The world’s marine ecosystems risk being severely damaged by ocean acidification unless there are dramatic cuts in CO2 emissions, warn scientists.
The researchers warn that ocean acidification, which they refer to as “the other CO2 problem”, could make most regions of the ocean inhospitable to coral reefs by 2050, if atmospheric CO2 levels continue to increase.
This does indeed sound alarming, until you consider that corals became common in the oceans during the Ordovician Era – nearly 500 million years ago – when atmospheric CO2 levels were about 10X greater than they are today. (One might also note in the graph below that there was an ice age during the late Ordovician and early Silurian with CO2 levels 10X higher than current levels, and the correlation between CO2 and temperature is essentially nil throughout the Phanerozoic.)
Perhaps corals are not so tough as they used to be? In 1954, the US detonated the world’s largest nuclear weapon at Bikini Island in the South Pacific. The bomb was equivalent to 30 billion pounds of TNT, vapourised three islands, and raised water temperatures to 55,000 degrees. Yet half a century of rising CO2 later, the corals at Bikini are thriving. Another drop in pH of 0.075 will likely have less impact on the corals than a thermonuclear blast. The corals might even survive a rise in ocean temperatures of half a degree, since they flourished at times when the earth’s temperature was 10C higher than the present.
I’ve just been reading another BBC article titled “Mammoth-killing comet questioned”
You would think that this wouldn’t have a “climate change” angle but you would be wrong. The end section nicely weaves it in.
Its seems that any article on the BBC has to make a claim that we heading for a catastrophe.
Robert S (21:27:59) :
“The ocean currently has a pH of 8.1, which is alkaline not acid. ”
Acidification is the process of becoming acidic
Correct, but irrelevant, since the oceans are not becoming acidic, they are becoming very slightly less alkaline, or if you like, more PH neutral.
Get it right.
I really really dislike scaremongering foolishness such as that displayed by these AGW ‘scientists’.
TerryS (16:43:52) :
“Its seems that any article on the BBC has to make a claim that we heading for a catastrophe.”
This is welcome. It means that desperation is setting in.
DaveE.
Ye gods man, do you guys get anything right before you criticize, comment and disparage? I’ll keep submitting comments here until you decide to actually publish them.
1) “Acidification” refers to the lowering of pH, not whether the liquid is an acid or alkili. Acidity refers to the concentration of hydrogen ions in the liquid, of which pH is a logarithmic measure. So a decline in pH indicates an increase in the acidic properties of the liquid, regardless of what the actual pH number is. The ocean is a tremendous buffer, and pH should generally change only on geological timescales, as indeed we know it has. The fact that we have been able to measure a decrease in modern instrumental time is very disturbing.
2) The decrease is driven by the increased concentration of carbon dioxide in the atmosphere. When CO2, which is very soluble, dissolves in seawater, it undergoes a series of chemical dissociations, first to form carbonic acid, then free bicarbonate ions, and finally carbonate ions. As the ocean becomes more saturated with CO2, this equilibrium is being shifted so that solid carbonate salts become more soluble. The most common biologically produced carbonate is calcium carbonate, one form of which is used by corals for the construction of their skeletons. Therein lies the reasons to worry about the corals as atmospheric CO2 concentration rises.
3) There is a lot that we don’t know about the potential impact of this issue. It will definitely be detrimental for a lot of organisms, and not only because of the attack on their skeletons, but also because the increase in CO2 in the water often causes hypercapnia; think of this as strangulation underwater.
4) Some organisms might benefit, and there is some experimental evidence to support this now. However, before we celebrate this, I’ve noted that the reports of these organisms generally involve species that are currently minor ecological components. If they rise to more dominant ecological roles, we’ll see a shift in community/ecosystem compositions and functioning. Whether these changes will be bad, neutral, or beneficial to other species, as well as human economic dependencies, is a wide open question. Be concerned gentlemen.
5) To the coral aquarium enthusiast who claimed that his corals have never done better since adding CO2 to his water, I’ll point out simply that he is making it easier for the corals to mineralize their carbonate skeletons. His aquarium water is definitely not at a saturation point. If he’s interested, keep ramping up the CO2 concentration, and see what happens. Science at home.
This is a misrepresentation of the basic chemistry.
There are two aqueous dissociation constants involved:
(1) H2CO3 H+ & HCO3- 2H+ & CO3–
as well as the solubility reaction involving Henry’s Law at the surface:
(2) H20 + CO2 H2CO3
Adding more CO2 to the sea whether by increasing atmospheric CO2 or by cooling the water which modifies Ks can only drive equation 1 to the right, increasing the amount of CO3– in the water.
