Most climate scientists, even "skeptics", like Roy Spencer and Judith Curry agree with the greenhouse effect by which water, carbon dioxide and some other gases trap heat in the atmosphere for longer than it would otherwise be kept so keep the earth's atmosphere warmish. I.e. the GHG effect slows down the loss of heat to space. Most of the disagreement with regards to warming relate to:
- whether or not more water vapour (an theoretical extra 7% per doubling of CO2 from pre-industrial times) will amplify the CO2 GHG effect. Whether it will be neutral, or even negative, and whether there will be any extra water in the atmosphere at all.
- whether scientists should lie and torture the data to galvanize the public into action on climate change - to scare the living wits out of us.
Some do not agree with the GHG effect, but explain, by a different mechanism, how the atmosphere is, in practice, warmer than basic theory tells us it should be. I don't necessarily agree with what's written below but...
- I've not seen this before. Which is strange. It's all: GHG is will make earth's atmosphere intolerably hot, etc.
- Given how little experimental work climate scientists do in support of the massive changes they propose to make to our lifestyles - where are the experimental studies showing the GHG effect? - I think in the interest of balance, the other side of the story should be told.
willhaas February 8, 2017 at 3:09 am
This paper makes a good point of discussing that there is no real evidence particularly in the palaeoclimate record that CO2 has any effect on climate. At least a few more points need to be made.
The AGW conjecture is based on the existence of a radiant greenhouse effect caused by the LWIR absorption properties of so called greenhouse gases. But so far such a radiant greenhouse effect has not been observed, in a real greenhouse, in the Earth’s atmosphere, or on any planet in the solar system with a thick atmosphere. Without the existence of a radiant greenhouse effect the AGW conjecture is just science fiction. From first principals, one can derive that gravity, the depth of the atmosphere, and the heat capacity of the atmosphere will act to keep the surface of the Earth on average 33 degrees C warmer than it would be without an atmosphere. 33 degrees C is calculated from first principals and 33 degrees C is what has been observed. There is no additional radiant greenhouse effect.
A researcher has pointed out the original calculations of the Planck effect (disregarding feedbacks) climate sensitivity of CO2 were too great by a factor of more than 20 because what was neglected is that a doubling of CO2 will cause a small but very significant decrease in the dry lapse rate in the troposphere which is a cooling effect. So instead of 1.2 degrees C the Planck effect climate sensitivity of CO2 should be more like .06 degrees C, a trivial amount.
To make the warming effect of CO2 to appear significant, the AGW conjecture assumes that the H2O feedback is positive but the fact that the wet lapse rate is significantly less that the dry lapse rate indicates that more H2O has a cooling effect and hence must provide a negative feedback effect. The negative feedback effect must also have had to be there for the Earth’s climate to have been as stable as it has been for life to evolve because we are here.
The AGW conjecture would have one believe that LWIR absorption band radiation where the dominant means of heat transport in the troposphere but in the pressure regime of the troposphere, conduction and convection dominate. The climate system does not work the way that the AGW conjecture assumes that it does.
After more than 20 years of effort the IPCC has been able to refine the range of their guesses as to the climate sensitivity of CO2 one iota. The have not been able to measure it and a very plausible reason for that is there is nothing there to measure.
willhaas February 8, 2017 at 2:15 pm
The idea that CO2 causes warming is so oversold that most people feel they must at least pay homage to it. It does sound plausible because CO2 does have LWIR absorption bands however a good absorber is also a good radiator and at tropospheric pressures heat energy transfer by conduction and convection dominates over heat energy transfer by LWIR absorption band radiation. The claim is that greenhouse gases trap heat but that is really not so because they are LWIR radiators and radiate energy to space that the non-greenhouse gases do not radiate.
