The Oceans Won’t Suffocate!

What’s Natural?

Published in Pacifica Tribune August 12, 2020

byJim Steele

The Oceans Won’t Suffocate!

There is a saying in the journalistic community: ‘Bad news is  good news! Good news is no news!” Bad news sells papers. It’s internet click-bait. So, we’re bombarded with a disproportionate amount of fearful news. Unfortunately, scientific journals also succumb to the same profit incentives. Indeed, pictures of thousands of suffocated fish floating belly-up is very disturbing. However, media outlets amplified our fears with headlines like “A Horrifying New Study Found that the Ocean is on its Way to Suffocating by 2030”. Only slightly less sensational, the Smithsonian promoted one of their researchers articles as “Why Our Oceans Are Starting to Suffocate”, while the NY Times suggests “World’s Oceans Are Losing Oxygen Rapidly”.

Changing oxygen concentrations is determined by the balance between oxygen addition versus consumption. Oxygen is only added at the surface, via diffusion from the atmosphere or via photosynthesis.  The chemical wizardry of photosynthesis uses sunlight to break apart water molecules and generate new oxygen while creating organic matter. Although this organic matter forms the base of the ocean food web, its digestion and decay consumes oxygen.  Paradoxically, wherever the surface ocean food web is most bountiful, the waters below lose the most oxygen.

To analyze natural- versus human-caused losses of oxygen, we must consider how the supply of nutrients for photosynthesis differs between the open ocean and coastal oceans. In the open ocean digestion and decay of sinking organic matter consumes oxygen and releases nutrients  to be recycled. Those nutrients must then be upwelled from dark subsurface waters back into sunlit waters.

In contrast, the supply of nutrients to coastal waters is greatly affected by river discharge. In the early 20th century, chemists learned to convert atmospheric nitrogen into biologically useful nitrogen fertilizer. Starting around 1950, agriculture doubled, then tripled their use of synthesized fertilizer. While greatly benefitting  human food supplies, increased fertilizer use coincided with decreasing coastal oxygen.

Coastal populations and sewage also increased. Sewage and fertilizer run-off combined to stimulate coastal algal blooms that produced excessive organic matter which sank to shallow (< 100 meters) ocean floors, where its decay consumed bottom water oxygen. Along the Texas-Louisiana coast, the term “dead zone” was first used by shrimp fishermen to describe the resulting seasonal disappearance of shrimp and other invertebrates from the ocean floor.

The good news is people are now preventing and restoring dead zones. Sewage treatment plants extract solids and recycle it as fertilizer and farmers are engaging in more judicious use of fertilizers.

In contrast, the open ocean contains natural, permanent “oxygen minimum zones” (OMZ) at depths between about 200 and 800 meters. OMZs are maintained by the constant supply of sinking organic matter but OMZ size fluctuates. While some researchers blame global warming for any OMZ expansion, the evidence points to natural climate change that affects upwelling and ocean circulation.  

For example, in the eastern Pacific natural El Nino events reduce photosynthesis which decreases the supply of organic matter. Less decay causes OMZ’s oxygen to increase. Conversely during a La Nina, enhanced upwelling stimulates photosynthesis and organic matter production. Increased decay then expands the area of depleted oxygen.  Similarly, during the Little Ice Age, upwelling and photosynthesis off the coast of Peru was reduced and oxygen increased. Since the mid 1800s, upwelling has increased and Peru boasts one of the world’s largest fisheries. However, the increase in decaying organic matter has steadily consumed oxygen, and Peru’s expanding OMZ is also the world’s largest.

Open ocean OMZs are ancient, allowing a highly diverse ecosystem to evolve and adapt to the low oxygen environment.  A great diversity of jellyfish, squid, krill, sea snails, and other invertebrates inhabit the OMZs. Sperm whales (i.e. Moby Dick) evolved to hunt abundant squid at those depths. Researchers estimate that 95% of the global ocean fish mass inhabits OMZ depths. Most of these abundant organisms migrate nightly to feed in surface waters, then during the day migrate back to depths where they digest their food, further reducing the oxygen.

