Thomas Mortlock, Macquarie University; Itxaso Odériz, Universidad Nacional Autónoma de México (UNAM); Nobuhito Mori, Kyoto University, and Rodolfo Silva, Universidad Nacional Autónoma de México (UNAM)
Sea level rise isn’t the only way climate change will devastate the coast. Our research, published today, found it is also making waves more powerful, particularly in the Southern Hemisphere.
We plotted the trajectory of these stronger waves and found the coasts of South Australia and Western Australia, Pacific and Caribbean Islands, East Indonesia and Japan, and South Africa are already experiencing more powerful waves because of global warming.
This will compound the effects of sea level rise, putting low-lying island nations in the Pacific — such as Tuvalu, Kiribati and the Marshall Islands — in further danger, and changing how we manage coasts worldwide.
But it’s not too late to stop the worst effects — that is, if we drastically and urgently cut greenhouse gas emissions.
An energetic ocean
Since the 1970s, the ocean has absorbed more than 90% of the heat gained by the planet. This has a range of impacts, including longer and more frequent marine heatwaves, coral bleaching, and providing an energy source for more powerful storms.
But our focus was on how warming oceans boost wave power. We looked at wave conditions over the past 35 years, and found global wave power has increased since at least the 1980s, mostly concentrated in the Southern Hemisphere, as more energy is being pumped into the oceans in the form of heat.
And a more energetic ocean means larger wave heights and more erosive energy potential for coastlines in some parts of the world than before.
Read more: Ocean warming threatens coral reefs and soon could make it harder to restore them
Ocean waves have shaped Earth’s coastlines for millions of years. So any small, sustained changes in waves can have long-term consequences for coastal ecosystems and the people who rely on them.
Mangroves and salt marshes, for example, are particularly vulnerable to increases in wave energy when combined with sea level rise.
To escape, mangroves and marshes naturally migrate to higher ground. But when these ecosystems back onto urban areas, they have nowhere to go and die out. This process is known as “coastal squeeze”.
These ecosystems often provide a natural buffer to wave attack for low-lying coastal areas. So without these fringing ecosystems, the coastal communities behind them will be exposed to more wave energy and, potentially, higher erosion.
So why is this happening?
Ocean waves are generated by winds blowing along the ocean surface. And when the ocean absorbs heat, the sea surface warms, encouraging the warm air over the top of it to rise (this is called convection). This helps spin up atmospheric circulation and winds.
In other words, we come to a cascade of impacts: warmer sea surface temperatures bring about stronger winds, which alter global ocean wave conditions.
Read more: Curious Kids: why are there waves?
Our research shows, in some parts of the world’s oceans, wave power is increasing because of stronger wind energy and the shift of westerly winds towards the poles. This is most noticeable in the tropical regions of the Atlantic and Pacific Oceans, and the subtropical regions of the Indian Ocean.
But not all changes in wave conditions are driven by ocean warming from human-caused climate change. Some areas of the world’s oceans are still more influenced by natural climate variability — such as El Niño and La Niña — than long-term ocean warming.
In general, it appears changes to wave conditions towards the equator are more driven by ocean warming from human-caused climate change, whereas changes to waves towards the poles remain more impacted by natural climate variability.
How this could erode the coasts
While the response of coastlines to climate change is a complex interplay of many processes, waves remain the principal driver of change along many of the world’s open, sandy coastlines.
So how might coastlines respond to getting hit by more powerful waves? It generally depends on how much sand there is, and how, exactly, wave power increases.
For example, if there’s an increase in wave height, this may cause increased erosion. But if the waves become longer (a lengthening of the wave period), then this may have the opposite effect, by transporting sand from deeper water to help the coast keep pace with sea level rise.
For low-lying nations in areas of warming sea surface temperatures around the equator, higher waves – combined with sea level rise – poses an existential problem.
People in these nations may experience both sea level rise and increasing wave power on their coastlines, eroding land further up the beach and damaging property. These areas should be regarded as coastal climate hotspots, where continued adaption or mitigation funding is needed.
