The American Geophysical Union blog from February 18 discusses the “real surprise” behind the 3rd hottest January on record, which occurred last month. One of the things I thought was really interesting about the article was a graph which showed the trend lines for all of the different radiative forcings that are acting on the atmosphere, including solar radiation, volcanic aerosols (which show up as stratospheric aerosols in the graph–you can see Krakatoa back in 1883 through Pinatubo in 1992) and changes in snow and ice albedo (reflectivity).
When you look at all of the forcings together and understand how the physics behind radiation balance works, it is very clear that the recent warming has to be coming from greenhouse gases and not changes in solar radiation or the recent El Niñ0. As the author, Dan Satterfield, says: “It’s not El Niño, and it’s not some unknown cycle. It’s us.”
