How quickly could heat resistant fish be reproduced through natural selection? Years? Fish breed fast right? Sharks have been around for millions of years with a lot of variance in ocean temperatures.
We could see a rapid change if it’s prolonged enough.
Species that need a coast are in less luck, for example. The next appropriate coast may be far away. The Great Barrier Reef can't just migrate to Antarctica, even if there is a suitable coastline down there, because it can't get there from where it is. There is no continuously habitable area from where it is now to the potential new habitat.
Some sharks are. There are 400+ species and plenty of them live near coasts or the bottom.
But have the non-pelagic shark species survived any climate changes that would force them to migrate across a large inhospitable area? Sharks have survived very long as a group, but it's not clear to me that most/all of the individual species that have existed still do.
Though I'd be more worried about effects like seasonal oceanic dead zones increasing in size and persisting longer. I don't think too many fish will evolve into a species not requiring oxygen anytime soon.
https://today.oregonstate.edu/archives/2011/aug/lasting-evol...
https://xkcd.com/1732/ (natural speed of changes vs. anthropocene)
https://www.researchgate.net/figure/The-trajectory-of-the-An...
https://en.wikipedia.org/wiki/Great_Acceleration
The "hockey stick" is just starting.
- Marine life: Warmer sea temperatures can lead to changes in the distribution and behavior of marine species, with some moving to cooler waters or changing their migration patterns. This can also affect the growth and reproduction rates of different marine organisms, which can have cascading effects on the food chain.
- Coral reefs: Coral reefs are highly sensitive to changes in sea temperature, and prolonged exposure to temperatures above 21 degrees Celsius can cause coral bleaching, which can lead to their death. This can have significant impacts on the many species that depend on coral reefs for food and habitat.
- Ocean currents: Changes in sea temperature can affect ocean currents, which can in turn impact weather patterns and climate. Warmer sea temperatures can lead to more frequent and severe weather events such as hurricanes and typhoons.
https://en.wikipedia.org/wiki/Thermohaline_circulation
https://en.wikipedia.org/wiki/Atlantic_meridional_overturnin...
- Sea level rise: As sea temperatures rise, the water expands, contributing to sea level rise. This can lead to flooding and erosion in coastal areas and impact the livelihoods of people who depend on these areas for fishing and tourism.
- Decreased solubility: As sea temperature increases, the solubility of oxygen in seawater decreases. This means that warmer water holds less dissolved oxygen than cooler water. Therefore, as sea temperatures rise, the amount of oxygen available for marine life decreases.
- Increased stratification: Warmer water is less dense than cooler water, so as the sea temperature rises, the water column becomes more stratified, with warmer water sitting on top of cooler water. This can prevent oxygen-rich surface water from mixing with deeper water, leading to the formation of oxygen-depleted zones.
- Algae blooms: Warmer sea temperatures can promote the growth of certain types of algae, such as harmful algal blooms. These blooms can consume large amounts of oxygen when they decompose, leading to oxygen-depleted zones in the surrounding water.
- Oxygen-depleted zones, also known as hypoxic or anoxic zones, can have significant impacts on marine ecosystems. When oxygen levels become too low, many marine organisms, such as fish, shellfish, and crabs, can suffocate and die. This can have cascading effects on the food chain and lead to the loss of commercially important species. Additionally, the decomposition of dead marine organisms in these zones can release harmful gases such as hydrogen sulfide, which can be toxic to marine life and humans.
W.R.T. corals, claims of coral reefs being harmed by climate change have been discredited in recent years. Although scientists claimed for years that the corals were being severely harmed by emissions, 2022 had the highest coral cover in the GBR since records began in the mid 80s. It's confusing because the media reported several supposedly severe die-offs in the corals in the six years before 2022, but coral takes 5-10 years to regrow after a major die-off so those reports cannot have been correct.
Coral bleaching is caused by sudden changes in temperature, but most bleachings don't seem to cause die-offs and it's the speed of change that seems to trigger it, not so much the absolute temperature.
Sea level rise is small, constant over a much longer time period than the industrial era, and primarily caused by changes in the height of the land not the sea. That's why the Pacific islands that were supposedly in danger from climate change have actually grown over time, not shrunk.
https://www.nature.com/articles/s41467-018-02954-1
Finally, the hockey stick graphs that are so famous are all scientifically fraudulent, being based on techniques like dropping any input data that doesn't yield hockey stick graphs.
https://theconversation.com/record-coral-cover-doesnt-necess...
"it’s more likely the reef is being dominated by only few species, as the report states that branching and plating Acropora species have driven the recovery of coral cover"
"these same corals are often susceptible to wave damage, disease or coral bleaching and tend to go bust within a few years"
"Without more information at the level of individual species, it is impossible to understand how much of the Great Barrier Reef has been lost, or recovered, since the last mass bleaching event"
https://www.theguardian.com/environment/2022/aug/06/great-ba...
