In class on Tuesday we spent most of the period discussing the evidence (the things we see happening) that shows the earth is warming.
The first piece of evidence we have are record global temperatures. NASA concluded 2009 to be the second warmest hear on record. With average global temperatures continuing to increase each year, scientists are starting to relate the temperature increase to global warming and pollutants that create it.
This picture shows the difference between a glacier before and after temperature rises--the glacier has melted significantly.
Glaciers are taking a major hit because of the earth’s global warming. According the the National Snow and Ice Data Center, there has been a global 0.74 degree celcius average temperature increase. This has decreased both the size and number of glaciers found. In Asia and South America especially, glacier water is a major life support for many people. The glacier water keeps streams cool, preserve wildlife, and provide water for cities. As glaciers continue to melt at an increasing rate, the sea level will eventually rise threatening coastal cities and shorelines in the future.
Polar ice is another indicator that the earth is warming.
-The Arctic (North Pole-which contains NO penguins) has perennial ice, which reoccurs each year, up to 10 feet thick. Though since 1970, there has been a 10% loss of this ice per decade. The Arctic also contains permafrost that if melted, can seriously damage the tundra and taiga, where it is most prevalent, in a few ways: forest damage, sinking roads and buildings, eroding riverbanks, and increased carbon dioxide and methane emissions. There are estimates of billions of tons of methane stored in permafrost around the world-almost double the amount in the atmosphere today. By releasing this methane, there would be a 10-25% increase in global warming.
Drunken Forests are an example of the effects of permafrost melting...the trees become weak in the soil and bend because they are unable to hold themselves up
-Antarctica ( South Pole), covers about 10% of all of earth’s landmass and is covered by many glaciers up to 8000 feet thick.
-Greenland ice is spread out between three islands. Greenland loses 20% more ice than it gains each year.
Next in class, we discussed the albedo effect and the positive feedback loop. The albedo effect is a measure of how strongly an object reflects light. Lighter materials such as ice, sand, and snow all have a higher albedo. The positive feedback loop, ironically, has a negative effect–it goes like this: rise in average temperatures, ice melts (glaciers, polar caps, arctic), loss of reflective ability as ice melts, water temperatures rise, more ice melts, etc. Between 2004 and 2005, ice masses shrunk by 14% because of the positive feedback loop.
Positive Feedback Loop for Oceans
Other pieces of evidence we have that shows the earth is become warming includes weather severity and biome changes.
-Droughts have become very prevalent in the past few years because of rising temperatures. Wild fires have become more sever in recent years as well.
-Coral bleaching in the ocean due to changing acidity of ocean water could impact a large percentage of underwater biodiversity.
-Temperature increases can effect animals and reduce biodiversity if animals are unaccustomed to the new higher temperatures.
*Again another positive feedback loop can be made for this: Warmer oceans->less carbon dioxide uptake, carbon dioxide increases, atmosphere becomes warmer, etc.
We finished class by mentioning a few consequences of earth’s global warming:
-A colder Europe
-Lower salinity in Arctic waters
-Smog increase-air quality worsens
-Spread of tropical diseases
-Changes in Biodiversity
(You can find more/see them all on the handout Mr. W gave out)
Any questions or comments, just post!