A Graphical Explanation of Climate Change

Abstract

Volcanic eruptions with an intensity of VEI4, or higher, affect Earth’s climate by injecting sulfurous compounds into the stratosphere, where they are quickly converted to the SO2 aerosol, H2SO4. These aerosols circulate around the globe, temporarily cooling the climate, with the maximum cooling generally occurring a year or more after the date of the eruption. These aerosols eventually settle out of the atmosphere, after about 18-30 months, and temperatures recover to pre-eruption levels, or a bit higher, as the descending aerosol droplets coalesce with others in the troposphere, causing some temporary cleansing of the atmosphere. Warming due to the less polluted air usually results in the formation of a volcanic-induced El Nino, if there have been no other eruptions in the interim. Global “Clean Air” activities since the late 1970’s focused strongly upon the reduction in industrial (anthropogenic) SO2 aerosol emissions, primarily because of acid-rain and health concerns. As a result, a plot of average anomalous global temperatures will reflect the increases and decreases caused by the changing amounts of SO2 in the atmosphere, from both “Clean Air” reductions in industrial emissions and volcanic eruptions. In examining such a plot, increases in average anomalous global temperatures were occasionally observed which appeared to be unrelated to either volcanic eruptions or to “Clean Air” activities. One such increase was noted for the year 1958, when the author graduated from college, and jobs were difficult to find because of the ongoing business recession (1957 Aug-1958 Sept.). It thus seemed possible that other recessions might also be responsible for the unexpected temperature increases, since industrial SO2 aerosol pollution of the atmosphere decreases during such times.