Likewise, increasing the amount of CO3– in the water (by dissolving Calcium Carbonate can only drive equation (1) to the left (incidentally making the water more alkaline.)
In this scenario the only way the ocean can be made more acidic without also increasing carbonate concentrations is to remove the carbonate by forming more shells and coral, not less.
So the alarmists are actually complaining that the increased coral and shell productivity over the last two centuries is going to slow down because of the decreased alkalinity it has caused. That is the real message of Feeny et al., in basic chemistry stripped of its spin.
And one more point. Corals from the Ordovician were in no way comparable to modern corals. They were evolutionary distinct. Those reef builders were rugose corals. Today’s scleractinian corals evolved from a separate evolutionary lineage probably no earlier than the Triassic.
It appears coral bleaching can be an ‘survival’/’evolutionary’ strategy:
http://www.worldclimatereport.com/index.php/2004/06/07/bleached-bond/
http://www.nature.com/nature/journal/v411/n6839/full/411765a0.html
and an alternative explanation for bleaching other than ocean temperature can be found at:
http://www.co2science.org/education/reports/corals/p1ch3.php
Sorry, HTML tags wrecked my equations. Trying again:
This is a misrepresentation of the basic chemistry.
There are two aqueous dissociation constants involved:
(1) H2CO3 ← K1 → H+ & HCO3- ← K2 → 2H+ & CO3–
as well as the solubility reaction involving Henry’s Law at the surface:
(2) H20 + CO2 ← Ks → H2CO3
Adding more CO2 to the sea whether by increasing atmospheric CO2 or by cooling the water which modifies Ks can only drive equation 1 to the right, increasing the amount of CO3– in the water.
Likewise, increasing the amount of CO3– in the water (by dissolving Calcium Carbonate can only drive equation (1) to the left (incidentally making the water more alkaline.)
In this scenario the only way the ocean can be made more acidic without also increasing carbonate concentrations is to remove the carbonate by forming more shells and coral, not less.
So the alarmists are actually complaining that the increased coral and shell productivity over the last two centuries is going to slow down because of the decreased alkalinity it has caused. That is the real message of Feeny et al., in basic chemistry stripped of its spin.
Still having trouble with my HTML – obviously the carbonate ions should have two negative charges rather than the one HTML left me with.
Bill D (11:23:10) :
if you want make predictions about the future, you need to know whether water temperature will continue to rise and if humans will continue to use large amounts of fossil fuels.
And of course, you’ll need to know if there is any measurable connection between the two. Until then, it remains a non secuiteur.
Happily though, water temperature is falling. While co2 continues to rise.
http://www.woodfortrees.org/plot/hadsst2gl/from:2004/scale:100/offset:-40/plot/esrl-co2/from:2004/offset:-380
OT sort of.
Don’t let ’em fool you. This too will be blamed on AGW…
http://apnews.myway.com/article/20090201/D962KB401.html
Tim Clark (12:19:04) :
If you really think that Hoegh-Guldberg and his co-authors have got carbonate chemistry wrong, but you have it right, then you should write a letter to the editors of Science Magazine, correcting their mistake(s). I will be watching for it, but not holding my breath.
“When I see a post like this from Bill D AFTER the post from Fraizer – I have to conclude that one’s intuition carries more weight than facts.”
The moderators are not constantly monitoring posts nowadays, as their number has been reduced from five to two, as Anthony has mentioned a few times here and there. Therefore posts are “batch processed” in bunches, and it will often appear as though a subsequent poster has ignored a previous one.
Reply: Well I just got back from Brazil so the number (of moderators) is creeping back up again ~ charles the moderator
John Game,
Good point about the 3500 years to neutral. The number isn’t terribly meaningful though because of the buffering effects of limestone in the oceans. As pH decreases, more CaCO3 dissolves, tending to drive the pH back up. It would be simple enough to dump powdered CaCO3 into the oceans to keep the pH up, if people are worried about it. Remember that shellfish appeared in the oceans when atmospheric CO2 levels were much higher than the present.
As far as the bomb effect goes, of course it is important. The fact that the ecosystem has recovered from completely annihilated and highly radioactive in just 55 years, indicates a tremendous resiliency.
A problem with the hypothesis of CO2 causing dead zones in the ocean is the evidence from the deep oceans, where acidic fluids from black smokers associated with submarine volcanic activity are where life flourishes. I know from grad school days that the fluids measured at the vents are pH of between 2.0 to 5.5 (i.e weakly to strongly acidic).
Steven Goddard (06:49:14) : I don’t know how to construct an argument against arm waving speculation, other than to point out again that CO2 levels were much, much higher in the past – and the oceans were teaming with life.
