By Paul Homewood
Images from Cold War spy satellites have revealed the dramatic extent of ice loss in the Himalayan glaciers.
Scientists compared photographs taken by a US reconnaissance programme with recent spacecraft observations and found that melting in the region has doubled over the last 40 years.
The study shows that since 2000, glaciers heights have been shrinking by an average of 0.5m per year.
The researchers say that climate change is the main cause.
"From this study, we really see the clearest picture yet of how Himalayan glaciers have changed," Joshua Maurer, from Columbia University’s Lamont-Doherty Earth Observatory in New York, told BBC News.
As usual the BBC fail to explain the wider picture.
Glaciers worldwide have been retreating since the mid 19thC, which marked the ending of the Little Ice Age. The Himalayas are no exception.
This is what the first IPCC Report had to say in 1990:
Note the comment about the period 1920 to 1960.
They add this chart:
In other words, glacier melt may in large part be due to natural phenomenon, rather than man-made.
The rate of recession since the 19thC has not always been constant, as the IPCC noted:
Wood (1988) found that from 1960 to 1980 the number of retreating glaciers decreased This may be related to the relatively cool period in the Northern Hemisphere over much of this time (Figure 7 10)
In other words, the fact that the rate of retreat seems to have speeded up in the Himalayas in recent years is of little significance, at least for such a short period of time.
Moreover recent studies have found that many glaciers in the Himalayas have actually started growing again in recent years:
Contrary to the UN’s report that the Himalayan glaciers would melt within a quarter of a century, a new study by researchers at the Universities of California and Potsdam has found out that the Himalayan glaciers are advancing rather than retreating.
Researchers studied 286 glaciers in six areas between the Hindu Kush on the Afghan-Pakistan border till Bhutan.
The report published in the journal Nature Geoscience found that the key factor affecting the advance or retreat of the Himalayan glaciers is the amount of debris— rocks and mud— strewn on their surface and not the general nature of climate change.
The report states that glaciers surrounded by high mountains and covered with more than two centimetres of debris are protected from melting.
Debris-covered glaciers are common in the rugged central Himalayas, but they are almost absent in subdued landscapes on the Tibetan Plateau, where retreat rates are higher.
In contrast, more than 50 percent of observed glaciers in the Karakoram range spanning the borders between Pakistan, India and China region in the north-western Himalayas are advancing or stable, states the report.
“Our study shows that there is no uniform response of Himalayan glaciers to climate change and highlights the importance of debris cover for understanding glacier retreat, an effect that has so far been neglected in predictions of future water availability or global sea level,” the authors wrote in the journal.
Contrary to popular belief, researchers have also discovered that half of the ice flows in the Himalayas are actually growing rather than shrinking.
The discovery adds a new twist to the row over whether global warming is causing the world’s highest mountain range to lose its ice cover.
The new study has found that half of the glaciers in the Karakoram range in the north-western Himalayas are in fact advancing and that global warming is not the deciding factor in whether a glacier survives or melts.
The real picture is much more complex than the BBC misleadingly portray.
via NOT A LOT OF PEOPLE KNOW THAT
June 30, 2019 at 12:33PM