AP Biology class blog for discussing current research in Biology

Tag: glaciers

Melting Glaciers & Rising Sea Levels

Because of ocean warming and melting of land ice, sea levels have risen all over the world. However, sea levels have not risen by the same amount everywhere. Along the coast of North Carolina, for example, the sea level has risen by about 18 inches (a foot and a half). Along Miami and New York City, the sea has risen by approximately 12 inches. And in Portland Maine, the sea has only risen by 6 inches. According to a study done by the Woods Hole Oceanographic Institution (WHOI), these variations can be attributed to a “post-glacial rebound.”

Image result for picture of the ocean“View of the ocean from Zamami Island, Okinawa, Japan. October 2015.”

In short, during the most recent Ice Age, Canada and parts of the Northeast United States were covered by colossal “sheets of ice.” The immense weight of the ice caused the land to sink. Areas on the periphery of these ice sheets, however, began to rise. Once the ice sheets began to melt approximately 26, 500 years ago, the “weighed-down” land gradually rose, whereas the peripheral lands started to sink. The ice sheets melted away about 7,000 years ago, but this “post-glacial rebound” is still taking place.

File:Icebergs.jpgIcebergs | St. Anthony, Newfoundland

The lead author of a study published in the journal Nature, Chris Piecuch, wanted to determine why sea levels rose at quicker rate in certain areas during the last century. He and his colleagues used advanced technology to take sea level measurements and combined “observational data with complex geophysical models — something that has not been done before — to give a more complete view of sea level changes since 1900.” The team ultimately determined that most of the sea level changes have been due to “post-glacial rebound,” and that “sea level trends increased steadily from Maine all the way down to Florida.” Pieuch attributes these changes to groundwater extraction, as well as to more recent melting of glaciers and ice sheets. These occurrences can cause masses of water around the Earth to move, and affect the planets crust. Although Piecuch is uncertain as to why water is redistributed to certain locations, he is pleased with his findings, stating: “Post-glacial rebound is definitely the most important process causing spatial differences in sea level rise on the U.S. East Coast over the last century. And since that process plays out over millennia, we’re confident projecting its influence centuries into the future.”


Climate Concerns and Rising Sea Levels: Antarctic Edition

    Photo Source

   Climate change has been a recent concern as it affects all aspects of human life. More evidence to climate change and the rise of sea levels was expressed in a very recent study conducted by IMAS PhD student: Alessandro Silvano. By doing so, he ultimately found that this process quickens the rate that ice melts and sea levels rise.

The study was conducted using ocean measurements off the coast of east Antartica. The study showed that glaciers are freshening the ocean, as the glaciers do not consist of salt. This dilutes the natural salt content of the ocean. He found that the melted water from the glaciers causes the ocean’s surface layer less salty and more buoyant, which prevented deep mixing during the winter months. Therefore it allowed warm water to retain its heat and melt glaciers from below. This process allowed the water to exist in layers, similar to when one attempts to mix oil and water. The study found a positive feedback mechanism, in which glacial melt water caused further melting of ice shelves, leading to an increase in sea level.

In some areas around Antartica, the study also found fresh meltwater decreased the formation and sinking of dense water. This results in decreasing the rate of ocean circulation, which stores heat and carbon dioxide. Because the cold glacial melt waters cause a slowing of the currents, which then decrease the ocean’s ability to decrease carbon dioxide and heat from the atmosphere. These two processes feed off of each other and induce and speed up climate change.

I enjoyed reading this article because I am personally passionate about decreasing the rate of climate change and educating myself on global warming. Backing global climate change due to its concerning effect – only one of which is sea level – with scientific evidence is important for gaining support of our communities.

Secondary Source Article: The Washington Post: One of the most worrisome predictions about climate change may be coming true

Global Warming can alter the shape of the planet

Climate change is an element in our world which has been around for many years. It has been believed to cause warmer oceans and erratic weather, but a new study, according to scientists, declares it also has the potential to alter the shape of the planet we live in. Global Warming is a gradual increase in the overall temperature of the earth’s atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, chlorofluorocarbons, and other pollutants. (read more about Global Warming) Michele Koppes,  assistant professor in the Department of Geography at the University of British Columbia, conducted a five year study in which she compared glaciers in Patagonia and in the Antarctic Peninsula. Koppes and her team discovered that glaciers in warmer Patagonia moved faster and caused more erosion than those in Antarctica, as warmer temperatures and melting ice helped lubricate the bed of the glaciers.

global warming

 Glaciers erode 100 to 1,000 times faster in Patagonia than they do in Antarctica.   “Antarctica is warming up, and as it moves to temperatures above 0 degrees Celsius, the glaciers are all going to start moving faster,” states Koppes. These ice sheets are apparently beginning  to move faster and should become more erosive. As a result, this will dig deeper valleys and shed more sediment into the oceans. The outcomes of this erosion add to the already complex effects of climate change in the polar regions.  “The polar continental margins in particular are hotspots of biodiversity, If you’re pumping out that much more sediment into the water, you’re changing the aquatic habitat,” Koppes states.  The Canadian Arctic, one of the most rapidly warming regions of the world, will most definitely feel these effects. These glaciers are on the verge of a major shift. The Canadian Arctic is becoming warmer in temperature more than four degrees Celsius spanning over the last 50 years. These glaciers will be flowing up to 100 times faster if the climate continues to shift and shifts above zero degrees Celsius. The findings by Koppes settle a scientific debate about when glaciers have the greatest impact on shaping landscapes and creating relief, suggesting that they do the most erosive work near the end of each cycle of glaciation, rather than at the peak of ice cover. If global warming continues to occur, change in formation of landscape due to higher water levels from melting glaciers is a strong possibility and may already be taking place. This will significantly affect all forms of life on earth.


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