Finally, the claim that global warming is causing OMZ’s to expand and oceans to suffocate is largely based on simplistic physics that less oxygen will dissolve from the atmosphere into warmer waters. Although that is true, the scientific consensus still finds most of the oceans’ surface is supersaturated with oxygen. That’s because warmer waters also stimulate photosynthesis and produce more oxygen. Some researchers found photosynthesis could contribute 2.4 times more new oxygen than is absorbed from the atmosphere.  Accordingly, scientists estimate  50% – 80% of the earth’s oxygen is produced by ocean plankton. Based on natural ocean dynamics and its historical changes, we can breathe easy. Global warming is not suffocating our oceans!

Jim Steele is director emeritus of the Sierra Nevada Field Campus, SFSU and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism.

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Climate believer
August 12, 2020 10:29 am

So where’s the dead fish photo from?

Reply to  Climate believer
August 12, 2020 11:08 am

Could be almost anywhere, fish kills happen all the time, all over the planet.

Climate believer
Reply to  MarkW
August 12, 2020 12:16 pm

Yes I’m aware of that, the photo looks like a river bank, the article is about oceans.

Just inquisitiveness, photos are generally labelled.

Right-Handed Shark
Reply to  Climate believer
August 12, 2020 3:05 pm

Same picture appears here:


(right=click picture, select ‘search google for image’)

Climate believer
Reply to  Right-Handed Shark
August 12, 2020 11:47 pm

Thanks, the right click trick depends on your browser. I’m using Opera which doesn’t have that option as standard, there’s probably an extension now to do this.

Anyway, as I thought the image is not a great choice for the article, but hey first world problems an all…..

Reply to  Climate believer
August 13, 2020 4:23 am

It’s canyon lakes in Texas

J Mac
Reply to  Climate believer
August 12, 2020 11:43 am

Hood Canal, a long natural channel off of Puget Sound WA, is notorious for ‘fish kills’ due to low oxygen waters.

Reply to  Climate believer
August 12, 2020 11:54 am

It is a USGS photo identified as from Lubbock Texas. So must be a local freshwater harbor.

Old Retired Guy
Reply to  Jim Steele
August 12, 2020 12:10 pm

Jim, not sure what you mean by freshwater harbor, but Lubbock is up near the panhandle. A loooong way from the ocean or GoM.

Reply to  Old Retired Guy
August 12, 2020 12:48 pm

Yes indeed. That is why it must be freshwater

Climate believer
Reply to  Jim Steele
August 12, 2020 12:25 pm

Thanks, interesting article btw.

old engineer
Reply to  Jim Steele
August 12, 2020 1:52 pm

Jim –

Not sure who chose the picture for this post. I did quick google search for “Lubbock, tx” and “dead fish” and came up with the following from a March 26, 2012 on-line article from KCBD ,a Lubbock TV or radio station, (not sure which):

“LUBBOCK, TX (KCBD) – Hundreds of dead fish were spotted at Ransom Canyon Lake Sunday. Wildlife officials say they “highly suspect” the culprit is Golden Algae.”


“State biologists will not investigate the death of these fish, since Ransom Canyon Lake lies on private property.”


Reply to  Jim Steele
August 12, 2020 8:11 pm

I used to fish around the Cape May area in southern New Jersey.

There was one harbor area whose sole current were the daily tides through a small entryway.
When large ships came in empty, they caused fish kills when they emptied their ballast tanks prior to getting loaded.

Significant amounts of near hypoxic water would stratify, suffocating all oxygen dependent organisms unable to swim free.
A law was passed requiring large ships to flush their ballasts while at sea. A law that only reduced fish/creature kills as ships still dumped ballast tanks in the port.

Clyde Spencer
August 12, 2020 10:29 am

I always appreciate your articles. They are of the highest quality. I think that your first graphic would be more interesting if recast as a percentage of saturation instead of absolute values.

Reply to  Clyde Spencer
August 13, 2020 2:03 pm

Clyde…totally agree. Jim is an automatic must-read for me.


August 12, 2020 10:32 am

Yet another doomsday prophecy that won’t come true. I’ve lost count since the 70s ice age scare.

Gregory Woods
August 12, 2020 11:20 am

Just more Green Porn to titillate The True Believers…

Ron Long
August 12, 2020 11:37 am

Jim Steele is the real deal. How he survives in Kalifornia is beyond me. Thanks for another interesting posting.

