Guest essay by Eric Worrall
Even 1.5C would kill 99% of all coral, according to the study. But I think there is room for a little doubt.
Corals doomed even if global climate goals met: study
by Marlowe Hood
FEBRUARY 6, 2022Coral reefs that anchor a quarter of marine wildlife and the livelihoods of more than half-a-billion people will most likely be wiped out even if global warming is capped within Paris climate goals, researchers said Tuesday.
An average increase of 1.5 degrees Celsius above pre-industrial levels would see more than 99 percent of the world’s coral reefs unable to recover from ever more frequent marine heat waves, they reported in the journal PLOS Climate.
At two degrees of warming, mortality will be 100 percent according to the study, which used a new generation of climate models with an unprecedented resolution of one square kilometre.
“The stark reality is that there is no safe limit of global warming for coral reefs,” lead author Adele Dixon, a researcher at the University of Leeds’ School of Biology, told AFP.
“1.5C is still too much warming for the ecosystems on the frontline of climate change.”
…
Read more: https://phys.org/news/2022-02-corals-doomed-global-climate-goals.html
The abstract of the study;
Future loss of local-scale thermal refugia in coral reef ecosystems
Adele M. Dixon, Piers M. Forster, Scott F. Heron, Anne M. K. Stoner, Maria Beger
Published: February 1, 2022
Thermal refugia underpin climate-smart management of coral reefs, but whether current thermal refugia will remain so under future warming is uncertain. We use statistical downscaling to provide the highest resolution thermal stress projections (0.01°/1 km, >230,000 reef pixels) currently available for coral reefs and identify future refugia on locally manageable scales. Here, we show that climate change will overwhelm current local-scale refugia, with declines in global thermal refugia from 84% of global coral reef pixels in the present-day climate to 0.2% at 1.5°C, and 0% at 2.0°C of global warming. Local-scale oceanographic features such as upwelling and strong ocean currents only rarely provide future thermal refugia. We confirm that warming of 1.5°C relative to pre-industrial levels will be catastrophic for coral reefs. Focusing management efforts on thermal refugia may only be effective in the short-term. Promoting adaptation to higher temperatures and facilitating migration will instead be needed to secure coral reef survival.
Read more: https://journals.plos.org/climate/article?id=10.1371/journal.pclm.0000004
Given that there is at least 6C climatic range from the subtropical Southern to the tropical Northern tip of the Great Barrier Reef, it is impossible that 0.5-1C of warming would wipe out the entire reef.
So where did the study authors go wrong?
Delving into the study, it appears they pulled the marine version of the agriculture study trick.
Agricultural studies which predict imminent climate doom usually make completely unrealistic assumptions, like assuming farmers won’t try anything new, that they’ll keep dumbly planting exactly the same crop mix, year after year, regardless of what happens to yield.
In a similar way, the authors of this coral study appear to have assumed low coral mobility.
A lack of coral mobility is not a reasonable representation of nature. Mature corals might be stuck in place, anchored to rocks or other corals, but every year corals spawn countless billions of highly mobile larvae, which seek out favourable sites to colonise.
So any overheated reefs would be rapidly colonised by coral larvae whose parents are adapted to warmer water.
The researchers assigned a temperature value to each point on a very fine grid, compared it to the modelled pre-industrial temperature, and set a threshold which according to climate models will shortly be breached. This led to the unrealistic study conclusion that stressed grid points will rapidly increase from 6.8% of the study region (according to their assumptions) to 99-100% of the study region.
There is no serious upper temperature limit to coral heat endurance. Hot water extremophile corals like those from the Persian Gulf endure far hotter water temperatures than any open ocean, yet they are just as mobile as any other coral.
Even if the world were to experience insanely implausible levels of global warming, the extremophile corals would erupt out of their limited hot water ecological niches and colonise the entire rest of the ocean. The mix of species might change, but the reef as a whole would stay healthy.
These studies have a place, as a mathematically modelling exercise, or a baseline exercise. But the suggestion of real world applicability, the suggestion that corals cannot survive a small long term temperature shift is utterly contradicted by the wide climatic range of real world reefs like the Great Barrier Reef, which contain more or less continuous stretches of different climatic conditions, from the subtropics to the far Northern high tropics.
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Was this peer reviewed? If so, who reviewed it? These are the ones who really need to answer questions. Come on now. who are you? I know you are reading this thread.
And as for you Adele, you are an embarrassment to science.
I wonder if she can bake a cake. Maybe she would do well working in a bakery. Unless, of course, the thermal gradients involved terrify her.
Let’s just throw a few more billions of dollars at them and see if they get any better!
Morons going on record, apparently to prove they are morons to future generations.
