CO₂ Back-Radiation Sensitivity Studies under Laboratory and Field Conditions

We measured the IR back radiation using a relatively low-cost experimental setup and a test chamber with increasing CO₂ concentrations starting with a pure N₂ atmosphere against a temperature-controlled black reference background. The results confirm estimations within this work and previous finding about CO₂-induced infrared radiation saturation within realistic atmospheric conditions. We used this setup also to study thermal forcing effects with stronger and rare greenhouse gases against a clear night sky. Our results and their interpretation are another indication for having a more critical approach in climate modelling and against monocausal interpretation of climate indices only caused by anthropogenic greenhouse gas emissions. Basic physics combined with measurements and data taken from the literature allow us to conclude that CO₂ induced infrared back-radiation must follow an asymptotic logarithmic-like behavior, which is also widely accepted in the climate-change community. The important question of climate sensitivity by doubling current CO₂ concentrations is estimated to be below 1？C. This value is important when the United Nations consider climate change as an existential threat and many governments intend rigorously to reduce net greenhouse gas emissions, led by an ambitious European Union inspired by IPCC assessments is targeting for more than 55% in 2030 and up to 100% in 2050 [1]. But probably they should also listen to experts [2] [3] who found that all these predictions have considerable flaws in basic models, data and impact scenarios.