Climate Change in Four Dimensions
by Richard Somerville, PhD, Dr. David G. Victor, Veerabhadran Ramanathan, PhD, Charles Kennel, PhD, Naomi Oreskes, PhD
For Week 5: The Impacts of Climate Change - Lesson Ten: Impacts of Climate Change, one of the "Optional Activities" was to watch the NOAA Ocean Acidification Demonstration video which was originally posted Feb 26, 2010, on YouTube - as I write this page, it has 12,843 views. (14,500 as of 11-13-14)
This is not just some fly-by-night video by some wacko, but an official NOAA video, presented by the head of NOAA, and posted on the NOAA YouTube channel! I decided to write this page because of what I thought was a pretty obvious error - it turned out that I was wrong, but, with additional research, another error was discovered.
(The two coursera.org links above will require a free account - though I expect they will quit working shortly after the "course" ends.)
Watch the Video First
Before reading the rest of this page, I strongly suggest that you view the video! I really don't want to influence your opinion before you see it.
|she is a marine ecologist and environmental scientist by training, with expertise in oceans [and] climate change [ref]|
|osteoporosis of the sea [00:34 in the video]|
|heat trapping pollutant [04:43 in the video]|
Calcium carbonate - CaCO3 - occurs in several different crystal forms (polymorphs). The following table describes 2 of them.
|The hard parts of many familiar animals, such as oysters, clams, corals, lobsters, crabs, such as the ones on this table, are made of calcium carbonate. [01:30 in the video]|
Based on my education, her statement was wrong!
Well, I was wrong. Continuing from Wikipedia,
|Combined with calcium carbonate, as in the shells of Crustacea and mollusks, chitin produces a much stronger composite.|
|Acidic ocean water is corrosive to all of these calcium carbonate shells and skeletons. [02:10 in the video]|
Specifically, this article
Ocean Acidification: A Risky Shell Game
How will climate change affect the shells and skeletons of sea life?
By Kate Madin
Originally published online December 4, 2009
In print: Oceanus, Vol. 48, No. 1, Jun. 2010
Woods Hole Oceanographic Institution - the world's leading non-profit oceanographic research organization.
Under very high experimental CO2 conditions, the shells of clams, oysters, and some snails and urchins partially dissolved. But other species seemed as if they would not be harmed, and crustaceans, such as lobsters, crabs, and prawns, appeared to increase their shell-building.
In tanks filled with seawater, they raised 18 species of marine organisms that build calcium carbonate shells or skeletons. The scientists exposed the tanks to air containing CO2 at today’s level (400 parts per million, or ppm), at levels that climate models forecast for 100 years from now (600 ppm) and 200 years from now (900 ppm), and at a level (2,850 ppm) that should cause the types of calcium carbonate in shells (aragonite and high-magnesium calcite) to dissolve in seawater.
They included organisms such as corals and coralline algae, which form foundations for critical habitats, and organisms that support seafood industries (clams, oysters, scallops, conchs, urchins, crabs, lobsters, and prawns).
Even though some shells loss mass, all the test organisms continued to create new shell material, even at the highest test level - about 2,800 parts per million (ppm) of CO2.
The IPCC AR5 (2014) worst case scenario
(RPC8.5 - click the plus signs to see the data) places CO2 at about 936 ppm by 2100.
The more likely guess, as stated in the paper, is about
|Note:||The reference was published June 1, 2010 - several months after the video was made.|
|Note:||RCP - Representative Concentration Pathway - just a guess used to build models.|
Coral as an example
|Acidic ocean water is corrosive to all of these calcium carbonate shells and skeletons. [02:10 in the video]|
|Corals ... make their skeletons with calcium carbonate. If ocean water is acidic, it's harder for corals to make their hard parts. If it becomes too acidic, coral reefs may well disappear. [02:20 in the video]|
|Some species are equipped to thrive in increased acidity, but the adaptability of most organisms to increased acidity is unknown. [04:00 in the video]|
However, it is what's not said and what's implied that is a problem.
Fresh water has a pH of 7 - meaning that it is neutral. Using a blue indicator to show relative pH, she adds dry ice (solid CO2) and the indicator changes from blue to yellow - proving that CO2 reduces the pH and makes a neutral solution acidic.
What she didn't point out is that the current atmospheric CO2 mixing ratio is about 400 ppm, and that the amount of CO2 in the demonstration was about 1,000,000 ppm (one million parts per million). The implication for most viewers if that a little CO2 (it was a small piece of dry ice) will make a big change in pH.
In addition, sea water is not fresh water. It isn't that sea water is basic (not neutral) that matters, it is that sea water contains lots of calcium and that it is in equilibrium with existing calcium carbonate deposits (shells, coral, limestone, and the like). As a result, the sea is a buffered solution, meaning that the pH is fairly stable over a wide change in available CO2.
The "purpose" of this demonstration was to dramatize the fact that calcium carbonate (sea shells) dissolves faster as the solution becomes more acidic. She prepared 3 glasses and placed a stick of chalk - CaCO3 - in each.
|Just water||Nothing happened|
|50/50 water/vinegar||A few bubbles|
|Just vinegar||Lots of bubbles|
According to Wikipedia, household vinegar has a pH of about 2.4.
