In regards to pH fluctuation in the ocean, the pH IS dropping and CO2 in the atmosphere IS rising. This is just a basic, physical fact. See the Mona Loa Observatory for daily/historical atmospheric CO2 data.
http://www.esrl.noaa.gov/gmd/ccgg/trends/
The ocean is the largest sink for atmospheric CO2. As we add more CO2 to the atmosphere, more of it ends up in the oceans. This, invariably, produces Carbonic Acid through the combination of CO2 and H2O. This is a physical fact. Undeniable. Irrefutable. The question everyone likes to point to is whether the rise in CO2 (and thus temperature) is our fault or whether it is related somehow to Milankovich Cycles (minute fluxuations in the Earth's orbit that cause the very slow rise and fall of global temperatures).
http://en.wikipedia.org/wiki/Milankovitch_cycles (yes, wikipedia is a very good source for information)
Temperature aside, we were talking about ocean pH. A previous poster pointed out that pH in the oceans can vary more than the worst predicted long term pH changes. This is absolutely correct. The key here (as with any climate change topic) is a matter of rate. Consider a barrier reef, such as in Australia. We all know what tides are and what they do. They cause the local water level to rise and fall. When tides are low, you restrict water flow in shallow areas and can stop flow all together. All those critters living in that water are still respiring and pumping additional CO2 into the water. This can locally drop pH levels to relatively extreme levels. Sounds pretty bad, right? Well, it's not THAT bad. Over millions of years these organisms have found ways to cope with these short perturbations in pH. When the tide comes in, the bad water is flushed out, the pH returns to normal, and everyone is happy again.
Here's the problem. That was a SHORT time. The pH changes involved in wholesale ocean acidification may seem small (they are not because pH is a logarithmic scale
http://www.elmhurst.edu/~chm/vchembook/184ph.html), but these are long term changes that most organisms are not equipped to handle.
The other point that is often brought up in these discussions is that CO2 used to be higher in the past and pH lower and everything did just fine. That's absolutely true, but again it's a question of rate. Organisms have millions of years to adjust and change to deal with those very slow changing conditions. The Earth's organisms are not getting those millions of years this time. What happens when there are sudden (geologically speaking) changes in environmental conditions? We get an extinction event. There have been 5, that we know of, in Earth's history.
(
http://www.bbc.co.uk/nature/extinction_events)
What these all have in common is that they were all sudden, again, geologically speaking.
The change in atmospheric CO2 since the industrial revolution has been staggering when compared to the normal change in CO2 throughout geologic history. This rate of change is only increasing as we burn fossil fuels. Much of that CO2 ends up in the oceans, causing increasing ocean acidification. This is a very real problem and will have very real consequences in the coming decades.
Here are a few papers/links that could be of interest for further reading.
http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification?
http://nuweb2.neu.edu/rieslab/Hoeni...e_Geologic_history_of_ocean_acidification.pdf
http://nuweb2.neu.edu/rieslab/Ries_2011_Nature_Climate_Change_Acid_Ocean_Cover_Up.pdf
http://www.sciencemag.org/content/333/6041/418.full.pdf
Here is how I look at the overall climate change debate. We can try and do what we can about it and not ignore it. If climate scientists are wrong, all we have done is improve the world. If climate scientists are right, we may have saved our children and their children and so on down the line.
Lastly, I apologize if some of those articles are behind a paywall. I'm posting this from a university system, so I have access to most journals by default.
