At the heart of all climate models is an equation of the form:
Warming = CO2_Warming x feedbacks.
Forget feedbacks, now this paper shows the IPCC are vastly exaggerated the direct warming effect of CO2 - global temperature must be scaled back by up to 50%!
Or in the words of the paper:
The objective of this paper was to examine and to quantify the influence of GH-gases on our climate. Based on the HITRAN-2008 database [the IPCC’s value comes from an older version] detailed spectroscopic calculations on the absorptivities of water vapour and the gases carbon dioxide, methane and ozone in the atmosphere are presented. The line-by-line calculations for solar radiation from 0.1–8 mm (sw radiation) as well as for the terrestrial radiation from 3–100 mm (lw radiation) show, that due to the strong overlap of the CO2 and CH4 spectra with water vapour lines the influence of these gases significantly declines with increasing water vapour pressure, and that with increasing CO2-concentration well noticeable saturation effects are observed limiting substantially the impact of CO2 on global warming. The calculations were performed for three climate zones, the tropics,
… Simulations including an increased solar
activity over the last century give a CO2 initiated warming of 0.2 °C and a solar influence of 0.54 °C over this period, corresponding to a CO2 climate sensitivity of 0.6 °C (doubling of CO2) and a solar sensitivity of 0.5 °C (0.1 % increase of the solar constant).
This work is arguably the single most important work in this area, because on its own it shows that there is no case for policy action on climate as the combined effect of all known warming gases will be below the 2C limit below which even the most strident advocates of action like Stern agree that …
THERE IS NO NEED FOR ACTION.
To illustrate how this demolishes the case for action I will break one of my own rules and quote from DeSmugBlog:
Climate sensitivity describes how sensitive the global climate is to a change in the amount of energy reaching the Earth’s surface and lower atmosphere (a.k.a. a radiative forcing). For example, we know that if the amount of carbon dioxide (CO2) in the Earth’s atmosphere doubles from the pre-industrial level of 280 parts per million by volume (ppmv) to 560 ppmv, this will cause an energy imbalance by trapping more outgoing thermal radiation in the atmosphere, enough to directly warm the surface approximately 1.2°C. However, this doesn’t account for feedbacks, for example ice melting and making the planet less reflective, and the warmer atmosphere holding more water vapor (another greenhouse gas).
Climate sensitivity is the amount the planet will warm when accounting for the various feedbacks affecting the global climate. The relevant formula is:
dT = λ*dF
Where ‘dT’ is the change in the Earth’s average surface temperature, ‘λ’ is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C/[W m-2]), and ‘dF’ is the radiative forcing.
So, here we have the admission that if (using their nomenclature) λ reduces by 50% then it is unarguable that dT also reduces by 50%.
Prof Harde the expert’s expert.
To explain why I have so much confidence in this paper, I must explain the background of the author Professor Hermann Harde. Hermann is not a climate scientist (but has had to become one, and a good one at that), instead he is a physicist with specialising in real-life calculations of heat absorption of trace gases. In other words, if a court were looking for an expert to verify the calculations of the effect of CO2 & other trace gases on the radiative absorption and transmission of the atmosphere, he is the person they would turn to. Not Mann, not Hansen, not Jones et al, not all these mere amateurs who have no expertise in this area, but to the people like Hermann Harde who are experts in the area of trace gas and radiative absorption/transmission.
Moreover, unlike so much in “climate science” which is a mere numerical model where parameters are being adjusted to curve-match, the core of Herman Harde’s paper is almost the only empirical science in this whole subject.
So, when Harde says that the direct effect of CO2 warming has been vastly overstated by the IPCC, world governments must take note. Because this is what the IPCC term the “settled science” at the heart of their predictions. It is the empirical calculation of the expected warming of CO2 – one of the few values that can be calculated from real science.
Using older spectral data, those like Hansen convinced the IPCC that at the core of global warming is an empirically based 1.2C for a doubling of CO2 in the atmosphere.
That was wrong!
If so called “greenhouse gases” cannot have been reponsible for the late 20th century warming what was? To quote from the paper:
… this is even confirmed by paleo-climate investigations, indicating that EASy obviously stabilizes itself within temperature variations of about 6 – 7 ° C, and this still under the influence of even much stronger solar changes as well as under 10x larger CO2 concentrations, as they were found 500 Mio years ago.
If the warming over the eighties and nineties additionally might have been superimposed by some other thermal processes, e.g., an increased solar activity, Pacific Decadal Oscillations (PDO), the Southern Oscillation Index (SOI) or other GH-gases, the respective CO2 initiated contribution to the cloud changes further diminishes and in the same way the climate sensitivity.
Altogether, we see that the dominating positive feedbacks, originating from clouds, water vapour, lapse rate and albedo, are partially compensated by evaporation and convection. Particularly clouds have two stronger ambivalent effects on the energy balance, which to some degree neutralize each other. However, which of them can dominate under special conditions, is still largely unknown.
Up to now it is even not clear, if the ISCCP observations are really only a consequence of the increased temperature or at least to some degree are stimulated by a non-thermal solar activity over the observation period. In the latter case the strong thermal cloud feedback had to be cancelled with the effect, that at otherwise same conditions the climate sensitivity would drop to less than 0.5 °C.
An important criterion for any serious validation, which mechanism really might control the cloud cover changes, can be derived from model simulations, which additionally include any solar activity variations and compare these simulations directly with the observed global warming over the last century. Such kind of investigations have been performed by Ziskin and Shaviv, using an energy balance model with a diffusive deep ocean and additionally taking into account a non-thermal solar component. They show that obviously such solar induced component is necessarily to reproduce the 20th century global warming and that the total solar contribution is much larger than can be expected from variations of the total solar irradiance (TSI) alone. Altogether they attribute 40 % of global warming to the solar influence and 60 % to anthropogenic activities.
To verify the existence and size of a solar effect in the total energy budget we have performed quite similar analyses, which also include solar variations and orientate at the observed warming over the last century, but which are based on our two-layer model, including all discussed feedback processes and especially reproducing the ISCCP observations of cloud cover changes. Of course, any conclusions deduced from such comparison sensitively depend on the reliability of the measured cloud cover, the solar activity and temperature changes over this period.