Analyzing Sea Ice Extent For Evidence Of Climate Change A. Sea ice extent data for March and September in the Arctic and for September and February in the Antarctic. B. How maximum and minimum sea ice extents in the Arctic have changed since 1979. C. How maximum and minimum sea ice extents in the Antarctic have changed since 1979. D. Write a short summary describing how sea ice extent in the Arctic and the Antarctic has changed since 1979. ● In Arctic September, it is clear that the sea ice extent is declining. In 1979, the line of best ﬁt is around the 7.5 million km^2 mark. By the time it reaches 2011, it is down to almost 5 million km^2. This shows us that sea ice extent in Arctic September has declined by almost 2.5 million km^2. This is close to tying all-time record lows for Arctic sea ice extent in September. ● The Arctic in March is also seeing a decline in its sea ice extent. The line of best ﬁt starts around the 16 million km^2 mark and by the time it reaches 2011, it is just below the 15 million km^2 mark. Based on this, we can conclude that the Arctic in March has seen a sea ice extent decline of almost 1 million km^2. ● Meanwhile in the Antarctic, sea ice extents have been rising. In Antarctic March, sea ice extents have risen by almost .5 million km^2, as we can see that the line of best ﬁt is going in an upward direction. ● In Antarctic September, sea ice extent has risen by about .5 million km^2 as well. If we look closely at the line of best ﬁt, we can see that in 1979 it is around 18.5, and by 2011 it has risen to about 19. ● In conclusion, sea ice extents in the Arctic have been declining rapidly since 1979, while in the Antarctic, sea ice extents have seen a gradual increase since 1979. E. Do the results of this activity support the idea that Earth has been warming up over the past few decades? ● Yes, the results of this activity do support the idea that the Earth has been warming up over the past few decades. By examining the data, we can see that the Arctic has seen a rapid decline in its sea ice extent. And although sea ice extents have not been declining in the Antarctic, they have not been drastically increasing either. ● In addition, sea ice in the Antarctic does not melt as easily as the sea ice in the Arctic because Antarctica is at a higher elevation and 98% of the continent is covered in ice at least one mile in thickness. Since the Arctic is really just frozen ocean, it will experience more drastic temperature changes as the oceans warm. F. If you were skeptical about climate change, how might you use this data to support your position that we cannot be sure that long-range warming of the Earth is taking place? ● If you were skeptical about climate change, you might use this data to support your position by looking at the sea ice extents in the Antarctic. You can argue that if climate change was really real, then sea ice extents in the Antarctic would be declining like the sea ice extents in the Arctic, rather than increasing. ● You can also argue that the earth’s climate has always changed and may just be going through a warming period and we are in the middle of it, which would explain the warming of the Arctic and why the Antarctic has not seen the same changes in sea ice extent that the Arctic has seen. The controversy of Antarctica’s sea ice is a major reason why some believe that climate change is a hoax, and the data collected from this assignment supports that reason. G. In this activity, you worked with maps made from satellite photographs. What other data would you want to know to further support or test your conclusions? ● To further support/test my conclusions, ice core samples would be valuable pieces of data because scientists can use the ice core data to track CO2 levels in the ice from as far back as 800,00 years. ● If the ice core data shows an increase in CO2 levels over the past 31 years, then it would further prove that sea ice is melting due to the increased levels of CO2 in the atmosphere, causing climate change. H. How might the continued reduction of the polar ice cap inﬂuence transportation and shipping? ● The continued reduction of the polar ice cap will inﬂuence transportation and shipping because it will open up new transportation routes that were once thought to be impossible, including one directly over the North Pole. ● The changing conditions of the sea ice in the Arctic offer an opening to companies that deal with shipping by boat. The Arctic is most likely a faster, more direct route between Asia and ports in Europe and eastern North America. ● As of today, there are only little amounts of cargo shipped through the Arctic region. Although shipping in the region is expected to increase over the next few years, total Arctic cargo tonnage is expected to remain only a small fraction compared to the total amount carried along through other canals. I. What is the average thickness of the sea ice in Canada’s Arctic? What has been happening to the thickness of the Arctic sea ice? ● The average thickness of sea ice in the Arctic is around 2 to 3 meters thick. However, due to climate change, the thickness of the Arctic sea ice has been shrinking. ● Since the Arctic is really just frozen ocean, the amount of time that it has to warm up and cool down is crucial. Recently, sea ice in the Arctic Ocean has been melting faster than it re-freezes. In addition, temperatures across the Arctic have been extraordinarily warm for midwinter. ● Because of this, sea ice in Canada’s Arctic has not had enough time to reach the thickness that it is capable of reaching. Warmer temperatures are giving sea ice less time to thicken, which in turn is reducing the overall year-round average thickness. J. How does ice in the Arctic and Antarctic help keep Earth cool? ● Ice in the Arctic and Antarctic is very important in regulating global temperature. ● The colour of Arctic and Antarctic sea ice is white, giving it a very bright surface. Because of this, 50-70 percent of incoming energy from the sun is reﬂected back into space. Because the sun’s energy is “bouncing back” and is not being absorbed by the ocean, temperatures near the Arctic and Antarctic regions remain cool relative to the equator. Since what happens in the polar regions affects global temperatures and ocean currents, this helps to keep the earth cool. ● During the summer months, however, the sea ice melts, exposing the dark ocean surface. Instead of reﬂecting the energy from the sun, the ocean now absorbs 90 percent of it. When the ocean warms, global temperatures increase because fewer bright surfaces are available to reﬂect sunlight back into the atmosphere.