“All Coral Reefs will Die if 2C Climate Target Breached”
Tell that to the coral reef in my living room that experience 2C temperature variation every day. I guess my reef didn’t get the memo!
My introduction to Anthony Watts was regarding a weather station inside Los Angeles where urban heat islands would impact the weather station. It is important for readers to understand that urban heat islands are in fact urban heat generators first.
In Canada, Environment Canada, Meteorological Services provides Regional Climatic Data through Building Codes. Buildings are designed and insulated to accommodate different regions from the deserts to the Arctic. The goal is not to impose on the atmosphere and be energy efficient so less fossil fuels are used which reduces GHG emissions.
In my area Building Code uses -20 degree C to simulate the coldest time of the year and 35 degree C for the hottest time of the year. Buildings will be insulated and their energy systems will be designed to accommodate those temperature extremes. Building Code warns of solar radiation impact being more significant than Climatic Data.
Municipalities or regions depend on this as do banks, lenders or insurers. A building not compliant with applicable codes would not get financing or allow occupancy.
Exterior finishes of buildings has to be low emissivity(not absorbent) or shaded all year to protect the building from solar exposure. White washed buildings reflect solar radiation.
The deregulation of the construction industry has allowed contractors and public to use absorbent siding, paint or finishes on the solar exposed exteriors. Here is an example of what that looks like in the winter. Keep in mind when you talk about heat transfer, hot excited energy always transfers to cold. As a thermal radiation consultant with a 43 year background, temperature for us starts at Absolute Zero(-273 deg. C or -496 deg. F). As far as accuracy, we have been within 1/10 of a deg. C imaging groundwater upwellings in a river. Canadian Department of Fisheries and Oceans used our work as their standard due to the fact no one else had developed the imaging application.
UN is worries about a 2 deg. rise in atmospheric temperature, here is a brand new building generating extreme heat in the winter. It is 39 deg. F day in January and the exposed exterior is as hot as 155 deg. F. The UV index is lower and the radiation weaker. In the summer months, air conditioning will run 24/7 using 1000s of watts per hour responding to symptoms.
Air conditioning is in fact refrigeration.
Is 155 degrees F more than a 2 degree rise? Hell is here for what politics and special interests have allowed to happen.
155F would blister anyone who touched it instantly.
If it’s that hot in the winter, how hot does it get in the summer.
I strongly suspect your calibrations are way off.
You’re right. See the sun shining upon the dark surfaces in front. The same dark surfaces around the corner in the shadow are far colder even though are at walls from the same room inside.
Dang! Soon there will be coral reefs in Nova Scotia. Next trip to Canada, I’ll bring my snorkel, flippers and baggies!
This isn’t science … it’s bullshit, not to put too fine a point on it.
Clearly I’m too stupid, as are all of you, to read history and note some inconvenient facts such as the climate has always changed? Sometimes hotter, sometimes colder. Always and ever changing.
But no – “trust the seance”. Communism will solve our problems.
Too stupid for words, in the event of warming the Australian reef could migrate from Queensland in the direction of Tasmania as it dies off at the top and extends at the bottom.
But there is no need for that as the commentary explained.
It is stunning idiocy that they modeled this and have ZERO clue about the aquatic environment. With upwells, winds, slacks, etc., the reef temperature varies more than 2.0C. A quick search would have shown them that there is already a 6 degree change seasonally. Their model PROVES that having a salt water aquarium with coral is beyond impossible. How stupid do you have to be to make the assumptions they do? So the new low bar is, if you can succeed at any major, become a climate ‘scientist’? Bachelor degrees in basket weaving now have someone to sniff their noses at.
PhD students have typically graduated from lower levels of academia, have they not? Has the education system so degenerated that the very concept of critical thinking no longer exists?
Yes.
I think I’ve figured out how this works. If it’s 2 degrees of natural warming the corals will do fine because natural systems work in harmony. If it’s 2 degrees of manmade warming the corals will die because mankind is a relentlessly destructive influence.
But, but, but, don’t they claim that the earth has already warmed by 1C? And corals seem to be doing just fine. Yet another 0.5C will be a disaster?
The year 2016 hit 1.1C above the average, according to NASA/NOAA, and, as you note, the corals did just fine then.
Now the temperatures are 0.7C cooler than 2016, so the coral reefs are getting farther from “danger” instead of closer.
Coral larvae don’t “seek out” suitable habitat except on a small scale. They aren’t going to swim 100 kilometers looking for cooler waters; they are at the mercy of the currents. The ability to adapt to temperature changes depends on the genetic diversity of the corals, and there’s not reason to assume that it’s enough to handle extreme temperature changes. It’s not the average water temperature that’s the issue, but periodic extremes. They can recover to some extent, but if you have extremes that are more frequent, they don’t have a chance to do so,
History tells a different story.
