Galactic cosmic rays, TSI, sunspots,and Earth surface air temperature

Abstract

Theannual mean Earth surface air temperature change is a key indicator of the climatechange. An empirical search explores the connection between the long-termsurface air temperature change (∆T), the ionization caused by the galacticcosmic rays (GCRs) in the upper atmosphere, the interplanetary magnetic field (IMF)intensity (B) at earth orbit, the total solar irradiance (TSI) and the sunspotnumbers (SSNs). Several scenarios are investigated with the world’s longest androbust GCR data string for the instrumentalera (1937-2013), covering 8 SSN cycles (17-24); the data are further extendedto 1900 to include three additional cycles (14-16). For ∆T comparisons, we usethree datasets, the U.S. surface air temperature (UST), the global surface airtemperature (GST), and the Land Ocean temperature (LOT). For 1900-1955 and1968-1987, we obtain an inverse correlation between GCR and GST. For 1956-1967,GCR intensity changes significantly (~18%) with little change in GST.  A positive correlation is obtained between GCRand GST for 1988-2008, implying that GCRs contribute to global warming. Theseresults lead us to infer that there is no sustained GCR- GST relationship i.e.changes in GCR flux does not affect GST. Recent results from the CLOUDexperiment are consistent with this inference. A comparison between the amplitude of the solar wind electricfield and GST leads to an inconclusive result aswell. We also note that TSI does not contribute to ∆T either. The historicevidence and the predicted trend for peak activity [Ahluwalia and Jackewicz,2012] for future cycles (25 and 26), suggests that earth may cool in the nextthree decades, in contrast to IPCC [2007] consensus that GST will rise 40 C ± 20 C in 2100.