Glacier National Park in Montana (USA) has been removing its signs that said the glaciers would be gone by 2020. It's 2019 and there are still several glaciers there to see. Some reports now say there will be no glaciers by 2030 or thereafter. Within in the next 10 to 50 years is now the most cited number. Considering the signs were stating quite clearly that by 2020, the glaciers would be gone, there would seem to be problem with the entire ability of scientists to accurately predict the future. It's very possible there will be plenty of glaciers in 2030 and far into the future. There's really no way to know. This is a perfect example of over-certainty in science and why all scientific predictions based on statistics and modeling should be regarded as very possibly wrong. (Additional note: The prediction of 2030 was changed to 2020 in 2009 because things were happening faster than projected. There were double mistakes made in these projections.)
There are other glaciers in the Rocky Mountains that are larger than those in Glacier National Park and mountain areas where there are more glaciers. However, many require hiking in for miles to observe up close. Also, there is a commercial component to the glaciers in Glacier National Park, making them the focus of many melting glacier discussions.
So what is a glacier and should we be worried when they melt? A glacier is a mass of ice that moves under its own weight. Generally, that requires it be approximately 100 feet thick. Also, a glacier must cover at least 25 acres (for those who live in the city, this is 5 to 12 blocks, depending on the size of the block. Blocks are from between 2 and 5 acres per block.) It seems a rather small size, that 25 acres, for a glacier, but that is the definition. The small size may account for why many glaciers are not very permanent. Larger ones would be longer lasting.
There does not exist a complete listing of glaciers. Until satellites came into being, the only way to find a glacier was to physically go there. Needless to say, this was no small task. Glaciers outside the two poles tend to be in the high elevations where access is very difficult. Satellites made it possible to get a much clearer picture of the number of glacier out there. Satellite mapping of glaciers is not a perfected technology. Snow can be read as a glacier and you need evidence of movement of the snow/ice to distinguish between a glacier and not just snowpack. Still, it's better than having to reach all the glaciers in person. There are nearly 200,000 glaciers in the world currently--those that are mapped and known at this time.
Melting glaciers are of concern mostly because they are of value for fresh water. Many places depend on the glacier melt for water. So what happens when the glaciers are gone? One supposes the same thing that happened when people's other water supplies dried up. They either found new sources in the areas or migrated to a place where there was water. While we now seem to fear the "end of the water", this was actually very, very common throughout all of mankind's and the earth's history. The modern world has ways of moving water from one location to another via pipelines, water tankers, etc. Bottled water has been trucked into cities that lose their water supply temporarily due to natural disasters. There is also desalination. While it requires a fair amount of energy and is quite expensive, it can and does provide water to many locations. The Middle East and desert areas are the major uses, plus areas that have concentrations of humans high enough to exceed local water supplies and are close enough to the ocean.
Glaciers also have a commercial value for tourism. National Parks and mountain ranges worldwide have people come to see the glaciers and to study them. If the glaciers disappear, then the focus of the tourism would have to change.
Those who study global warming have tended to use the glaciers as a measure of the seriousness and rate of change due to human-caused warming. There appears to be little justification for this other than glaciers are visible and fascinating, which draws people to any narrative about changes in them and the possible loss of the glaciers.
Temperature is not the sole factor in the formation of glaciers. It does have to remain cold enough for the snow to remain pretty much year round in order to compact into ice and then a glacier, but there also has to be sufficient snow to build upon the foundation and cause the glacier to grow or at least maintain size. Especially dry, but cold years, result in the glacier not growing. Additionally, wind can melt a glacier even when there are cold temperatures. It's not uncommon to see water on top of ice on a cold winter day due to the wind. Abrasion can also cause melting, as can particles of dust and other materials on the surface. The dust causes the surface of the glacier to darken and thus warm more than it would without the dust, and can result in more rapid melting.
How serious is it that glaciers are melting? It depends on the concern. Economically, it may be of great concern. The need for easily obtained water may cause great concern. Do the glaciers indicate the rate of planetary warming? Considering how many times the dates for when all the glaciers will be gone has changed and changed, if they do, we have no clue as to what rate of warming correlates to how much glaciers melt.
Perhaps most interesting, is that as glaciers melt, artifacts from past civilizations and warmer climates with trees are found. A whole new field of study, glacial archeology, has developed. While there is often a reference to climate change making this possible, logically, the climate changed multiple times in the recent past or the artifacts would not be there. It was warm when the artifacts were laid down. This was before human beings started emitting CO2 at a high level. Thus, there is a contradiction in the theory of CO2 driving the melting of glaciers. There are many things that need to be understood, studied and worked out before any science about climate is even marginally close to settled.
Glaciers are fascinating natural phenomena. How they change, form and melt is worth studying to help us understand more of our world. It's far too soon to even pretend we understand and predict climate, weather or most anything based on a shrinking glacier.
This is an example of the the obsession with CO2 and human-caused warming crossing over to very nearly a religion. It brought to mind the worship of nature, including sacrifices to weather and sun gods. Glaciers melt. There is nothing magical or special in 2019 that changes this. A sign marking the first human-cased demise of a natural event is ridiculous. It's not rational to mourn the way nature works nor commemorate what amounts to a fictitious event.
This glacier is atop a volcano in Iceland. It has not grown since 2003. However, as noted in this posting, other things cause glaciers to stop growing or wither, other than increased temperature. If no snow falls, the glacier will begin to sublimate and shrink. It's a delicate balance and completely natural. When you see signs like this one in Iceland in the news, remember the twice wrong projections concerning Glacier National Park.