Look closer - the graphs show the melting rates of two typical glaciers.
They have been slowly melting since, at least, the little ice age. In the 1930s the
melting rate increased dramatically. Most of the melting occurred in that period.
Slow melting resumed after the 1930s.
Claims of rapid glacier melting are 80- years out of date.
Most Glacier Melting was in the 1930s
Greenland ice sheet the summer average temperature has decreased at the rate of 2.2
◦C per decade
Since 1940, however, the Greenland coastal stations data have undergone predominantly
a cooling trend. At the summit of the Greenland ice sheet the summer average temperature
has decreased at the rate of 2.2 ◦C per decade since the beginning of the measurements
in 1987. This suggests that the Greenland ice sheet and coastal regions are not following
the current global warming trend. A considerable and rapid warming over all of coastal
Greenland occurred in the 1920s when the average annual surface air temperature rose
between 2 and 4 ◦C in less than ten years (at some stations the increase in winter
temperature was as high as 6 ◦C). This rapid warming, at a time when the change in
anthropogenic production of greenhouse gases was well below the current level, suggests
a high natural variability in the regional climate.
With the moraines mapped and the ecesis intervals determined, Cusick could now visit
each moraine, sample the oldest trees and determine the age of each moraine. Using
the moraine dates, Cusick could reconstruct the history of Exit Glacier and its dramatic
retreat up the valley.
The Little Ice Age (LIA) was a time of global cooling from approximately 1350 to
1870 AD. During this time glaciers expanded in the northern regions, moving down
the mountains and scouring the vegetation that had been in the valleys below. Park
Service personnel recently discovered evidence of a buried forest dating back to
at least 1170 AD high in the Forelands near the current glacier’s edge. Exit Glacier
advanced from the Harding Icefield during the Little Ice Age, burying this existing
forest and advancing to a maximum marked by the terminal moraine dated to 1815.
With the warming trend of the 1800s, Exit Glacier began to retreat from its 1815
maximum. Very slowly, the glacier retreated 230 feet (70 m) from 1815 to 1889, averaging
about 3.1 ft/year (1 m/yr) (see Table 1). The glacier then retreated much more rapidly
between 1889-1899, interspersed with periods of stagnation, which are marked by linear
moraines (1889, 1891, 1894 and 1899). During this time, the glacier retreated 1680
ft (512 m), about 168 ft/yr (51 m/yr).
The next fifteen years was a period of a slow but s teady retreat, as t he g lacier
retreated only 42 ft/yr (13 m/yr). In the years between 1914 and 1917, Exit Glacier
experienced its most rapid retreat. In just 3 years, the glacier retreated 908 ft
(277 m) or almost a foot per day. From 1917 to 1973, Exit Glacier continued to retreat
with periods of slow to moderate retreat. There were five periods of retreat, with
the ice melting fastest between 1961 and 1968 (115 ft/yr or 35 m/yr).
During the retreat of Exit Glacier from its Little Ice Age maximum in 1815 until
recent times, the glacier has left a series of more than 11 moraines and retreated
more than 1.25 miles (2 km). The glacier had an average retreat of roughly 6/10 of
a mile each century or one kilometer each century.
The headline of the September 8, 2015 Seattle Times states:
‘Disastrous’: Low snow, heat eat away at Northwest glaciers
“Glaciers across the North Cascades could lose 5 to 10 percent of their volume this
year, accelerating decades of steady decline. One scientist estimates the region’s
glaciers are smaller than they have been in at least 4,000 years.” “The best word
for it is disastrous,” said Pelto”
This was a multi-page story with numerous photographs and many predictions that glaciers
in the North Cascade Mts. will be gone in 50 years. Having just finished a major
analysis of Mt. Baker’s glaciers dating back thousands of years, I thought, what
kind of nonsense is this? So I put together some of the data on Mt. Baker glaciers
that will soon be published.
Photos and maps from a large collection dating back to 1909 document exactly what
Mt. Baker glaciers have done in the past. What these photos and maps clearly show
is the Mt. Baker glaciers reached their maximum extent of the past century in 1915
at the end of the 1880 to 1915 cold period. The glaciers then melted back strongly
during the 1915 to 1950 warm period. The climate then turned cool again, and Mt.
Baker glaciers advanced strongly for 30 years. In 1977, the climate turned warm again
and since about 1980, glaciers have been retreating again. However, photos and maps
prove that all Mt. Baker glaciers are more extensive today than they were in 1950.
Here are a few examples.
75% Of Total Modern Glacier Melt Occurred Before 1950
(IPCC says that man’s CO2 had little effect before 1950)
“The abrupt climatic transition of the early 20th century and the 25-year warm period
1925–1950 triggered the main retreat and volume loss of these glaciers since the
end of the ‘Little Ice Age’. Meanwhile, cooling during the 1960s, 1970s and 1980s
altered the trend, with advances of the glacier snouts. Stötter et al. (1999) indicate
that the coldest period after the LIA was from the early 1960s to the mid-1970s,
when temperatures fell to levels equivalent to the warmest recorded in the 19th century.
This cooling is the reason given by Caseldine (1983, 1985a, 1985b, 1988) to explain
the advance of the Gljúfurárjökull between the mid-1970s and the mid-1980s … Studies
of aerial photographs and satellite images show that the glacier snouts have retreated
by more than 1300 m on average since the LIA maximum (considered to be AD 1898 in
Gljúfurárjökull and AD 1868 in both Western and Eastern Tungnahryggsjökull), with
an altitudinal rise of more than 100 m. The retreat accelerated rapidly (15.3 m yr−1)
during the first half of the 20th century. In the second half of the 20th century,
the retreat decelerated considerably, reflected in the lowest values around 1985
(5.2 m yr−1) and a trend shift in 1994, with an advance observed in Gljúfurárjökull.
… The retreat rate intensified in the period 2000–2005 compared with 1994–2000, but
did not reach the rates recorded before 1946.” - See more at: http://notrickszone.com/2017/02/09/new-paper-glacier-melt-rates-were-up-to-3-times-greater-faster-during-early-20th-century/#sthash.GGGqBVLx.dpuf