A study on Swiss Glaciers shows that the fastest melting was in the 1860s and 1870s, long before the first coal fired power. (See that steep decline from 1850-70 in Part a in the graph below.) In Part b see the glaciers have been going back and forward in cycles that somehow have no correlation with human emissions.
Climate models can’t predict any of these turning points, don’t understand any of these cycles, but “doom is coming”.
Pay up your money to make glaciers grow again.
In Part c (above) — glacier lengths correlate with temperatures. In part d the brown spikes are the Stratospheric Aerosol Optical Depth [SAOD] — meaning volcanic dust, black carbon, soot. These were bad years to head to the beach.
In terms of speed, note the lack of any spooky “unprecedented” retreat. The glaciers are shorter now, but the rate they are shortening is slower than in 1870.
Unlike CO2, volcanoes and solar activity do correlate with glacier length
See this longer graph — the red line estimate of summer temperature bottoms twice in 1600 and 1810 which also coincides with volcanic activity and solar minima.
It could get pretty expensive to control glacier length since we have to reduce the suns activity and probably set off some nukes in lieu of a handy volcano.Long glaciers coincide with the solar minima and with volcanic forcing:
A strong negative radiative forcing resulting from at least five large tropical eruptions between 1809 and 1835 (Sigl et al., 2015; Toohey and Sigl, 2017), in tandem with the Dalton solar minimum (Jungclaus et al., 2017; Usoskin, 2013) appeared to have forced the glaciers to strongly advance until the 1850s, in some cases probably far outside their range of typical long-term natural variability (Fig. 8). Similarly, later glacier advances (e.g. in the 1890s and 1910s) followed other major volcanic eruptions including Krakatau (1883) and Katmai (1912)
Analysis of ice cores delivers continuous data for the first time on industrial soot from 1740 to today.
In the first half of the 19th century, a series of large volcanic eruptions in the tropics led to a temporary global cooling of Earth’s climate. It was a natural process that caused Alpine glaciers to grow and subsequently recede again during the final phase of the so-called Little Ice Age.
This has now been proven by PSI researchers, on the basis of ice cores. Up to now, it was hypothesised that industrial soot in the second half of the 19th century had triggered the rapid melting of glaciers occurring at that time. The first-ever analysis of the amount of soot (also called black carbon) locked in the ice and thus historically archived now contradicts this assumption. The resulting continuous timeseries of soot concentrations will, in addition, help researchers in the future to improve climate model simulations by enabling them to use experimental data. The results were published today in the scientific journal The Cryosphere.
Images of Alpine glaciers from the 1850s compared to the present day are often used in order to visualise anthropogenic climate change. This is wrong, however, as researchers have now proven on the basis of data from ice cores. Scientists associated with Michael Sigl of PSI analysed atmospheric pollutants archived in the ice at different depths, with a focus on the amounts of industrial soot. Thus they created the first continuous data series for central Europe for the period from the 1740s to today on the amount of industrial soot in the atmosphere.
These data clearly show that industrial soot can hardly be responsible for the melting of the Alpine glaciers at the time, taking place mainly between 1850 and 1875. “By 1875, the glacier retreat under way then was already around 80 percent complete”, Sigl says. But it was not until 1875 that the amount of industrial soot in central Europe exceeded the levels of black carbon naturally present in the atmosphere. Sigl clarifies: “It’s only in the last 20 percent of that episode of glacier retreat in the 19th century that the soot could have had an influence.”
These data clearly show that industrial soot can hardly be responsible for the melting of the Alpine glaciers at the time, taking place mainly between 1850 and 1875.
By 1875, the glacier retreat under way then was already around 80 percent complete, Sigl says. But it was not until 1875 that the amount of industrial soot in central Europe exceeded the levels of black carbon naturally present in the atmosphere. Sigl clarifies:
It’s only in the last 20 percent of that episode of glacier retreat in the 19th century that the soot could have had an influence.
The first half of the 19th century bore the stamp of several large volcanic eruptions in the tropics; their emissions of sulphur particles led to a temporary global cooling. During this final phase of the so-called Little Ice Age, cooling culminated, which caused Alpine glaciers to strongly advance. Up to now it had been thought that their retreat starting in the 1860s could be traced back to the beginning of industrialisation. But the PSI results now clearly contradict this hypothesis: It’s simply a matter of a retreat to the glaciers’ previous undisturbed extent.
1850 is not suitable as a reference year for climate models
BC = Black Carbon.
rBC = refractory Black Carbon.
M. Sigl, N. J. Abram, J. Gabrieli, T. M. Jenk, D. Osmont, M. Schwikowski (2018) 19th century glacier retreat in the Alps preceded the emergence of industrial black carbon deposition on high-alpine glaciers, The Cryosphere, 16 October 2018 (online) DOI: 10.5194/tc-12-3311-2018.
PDF is freely available.