It’s not too late
It’s not surprising for us to find the fingerprints of greenhouse warming in ocean waves and, consequentially, along our coastlines. Our study looked only at historical wave conditions and how these are already being impacted by climate change.
But if warming continues in line with current trends over the coming century, we can expect to see more significant changes in wave conditions along the world’s coasts than uncovered in our backward-looking research.
However, if we can mitigate greenhouse warming in line with the 2℃ Paris agreement, studies indicate we could still keep changes in wave patterns within the bounds of natural climate variability.
Read more: Seabirds are today’s canaries in the coal mine – and they’re sending us an urgent message
Still, one thing is abundantly clear: the impacts of climate change on waves is not a thing of the future, and is already occurring in large parts of the world’s oceans.
The extent to which these changes continue and the risk this poses to global coastlines will be closely linked to decarbonisation efforts over the coming decades.
This story is part of Oceans 21
Our series on the global ocean opened with five in depth profiles. Look out for new articles on the state of our oceans in the lead up to the UN’s next climate conference, COP26. The series is brought to you by The Conversation’s international network.
Thomas Mortlock, Senior Risk Scientist, Risk Frontiers, Adjunct Fellow, Macquarie University; Itxaso Odériz, Research assistant, Universidad Nacional Autónoma de México (UNAM); Nobuhito Mori, Professor, Kyoto University, and Rodolfo Silva, Professor, Universidad Nacional Autónoma de México (UNAM)
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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So is climate change affecting the moon now?
Can’t we have a monthly competition whereby we have to vote as to which of the articles carried here during that month was a hoax?
I am sure many of us could write a plausible hoax article which might escape detection.
These days every child wins a prize. Otherwise, it’s discrimination.
In today’s post modern, post truth cancel culture, everyone gets full Marx.
tonyb,
Consider this-
“Aliens may destroy humanity to save other civilisations,say Scientists.”-
Ian Sample in The Guardian,Friday,19 August,2011.
Sample (excuse the pun)-
“Rising greenhouse emissions could tip off aliens that we are a rapidly expanding threat,warns a report….
When they see what we have done to our planet,extraterrestrials may be forced to take drastic action…..”
This was a straight news report not a parody.
How could you beat that with a hoax competition?
Back during the Cold War there was a lot of talk that the only thing that would save mankind was a common enemy. We would have to be attacked by extraterrestrials before we would forget our differences and joint together to fight ’em.
Now that Global Warming (i.e., ‘Climate Change’) is losing it’s appeal this whole ‘Unidentified Aerial Phenomena’ (UAP) video release is most likely the next big ticket to One World Government if it’s presented right and properly frightens the masses. You can be sure they’ll play it for all its worth, but if it doesn’t do the job they’ll think of something else to get everyone in line.
“I am sure many of us could write a plausible hoax article which might escape detection.” And make it absurdly over the top- and see how many people eat it up as facts- put it on Facebook and see if it’s deleted. Maybe it’ll get quoted in the NYT or Guardian or Unscientific UnAmerican.
The winner of the competition for best “is it a hoax?” article would be the paper that not only got the most votes but the most comments endorsing it in the Guardian, New York times or social media generally.
tonyb
Bonus points if Biden raves about it.
Be careful what you ask for!
A few years ago, a parody website created a spoof article claiming that the “OK” hand sign was really a white power sign used by white supremacists. Now people actually believe it and people have gotten fired over it because they used the hand sign in a photograph. People are even dumber than you think, and they may outnumber the educated soon, if they haven’t already.
People are even dumber than you think, and they may outnumber the educated soon, if they haven’t already.
Sorry,I have to take exception with this assertion. Nowadays, thanks to Marxist indoctrination in Western Universities, “educated” people are substantially more stupid and ignorant than those who have attended the Great University of Life.
tonyb,
Hasn’t The Conversation already cornered the market? You’d have to hide the source.
Yes!
The moon is sick and tired of humans destroying the Earth with their CO2 emissions, so decided to leave the Earth’s orbit decades ago.