Krusti has never explained how corals survived far hotter conditions in the geologically-recent past.
So they spawn and just sit still … you really can’t be that retarded 🙂
Once again you demonstrate a complete lack of knowledge regarding the real world.
Ocean currents distribute each generations coral larvae over a wide area. When the get deposited in habitable environments, they thrive. If they don’t, they die. If they need to move a mile or two polewards in order to find that habitable environments, the currents will take care of that.
It is a similar survival strategy to pine trees that put out such a copious quantity of yellow pollen that roofs, sidewalks, and cars get covered with it, all in the ‘hope’ that a few find a receptive location.
Kristi, have you ever read what Charles Darwin (yes, that fellow who has its picture in every book on evolution) has written about the life of corals? In the geologic time scale? And speaking abut evolution, adaptation, extremes, distances, etc.: have you ever read the two volumes on cirripeds, written by the same Charles D.? There you have a lot of PRACTICAL information on methods to observe, evaluate and understand all those concepts.
You wrote somewhere in this thread that someone was “taking an extremely complex system and boiling it down to a simple calculation“: well, are you not doing the same thing?
Quoting from the paper “Oceans absorb about 93 percent of the excess heat from greenhouse gas emissions…” So anyone who is this incapable of basic calculations would be easily convinced that 1.5 C temp rise will kill all corals…
I thought it was supposed to be 97%?
This post is an example of a little knowledge being worse that none at all. You can’t understand the complexities of coral reels through argument.
Kristi Silber, you have spammed this thread relentlessly with inane comments. Are you getting paid by the word?
Kristi,it is apparent to me that you don’t understand the complexities of coral reefs,or the oceans and indeed the climate.
Keep digging. You are taking Leeds to a whole new level.
If you have no physical experiment data you are just guessing.
Kristi, thanks for the comments, your “input” is welcome. The knowledge I have gleaned from this website is far from “little”.
The instrumental record, such as it is, indicates the planet has been sporadically warming since the coldest decade (1640-50) of the “The Little Ice Age” (1250-1850), one of several cooling periods within the current interglacial epoch, The Holocene. From the mid-17th century existing data indicates mean temperature has increased .5 degrees C. per century. The ice-core millenial temperature reconstructions (GISP2) suggest the idea of a recovery out of the LIA is reasonable.
The United Nation’s Intergovernmental Panel for Climate Change (IPCC) supports the Anthropogenic Global Warming (AGW) hypothesis claiming the late 20th century warming (.5°C.) was mostly man-made. The academic climate science community explains the heat “trapped” by the additional CO2 (est.100 parts per million of the 410 ppm level) from our emissions along with the supposed lack of any other valid explanation affirms the position.
Carbon dioxide (CO2) does not “trap” heat, rather it convects it, (hot air rises, even if that “air” is CO2). Heat flux at the surface is “evaporation and convection”, scientifically described as “latent and sensible”. The surface is also where CO2 plays its vital role; the macroscopic effect of allowing photosynthesis and life on earth.
CO2 is a radiatively active molecule, its spectral properties are measured (MODTRAN), it absorbs and emits in the far infrared (IR) of the electromagnetic scale, centered on an amplitude of 15 microns, for which the corresponding (Wien’s law) temperature of minus -80°C. is found 5 to 6 kilometers above the surface, above the cloud deck where there is no water vapor yet still within the troposphere. Heat flux at this level is primarily radiative, it is academically described as the “Average Emission Level” where incoming solar shortwave IR is balanced with outgoing terrestrial longwave (OLR). Energy in = energy out (thermodynamics 1st law). The man-made CO2 raises the level to a colder altitude thus delaying the radiative cooling process ergo the temperatures below, including the surface, must increase to re-establish equilibrium. Entropy never decreases, maximum entropy is equilibrium (thermodynamics 2nd law.)
So the entire AGW premise is that there is an imbalance in the amount of radiant energy delivered to Earth by the Sun and the amount of radiant energy lost by the Earth via OLR . The difference shows up as an increase in temperature, and thus we have the concept of “global warming.” How much it warms is the debate. The IPCC places estimates of mean temperature increase from 1.5 to 4°C per atmospheric doubling from ice-core measured pre-industrial CO2 levels (270ppm). Observational studies lead to estimates around 1°C….i.e. marginal.
