Global Warming In The Arctic

Overview of Global Warming:

Currently, the effects of global warming on the Arctic are no surprise to any one. As time goes by the Arctic slowly increases in temperature. Over the past hundred years there has been a 2-3 degree Celsius increase in the Arctic's temperature (1). Researchers and scientists have concluded that the Arctic will gradually increase in temperature, with rates increasing over time.  There are two prominent positive feedback cycles that are causing this steady increase to happen. One is a reduction in albedo from the loss of sea ice (7). This allows for increased heat absorption by the ground and sea water, thus increasing Arctic temperatures. The other feedback cycle is the release of carbon and methane from the ice and permafrost back into the atmosphere (7). This also increases the Arctic temperatures. A system exhibiting positive feedback, in response to a disturbance, acts to increase the magnitude of the disturbance. Positive feedback cycles lead to increasing instability within a system (13). Both of the previously discussed feedback cycles are started by the combustion of fossil fuels,which humans use for their energy needs. When burned, fossil fuels release carbon, normally stored in the earth, into the atmosphere as CO2 (9). As a greenhouse gas, CO2 traps the energy from the sun and prevents it from being reflected on the earth. The earth then begins to warm, which causes the snow and ice in the Arctic to begin melting (13). These processes are summarized in the diagrams below. (click on the diagrams to enlarge for better clarity).

Albedo Feedback Cycle
(Click On Figure To Enlarge)
Original Image

Albedo Positive Feedback Cycle:

Increasing temperatures in the Arctic, due to the green house effect, melt the sea ice and permafrost (9). With the loss of the snow covering the ground and ice covering the sea, a decreased albedo surface is created over the bare ground and sea waters. Albedo is the reflecting power of a surface (7). This increases heat absorption of the ground and of the dark waters. The result is a continued increase in Arctic temperatures, thus melting more ice and allowing the cycle to continue at increasing rates each year (13).

Carbon/Methane Feedback Cycle
(Click On Figure To Enlarge)
Original Image

                                                                           Carbon/Methane Positive Feedback Cycle:

As temperatures increase in the Arctic, the sea ice and permafrost melt. Stores of carbon dioxide and methane trapped within them are released. The amount of carbon stored in the ice and permafrost is at least 2 to 3 times the total amount of atmospheric carbon (9). The release of these two gases increases their concentrations in the atmosphere. This directly influences the green house effect. Methane has 100 times the heat storage of carbon dioxide (13). Increasing concentrations of these green house gases leads to increased heat absorption and ultimately to temperature increases in the Arctic. Thereby causing the cycle to begin again (13).





Change in Arctic Sea Ice Cover Over Time:

Below are two images that show the change in sea ice cover in the month of September between the years of 2002 and 2012. The purple line on both images shows where the sea ice had been expanding out to during the month of September between the years of 1980 and 2000. When comparing the two images, one will see larger and larger expanses of water are exposed after ice melt. These images show the drastic and profound changes that are taking place in this ecosystem due to increases in climate change.

               Sea Ice Extent in September 2002
http://www.arctic.noaa.gov/detect/ice-seaice.shtml

Sea Ice Extent in September 2012
http://www.arctic.noaa.gov/detect/ice-seaice.shtml

Global Warming Take Home Message:

Human reliance on fossil fuels is responsible for global warming. This in turn has generated at least two feedback cycles which have been previously described. Arctic temperatures will continue to increase as a result of these feedback cycles. Additionally, species in the Arctic will continue to lose more and more of their environments over time. Reducing global warming by means of decreasing fossil fuel emissions is only the tip of the iceberg in trying to stop the increase of global temperatures.