August 12, 2020 11:51 am

The Oceans: “I Can’t Breathe!
BLM: Benthic Lives Matter
Stingrays are a raycis fish. Raaayyciiisss!

I think that covers it.
For those who have not been watching, the oceans are dying from oxygen depletion since the mid 1960s, at least. The Ocean die-off was a major feature and cause of world collapse in Paul Ehrlich’s “The Population Bomb”. That was in 1968. Starvation and DOOM was to follow in the 1970s and early 1980s at the latest. We all know how that worked out. This bit of disaster porn has been flogged by the Enviro crowd ever since.

This is getting old, really old. And tired, really tired.

August 12, 2020 12:01 pm

This climate alarmist oxygen deficient narrative will go soon morph into ‘I can’t breath’ and then brainwashed and gullible people will be saying that the oceans and atmosphere are running out of oxygen based upon biased and poorly chosen data from some study and/or models. If anything, more photosynthesis from increasing CO2 will guarantee more oxygen, not less. Especially if the world warms a little, and more life is growing everywhere, which it has been doing since the depths of the LIA of the 17th and 18th centuries.

Clyde Spencer
Reply to  Earthling2
August 12, 2020 8:39 pm

We can call it anoxification.

Reply to  Clyde Spencer
August 12, 2020 9:42 pm

Thanks Clyde…I learn a new word today, along with the concept. Will have to study up on this more since is one of my core interests. I see they use another word as well, called ‘eutrophication’ which I do understand, sort of.

“Depletion of dissolved oxygen was detected at the water table region (upper 2.5 m) of a 30‐m‐deep, sandy, phreatic aquifer containing high oxygen concentrations (7.5 mg L−1) in bulk groundwater. Samples spaced at 3‐cm intervals disclosed very sharp oxygen gradients of up to 1.9 mg O2 L−1 cm−1 between two consecutive samples. High concentrations of labile organic matter arrive at the water table region after a transport period of more than 15 years through the unsaturated zone. Part of the organic matter oxidizes at the water table region, as evidenced by the decrease in the dissolved oxygen content.”

Clyde Spencer
Reply to  Earthling2
August 13, 2020 7:28 pm

I was being sarcastic. It was intended as a play on “acidification.” However, I see that it is already being used in the literature to describe a process that may never achieve the end result of a complete lack of oxygen — just like acidification! I guess it is too simple to refer to a reduction in oxygen and state the amount of the reduction.

August 12, 2020 12:07 pm
Reply to  griff
August 12, 2020 12:15 pm

Fascinating how it’s only “actual science” when you agree with it.

Reply to  griff
August 12, 2020 12:21 pm

oceans have warmed 0.7 C since 1880…..that has had no effect on oxygen levels

Reply to  griff
August 12, 2020 12:30 pm

Oh Griff you are such a troll.

I suggest you read the entire report- over 500 pages. I doubt you have.

Although many authors speculate about the effects of warming, if you read the papers you will see their great uncertainty stating “Natural climate fluctuations can substantially contribute to the interannual to decadal variation in oxygen and can preclude unequivocal detection of any climate driven signal.”

The report supports the claim of ancient OMZ’s saying “studies show that such conditions were present in deep waters long before anthropogenic activities started to have an influence on the marine environment.”

The report also confirms the effects of natural dynamics writing ” Oxygen Minimum Zones (OMZs)
show that the rate of ventilation changes on multiple time scales. Climatic phenomena like El Niño, the Pacific Decadal Oscillation (PDO) and Ice Ages all change the rate at which the deep ocean gets replenished with oxygen”

The report confirms the claim about rich upwelling zones stating, ” upwelling zones have high levels of primary and secondary production that biologically support many of the world’s important fisheries. They have very high oxygen consumption rates, and this is where the most intense and thick OMZs tend to be found.”

Seems to me Griff it is you who ignores a lot of “actual science” !

Right-Handed Shark
Reply to  griff
August 12, 2020 3:12 pm

grief, it’s spelled B-I-A=S. Other actual BIAS says differently.

Reply to  griff
August 12, 2020 3:47 pm

Southern oceans REALLY COLD …. same temp as during ice age !

And when someone can write such trash as “Ocean oxygen depletion is menacing marine ecosystems already under stress from ocean warming and acidification.” (from griff’s link)

You know their science is highly questionable and that they are only following the alarmist mantra.. !!

