How bad is Ocean Warming caused by anthropogenic climate change?
To answer my question, the effects of the current rise in temperatures of our oceans is worse than you or I could have imagined. It’s so bad that it may take thousands of years for ocean life to recover. That’s a recovery time measured in millennia, for those who prefer polysyllabic Latinate words:
A study has found that it might take thousands of years for the ocean to recover from climate change. Researchers studied more than 5,400 fossils from a 30-foot-long core sample taken from the Pacific Ocean floor near Santa Barbara, California, and found that it can take millennia for ocean ecosystems to recover after periods of deoxygenation and warming waters. […] “In this study, we used the past to forecast the future,” Peter Roopnarine, curator of invertebrate zoology and geology at the California Academy of Sciences and co-author of the study, said in a statement. “We don’t want to hear that ecosystems need thousands of years to recover from disruption, but it’s critical that we understand the global need to combat modern climate impacts.”
Here is what the article posted at Science News regarding this research study has to say about its importance to our understanding of the impacts of global warming on Ocean ecosystems and biodiversity:
A 30-foot-long core sample of Pacific Ocean seafloor is changing what we know about ocean resiliency in the face of rapidly changing climate. A new study reports that marine ecosystems can take thousands, rather than hundreds, of years to recover from climate-related upheavals. The study’s authors–including Peter Roopnarine, PhD, of the California Academy of Sciences–analyzed thousands of invertebrate fossils to show that ecosystem recovery from climate change and seawater deoxygenation might take place on a millennial scale. The revolutionary study is the first of its kind, and is published today in the Early Edition of the journal PNAS.
The published study which looked at the fossil record from roughly 16,000 years ago until 3,400 years ago, a period that includes a significant period of time during the current interglacial period (the Holocene) can be found here: Response of seafloor ecosystems to abrupt global climate change. From the Abstract:
Anthropogenic climate change is predicted to decrease oceanic oxygen (O2) concentrations, with potentially significant effects on marine ecosystems. Geologically recent episodes of abrupt climatic warming provide opportunities to assess the effects of changing oxygenation on marine communities. […] This [fossil] record … demonstrates that seafloor invertebrate communities are subject to major turnover in response to relatively minor inferred changes in oxygenation (>1.5 to <0.5 mL⋅L−1 [O2]) associated with abrupt (<100 y) warming of the eastern Pacific.
How the researchers characterize their study’s significance:
We demonstrate here that ocean sediments harbor metazoan fossil material that can be used to reconstruct the response of seafloor biodiversity to global-scale climate events. We show that the last deglaciation, the most recent episode of climate warming, was accompanied by abrupt reorganizations of continental margin seafloor ecosystems through expansions and contractions of the subsurface low-oxygen zones. This archive reveals that global climate change disturbs seafloor ecosystems on continental margins and commits them to millennia of ecological recovery.
The basic cause of the loss of biodiversity in the oceans is that warming oceans lose oxygen, which results in a die-off of invertebrate life, the foundation on which our complex ocean ecosystems are based. Once you wipe out entire species of invertebrates it can take a very long time for a complex system such as the Earth’s oceans to recover. These impacts stretch far beyond our short time-scale concerns regarding the effects of climate change on human civilization in this century.
Again from the Science News article:
This week’s study explores multicellular life–in the form of invertebrates–in pursuit of a more complete picture of ocean ecosystem resilience during past periods of climate change.
“The complexity and diversity of a community depends on how much energy is available,” says [study co-author Peter] Roopnarine. “To truly understand the health of an ecosystem and the food webs within, we have to look at the simple and small as well as the complex. In this case, marine invertebrates give us a better understanding of the health of ecosystems as a whole.”
The study’s all-important sediment core revealed an ancient history of abundant, diverse, and well-oxygenated seafloor ecosystems, followed by a period of oxygen loss and warming that seems to have triggered a rapid loss of biodiversity. The study reports that invertebrate fossils are nearly non-existent during times of lower-than-average oxygen levels.
News like this should be cause for all of us to be running around screaming with our heads on fire. It should be front page banner headline news on every media outlet, online, print or televised. Instead, it will likely be ignored or marginalized by major media outlets. And that will be not only an immensely stupid reaction, but a tragic one as well.
Yes, oceanic ecology changes seem to be sometimes very persistent. After grotesque overfishing of cod and Southern Ocean whales, even near-total bans don’t seem to allow recovery. In the case of the Southern Ocean whales it seems whales ate krill which ate plankton – which were fertilized with whale poop. So taking out the whales results in a lot fewer of the krill that they ate. With the cod, they’re still playing with models, but one idea is that cod actually had a social system for learning how to catch prey and with so few cod they can’t maintain their “culture”.
What’s particularly frightening is the humans are attacking ocean ecologies in so many different ways – global warming, ocean acidification, eutrophication from overfertilizing and wetland destruction, and of course overfishing. It’s very hard for organisms to adapt to three simultaneous stressors (the basis of HIV multidrug therapy) and we’re hitting ocean organisms with four.
The study is actually optimistic. Oceanwide eutrophic episodes generally last hundreds of thousands of years.
In the same way that global climate change is already well underway and to a large extent unstoppable, mass extinction is already underway and massive species loss is inevitable, barring a whole series of miraculous technological innovations. This means global ecosystem collapses. For instance, marine biologists are now saying that the utter loss of coral ecosystems worldwide could happen (will very likely happen) in the next 30-40 years.
The combined forces of climate change, habitat destruction and fragmentation, over-hunting, invasive species, genetic bottlenecks, etc. mean that many (thousands, tens of thousands, take your pick) species are “walking dead” right now, doomed to extinction in coming generations, even if damaging trends were stopped right now, which is terribly unlikely.
We’ll be quite lucky if recovery takes “millennia”. In my opinion a more likely scenario is that recovery of global diversity and climate stability will take millions of years.
That’s not to say that massive global action isn’t desperately needed. Every dollar we spend to improve the situation will save us incalculable sums in the future. It’s just to properly frame the issue. Do we want to lose 30-50% of all species on earth, or do we want to lose 80-99%? The former will have brutal consequences for humanity. The latter will lead to the wholesale breakdown of human society and indescribable catastrophes.
There has never been, if not in human history than certainly since the beginning of civilization, a greater crisis than the combination of anthropogenic climate change and mass human-caused extinction. We need to get to a place where this is widely understood and policy makers are expected to act accordingly.
Just think:
Everything we’re living through now has resulted from early 20th century carbon output, what with the lag and all of carbon output on temperatures, etc.
So, when you see what we’re experiencing now, just imagine how much worse it will be 100 year from now regardless of the entire planet stopping carbon output tomorrow at noon.
Have a great day!