Glacial Melting (Week 7) - Post 2

Glacial Melting due to Climate Change 

          In recent years the world's glaciers have seen unprecedented levels of melting due only to global warming effects. One of the largest opposing arguments to global warming is it's effects are actually just natural variability. However, through the study of ice scientists have found undeniable proof that the warming in the last hundred and fifty years is in fact due to human caused global warming. One of the main sources of information about historical climate is ice cores. Scientists will drill small holes down hundreds of feet into glaciers and extract what is called ice cores. Ice cores keep record of previous climate similar to the way tree rings keep record of a tree. Each year a new layer of snow is added on top of the ice caps, and that year's snow is there forever. In addition to snow, sometimes when the ices freezes it traps air bubbles. By looking at the chemistry of the frozen snow layers scientists can learn about past temperature. And by looking at trapped air bubbles scientists can actually measure ancient carbon dioxide levels. Through ice cores scientists have found that carbon dioxide and temperature vary together. Over the past eight hundred thousand years carbon dioxide has never been higher than two hundred and eighty parts per million, until the industrial revolution. Since humans started adding carbon dioxide to the atmosphere carbon dioxide levels have reached three hundred and ninety parts per million, and are fast approaching five hundred parts per million. This is a forty percent increase, beyond natural variability, in carbon dioxide atmospheric concentration. Humans are changing the basic chemistry of the air. And by changing the air, temperature is changed. Since the eighteen hundreds humans have increased the global temperature by about one degree Celsius, this has caused glaciers to melt at incredible rates. As temperature warms glaciers begin to melt, and it creates a melt zone. Up and down the an ice sheet it begins calving. Calving is when huge pieces of an ice sheet break off into the ocean. Recently a Greenland glacier lost a section of ice the size and height of lower Manhattan in a calving event. However, glaciers are not just receding due to calving caused by melting, they are also thinning. In addition to melt zones along the edge of the ice sheets, their is also melt zones in the middle regions of the ice sheet. Cryoconite is a substance  made from a mixture of natural dust that blows in from the deserts of central Asia, and little flakes of carbon, or fine particles of soot that blow in from car exhaust, coal power plants, and wild fires. Cryoconite is a dark substance that builds up on the surface of glaciers and attracts heat, which creates melted holes in a glacier, giving the surface of a glacier the appearance of swiss cheese. There will literally be millions of holes in the surface of a glacier. All of this melt water collected in these millions of holes will melt down through bigger and bigger channels into what scientists call moulin caverns. Moulin caverns are huge holes that run down through the center to the base of the glacier, and then out under the glacier to sea. Everyday massive amounts of melt water flows down through the moulin caverns out to sea effectively undercutting the healthy ice and as a result thinning out the ice sheet. Ordinarily in the summer climate gets a little warmer and the glacier shrinks a little bit, and in the winter climate gets a little colder and the glacier grows a little bit; and those two things make a balance. But, if the climate gets too warm it creates an amplifying feedback loop and the ice continues to recede and thin. If that ice gets too thin, the ice does not melt just a little bit, it melts alot. There is a tipping point with glaciers, and if it's crossed the climate no longer matters, the melting just keeps going. An example of this is the Iluissat Glacier in Greenland, it is one of the largest glaciers in the Northern Hemisphere. It is rumored that it was this glacier's ice berg that sank the Titanic. In the last one hundred years this glacier receded eight miles, and in ten years it receded nine miles. So In the last ten years this glacier has receded and thinned more than it had in the previous one hundred. Another dying glacier is the Colombia Glacier in Alaska, it receded two and a half miles in the last three years. It is such an unhealthy glacier that it is actually receding through the winter. There was a study done between 1958 and 2008 on the Yukon Territory Glaciers. In that study scientists found that of the glaciers, four got bigger, over three hundred disappeared completely, and all of the rest, over one thousand, got smaller. Yes, there is and always will be a component of natural variability to glacial melting and further climate change, but it is not enough to explain everything that is happening. These changes that are happening are real, they are visible, and they are measurable. As environmental photographer and founder of the Extreme Ice Survey James Balog has said "The great irony and tragedy of our time is that a lot of the general public thinks science is still arguing about that [Climate Change]. Science is not arguing about that." 

          The climate is getting warmer due to human actions, and the effects are all around. The glaciers are melting, there is tangible, visible, measurable evidence of that. But, glaciers melting is not just it's own thing, everything in the ecosystem is connected, when the glaciers melt the sea levels rise. In the next one hundred years the sea levels will rise between three and eight feet. That does not sound like a lot living in Iowa of the Rocky mountains, but it is to those living in Florida or the Hawaiian Islands. It matters to the one hundred and fifty million people that live at sea level. It matters because sea level rise intensifies the impact of hurricanes and typhoons. Higher sea levels means more high water along the coast lines, which means when those big storms come, they push that much more water that much further inland. Beyond ice, warmer temperatures also intensifies natural disasters. In the past thirty years there's been an increase in forest fire disasters. There has been increase in the length of the fire season, the size of the fires, and the heat. Fires have been hotter, more extreme. Pretty much every natural disaster whether climatological, hydrological, or meteorological, has seen a steady increase in number and severity in the last thirty years. Climate change is real and it is all around, it is up to humans to see that and to make a change before it is too late.