A variety of sources (See "SOURCES" below) have led me to think a bit more about three questions:
1. What do we know about the risk that ocean stratification will lead to a huge buildup of H2S poison
deep in the oceans of the earth, enough to kill us all?
2. What do we know about the risk that such poison, once formed, will be released to the surface,
actually killing us (perhaps first by radiation, as it affects the ozone layer, but inexorably pressing further)?
3. What do we really know about the risks from the Black Sea, which is already stratified, and where the "chemocline" --
the barrier between the poisoned water and the surface -- has risen from about 200 meter depth to less than 100 meters in
There is a HUGE amount of uncertainty here, and gross ignorance about what is going on, in every source I have found.
I don't claim to know the answers, but someone really needs to follow up somehow.
I am NOT speaking for NSF on this. In fact, I wonder what different people in our geosciences directorate would say about this; however,
they were the ones who invited me to a presentation by Peter Ward a couple of years ago, and urged us to pay attention. I disagree with many of things that Ward says, based on sheer logic and independent thinking, but it seems very clear that he is right that there has been a huge disconnect between
folks like him studying the history of the earth before about 2-3 million years ago (Rod tells me that the formation of Panama was the key dividing time)
and folks studying "thermohaline" currents in the modern ocean:
The more I look at this, the less reason I see for complacency. (Though to be honest, I also see more reason to think about
issues like afterlife, which is beyond the scope of these lists. Santorum seems to be saying it is antiChristian and
antiBiblical to be worried about fire and brimstone, but I personally disagree... but again, this is not the place to elaborate.)
One reason I worry is that shifts in things like water currents have certain analogies to shifts in things like electrical currents, which
I tend to take for granted in my own thinking. Things can change quite abruptly when someone throws a switch.
Our society is particularly incompetent when it comes to threats which become tangible and direct very quickly. Whatever we may say about global warming, it is a RELATIVELY gradual process. But current can change quite quickly. And, in the Black Sea, the rise
of the chemocline to the surface would be a very discrete event... "discrete" as in abrupt, not as in diplomatic.
(It would not surprise me if the first big news would be a sudden death of Russian Navy people among others. They
have had small outbreaks and deaths due to occasional upwelling already, but if the chemocline reaches the surface,
it will be worse. I have no idea how MUCH worse, but much worse.)
Another reason I worry... is... though I am not an expert in ocean currents, I can read. I know that the direction of differences
in water temperature and salt content drive which way the currents flow. From Ward, I know that if they change directions
(to what they were for most of the history of the earth), we pass step one -- we get stratified oceans and poison.
The Arctic is clearly warming, and the gradients are changing. Will we know where the switching point is, before it is too late?
Currents can change quickly as certain thresholds are reached....
But how does this relate to the "good news" that we might be seeing cooling in Europe rather than warming, due to changes in the Gulf Stream?
A few years ago, the Economist had a cover story something like "Will England freeze over?" due to preliminary measurements
from the few bouys collecting relevant data, suggesting that the warming currents of the Gulf Stream (crucial to the climate of all of northern Europe
and even northeast US) had suddenly started to slow down. New bouys were installed, and the debunkers worked overtime... and I haven't heard much about that issue lately... but it is not off the table.
If you look to the wiki URL above...
it seems clear that the warm Gulf Stream current brings warmth to northeast US and Europe AT THE SURFACE (the red lines).
Because we are not increasing the height of the ocean in the north (???), there is an exactly counterbalancing DEEP current
(the blue lines) carrying cool oxygenated water to the south. That is exactly the kind of NEW circulation pattern which Ward discusses --
in emphasizing how different it is from most of earth's history.
So of course, there is a direct link between the "cooling" news of a reduced northern surface Gulf stream, and a reduction
in the corresponding deep current which keeps the North Atlantic oxygenated and prevents the stratification which was most of
the earth's history. The bottom line which could poison us is the stratification, and it's not clear how far away it is. Maybe quite far...
but maybe closer than we think.
On the reassuring side, what of the possibility that the poison will just stay locked up in deep water, and the memory that the warming current
has weakened before?
In fact, the major intellectual novelty in Ward's book (beyond the Penn State work he cites, and the nice popularization) is his
discussion of question 2 -- what triggers the actual release of H2S from deep ocean to above? He proposes a very rapid rise
on the chemocline (such as we may be seeing right now in the Black Sea), somehow caused by the rate of increase of CO2.
On that I disagree. (See sources below). More precisely... it is caused by the degree of anoxia, which in turn
CAN be caused by many possible combinations of factors. In our times, it seems that simple agfricultural runoff, essentially unavoidable
with today's world population, may well be enough...
But must run.
The best primary starting point is Ward's book Under a Green Sky, $7 in paperback from amazon.
Having read a bit beyond that, I have my own views, initially stated in:
I also have a condensed "cliff notes" summary of the relevant technical content of the book:
========== ADDED LATER:
The chemocline of the Black Sea has risen from 200 meters to less than 100. One book on the Black Sea describes it as the greatest reservoir of poison
on the earth, with H2S "filling 90% of the water," from its 2000 meter depth to 200 meters. But recent data has shown much less depth
of the chemocline.
I have done some web search on the Black Sea situation, but it was not really reassuring. There is a big international project
addressing the health of the Black Sea. It has an extensive web page on how wonderful they are,
how many happy diplomats worked really hard, and mow much money they spent on many, many things. But ...
on a reasonable search ... I didn't find anything really relevant to the key uncertainties I have. After they spent all that money, I do hope
someone knows, but they sure weren't advertizing it. I couldn't find a simple time-series on the depth of the chemocline
by region of the Sea, or in total... but common sense says it ought to exist somewhere, if they are spending all that money.
I also tried google scholar search, of course.
There have been a few minor scandals over the past decade or two, but it is sad how such things sometimes just create antibodies
which make people LESS aware of the larger future dangers. (Hey, oil dependency in the US provides some other scary examples
of such psychology.)
I saw a statement by the President of Rumania, who sounded really worried... but, as in Ukraine, I saw stringent efforts by Russia-oriented folks
to get rid of him, and shut him up.
I really don't know, for example, what the implications would be for the ozone layer if the chemocline of the Black Sea reaches the surface,
in the kind of breakout that Peter Ward has discussed. I just don't know. Likewise for the North Atlantic scenario.