Tom Foley
Reply to  fred250
August 12, 2020 6:34 pm

Interesting. The paper it’s based on is dated September 2020. Always good to go to the future for the real science.

Reply to  griff
August 13, 2020 10:45 am

From the study cited in your link “Laffoley, D. & Baxter, J.M. (eds.) (2019). Section 3.1 Ocean deoxygenation from climate change / Paragraph 3.1.1 Introduction”:

Based on our still immature quantitative understanding of the climate sensitivity of the various processes at play, estimates will be provided, wherever possible, to what extent past and likely future changes in marine dissolved oxygen can be attributed to individual mechanisms and, ultimately, to anthropogenic climate change.

A cursory review suggests it’s more hypothesizing than actual scientific inquiry. I mean, even if you maintain a strict faith in the accuracy of the models, it presupposes things that we just don’t know. To quote Judith Curry on her review in January 2019 of recent literature discussing OHC:

The most striking findings from these papers are:

-the oceans appear to have absorbed as much heat in the early 20th century as in recent decades (stay tuned for a forthcoming blog post on the early 20th century warming)
-historical model simulations are biased toward overestimating ocean heat uptake when initialized at equilibrium during the Little Ice Age
-the implied heat loss in the deep ocean since 1750 offsets one-fourth of the global heat gain in the upper ocean.
-cooling below 2000 m offsets more than one-third of the heat gain above 2000 m.
-the deep Pacific cooling trend leads to a downward revision of heat absorbed over the 20th century by about 30 percent.
-an estimated 20% contribution by geothermal forcing to overall global ocean warming over the past two decades.
-we do not properly understand the centennial to millennia ocean warming patterns, mainly due to a limited understanding of circulation and mixing changes

The question of Ocean Heat Content is relevant since the “it’s the CO2 wut dun it” crowd stakes its theory on the deltas in oxygen solubility due to temperature fluctuation…yet…we don’t appear to have a good understanding of these temperature fluctuations through the deep ocean.

Anyway, Jim’s explanation seems reasonable and certainly less dependent upon a theory backed by inconclusive scientific literature.


Gary Pearse
August 12, 2020 12:14 pm

There is a beautiful poker player’s ‘tell’ right in the title. It’s the date. IPCC last report, which abandoned any semblance of science under pressure from activists who had sidelined the body because it wasn’t alarming enough anymore, came out with the 12 year deadline for massive action before everything goes to hell. This is where Ocasio-Cortez’s GND, get-it-all-done by 2030 comes from and which is copied by the other woke activist clones’ as their doom deadline.

Clearly word is out to all Climate Wroughters to pound this date in lock-step with this widely successful political notion. Everything hits at once, scientifically impossible but beautiful Madison Avenue messaging. Mad Ave was indeed engaged by failing Climate Wroughters after Climategate and the 18 year Pause to up their game in Climate Communications – something needed when a subject doesn’t speak for itself, or seems to be giving the wrong message. After all, Mad Ave sold the world on tobacco, thalidomide, Radon Therapy and other products similar to climate doom.

Coeur de Lion
August 12, 2020 12:23 pm

If it’s global warming then it must have been awful during the Roman Warm Period . But three or four per cent loss ain’t much. The ocean is huge. No need to worry.

HD Hoese
August 12, 2020 12:25 pm

Unfortunately, the “Dead Zone” ain’t dead, never was, first I ever heard that the shrimpers started the term, anyway ‘scientists’ never stopped its use. They always knew how to shrimp it, fish and shrimp collect along the edge, turns over in fall, in summer with storms. Even with little oxygen, rich mostly bacterial mat, never have found a study about possible food surely one somewhere, except that it runs out some aerobic worms and clams making them better prey. They have consistently given the extent in 2 dimensions, square kilometers, square miles, for a thin bottom layer, above it fish all the way up. Somebody finally discovered that the ocean is 3 dimensional.

Scavia, D., et al., 2019. Hypoxic volume is more responsive than hypoxic area to nutrient load reductions in the northern Gulf of Mexico—and it matters to fish and fisheries. Environmental Research Letters.14(2):024012.

