|Glacier length variation|
It shows an unmistakable 30 year cycle followed by a 60 year cycle. Even a novice should be able to see that we are currently in the trough of another 60 year cycle.
Also note that the number of "stationary" glaciers (green bars) remains about the same.
|Griesgletscher, Ulrichen (VS) - 5.70 km (1973)|
||Blüemlisalpgletscher, Kandersteg (BE) - 2.70 km (1973)
The primary claim of AGW is that the world is warming because we are adding CO2 to the atmosphere. To support that, the warmists claim that glaciers are melting faster now (meaning since 1950) that at any time in the past. From these images, it should be obvious that the melting started before 1850 (regular data collection began in 1880) and that the rate of change is about the same now as it was then. The warmist "solve" this problem by moving their starting point to about 1900, when the rate of melting slowed for a few years. This allows them to claim unprecedented increased melting since 1950. However, when the entire record is considered, it is obvious that the warmist claims are unfounded and that the pause in glacial retreat appears to be part of a natural cycle.
The Cheillon Glacier shows 3 sections - all with about the same slope - which indicates to me that the rate of melting has not changed as the CO2 concentration increased. The 2 step discontinuities are interesting. In the Gries Glacier, the step discontinuity is around 1965, while the Cheillon Glacier has a discontinuity in 1973. (The links provide access to the actual data.) If "Global Warming" was responsible for these, then I would expect both discontinuities to be in the same year. Unfortunately, I do not have enough data to suggest why these occurred.
|Glacier de Cheillon, Hérémence (VS) - 3.70 km (1973)|
To be fair, there are a few glaciers that support the AGW claim that glaciers are melting faster now than before. However, sudden changes in slope, like the one below, usually have an explanation not related to external forcing .. otherwise, that feature would be seen in all the glaciers.
|Fieschergletscher, Fieschertal (VS) - 15.35 km (1973)|
|Oberer Grindelwaldgletscher, Grindelwald (BE) - 6.65 km (1973)|
|Glacier de Saleina, Orsières (VS) - 6.45 km (1973)|
||Glacier du Trient, Trient (VS) - 4.90 km (1973)
Several of the larger glaciers have become 1 to 3 km shorter over 150 years. On the one hand, that sounds like a lot. However, compare that to the pixel resolution of the infrared satellites that monitor the planet. For some of the CERES (Clouds and Earth's Radiant Energy System) instruments, a single pixel is about 40 km square.
Remember, the length of a glacier is determined by the amount of winter snow, the temperature of the air, the amount of rain (if any), the type and shape of the rocks beneath it, and perhaps a few other things. Also, length is not the only important measurement - thickness and width are also a part of the story. As a result, many papers focus on total mass balance. Others focus on "ablation" - the amount of material loss from the upper surface. Glaciology is a complicated field of study. It is fortunate that these scientists publish their data so that everyone can see what is actually happening (unlike some fields where only the "results" are publicly available).