Galactic cosmic rays, total solar irradiance, sunspots, Earth surface air temperature: Correlations

Abstract

The variation in the annual mean Earth surface air temperature is a key indicator of the climate change. An empirical search explores the connection among the long-term surface air temperature change (∆T), the ionization caused by the galactic cosmic rays (GCRs) in the upper atmosphere, the interplanetary magnetic field (IMF) intensity (B) at the Earth orbit, the total solar irradiance (TSI) and the sunspot numbers (SSNs). Several scenarios are investigated with the world’s longest and robust GCR data string for the instrumental era (1937-2013) covering eight SSN cycles (17-24). The data are further extended to 1900 to include three additional cycles (14-16). For ∆T comparisons, three datasets used are: the US surface air temperature (UST), the global surface air temperature (GST), and the land ocean temperature (LOT). For 1900-1955 and 1968-1987, an inverse correlation between GCR and GST is obtained. For 1956-1967, GCR intensity changes significantly (~18%) with little change in GST. A positive correlation is obtained between GCR and GST for 1988-2008, implying that GCRs contribute to global warming. These results lead to infer that there is no sustained GCR - GST relationship, i.e. changes in GCR flux does not affect GST. Recent results from the CLOUD experiment are consistent with this inference. A comparison between the amplitude of the solar wind electric field and GST leads to an inconclusive result as well. It is also noted that TSI does not contribute to ∆T either. The historic evidence and the predicted trend for peak activity [Ahluwalia H S & Jackiewicz J, Sunspot cycle 23 descent to an unusual minimum and forecasts for cycle 24 activity, Adv Space Res (UK), 50 (2012) pp 662-668, doi:10.1016/j.asr.2011.04.023, 2012] for future cycles (25 and 26) suggests that Earth may cool in the next three decades, in contrast to IPCC [IPCC, Climate change 2007: The physical basis, Eds: S Solomon <i>et al</i>. (Cambridge Press, New York), 2007] consensus that GST will rise 4°C <span style="font-family:Symbol;mso-ascii-font-family: " times="" new="" roman";mso-hansi-font-family:"times="" roman";mso-char-type:symbol;="" mso-symbol-font-family:symbol"="" lang="EN-GB">± 2°C in the year 2100.

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