New research claims to have found evidence of long term oscillations in solar activity which span around 9,500 years and affect the climate. Solar activity levels are declining as a result of this cyclical pattern which will have a cooling impact on the Earth’s climate this century, separate to the affects of human-driven climate change and volcanoes, according to the research which has been published in a paper in the journal Earth System Dynamics.
These long term cycles are evidenced in ice core and tree ring data and persisted throughout the last glacial cycle, according to the paper, entitled “Multi-millennial-scale solar activity and its influences on continental tropical climate: empirical evidence of recurrent cosmic and terrestrial patterns”.
The paper follows research reported this month to the UK Royal Astronomical Society’s National Astronomy Meeting in Llandudno, Wales, by physicists who predicted that solar activity will fall by 60 per cent during the 2030s to conditions last seen during the “mini ice age” that began in 1645.
It also follows a Nature Communications paper published in June which stated that solar activity was declining faster than at any time in the last 9,300 years and that there was a 15-20 per cent chance that the Sun will return to the extremely low levels of activity last seen during the time of the “mini ice age”.
For this new paper, author Jorge Sanchez-Sesma, from the Mexican Institute of Water Technology, analysed data going back 100,000 years and found evidence for long term oscillations in solar activity. Such variations in solar activity affect the amount of sunlight reaching the Earth, or total solar irradiance (TSI).
Sanchez-Sesma states that these solar oscillations could have potential climatic impacts since “information from reconstructions and models indicates a potential continental tropical temperature cooling of around 0.5oC for the rest of the 21st century”. This implies a larger global cooling effect than the 0.1oC cooling predicted in the Nature Communications paper based on research led by a UK Meteorological Office scientist. […]
Prediction
In particular, the research confirms a “Grand Minimum” for the period from 2050 to 2200 as forecast in 2013 by Friedhelm Steinhilber of the Swiss Federal Institute of Aquatic Science and Technology. This minimum will be characterised by a sustained deficit in solar warming of 0.5Wm-2, according to Sanchez-Sesma.
The author uses the historical association between solar activity and Congo River basin temperatures to predict that this upcoming decline will result in cooling: “our model provides an estimation of a cooling for the 21st century of about 0.5oC, followed by a slow warming trend with small oscillations during more than 4 centuries”, he writes.
This research builds on the discovery of millennia-scale oscillations of around 6,000 years in 2009 and 2,400 years in 2000. The research does not provide an explanation for the physical causes of these solar oscillations but solar physicists have proposed a number of possible mechanisms which include chaotic behaviour within the solar core, stochastic instabilities forcing the solar dynamo and also planetary gravitational forcing with recurrent multi-decadal, multicentennial and longer patterns.
Citation
Multi-millennial-scale solar activity and its influences on continental tropical climate: empirical evidence of recurrent cosmic and terrestrial patterns by J. Sánchez-Sesma published in Earth System Dynamics, doi:10.5194/esdd-6-1237-2015
Read the abstract and get the paper here.
See our stories: Physicists Predict Rapid Fall In Solar Activity here, Fastest Recorded Solar Decline Will Cool Global Climate here, Cosmic Rays Affect Global Temperatures Says Researchhere, Chinese Study Puts Sun In The Frame For Global Warming here, Astronomy Paper Implies Solar Role In Climate Change here and Sun Is At Its Weakest In Over 100 Years here.