Reply To: DREAD Weapon System: Devastating, Jam proof, silent

[vansig]

Brian H wrote:
The sea ice and acidification and methane scares are all hooey.
[…]
–The slight predicted reduction in the alkaline balance of the oceans (not “acidification”!) is a small fraction of the range experienced by ocean organisms throughout paleohistory, while they were evolving – including many types of coral.
[…]
–Finally, MUCH warmer periods in history have been boom times for humanity, with expansion of population, culture, wealth, and nutrition. Vice versa for cooling periods. So — pray for warming!

Well, recent trends in both northern and southern sea ice can be found at
http://nsidc.org/data/seaice_index/images/n_plot_hires.png
http://nsidc.org/data/seaice_index/images/s_plot_hires.png

These are consistent with the ~21,600-year Milankovitch cycle, which alternates longer-or-shorter winters versus summers for northern and southern hemispheres…
http://en.wikipedia.org/wiki/File:Precession_and_seasons.jpg

Re ocean acidification: calcium carbonate is the main buffer of pH in the ocean. I found a chart of
calcium carbonate solubility as a function of CO2 partial pressure, at
http://en.wikipedia.org/wiki/Calcium_carbonate#Solubility

P(CO2) atm pH solubility [Ca2+] (mol/L)
3.5 × 10^-4 8.27 4.70×10^-4
10^-3 7.96 6.62×10^-4

If i’m reading that right, then at 1000ppm CO2 in atmosphere, ~40% more CaCO3 will dissolve, which (some insist), drives shellfish and corals into crisis and degrades the ocean’s CO2 absorption capability. Decreasing the pH from 8 to 7 increases the maximum Ca2+ concentration by a factor 100.

There is a tipping point in there, somewhere, that could be good for some plants, but may be associated with past mass extinctions. The scenario is: CO2 spike triggers massive algae bloom, which carpets the sea floor, destroying ecosystems; then absorbs huge amounts of CO2, and drives Earth into an ice-age. I’m not trying to scare anyone, i would just like to understand these complex, nonlinear feedback mechanisms better.

http://www.physorg.com/news189066777.html
http://www.thekrib.com/Plants/CO2/caco3.html
http://findarticles.com/p/articles/mi_m1200/is_7_162/ai_91040540/