Own Climate Studies

An increasing number of humans get mad of the daily repeated horror scenarios about the influence of fossil fuel emissions on our climate. These scenarios are primarily based on computer models with irrational predictions, which are strongly diverging from observations. Thus, people feel they are manipulated, and although they are no climate experts they have their common sense. I’m also no climate scientist, but for more than half a century I was doing basic science, and I was involved in studies of long and short wavelength electromagnetic propagation through the atmosphere as well as doing experiments with greenhouse gases, see: Laser Research i) and Laser Research j). This qualification together with fundamental doubts about the size of the GHE, the widely scattering data for global warming and the announced sea level rise was motivation enough to critically scrutinize two central claims of the IPCC: • Almost only greenhouse gases - in particular CO 2 - are responsible for global warming, and • only fossil fuel emissions and land use change are responsible for an increasing CO 2 concen- tration in the atmosphere. My own climate studies started after retiring. They are not funded by any industrial or govern- mental partners. Only some resources of the university like the library or lecture rooms for seminars were used.

a) Greenhouse Effect

The existence or non-existence of the so-called atmospheric greenhouse effect continu- ously dominates the extremely emotional discussion about the human impact on global warming. Most scientists agree with the fundamental greenhouse theory, but like their opponents they are missing a reliable experimental verification of this effect. Measure- ments at the open atmosphere are too strongly affected by perturbations to quantify the relatively small contribution of greenhouse gases to local heating of the air or the Earth's surface. Therefore, Michael Schnell has developed an advanced set-up in his private labo- ratory, which allows to largely eliminate convection or heat conduction and to reproducib- ly study the direct influence of greenhouse gases under similar conditions as in the lower troposphere. With this equipment the additional warming of a pre-heated plate due to back-radiation of the greenhouse gases carbon dioxide, methane and nitrous oxide can be measured as a function of the gas concentration. These measurements are well con- firmed by radiation transfer calculations, from which we derive the radiative forcing of these gases. Our studies underline that there exists no climate emergency.

b) Climate Sensitivity

The IPCC declares that the observed warming with the start of the Industrial Era at the end of the Little Ice Age is predominantly caused by human emissions of CO 2 . To examine this statement extensive line-by-line calculations of the GHG water vapor (WV), carbon dioxide (CO 2 ), methane (CH 4 ) and ozone (O 3 ) were performed. The absorption and re-radi- ation of these gases together with sensible and latent heat fluxes is considered in a radi- ation and energy budget of the Earth-Atmosphere System (EASy). From this is derived the temperature response of EASy to a hypothetically assumed doubling of CO 2 in the atmo- sphere under steady state conditions. This temperature increase is known as the Equili- brium Climate Sensitivity (ECS) and represents an important measure for the influence of CO 2 on our climate. Own calculations show an almost 5x smaller ECS than published by the IPCC.

c) Methane Sensitivity

The global warming potential and the radiative efficiency of methane (CH 4 ) are classified to be at least 25x larger than CO 2 . From these figures IPCC infers an even more dramatic impact of CH 4 on the climate than CO 2 . Only due to the 200x lower concentration in the atmosphere the overall influence of CH 4 on global warming is assumed to be lower than that of CO 2 . However, when comparing both gases at identical concentrations, e.g., at 400 ppm, we find that instead of an increased warming potential and radiative efficiency CH 4 is about half as sensitive as carbon dioxide, this as a result of saturation effects and inter- ference with water vapor lines. Therefore, for a reliable comparison the same calculations have to be performed for me- thane as for carbon dioxide to determine an Equilibrium Methane Sensitivity (EMS) as temperature increase at doubled CH 4 concentration.

d) Carbon Cycle

The IPCC assumes that the inclining atmospheric CO 2 concentration over recent years was almost exclusively determined by anthropogenic emissions, and this increase is made re- sponsible for the rising temperature over the Industrial Era. When critically scrutinizing the carbon cycle one finds that the IPCC completely neglects temperature dependent natural emission and absorption processes over the last 270 years. Own studies show that anthropogenic emissions only contribute less than 5% to the actual atmospheric CO 2 concentration, which is only 17 ppm or 15% of the 113 ppm increase over the Industrial Era.

e) Solar Influence

IPCC classifies the human influence on our climate as extremely likely to be the main reason of global warming over the last decades. Particularly anthropogenic emissions of carbon dioxide are made responsible for the observed temperature changes, while any natural forcings are almost completely excluded. However, detailed own calculations with an advanced energy-radiation-balance model indicate that the temperature increase and its variations over the last 140 years can much better be explained by additionally including solar radiative forcing and its amplification by induced cloud cover changes. We present simulations based on different time series of the total solar irradiance and compare them with composed land-ocean-surface temperature measurements of the Northern Hemisphere. From these simulations we follow that CO 2 should not have contributed more than about one third to global warming over the last century, while solar variations over this period can well explain two thirds of the increase.

Physics & Climate