http://www.nytimes.com/2008/03/18/science/18griz.html?_r=1&scp=6&sq=cascade&st=nyt#

http://www.nytimes.com/2008/04/20/magazine/20wwln-lede-t.html?em&ex=1208836800&en=d1c754441761d09a&ei=5087%0A

         These two NY Times articles focus on climate change from different perspectives but both relate to the concepts of a cascade as discussed in lecture.  Cascades of ecological change are occurring across the planet.  The example detailed in the first article is about how the grizzly bear and gopher populations in Yellowstone Park are experiencing a tremendous increase like never before.  This cascade in population was found by researchers to be due to the flourishing of the Canada thistle plant.  The plant is Mediterranean in origin and is supported by a warmer climate.  It has doubled its area since 1989, pushing other plants out, but providing ample food for grizzlies in the process.  The Canada thistle was also helped by a drought in the region beginning in 2000.  It was one of the few plants to thrive during this time because of its extensive root system.  The Canada thistle has created a self rewarding positive feedback loop for the new ecosystem being established in Yellowstone.  The gopher eats the thistle roots, stimulating their growth, and then the grizzly raids the gopher huts, consuming thistle and gophers.  Gopher population has tripled since 1980, showing no signs of being depleted by bears.  This situation can be analyzed as a cascade because a few small characteristics of the environment gave way to a climate change and ecosystem shift. 

            The second article presents the dilemma humans have regarding changing their lifestyles to reduce their carbon footprint.  This is a depiction of the absence of a global cascade in a positive direction, but the presence of some of the characteristics essential to cascades.  The article presents the view that there is uncertainty whether buying local food, walking to work, and the like will actually reduce CO₂ emissions.  It also mentions that there is a disparity of the seriousness of the problem throughout the world.  The potential for a cascade lies in the fact that there is such uncertainty of information.  If activists could form a convincing enough argument to win over all the skeptics on the matter, a cascade could follow even with false information.  The problem is that the switch is not enticing enough for humans who are acclimated to their current living situation.  The skeptics are winning out because people lack concrete and short term incentive to change their lifestyles.  The global disparity is part of this, the article giving the example of a person on the other half of the globe beginning to pollute more just as one here decreases his footprint. 

            A cascade towards climate change can only be started from natural initiatives as a result of the current environment.  The grizzlies in Yellowstone were happy to feed off of the Canada thistle because their main source of food, the white bark pine nut, had experienced consecutive poor growing years.  The Canada thistle was only able to start spreading in the first place due to global warming.  Until humans are forced to adapt to such small, yet meaningful, changes in the ecosystem we will not be able to create a cascade to stop global warming as it is not a significant threat to our immediate existence and evolution.