Currently, the moon is moving away at a rate of 38 mm or 1.5″ per annum.
..Currently, the moon is moving away at a rate of 38 mm or 1.5″ per annum.
I thought I noticed it seems smaller, and the colour is not so blue, bit of red shift maybe?
Thanks Redge.
Cheers
Mike
Didn’t that come about after the moon landings left a laser device beaming back to Earth? I also thought that it was as a result of realising that the moon’s orbit was elliptical & not circular!
I don’t think so although I do wonder if the moon moving away can affect cloud movement, wind patterns etc, even if imperceptible like a butterfly
Actually the moon’s orbit is neither elliptical nor circular. It is more like an Indian One Anna piece, from the 1950 coinage. This has a 12 scalloped edge, and the moon’s orbit is similar, as the distance from the sun moves in and out through about 147 to 153 million km. The difference is that the orbit is always convex to the sun – or is it always concave, not sure which – very confusing!
This makes it clear that the moon does not orbit the earth – we are in a twin planet system in approximately the same orbit, with alternatively the inner planet overtaking the outer, then being attracted out while the outer planet is attracted in, and thus then becoming the faster planet!
Saturn has two similar moons but as their diameters are larger than the difference in the inner and outer orbits, the inner as it approaches the outer is attracted out and the outer is attracted in, so they just switch orbits and never collide. Just as well!
The Moon used to be closer to the earth.
In fact, about 66 million years ago it was so close that the dinosaurs died out.
Well, the tall ones, anyway!
Auto.
Climate change is heating up the earth’s atmosphere so much that it’s expanded to the moon’s orbit and is slowing it down.
Hey, they said that about meteors, so why not?
OMG! OMG! Maybe it’s time for us to give up our denialism ways and listen to the science
https://wp.me/pTN8Y-7oa
Apparently Bill Gates and Barack Obama didn’t get the memo:
https://www.forbes.com/sites/kathleenhowley/2019/12/08/barack-and-michelle-obama-buy-marthas-vineyard-estate/
https://www.sandiegouniontribune.com/business/real-estate/story/2020-04-22/report-bill-and-melinda-gates-buy-43m-del-mar-home
Or maybe they’re counting on the finding that the waves will be worse in other parts of the world?
You left out little Leo’s island estate in Belize and his Malibu house. https://www.velvetropes.com/backstage/leonardo-dicaprio-house
Yeah they really believe that sea levels are going to rise drastically.
It is funny why people don’t trust those that don’t walk the talk.
YUH…….the goreacle used to talk doom and more doom, about sea level rises of ‘upto 6 meters’ and then he was copped investing in Miami beachfront condos.
Send em thru Huey
Surfs up … sweet.
Yeh haa
The article is a really bad bucket of bullshit. Doesn’t mention what their results are, how significant or what the error bars are. After all how does one measure all the waves, all the time, over some significant period like say 40-50 years. No sign either that these alarmists ever heard of ice ages and interglacials – if the world has been trying, with lots of difficulty, to come out of the deep freeze for the past few thousand years, how do they manage to turn it into a bad thing and blame it on humans? Do they not realize that the current cold snap (a few million years snap compared to the hundreds of millions years of very warm periods) is likely to be temporary – if the climate is like a pendulum that will swing back to Jurassic conditions – or God-forbid that it is a continual trend and we’re heading for another deep freeze (many posts on wuwt that pointing out the downward trend in the temperature peaks of the Warm Periods, where the Minoan Warm Period was a bit warmer than the Roman Warm Period, which was warmer than the Medieval Warm Period, which was still warmer than our climate emergency warm period (based at least on what and where could be grown 1000 years ago compared to now, in spite of all our tech).
”After all how does one measure all the waves, all the time, over some significant period like say 40-50 years.”
Like this…
”The primary source of the net long-term variability is evaluated based on historical wave simulations”.
Yeah, they measured nothing.
