What follows is a highly discomforting fact, and it’s not going to go away.
A small sensation goes unnoticed by the press: Solar activity indeed reached maximum value in late 20th century
By Dr. Sebastian Lüning and Fritz Vahrenholt
(German text translated/edited by P Gosselin)
Previously it was constantly claimed that solar activity couldn’t possibly have anything to do with the warming of the late 20th century because both curves fully diverged from each other. As proof, the following charts from Wikipedia were used:
Figure 1: Comparison of global temperature, CO2 and solar activity. From Wikipedia. Source: Leland McInnes at the English language Wikipedia [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons.
Solar activity is not made up merely by the shaky sunspots. The above figure is an update from 2014 and was provided by a user with a less than trustworthy name of “Kopiersperre”.
Figure 2: Fluctuations in solar climate drive on millennial, century and decadal scales. Top: The 20th century had the strongest solar activity in 11,000 years (here 7000 years are shown). Middle: The powerful drive of the Medieval Period and the scant amount of solar drive in the following centuries, followed by the extraordinary jump to the current level. Bottom chart: Only when using the short-term scale do we clearly see the 11-year cycle (Fröhlich 2000 aktual., Wagner and others 2007). Figure source: ZAMG.
Figure 3: Solar activity over the past 400 years. White curve; Total Solar Irradiance (TSI); Yellow curve shows sunspots. Figure source: PAGES.
The great changes in understanding solar activity were illustrated by Matthes & Funke at the end of 2015 at a conference contribution on page 9 (old curve SATIRE-TS in red):
Figure 4: The new and old curves for solar activity during the past 165 years. Source: page 9 in Matthes & Funke 2015.
But it gets even better
The sun not only reached its maximum at the end of the 20th century, but was apparently stronger than at any time over the past 10,000 years. Matthes et al. showed this in a very recent publication in the journal Geoscientific Model Development Discussions in 2016:
Figure 5: Source: Figure 20 in Matthes et al. 2016
By the way, the unusually powerful solar activity in the second half of the 20th century had been already reported on by Sami Solanki in Nature here more than 10 years ago. Afterwards he mysteriously retreated from the climate discussion. Is this perhaps the reason why solar scientists operate almost unnoticed below the media radar?
The unexpectedly strong sun casts especially discomforting questions that some would just prefer to dodge. Couldn’t the high solar activity have something to do with the 1980-2000 warming after all?
In any case, now no one can insist that the solar activity and temperature curves diverge and thus refute the relationship. The attribution has to be re-examined altogether. There is no alternative.