The term “greenhouse effect” describes a crucial property of certain atmospheric gases that can absorb long-wave radiation and re-radiate it, partially back to Earth’s surface. This process keeps the surface temperature approximately 30 °C warmer than it would be otherwise. The primary radiatively active (“greenhouse”) gases include water vapor, carbon dioxide, methane, and nitrogen monoxide. However, the actual mechanism differs from that of a physical greenhouse, which also prevents vertical mixing (convection), making the term “greenhouse effect” somewhat misleading.
According to the prevailing climate paradigm (or dogma), the warming observed since 1950 has been predominantly caused by an enhanced greenhouse effect, largely driven by anthropogenic emissions of key greenhouse gases except water vapor, which is mainly considered a feedback agent. This view is endorsed by the Intergovernmental Panel on Climate Change (IPCC), widely regarded as the primary authority on climate change attribution. Notably, these conclusions have been derived mainly from global circulation models.
If this hypothesis holds true, we would expect some decrease in outgoing long-wave radiation at the top of the atmosphere (until we see a noticeable temperature increase), provided other components of the radiation balance remain relatively stable.