The trouble with measurements is that after a few decades of more heat = more wind = more/bigger hurricanes, we’ve been able to measure nothing of the sort. So they forgot all about hurricanes and simply substituted to get more heat = more wind = more/bigger waves (go ahead and dispute us because you have no data and we have models).
The schools long ago forgot to teach that two thirds of the. world is coveored by water. How in ………do you even guess a measurement.
Oh .when you do the math don’t forget the weather
And the actual facts are the reverse of what these people claim. On the east coast of Australia where I live, up until the big Pacific climate shift of the late ’70s, cyclones were tearing the coast away and I spent many nights sandbagging ocean-front homes that often got washed out to sea in spite of huge efforts to save them. One time we had to dump dozens of car bodies to protect high-rise buildings.
Since then there has been almost no repeat of that coastal erosion and those ocean-front properties that you couldn’t give away in those days change hands today for tens of millions.
As are similar ocean fronts all around the world. The most sought-after properties.
Being somewhat old fashioned – where is the evidence?
Waves are driven by wind, wind by pressure differences, pressure differences by the temperature difference between the equator and the poles and the poles are warming faster than the equator. What am I missing?
“it is also making waves more powerful”
this is the sad state of science now…particularly climate science, but it has leached to other fields. All you have to do is measure a change in time of some variable, then attribute it to climate change (aka manmade co2 increases causing temperature increases causing whatever effect they are measuring) without any evidence or pushback whatsover. Where is the evidence that manmade co2 caused whatever observable atmospheric temperature change, and then where is the evidence this changed the rate of sea level rise, and then where is the evidence that this change in the rate of sea level rise caused more powerful waves? There is nothing offered along the entire causal chain, just assertions.
Science really is that simple now. X changed. Y also changed. Therefore X must have caused Y, send money.
”Science really is that simple now. X changed. Y also changed.”
First we need to see evidence that Y changed in the first place. This ain’t it.
It’s a cluster f**k. They said so themselves…””A novel “dynamic clustering” method was developed”
“…wave conditions towards the equator are more driven by ocean warming from human-caused climate change…”
Well it is a good thing that the oceans at the equator are essentially unable to warm at all because they immediately cool themselves with clouds. The warming at the equator is generally held to be nil and the warming at the poles is said to be enhanced, amplified.
If these claims are true, then there can be precious little warming at the equator, and the claim that it is anthropogenic while poleward warming is natural makes no sense at all. How can equatorial warming be essentially zero and anthropogenic while Arctic is significant and natural? Why wouldn’t the tiny amount of equatorial warming not be natural as well?
Is it even detectable? If it is detectable how do they disaggregate the anthropogenic portion? This article has the flavour of a Diszak-led investigation into the origins of SARS-Cov-2.
I was also struck by the essential inversion this paper asserted (wave energy higher at low latitude’s due to AGW, whereas most climate models assert AGW would impact the higher latitudes most. This flipped the script.
Wading through the linked research paper one finds dramatically less drama, which is typical for this genera. None of the graphs show any increase in wave power over the last 30 years, and it is only the quieter phase of the first 10 years that leads to an overall trend – that isn’t really a trend if things have been flat for 30 years, right? Also natural variability is shown as several times larger than even their made up anthropogenic portion.
This is welcome news for surfers! Burn more coal!
Farrago of bullshit which fits the criteria of science Written by idiots and peer reviewed by idiots .Two geological points
1) Maldives A carbonate factory where coral reefs keep up with sea level and land mass accretes during storm surges when ground up coral debris is swept ashore as gleaming white sand. good news for keeping the land above water…
2) In a transgressive system where sea level is increasing (At about the constant rate of 2 mm per yea)r the coastline has to retreat unless tectonics make it rise . This has been going on throughout the present interglacial . You can hold it back ;like Holland or learn to live with it. Cutting down mangroves and installing urban infrastucture or shrimp farms are probably the worst way to handle it. But it ain’t climate change -its just nature
From their ”conclusion”…. ”A novel “dynamic clustering” method was developed to classify the global ocean WCTs according to the planetary wind systems responsible for their genesis,
A novel ”dynamic clustering” no less, based on WCTs (Wave Climate Trends – oh yeah! wave climate!) which were based on close to 100 year global warming scenarios (according to their references) which determined the wind would possibly behave in a certain manner at some time in the future in some places – where they can tell the difference between that and natural variability – if everything goes according to plan.
