As noted in Silver’s post above scientists have been studying all of this for a long time. They have all kinds of scientific equipment all over the world gathering data. Even NASA has satellites looking at the planet trying to detect changes. The idea that this warming or whatever you want to call it has happened before is just so incorrect it is hard to believe anyone subscribes to that theory. What is happening today is a direct result of the industrial revolution or whatever you want to call it. Here is but one example of the effects of soot from coal fired plants that is happening to ice all over the world. Way back when they know this did happen before as a result of things like dust and soot from volcanoes. So yes it happened before. But nothing even remotely like what is happening today. Coal soot and other fossil fuel pollutants are affecting everything on the planet and many different negative ways. With all the science that has been gathered over the past century it is hard to believe there are still people out there who do not know much about this. So here is a tiny bit more of it to try to help you understand.
This one is from NASA
Sensing Glacial Surfaces
http://earthobservatory.nasa.gov/Features/PaintedGlaciers/page3.php
One feature that Casey knew satellites could observe is fairly straightforward: the color and brightness of debris layers on glaciers. The color of the surface has important consequences. Just as dark-colored clothes will make you warmer on a sunny day because they absorb sunlight, dark-toned particulates—such as soot from industrial pollution and wildfires, or basaltic tephra from volcanoes—heat glacial surfaces. Dark debris causes snow and ice to melt faster because it absorbs sunlight more readily than lighter-colored materials like salt and silica-rich dust.
The reflectivity of a substance is known as its albedo. Bright surfaces have high albedos (close to 1), while dark surfaces have low albedos (close to 0). Pure snow generally has a visible albedo of .95, meaning it reflects more than 95 percent of the visible light that hits it. Desert sand reflects about 40 percent (albedo of 0.4), and pure soot reflects less than ten percent of incoming light (albedo 0.1)
Small amounts of soot can have a big impact on albedo. As far back as 1980, scientist Warren Wiscombe (then at the National Center for Atmospheric Research, today at NASA) showed that just a few parts per billion of soot could reduce the albedo of snow by up to 15 percent. Leading climatologists, including former NASA scientist James Hansen, have argued that sooty smoke and industrial pollution from South Asia is one of the main factors to cause Tibetan glaciers to recede so rapidly during the past decade.
The composition of the debris on glacial surfaces also matters. Salts, for instance, dissolve into melt water on a glacier. Mixtures of soot, dust, pollen, and pulverized rock also make pockmarked, circular cavities in ice called cryoconites. These holes—which can grow to be meters deep—often fill with melt water that supports thriving colonies of cyanobacteria, fungi, and other microbes. The spread of these communities can even affect albedo as they spread over ice surfaces.
Layers of soot from coal burning melted Alpine glaciers even in cooler climate of the 19th Century
http://www.independent.co.uk/environment/climate-change/layers-of-soot-from-coal-burning-melted-alpine-glaciers-even-in-cooler-climate-of-the-19th-century-8795396.html
Sooty air from coal burning triggered the initial melting of the mountain glaciers in the European Alps in the second half of the 19th Century when it caused the snow to turn grey and so reflect less sunlight back into space, scientists said.
The soot, known as black carbon, caused the glaciers to absorb more heat than usual, causing the ice to recede year by year even though the regional temperatures were colder than today, the researchers found.
Alpine glaciers have receded significantly over the past century but much of this melting is believed to have resulted from rising global temperatures caused by climate change. Scientists could not explain why glaciers started to melt as long ago as the 1860s, when Alpine temperatures were still low.
However, the initial melting appears to have been caused by deposits of black carbon building up on the pristine snow covering the glaciers as a result of industrial expansion around Europe in the late 19th Century fuelled by coal burning, said Thomas Painter of the University of Colorado at Boulder.
“Snow without soot is the brightest surface on the planet. When soot is deposited on snow, it absorbs sunlight and then conducts that energy to the surrounding snow. This is effectively an additional way for sunlight to warm and melt the snow,” Dr Painter said.
“The soot on the glacier ice has a relatively small impact because the glacier ice is already quite dark. Soot darkens snow, warms it and melts it earlier, exposes glaciers to sunlight earlier and so leads to faster glacier melting and retreat,” he said.
Records of glacial retreat in the central European Alps go back as far as the 1500s. This data shows that between 1860 and 1930, the large valley glaciers of the Alps retreated on average by nearly 0.6 miles, yet the local temperatures had continued to cool by nearly 1C during the same period of time.
This mismatch between the regional temperatures of the Alps and what was happening to the glaciers posed a problem for scientists, Dr Painter said. “Something was missing from the equation,” he said.
The study, published in the journal Proceedings of the National Academy of Sciences, looked at ice core samples from a series of glaciers and posited that the heat absorption caused by industrial soot landing on the snow.
Computer models showed that the effect of the black carbon could explain why glaciers started to melt at a time when temperatures were continuing to be low at the end of a cooler-than-average period in Europe known as the ‘little ice age’, which had lasted about 300 years.
“Where soot was deposited on snow cover, the computer modelling data suggest that the impact reached at times to the equivalent of a 4C increase in air temperature – markedly greater than current warming by the modern industrialisation increases in carbon dioxide,” Dr Painter said.
“However, where the soot fell on vegetation or rock, the impact was negligible. They were already very absorptive of sunlight in the visible wavelengths, so the soot did little to change their energy fluxes. In effect, the soot targeted the glaciers,” he said.
In recent decades, sooty deposits are less of a problem in western European countries because of clean-air legislation and the use of filtering technology that has cleaned up industrial emissions of black carbon.
“The region of focus of soot into snow is now Asia. Soot is increasing in India and China due to industrialisation – sloshing back and forth across the snows of the Himalaya. The measurements are so sparse there, but initial results suggest profound impacts from dust and soot,” Dr Painter said.
This one is from National Georgraphic
Soot and Dirt Is Melting Snow and Ice Around the World
New report highlights increased loss in Greenland ice cap from dust and soot.
http://news.nationalgeographic.com/news/2014/06/140610-connecting-dots-dust-soot-snow-ice-climate-change-dimick/
It's easy to imagine new snow so bright that we must avert our eyes even while wearing sunglasses. What scientists are discovering, though, is this brilliant whiteness of snow and ice is increasingly being dimmed by air pollution.
From Greenland's ice sheets to Himalayan glaciers and the snowpacks of western North America, layers of dust and soot are darkening the color of glaciers and snowpacks, causing them to absorb more solar heat and melt more quickly, and earlier in spring.
This trend toward darker snow from soot and dirt has been observed for years. Sources vary from dust blowing off deserts and snow-free Arctic land, to soot from power plants, forest fires, and wood-burning stoves. But now soot and dust are taking a greater toll, according to a report released this week, causing Greenland's ice sheets to darken—and melt—at a faster rate in spring than before 2009.