Volume, what do you know, ask the shrimpers next time. Also attract cownose rays. I was on a ship that caught some there decades ago. Craig, J. K. et al.. 2010. Habitat use of cownose rays (Rhinoptera bonasus) in a highly productive, hypoxic continental shelf ecosystem. Fisheries Oceanography. 19(4):301-317.

But in bright red, just like high temperatures, “Scientists have determined this year’s Gulf of Mexico “dead zone,” an area of low oxygen that can kill fish and marine life, is 8,776 square miles, an area about the size of New Jersey. It is the largest measured since dead zone mapping began there in 1985.”

Too much literature for NOAA to comprehend, too many dimensions.

Reply to  HD Hoese
August 12, 2020 8:23 pm

“HD Hoese August 12, 2020 at 12:25 pm

Scientists have determined this year’s Gulf of Mexico “dead zone,” an area of low oxygen that can kill fish and marine life, is 8,776 square miles, an area about the size of New Jersey. It is the largest measured since dead zone mapping began there in 1985.”

Aye, HD Hoese!
News would claim dead zones along the Louisiana coast, yet everyone was catching fish, shrimp, crabs, whatever. I loved fishing along that coast.

As far as the activist NOAA, they’ve been claiming ever larger dead zones regularly, all based on their satellite imagery or activist reports. Yet relatives and friends who fish that same area never have problems.

August 12, 2020 12:47 pm

The use of global averages allows alarmists to misrepresent critical regional dynamics. For example it is commonly quoted that the “oceans are warming” and therefore less oxygen can diffuse into the surface and warming causes stratification that prevents mixing of oxygenated surface waters with deeper waters.

However, not all surface waters are warming and many are cooling and it is the top 100 meters that are truly critical to oxygen diffusion. In DESBRUYÈRES (2017) Global and Full-Depth Ocean Temperature Trends during the Early Twenty-First Century from Argo and Repeat Hydrography, the scientists analyzed temperature trends in the upper surfaces.

Although the upper 700 meter layer had warmed, “The Southern Ocean depicts a cooling trend in the top 100m but a significant warming over the remaining part of the upper layer. ”

Similarly “The Atlantic Ocean presents the smallest OHC trend within the upper layer as cooling above
300m compensates for a warming below.”

And “Cooling dominates in the Atlantic north of 20S, with particularly strong trends found over the central and eastern subpolar gyre, which locally explain up to 50% of the total variance. Minor cooling trends (compared to interannual variability) are observed in the southwestern Indian Ocean and within most of the northern subtropics(10 and 30N) and eastern basins of the Pacific Ocean.”

In other words there is enough surface cooling to offset warming fears, but that is ignored in the IUCN paper.

Tom Foley
Reply to  Jim Steele
August 12, 2020 7:46 pm

If the atmosphere was warming enough to melt glaciers and ice-caps, would not this add more cold water to the ocean surface, resulting in cooling of the upper layers? Sometimes the effect of change can be counter-intuitive. A serious question, I’d like to know whether this has been considered.

I think that the use of global averages is pretty useless. It allows BOTH sides of the debate to misrepresent critical regional dynamics.

Reply to  Jim Steele
August 13, 2020 1:50 am

Every time climate warms, the oceans also warm with it (they are part of it).
So surface layer cooling along with deeper warming suggests a slow overturning of climate from warming to cooling may be underway.

HD Hoese
August 12, 2020 1:25 pm “Back in 2010, Scripps Institution of Oceanography warned about the dangers of something called “oxygen minimum zones”, which are exactly what they sound like: large portions of the ocean, usually very deep, that don’t have enough oxygen to really sustain much life.”

I’ll have to double check, but think I heard that Scripps closed their library, apparently don’t read their own work in the canyon offshore. Vetter, E. W. 1998. Population dynamics of a dense assemblage of marine detritivores. J. Experimental Marine Biology Ecology. 226(1):131-161.

