Research team projects wind and wave changes as planet heats up

Jan 14, 2013 by Bob Yirka report
Credit: NASA

(Phys.org)—An international team of climate researchers has written and published an open letter in the journal Nature Climate Change, describing wind and wave pattern changes expected to come about due to global warming. In their letter, they suggest that much of the southern hemisphere will see increased winds along with higher waves, while the northern hemisphere will see the opposite.

More specifically, in their letter, the researchers write that after much study and analysis of data, it appears that areas such as Australia's east coast, much of Antarctica and Indonesia, will experience increased wave height as the planet heats up. This, they say, will be the result of changes in wind intensity over the southern hemisphere. Waves come about, they note, as energy is transferred between the atmosphere and ocean water. Rising atmospheric temperatures can change the height, direction and frequency of waves, resulting in wave changes in coastal regions.

The team came to its conclusions based on data given by five separate . Climate change data input into the models came from a special report called "Emissions Scenarios" created by the that gave predictions of global temperature changes for both air and sea over the next century. The models predicted changes to the southern annular mode, which is an area of that surrounds the South Pole. Because of that, the researchers predict an increase in over oceans in the . That in turn could mean bigger, stronger waves in such places as Australia's Gold Coast.

Because the models also predict a northward shifting of high pressure systems in the Pacific basin, they expect less wind and as a result lower wave height in the North Atlantic, which should mean less turmoil for fishing vessels and reduced waves pounding the shores of the eastern United States and Western Europe.

Wave size is important, the researchers note because it's such a determining factor in beach erosion, but also because it has an impact on fishing and drives plans for using waves to create energy for power grids. They also point out that their study shows that a means of quantifying wave size impact has yet to be created and note that in the end, despite changes in wave size, ocean levels will continue to be the overriding concern as polar ice melts, impacting shorelines across the globe.

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More information: Projected changes in wave climate from a multi-model ensemble, Nature Climate Change (2013) doi:10.1038/nclimate1791

Abstract
Future changes in wind-wave climate have broad implications for the operation and design of coastal, near- and off-shore industries and ecosystems, and may further exacerbate the anticipated vulnerabilities of coastal regions to projected sea-level rise1, 2. However, wind waves have received little attention in global assessments of projected future climate change. We present results from the first community-derived multi-model ensemble of wave-climate projections. We find an agreed projected decrease in annual mean significant wave height (HS) over 25.8% of the global ocean area. The area of projected decrease is greater during boreal winter (January–March, mean; 38.5% of the global ocean area) than austral winter (July–September, mean; 8.4%). A projected increase in annual mean HS is found over 7.1% of the global ocean, predominantly in the Southern Ocean, which is greater during austral winter (July–September; 8.8%). Increased Southern Ocean wave activity influences a larger proportion of the global ocean as swell propagates northwards into the other ocean basins, observed as an increase in annual mean wave period (TM) over 30.2% of the global ocean and associated rotation of the annual mean wave direction (θM). The multi-model ensemble is too limited to systematically sample total uncertainty associated with wave-climate projections. However, variance of wave-climate projections associated with study methodology dominates other sources of uncertainty (for example, climate scenario and model uncertainties).

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User comments : 9

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jough blough
1.7 / 5 (18) Jan 14, 2013
"The team came to its conclusions based on data given by five separate climate models."

How nice, basing more alarmist reporting on inaccurate, unaudited, unreliable climate models.

Case in point - 5 different models are needed why? Because they DON'T AGREE with each other.

Sheesh.
antialias_physorg
4.3 / 5 (15) Jan 14, 2013
Case in point - 5 different models are needed why? Because they DON'T AGREE with each other.

And if they had used one model you would have accused them of cherry-picking a model, right?

They use multiple models to make the results statistically more robust. You know - using mathematics and science instead of polemics.

There's nothing 'alarmist' about this. (What does that even mean? If something is scientifically sound but renders some unexpected results - should it be suppressed because it is 'alarmist'? Should, in your opinion, only research be permitted that deliveres "nothing to report" results?)

lowerarchy
1.6 / 5 (7) Jan 14, 2013
Recently, articles having anything to do with climate seem to draw 'alarmist' posters across many fora. Is there an organised troll squad out there?
Also, I wonder if these wave changes will affect the surfing beaches in USA and W Europe?
Caliban
4.2 / 5 (5) Jan 14, 2013
This could easily have an impact on the seasonal extent of Antarctic sea ice, upon the various ice shelves and the below-sea level portions of tne WAIS, maybe even causing further acceleration of ice balance loss.
Q-Star
3.9 / 5 (12) Jan 14, 2013
Case in point - 5 different models are needed why? Because they DON'T AGREE with each other.

Sheesh.


Name one area in science that doesn't use multiple models? It's the way science works. Depending on a single model leads stagnation and allows no opportunity to see how various parameters best predict reality.

Sheesh, back at you,,,, when five models converge on the same consequence, it means that you are getting real close to the actual picture of nature.
dav_daddy
1 / 5 (6) Jan 15, 2013
I believe his issue is with the fact that given the known parameters none of the models can come close to reproducing the climate of the past.

When you combine 5 models that can't "predict" what has already transpired with any reliability how can you expect to "predict" future outcomes in any accuracy?

Sheesh.
dav_daddy
1.4 / 5 (9) Jan 15, 2013
Today also set the all time lowest high temperature (45 degrees) for this day ever.

When you find some global warming please send it here. I didn't move to the desert to freeze!
vlaaing peerd
5 / 5 (3) Jan 15, 2013
@ Dav daddy

it's actually global warming that causes colder winters in desert climates. The global temperature rises only a tiny bit, but causes more weather extremes in general.

Have fun next few summers in your land/desert climate, it'll be warmer then you were used to.
alfie_null
5 / 5 (1) Jan 15, 2013
I believe his issue is with the fact that given the known parameters none of the models can come close to reproducing the climate of the past.

When you combine 5 models that can't "predict" what has already transpired with any reliability how can you expect to "predict" future outcomes in any accuracy?

Sheesh.

That's a pretty broad statement. Care to elaborate? For starters, what are the five referenced models, and under what conditions have they failed?