Patterns in Populations

1 November 2007. Is the ocean carbon sink sinking? RealClimate website. --David. Excerpt: The past few weeks and years have seen a bushel of papers finding that the natural world, in particular perhaps the ocean, is getting fed up with absorbing our CO2... evidence that thehypothesized carbon cycle positive feedback has begun.
...If changing climate were to cause the natural world to slow down its carbon uptake, or even begin to release carbon, that would exacerbate the climate forcing from fossil fuels: a positive feedback.
The ocean has a tendency to take up more carbon as the CO2 concentration in the air rises, because of Henry's Law, which states that in equilibrium, more in the air means more dissolved in the water. Stratification of the waters in the ocean, due to warming at the surface for example, tends to oppose CO2 invasion, by slowing the rate of replenishing surface waters by deep waters which haven't taken up fossil fuel CO2 yet.
... Le Quere et al. [2007] ... find that the Southern Ocean has begun to release carbon since about 1990....
A decrease in ocean uptake is more clearly documented in the North Atlantic by Schuster and Watson [2007]. They show surface ocean CO2 measurements ... rose by about 15 microatmospheres
...The warming at the end of the last ice age was prompted by changes in Earth's orbit around the sun, but it was greatly amplified by the rising CO2 concentration in the atmosphere. The orbits pushed on ice sheets, which pushed on climate. The climate changes triggered a strong positive carbon cycle feedback which is, yes, still poorly understood.
Now industrial activity is pushing on atmospheric CO2 directly. The question is when and how strongly the carbon cycle will push back.

January 2007. Logarithms and Modelling page has problems in exponential growth as part of the Exercises in Math Readiness[http://math.usask.ca/mrc-cgi bin/emr/first_page.cgi]

January 2007. Exponential growth applet - interactive. See also "logistic growth" http://www.otherwise.com/population/logistic.html

17 May 2002. Exponential Growth and The Rule of 70... explains the concepts of exponential growth and doubling time - the time it would take a population to double if it were growing exponentially at a constant rate. Throughout human history, human population has generally grown in an exponential manner, and discussion of exponential doubling times has been appropriate....


 

Articles from 2002–present


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