irradiance which follows the solar cycle but doesn't represent a lot of forcing. The other potentially larger effect is solar modulation of weather. One example is low solar ultraviolet allowing more stratospheric cooling which is uneven and causes blocking patterns (like the winter of 2009/2010). There are other effects like that from solar wind decreases, etc.

The net forcing from CO2 is not exaggerated but the water vapor feedback generally is (the models not useful). Water vapor feedback really depends on weather, not on overall CO2 warming. That's because uneven water vapor is net cooling, even water vapor is net warming. Weather determines which side we land on and weather is mostly solar modulated.

Solar can't be predicted too well but seems to be in a slump for at least a decade or two. So that's what's behind my prediction for some cooling. What happens after that is some more inevitable CO2 warming, but not necessarily a corresponding amplification by water vapor.

June 4, 2012 at 6:50 a.m. ( | suggest removal )

Where We Are Going

The reason I pointed to the black line is an easy way to depict my testable prediction. Spencer's zero line happens to be the 30 year average (1980-2010) and it not zero net warming. I don't believe in zero net because CO2 warming is net positive and solar will return to some long term average leaving us with net positive. But short term solar cooling could exceed CO2 warming.

BTW, extreme weather is a negative feedback.

June 3, 2012 at 5:17 p.m. ( | suggest removal )

Where We Are Going

CG, the important details are not known. The most important detail is the response of weather in a lot of specific locations in a CO2-warmed world. Some locations are a bit easier, using your example the Pacific should see expanded Hadley cells in summer in each hemisphere. Perhaps summer will start sooner and end later. But outside of that there is very little that can be predicted.

The weather changes in a CO2-warmed world will determine the extent of positive feedback from water vapor. An increase in average absolute humidity is predictable but not constant relative humidity and not humidity at any given location (other than to some extent the more predictable locations)

June 3, 2012 at 3:15 p.m. ( | suggest removal )

Where We Are Going

Doug, you are correct that there could be drying in Kansas in a warming world or flooding or both or nothing. Saying one scenario is more likely is unfounded speculation. So far there is minor warming and precipitation increases. My prediction for the effect of solar induced cooling is roughly the black sinusoid here hitting zero around 2020 Note that Spencer has indicated that line is "entertainment" not a prediction. But I think it is adequate as a prediction give the solar changes and lag.

The idea of a less detailed model to predict world average temperature is valid, but it is not valid for regional predictions or for water vapor feedback. The climate models simply cannot deal with ENSO or any other oceanic or atmospheric weather patterns. They don't predict them as they may change in a warming world, but more fundamentally, they don't simulate them well either. That's because all such weather patterns are ultimately modulated by mesoscale weather which is too fine for climate models. Eventually computational power will overcome the restriction on climate model resolution and solve this problem for us.

June 3, 2012 at 2:34 p.m. ( | suggest removal )