Furthermore, the academic emphasis on the CO2 “theory” of global warming overlooks the scrutiny required to dismiss the other arguments… namely natural variability, which, along with the glacial responses to the Earth’s orbital/axial cycles includes solar activity, the fluid dynamics for both ocean and atmosphere and the influence of the equator to pole temperature gradients. CO2 is a trace gas, its atmospheric portion is 400 molecules per million molecules of air, the man-made portion of that is estimated one molecule per 10-20,000 molecules of air. The “evidence” for AGW amounts to extrapolations of selected short-term trends apparent in the instrumental record, numerical model projections, comparing instrumental data with the mush of proxy data and treating a “consensus” as a scientific case for CO2 climate.
Long story short, there is no evidence supporting man-made global warming as a concern. Climate change is much more than CO2 and CO2 is much more than climate change.
Regards, M.W. Plia.
This from the girl who doesn’t understand how currents distribute coral larvae over a wide area.
BTW, so far all you have done is whine that us know nothings don’t agree with these scientists, therefore we must be wrong. Why don’t you actually try to refute any of the counter arguments? Or is whining truly all you are capable of?
Kristi: please, don’t say that! You don’t know who are the persons posting comments, what they are (or were; many of us are retired) professionally, what are, or were, their fields of activity.
Please, take the others seriously, don’t dare to judge or evaluate them, when they are exchanging sound arguments with you.
You seem to be quite young; I also was young, I can put myself in your shoes (at least, I try). All of us can help you, and (I speak blindly for them, without having asked their consent) many of us are WILLING to help you.
So, please, don’t break the bridges.
Very true. And it is likely that someone who is young and naive is inclined to assume that because we aren’t household names, or don’t flaunt our academic credentials, that we are bumpkins that don’t know anything.
Or understand it through a model. One fact that disputes it disproves a model. Just showing a seasonal variance > 6 degrees C shows put that far outside their model. My guess, their model would be 2 deg +/- 10 degrees.
/former Econometrics Masters candidate before I discovered computers were more fun and profitable.
Back here in “reality”, it would seem by all recent accounts that the GBR is doing fine despite the incessant petulant screeching of climate alarmists™ sat behind their computers.
Last year saw no prolonged high temperatures.
Outbreaks of crown-of-thorns starfish have decreased.
Hard coral cover was up 27% in the North, 26% in the Central GBR and 39% in the South.
How uncollegial of you. Daring to disprove the work of another scientist.
If you keep that up you will be declared a non-person and be fired.
Oh dear! One of my grandchildren is at Leeds University. Is this the sort of thing she will be taught? Where have all the standards gone?
It is unbelievable that people who claim to be scientists are being paid to produce such garbage. A quick look at the temperature profile along the GBR should have revealed a “catastrophic” spoiler alert for these drongos.
This is ridiculous. It is impossible for surface water temperature to increase above 31.5c due to evaporation/ equation of state.. It is a very well known phenomenon of tropical surface water temperatures. Coral is adapted to live comfortably up to 31.5c.
As several other commenters have noted data from the Great Barrier Reef (GBR) would indicate the media headlines resulting from the press release for this study are wildly exaggerated.
The HadISST dataset is a reanalysis of sea-surface temperatures on a 1°x1° grid with monthly time resolution since January 1870.
Following another “All corals are going to DIIIIIIIIIE ! ! !” story last April (2021), just out of idle curiosity I updated my spreadsheet to include HadISST numbers up to December 2020.
Selecting only those gridcells with at least 40% of their area included in the GBR, and calculating the “deltas” between each “summer max (/ winter min)” and “winter min (/ summer max)”, which have occurred every six months since 1870, I saw the screenshot below on my computer around 10 months ago …
Notes
– The minimum “deltas” (light-blue line / dots, right-hand axis of the graph) that have been “endured” by corals on the GBR every six months since 1870 are on the order of 3°C … i.e. more than the 2°C “hysterical headline” figure above.
– The maximum “deltas” (orange line / dots) for all gridcells (since 1870) are at least 6°C, and for some gridcells (close to the east coast of Australia, in the 20-22°S latitudes) around 9°C.
– Over the entire GBR, corals exist in temperature ranges from ~23°C to ~30°C in the northern (tropical) section down to ~20-21°C to ~29°C in the southern (sub-tropical) section.
NB : Other commenters have noted that there is a “hard upper limit” to open-ocean SSTs somewhere around the 31 to 32°C level.
– The “hottest” latitude for the GBR is in fact 14°S, whose 2 cells have (very slightly) higher “summer max” values than the 11-13°S rows.
2C merely gets the world back to where it was during the Medieval Warm Period.
Corals are old, they survived the PETM spike.
” Study: All Coral Reefs will Die if 2C Climate Target Breached ”
WRONG!
All they will die if 1.95C is breached!
Why do people insist on thinking that atmospheric temperatures cause marine heat?
The sun heats the ocean. Period. There is no other way demonstrated it can happen.