All charts used for this article are from a Günther Aigner released German video, with the title “Die Alpengletscher im Klimawandel: Status quo“ (The Alps glaciers in climate change: status quo). Sorry, they are in German.
The climate charts below are of the European upper Ostalpen where glaciers there have been receding over the recent decades.
The mean temperature chart of the region is the May to September period going back 133 years ( from the video):
Plotted below are data from the Austrian ZAMG and the Swiss MeteoSchwiez, 5-year smoothed (green line) and the linear trend (yellow circles diagonal straight line). There was a 30-year period of cooling since the early 1940s), warming mainly since the late 1970s, Similar to honest charts of global warming (the cooling trend from 1940 to 1975 is being "adjusted" away during the past 20 years -- doesn't fit the global warming narrative).
CO2 emissions rose since 1940, and summer temperatures high in the Ostalpen eventually rose too. One thing that could cause summertime temperatures to rise and glaciers to melt is sunshine. So Aigner plotted the number of sunshine hours for the May-September period for each year and produced the following chsrt (from the video):
The sun has shined considerably more over the recent decades than it used to in the 1970s, or late 19th century. Today the region gets about 200 hours more sunshine than 120 years ago! More sunshine means warmer. The plot of sunshine hours indeed looks similar to the plot of mean temperatures.
Aigner's video superimposed to two plots going back 50 years. Number of sunshine hours (yellow) compared to the mean temperature in degrees Celsius (red). Each curve is 10-year smoothed.
(from the video):
The region receives over 100 hours of sunshine more today on average than it did 40 years ago. So is it a surprise that the Alps have warmed and glaciers receded? Why the region is less cloudy today is currently unknown.
Climate alarmists merely assume the sun's incoming energy does not change. But the sun is dynamic system. Radiations, and electrical and magnetic fields vary over cyclic and quasi-cycle time scales. Our records about the sun are limited and only cover a short time period, Scientists do NOT have a complete picture of how the sun operates, and how the sun affects the Earth. From the few records that are available that the sun’s output has risen slowly since 1700 and peaked at some time around mid-late 1990.
NOTE:
Don Easterbrook’s book “The Solar Magnetic Cause of Climate Changes and Origin of the Ice Ages” looks at data over the past 800,000 years. His study looks at temperature, sunspot and cosmic ray activity. Cosmic ray penetration is generally constant, but penetration depends on sun radiation. The variation in cosmic ray penetration leads to more or less cloud formation (another way of saying more or less sunshine striking the earth surface.) Easterbrook clAIMS that warming, both large and small, are all explained by the variation in cloud cover. (The penetration level of cosmic rays is determined by the variance in beryllium-10 and radiocarbon.)
In 2019 the sun activity fell to record lows which should bring on cooling because there is higher penetration of cosmic rays which leads to more cloud cover. Sunspot activity usually involves cycles which are decades in duration. If the 800,000 year historical record is accurate then every warming or cooling during that period had to be, by definition, GLOBAL and that flies in the face of alarmist denials that claim warm and cool periods, such as the "Little Ice Age", were regional events, not global events.