Kids watching this video will get the impression that "carbon pollution" will make sea shells dissolve - which is what was intended. However, this demonstration simply showed that calcium carbonate (sea shells) dissolves in acid and missed the opportunity to introduce buffers and to explain some of the complexities of ocean chemistry.
It is interesting that as she placed the chalk in the neutral water (pH 7.0), she said
|We put it into water. Neutral acidity. And the chalk just sits there. Just like most shells in sea water are not affected by the water around them. [08:06 in the video]|
She does make it very clear that the ocean chemistry is quite different from the two demonstrations. She explains that vinegar was used just to speed things up. Her 2 main points are
Dr. Lubchenco continues the presentation by observing that the previous demonstrations were chemical and that this one will be biological. To show the effect of CO2 on oceans worldwide, she showed a clip a living pteropod - sea butterfly - swimming, and the shell of a dead pteropod dissolving over a period of 45 days in sea water that has the same acidity (meaning that it is really basic) as projected for 2100, assuming nothing is done to change the amount of CO2 produced by humans.
The effect is pretty dramatic and pretty scary. (I just wanted to cry.) It reminds me of the experiment kids do - placing a tooth in soda and seeing how it just rots away. That does not convince many people to quit drinking soda, and this pteropod video should have about the same effect.
Pteropods are small swimming mollusks that form a large part of the ocean food chain. And Dr. Lubchenco is correct that disrupting that chain will have major impacts. However, she failed to mention that the pteropods are part of a larger group of free swimming mollusks and that many of them have no shells at all.
Looking at one dead shell isn't science. In science, you have to look at the entire ecosystem. If other, very similar, organisms are living without shells, then a change in ocean chemistry may have no effect at all on the food chain - as one organism has problems surviving, another might do better. Overall, the total amount of fish food might increase, decrease, or stay the same. It is possible that a lower pH (a less basic environment) will cause more calcium to be recycled and for the ocean to become even more productive.
So, in my opinion, a video showing a dead shell dissolving is worthless. At least show a similar shell in current sea water as a control! A better video would also show living organisms in both environments.
Life over comes many thermodynamically prohibited chemical reactions. To use a dead, decaying, organism to suggest anything about how the ecological system will respond is anti-science! Period!
Actually, the Smithsonian agrees with me - they report that changes in ocean acidity appear to have only a minor impact on sea butterflies, and that small temperature changes have a much larger effect.
|Note:||I found still shots from the pteropod video on a number of web pages - they are credited as - (Photo credit: David Liittschwager/National Geographic Stock). However, I was not able to find the source for the original video.|
Comparison of living pteropods
|Researchers estimate that the percentage of pteropods in this region with dissolving shells due to ocean acidification has doubled in the nearshore habitat since the pre-industrial era and is on track to triple by 2050 when coastal waters become 70 percent more corrosive than in the pre-industrial era due to human-caused ocean acidification.|
|The new research documents the movement of corrosive waters onto the continental shelf from April to September during the upwelling season, when winds bring water rich in carbon dioxide up from depths of about 400-600 feet to the surface and onto the continental shelf.|
A similar November 25, 2012 press release claims that the pteropods near Antarctica have the same problem with upwelling water.
In both cases, it is water coming up from depth that is causing the problem. Upwelling water generally occurs when deep currents encounter a contenental shelf. One theory is that the deep water was last at the surface from 50 to 200 years ago (depending on the shelf it encounters) and that modern changes in CO2 will not be seen for another 100 years or so. However, both papers claim that the upwelling is seasonal, caused by wind, and that current CO2 levels are already affecting these deep waters.
Both studies also imply that we know what the conditions were over 100 years ago However, it is my opinion that there is no way we have enough data to make that claim. I checked the references from another source, and the hundred year ago values were based on a model.
From 1775 ?? I don't think so!
Then she claims
|Ocean acidity has increased by 30% since the beginning of the industrial revolution, just over 200 years ago. This increase is 100 times faster than any change in acidity experienced by marine organisms for at least 20 million years. [11:11 in the video]|
Not specifically related to the Younger Dryas, but since the end of the last glaciation (about 20 thousand years ago), sea levels have risen about 400 feet - that's a lot of fresh, acidic, water. Granted, that may have occurred over a few thousand years - but it did happen.
So, basically, I reject her claim of - worst in 20 million years - as irrelevant. Much larger changes have happened in the much more recent past, and to imply otherwise is not very scientific.
In this case, it is my opinion that NOAA, the primary source of scientific knowledge about the oceans, has intentionally lied to the people. I understand that this is a complex subject and that no 14 minute video will ever be able to cover most of the science. However, there could be a series of additional videos, all linked via their video descriptions, clarifying the issues I've pointed out above.
Just to be clear, in the US, one political party is attempting to control the production of CO2, and the other is resisting it. On January 20, 2009, President Obama (Democrat) took office and appointed Dr. Lubchenco, the presenter in this video, to be the head of NOAA. Since the video was published on YouTube February 26, 2010, while she was still the head of NOAA, it is understandable that she supports the party's position on controlling CO2.
Based on the facts I've seen, if CO2 changes the ocean's pH there will be winners and losers. So far, I have not seen a convincing case that the change will be a net loss. By reading between the lines, the argument appears to be
|We don't know what will happen, so let's be safe and stop producing CO2.|
I hate to suggest that NOAA placed misleading "facts" in this video just to push a political agenda, but that is how it appears.