"Dr Emslie, who leads the ... monitoring, says the rise in coral cover was expected, given the relatively benign conditions, but four bleaching events in seven years was uncharted territory."
In some conservative media, the survey has been used to push arguments the reef is not under threat. “The naysayers can put their heads in the sand all they like, but the frequency of disturbances is going gangbusters,” says Emslie.
Wachenfeld points out that scientists have never said the reef is dead. “Scientists have been ringing an alarm bell, not a funeral dirge,” he says. “The notion scientists have been misleading people is a nonsense.”
He likens the reef’s resilience to a rubber band that can be stretched many times, but only so far before it snaps.
“It’s hard to predict when that will happen, but it’s a bit like that with the reef,” he says. “We have a limited amount of time to slow and stop the warming. There is no way this resilience can last forever.”
The rest I will leave for somebody else.
Was it now. A Guardian news report featuring Dr Emslie in March 2019 has one of his colleagues saying this [1]:
the preliminary results of the study, and the lack of observed improvement in previously surveyed reefs, showed how difficult it was for corals to rebound after mass bleaching. “That doesn’t surprise me because it takes 10 years for coral to rebound,” Hughes said. “There’s been some reports of magical recovery, but the ecological memory of the bleaching will be long-lasting. “The big unknown is when it will bleach again, but it will almost certainly be before those reefs have time to recover.”
In 2019 it is being predicted to take 10 years to rebound, any reports of recovery are "magical" exceptions to the rule and the next bleaching will "almost certainly" be before the reefs have time to recover.
In 2022 it is not only fully recovered but at record breaking levels, this was fully expected, the idea scientists misled people is "nonsense" and only those dastardly "conservatives" and "naysayers" have any issues with what's happened.
Do you see the problem here? These people aren't behaving like scientists, they are behaving like political activists. They make assertions that they fully understand the corals and that their predictions are "almost certain", then when the corals do things that contradict their prior understanding they lash out and argue that only "conservatives" care about the confidence bounds of modelling predictions. Observe how wildly biased that is. In the world they inhabit anyone who is pointing out inconvenient facts can be immediately dismissed by saying they're not a part of the tribe, nothing else is needed!
> "We have a limited amount of time to slow and stop the warming. There is no way this resilience can last forever"
... he said, fervently hoping that the reefs will just hurry up and die already so they can stop being shown up.
[1] https://www.theguardian.com/environment/2019/mar/04/some-gre...
No.
From the article:
"Inferring that a reef has recovered by a person being towed behind a boat to obtain a rapid visual estimate of coral cover is like flying in a helicopter and saying a bushfire-hit forest has recovered because the canopy has grown back.
It provides no information about diversity, or the abundance and health of other animals and plants that live in and among the trees, or coral."
She's also moving the goalposts, but her argument makes no sense. Now the coral is at record-breaking coverage the problem has become that it's the wrong type of coral - except the justification for it being the wrong type is that it consists mostly of the type of coral that grows the fastest. Which is obvious and circular: in any natural ecosystem that involves regular dieoffs and regrowths, some species will grow back faster. That's inherent to a diverse natural world, the exact thing she claims to be worried about losing.
Putting corals aside for a moment, I hope we can find agreement on the underlying meta-scientific issue here. Scientists in whatever field should carefully study their domain and either come to fully understand it, or if they can't do that, at least understand their own level of understanding. What people need to see from universities is a recognition when they make confident predictions that are later falsified. Without the recognition that falsification has occurred, science cannot advance.
In this case they're refusing to accept that falsification has happened, instead engaging in ad hominem attacks, goalpost shifting, circular reasoning and other fallacies. The approach of these biologists is summed up by this chef's kiss statement:
"While there’s no data to prove or disprove it, it’s also probable ..."
If human extinction occurs due to climate change, this will be how. Anoxic ocean events can lead to massive emissions of hydrogen sulfide (H2S) into the atmosphere. This is the speculated mechanism for the end-Permian extinction event, also known as the Great Dying, and several other mass extinction events in Earth's history. H2S is immediately dangerous to human life at concentrations as low as 100ppm. It's so dangerous that humans have evolved to smell it in concentrations as low as 100 parts per billion.
UW-Seattle professor Peter Ward has spoken about this at length:
The H2S in question is produced mainly by sulfate-reducing bacteria in the ocean, so targeting these microorganisms might be one way to stave off disaster. That would require massive bio-engineering on a scale never before seen in history.
Right now we're just crossing our fingers and hoping we can reduce carbon emissions and ocean warming fast enough, and that we don't trigger (or haven't already triggered) runaway warming feedback loops such as the clathrate gun hypothesis.