The lead author… https://theconversation.com/profiles/thomas-mortlock-716584
…is paving his future. This is science made to order…again.
The climate of southern Australia is controlled by Climate DOGS.
https://agriculture.vic.gov.au/climate-and-weather/understanding-weather-climate-and-forecasting/the-climatedogs-the-six-drivers-that-influence-victorias-climate
Alarmist theory states that Ridgy ( sub tropical ridge) will strengthen and Sam ( southern annular mode) will weaken.
This theory is needed to spread fear that southern Australia will have more droughts and bushfires.
Alarmists however also try to state that SAM will be stronger to cause more storms, storm surge, floods and erosion.
They deceitfully don’t want to discuss the quantitative statistics of how a stronger and weaker SAM actually works.
Where are these wave strength metering machines located and where is a graph of the results?
Vapourware
Wind speed, fetch and duration = wave energy. Ask any sailor. The formula is as old as man’s love affair with the sea.
“My life, my love snd my lady is the sea”.
Looking Glass
One of the best songs ever
Yo, duuuude! … Rad barrels out there! (‘surfing stoke’).
What utter BS.
Australian response:
Yay, surf’s up!
The paper and The Conversation article do not mention cloud variability.
As climate4you states:
“… quite often a change in sea surface temperature appears to be initiated 1-3 months before the corresponding change in surface air temperature …” and “… the huge ocean surface in the Tropics is nearly perpendicular to the incoming direct solar radiation at daytime. Little of the direct short wave radiation reaching the ocean is therefore reflected, and the amount of absorbed solar radiation is essentially controlled by the tropical cloud cover. Variations in the tropical cloud cover may therefore be expected to represent an important control on the global surface air temperature, along with oceanographic phenomena (upwelling, etc.) within the tropical regions …”.
I am completely uncertain how I would even start evaluating the possibility of forming a selectively denial conspiracy that would manage to claim that “climate change” is altering the gravity of the solid mass of the Earth. Since waves AND temperature at sea level are both regulated in their upper limits by gravity I’m just going to chalk this article up as “another person who needs to be composted and re-born into a better education system.”
Based on no actual observations just models. Models of warming oceans increasing wind are pointless when the air temperature is said to warm faster & greater. If the air is already warmer, the warmer water won’t make it any warmer or greater. If the equator is no warmer (evaporation & clouds maintain limit) while poles are predicted to be warmer, the temperature difference decreases so wind will have less drive, therefore same or less waves. I want them to create a physical model to test the physics because the current computer models are toys.
Just how many times is it possible to spend One Single Joule of Energy…
Does it:
Cynically and with an evil glint we may looking on the bright side and The True Wonder of Climate Science:
How many times can Climate Science have one piece of cake and eat it, without choking.
Something they must surely do at present rates of cake consumption
Considering that ‘waves’ are what made Sandy Beaches and Coral Atolls, is it beyond the bounds that more waves will make more of same, not less.
Maybe they should have a side of Prozac with each slab of cake.
Peta,
Don’t you know that a single joule does all those things at least three times before lunch and the models prove it so.
It’s the trickle down theory of Joules. Human caused CO2 makes energy more efficient so it can do more work.
As soon as you read:
“However, if we can mitigate greenhouse warming in line with the 2℃ Paris agreement, studies indicate we could still keep changes in wave patterns within the bounds of natural climate variability.”
You know its just another bit of propaganda.
BTW -if the changes are within the “bounds of natural variability”, how can they say they are due to global warming?
Who gave grants to these authors? Are students aware of how their fees get wasted? Guess NOT..
Erosion from the sea and wind breaks down land defences over time ,
Of course it only makes headlines when the damage can be noticed .
Hmm , if we lived in caves , plugged into a windmill we would be safe .