But then I kept asking myself is there any truth to the AGW conjecture at all. It has always been a part of my education that higher pressures in a planetary atmosphere goes hand in hand with higher temperatures. The lapse rate is really a measure of the insulating effects of the atmosphere. The higher the lapse rate the greater the insulation effect. CO2 is not a source of energy so to cause warming it can only do so by acting as a thermal insulator. I would expect that if CO2 really caused warming that there would have been a measurable increase in the dry lapse rate over the past 30 years but apparently that has not occurred. If CO2 were really this supper insulating gas then there would exist some practical applications of it but I do not know of any. The more I looked into AGW the more I realized that it is based on only a partial understanding of science and rather than being a theory is only a very flawed conjecture.
commieBob February 8, 2017 at 4:59 am
Quoted: "To make the warming effect of CO2 to appear significant, the AGW conjecture assumes that the H2O feedback is positive"
Presumably H2O heat absorption is, like CO2 heat absorption, logarithmic. Each gram of atmospheric moisture absorbs less heat than the previous gram. On the other hand, evaporating the water from the ocean into the atmosphere takes the same energy for each and every gram. The heat is given back when the moisture condenses back to water in the upper atmosphere where the heat radiates to space. It seems reasonable to postulate that increased humidity leads to greater heat loss and is, indeed, a negative feedback.
willhaas February 8, 2017 at 1:43 pm
According to some energy balance models, more heat energy is moved by H2O via the heat of vaporization from the surface of the Earth to where clouds form then by both conduction plus convection and LWIR absorption band radiation combined. The equivalent average altitude for the atmosphere radiating to space is 17K feet but because of low emissivity the actual radiation comes from much lower. We re talking about the level of cloud decks which are much higher emissivity radiators then clear air. Adding H2O to the air lowers the lapse rate which allows more heat energy to rise which constitutes a cooling effect. The cooling effects of H2O outweighs any so called greenhouse gas warming effect that it could possible have. Then there is the effect of clouds which not only reflect incoming solar radiation but also radiate to space not only during the day but at night as well. Increasing the Earth’s albedo is certainly a cooling effect.
willhaas February 8, 2017 at 1:29 pm
No it is true. There is evidence that warmer temperatures have caused more CO2 to enter the atmosphere. It is well known the warmer water cannot hold as much CO2 as cooler water so as volumes of water warm, the water releases more CO2 to the atmosphere. There are other sources of CO2 as well but no real evidence that the increase in CO2 adds to any warming. It is all conjecture. If greenhouse gases really caused warming then the real culprit would be H2O. CO2 levels in the atmosphere increase as volumes of water increase but H2O levels in the atmosphere increase as just the air and the surface of bodies of water including damp earth warm. But H2O is really a net coolant.
- CO2: Carbon dioxide.
- GHG: Greenhouse gas = a gas which absorbs and emits infrared radiation due to its electron bonding. E.g. Water, CO2, methane, N2O, ozone ... Absorption of IR energy promotes an electron to a higher energy band, and release of IR energy demotes an already promoted electron back. The wavelength of the IR is characteristic for a type of absorption for each molecule. Of all common GHG, water is by far the most prolific, having the most degrees of freedom by which its electrons can temporarily absorb extra energy.
- LWIR: Long wave infrared - the type of radiation associated with the GHG effect
- AGW: Anthropogenic global warming = man-made global warming.
- 33 degrees C: In theory, without the GHG effect, the temperature at earth's surface should average: -18ºC. It averages about +15ºC in practice. The difference is 33ºC. 33ºC is the extra warming due to the GHG effect.
- climate sensitivity of CO2: Expected temperature increase at the earth's surface due to doubling of the amount of CO2 in the atmosphere. E.g. climate sensitivity = 1, says the temperature at earth's surface should rise by 1ºC on doubling of CO2.
- Lapse rate: The lapse rate is the rate at which atmospheric temperature decreases with an increase in altitude.
- Troposphere: Is the lowest portion of Earth's atmosphere, and is also where all weather takes place.
- IPCC: Intergovernmental Panel on Climate Change - Established by the World Meteorological Organization (WMO) and United Nations Environment Programme (UNEP) to assess evidence for man-made global warming and promote action by governments to stop, or slow, such warming.
- Planck effect: .