“During the calm summer months the bacterium Beggiatoa sp. spread out over large portions of the detritus mat. Beneath the bacteria oxygen concentration was reduced, and infaunal density was two orders of magnitude lower than in unaffected portions of the mat. The summer increase in bacterial cover constituted a biological disturbance that functionally reduced the habitat area available to the mat fauna and left them more vulnerable to predation. Secondary production in the detrital mats is among the highest reported from natural environments……The La Jolla/Scripps Canyon system, by accumulating organic debris, provides a large food source from shallow to continental slope depths. This resource supports large numbers of fishes and presumably increases local production in higher trophic levels”
This is a review paper with “Thus, direct and indirect effects of deoxygenation on a harvested population may not be easily traceable in monitoring or catch data because management actions adjust for the loss in abundance [smart shrimpers]. In addition, high nutrient loads can stimulate production in a habitat that remains well oxygenated, at least partially offsetting lost production within a hypoxic habitat (52). Total landings of finfish, cephalopods, and large mobile decapods are positively correlated with nitrogen loads (22), in spite of hypoxia in bottom waters (52).”

Reference 22 also calls nitrogen “demonized.” 52 is one of author’s papers. Breitburg did some really interesting and good research in Chesapeake Bay, for example. Breitburg, D. L. 1989. Demersal schooling prior to settlement by larvae of the naked goby. Environmental Biology Fishes. 26:97-103.

If you stat guys run out of climate papers there are plenty here that have problems. Mass balance study, big ocean. But they can fix it. “The key to effective management is raised awareness of the phenomenon of deoxygenation, as well as its causes, consequences, and remediation measures.” However, only if “Further research is needed to understand and predict long-term, global- and regional-scale oxygen changes and their effects on marine and estuarine fisheries and ecosystems.”

Ekman, 1962, Zoogeography of the Sea, discussed the complexity of the common mortality and death of the benthos of the South African Namaqua fauna, but notes the richness of the fauna outside of the area from nutrients from ocean upwelling as the land is desert.

August 12, 2020 2:31 pm

As others have already noted, the photo is from Lubbock, Tx, in 2008. The fish were killed by a Golden Algal Toxic Bloom. The USGS determined that climate change was NOT a factor, toxicity is caused by high salinity, sulfate and chloride concentrations although they go on to reason that climate change could be a factor in the future because climate change could increase salinity.

In fact, other studies have clearly shown that Golden Algae is less toxic in warmer water.

The author definitely shouldn’t have used a photo that has absolutely nothing to do with ocean oxygenation.

Reply to  Meab
August 12, 2020 2:59 pm

I simply Googled “ocean fish kill .gov” . The photo conveyed the effects of suffocating water (artistic license?) and .gov photos are usually free of copyright since our tax money already pays for their efforts.

Didnt think the photo would become a focus, but I will be more careful next time. I was simply hoping for a more critical discussion on fluctuating ocean oxygen content

Eamon Butler
Reply to  Jim Steele
August 13, 2020 2:34 am


Pat from kerbob
August 12, 2020 8:30 pm

Discovered and read your book recently, one of the best books I’ve read in a long time

Not sure if you’ve seen an uptick in canadian sales but I posted a link to my LinkedIn account on it

Keep up the good fight, can’t let lazy con artists who describe themselves as scientists define the future

Reply to  Pat from kerbob
August 13, 2020 5:56 am


August 12, 2020 9:27 pm

The ocean is what the ocean is and the ocean does what the ocean does. We are not the lords of the planet nor the managers of nature. We just live here as part of natire and subject to nature’s whims just like all other creatures. I can only hope that there is a cure for this insane madness of man as god and as lord and caretakers of nature. Environmentalism started out as a rational, sane, and much needed movement but has since lost its way.

August 13, 2020 1:54 am

Meanwhile developments in the equatorial Pacific indicate a major La Nina is on the way.
This includes strong upwelling of cold deep (and nutrient rich) water off Peru’s coast.
And judging from the fishing industry news, anchovies are abundant in the eastern equatorial Pacific:

The anchovy season started late due to the pandemic, but fished it’s full quota before the season ended:

“we started the fishing season late, with only 60% of the fleet and 80% of personnel…”

The Peruvian authorities have even opened a new fishery further south in response to the anchovy abundance.

So we know for sure that a big La Nina is developing.

August 13, 2020 8:51 am

Get yourself a bucket of cold water and a heat gun and try heating the water through its surface of the water and good luck. Anthropogenic global warming is utter nonsense.

Reply to  RMB
August 13, 2020 4:56 pm

The sun can heat the ocean. Only it takes 6-7000 years to do so. That’s the lag between obliquity peaks and interglacials.

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