Are there any corals were a volcanic vent makes locally acidified water? I’d use Iceland as and example if only it were a few thousand miles more south… 8-|
Any tropical underwater volcano growing corals?
Nothing like an existance proof if you can find it.
E.M.Smith,
I’m not trying to construct an argument that corals or shellfish can survive in acidic water. Because they can’t.
What I am saying is that corals and other shellfish have thrived at much higher atmospheric CO2 concentrations. The point being that the relationship between atmospheric CO2 and ocean pH is apparently not so simple as some might have us believe.
@Peter (17:02:48) :
[…]4) Some organisms might benefit, and there is some experimental evidence to support this now. However, before we celebrate this, I’ve noted that the reports of these organisms generally involve species that are currently minor ecological components. If they rise to more dominant ecological roles, we’ll see a shift in community/ecosystem compositions and functioning. Whether these changes will be bad, neutral, or beneficial to other species, as well as human economic dependencies, is a wide open question. Be concerned gentlemen.[…]
I was reading the chart and admittedly ignorant of the different species of coral involved multi-MYA vs the present. I thought your point #4 was good. Something is going to fill a niche left by a failed species. How far can various current coral species (‘X’) “migrate” to become established in favorable voids left by species (‘Y’) where the environment became unfavorable to species (‘Y’)? Just wondering. Someone somewhere is probably studying that.
I think the answer to “Whether these changes will be bad, neutral, or beneficial to other species,…” is, all three.
Bob Coats (17:30:34) :
If you really think that Hoegh-Guldberg and his co-authors have got carbonate chemistry wrong, but you have it right, then you should write a letter to the editors of Science Magazine, correcting their mistake(s). I will be watching for it, but not holding my breath.
There have been at least four other posters, including Alan above, that concur with my point, showing elementary equations. Either show where the chemistry we present is in error, or propose another hypothesis. If you can’t understand it now, how will you be able to read the magazine?
Well teenagers drink carbonic acid by the gallon and it doesn’t seem to bother them
So just where has it been tried out; growing Corals in acid that is.
I would think that as ocean surface waters became warmer, that the surface waters would hold less CO2, and the process of driving the CO2 to deeper cooler waters would accelerate.
You don’t find a lot of people diving on the coral reefs in the southern ocean. Corals can migrate and find the conditions they prefer, and mostly they seem to prefer warmer waters. I don’t know whether they pick the water based on its pH or whether they find the food chain to their liking in warmer waters.
CORALS WERE MEANT TO BLEACH? (another link for you, MikeT)
@E.M.Smith (18:09:27)
I looked for that yesterday, and found a few things which weren’t as clear as I wanted, but I think that line is definitely worth pursuing. My guess is that there isn’t much on it, and that if the environment proved the warmers’ points there would be, so the absence, while not proof they are wrong, is highly suggestive.
@pablo an ex pat
Indian Ocean winter pH range is about 7.87 to 8.23 (0.35 pH units!) over the Temperature Range of about 0.2 to 0.3 DegC.
http://www.mgac.nsysu.edu.tw/ctchen/Publications/A/58.pdf
If you haven’t seen these videos you might want to…
http://www.youtube.com/watch?v=m4SN1-vwBVs
…enjoy
arrrrggg
I’ll try this in two sections because it’s not appearing at all…
ONE OF TWO
CORALS WERE MEANT TO BLEACH? (another link for you, MikeT)
@E.M.Smith (18:09:27)
I looked for that yesterday, and found a few things which weren’t as clear as I wanted, but I think that line is definitely worth pursuing. My guess is that there isn’t much on it, and that if the environment proved the warmers’ points there would be, so the absence, while not proof they are wrong, is highly suggestive.
TWO OF TWO
@pablo an ex pat
Indian Ocean winter pH range is about 7.87 to 8.23 (0.35 pH units!) over the Temperature Range of about 0.2 to 0.3 DegC.
http://www.mgac.nsysu.edu.tw/ctchen/Publications/A/58.pdf
If you haven’t seen these videos you might want to…
http://www.youtube.com/watch?v=m4SN1-vwBVs
…enjoy
APPARENTLY THIS ONE’S THE PROBLEM…
TWO OF THREE, NOW
@pablo an ex pat
Indian Ocean winter pH range is about 7.87 to 8.23 (0.35 pH units!) over the Temperature Range of about 0.2 to 0.3 DegC.
http://www.mgac.nsysu.edu.tw/ctchen/Publications/A/58.pdf
THREE OF THREE
If you haven’t seen these videos you might want to…
http://www.youtube.com/watch?v=m4SN1-vwBVs