Solar change and climate: an update in the light of the current exceptional solar minimum

Abstract

Solar outputs during the current solar minimum are setting record low values for the space age. Evidence is here reviewed that this is part of a decline in solar activity from a grand solar maximum and that the Sun has returned to a state that last prevailed in 1924.Recent research into what this means, and does not mean, for climate change is reviewed.

Solar Influence on Global and Regional Climates

“…Persistent reports, mainly in the media and on the Internet, that absorption lines are saturated (such that adding more GHG does not cause any radiative forcing change) ignore a huge body of research that extends back to the 1950s and are demonstrably false when one considers the whole IR spectrum (Shine et al 1995). Energy balance shows that, for steady state, the observed GMAST rise since the Maunder Minimum would correspond to a total forcing, including feedbacks (which include water vapour effects), of Df = 5.15 W m -2 (Lockwood 2010). The uncertainty on this estimate is of order ±0.5 W m -2 , dominated by the uncertainty in the pre-industrial temperature, with a small contribution from the uncertainty in the power stored in the deep oceans.…”

“…None of this makes any difference to the scientific reality, or otherwise, of mechanisms connecting solar variability and Earth's climate; however, it does make evaluation of the evidence much more difficult. Recent reviews have been presented by Reid (2000), Rind (2002), Haigh (2003Haigh ( , 2007, Beer (2006), Foukal et al (2006), de Jager (2008), Gray et al (2010) and Lockwood ( , 2010Lockwood ( , 2012.…”

“…As a result, changes in solar power output on decadal, centennial and millennial timescales are limited to small changes in effective surface temperature (associated with magnetic fields) and potential, although as yet undetected, solar radius variations (see reviews by Solanki et al 2005;Lockwood 2010). Larger percentage variations are seen in solar UV emissions ) which arise from the lower solar atmosphere (the chromosphere) (Loukitcheva et al 2009) and which influence the stratosphere in Earth's middle atmosphere between about 10 and 50 km (see review by Gray et al 2010).…”

The 22-Year Hale Cycle in Cosmic Ray Flux – Evidence for Direct Heliospheric Modulation

“…During the recent solar minimum, which was longer and deeper than others observed for over a century (Lockwood, 2010), galactic cosmic ray (GCR) flux has reached its highest values of the space-age (Mewaldt et al, 2010). The high GCR flux has implications for satellites, space craft and aviation (e.g., Hapgood (2010)) due to their high energies, making the ability to predict times of greater fluxes of cosmic rays critical for mission planning and reducing such hazards.…”

The global warming debate

“…It was predicted in the late 20th century that a cold period would occur in the 2020s or 2030s. Recently, there have been more indications that a cold period will occur in the next few decades, considering the long-term change in solar activity [21][22][23]. Indeed, temperature change in the 20th century was ruled not only by enhancement of the greenhouse effect; the cold period from the 1950s to 1970s is difficult to attribute to anthropogenic influence because the concentration of CO 2 in the atmosphere increased significantly after World War II.…”