(From PhysOrg.com h/t to Leif Svalgaard) — The recent warming trend in the Atlantic Ocean is largely due to reductions in airborne dust and volcanic emissions during the past 30 years, according to a new study.
A new study by UW-Madison researcher Amato Evan shows that variability of African dust storms and tropical volcanic eruptions can account for 70 percent of the warming North Atlantic Ocean temperatures observed during the past three decades. Since warmer water is a key ingredient in hurricane formation and intensity, dust and other airborne particles will play a critical role in developing a better understanding of these storms in a changing climate.
Since 1980, the tropical North Atlantic has been warming by an average of a quarter-degree Celsius (a half-degree Fahrenheit) per decade. Though this number sounds small, it can translate to big impacts on hurricanes, which thrive on warmer water, says Amato Evan, a researcher with the University of Wisconsin-Madison’s Cooperative Institute for Meteorological Satellite Studies and lead author of the new study. For example, the ocean temperature difference between 1994, a quiet hurricane year, and 2005’s record-breaking year of storms, was just one degree Fahrenheit.
More than two-thirds of this upward trend in recent decades can be attributed to changes in African dust storm and tropical volcano activity during that time, report Evan and his colleagues at UW-Madison and the National Oceanic and Atmospheric Administration in a new paper. Their findings will appear in an upcoming issue of the journal Science and publish online March 26.
Evan and his colleagues have previously shown that African dust and other airborne particles can suppress hurricane activity by reducing how much sunlight reaches the ocean and keeping the sea surface cool. Dusty years predict mild hurricane seasons, while years with low dust activity — including 2004 and 2005 — have been linked to stronger and more frequent storms.
In the new study, they combined satellite data of dust and other particles with existing climate models to evaluate the effect on ocean temperature. They calculated how much of the Atlantic warming observed during the last 26 years can be accounted for by concurrent changes in African dust storms and tropical volcanic activity, primarily the eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo in the Philippines in 1991.
In fact, it is a surprisingly large amount, Evan says. “A lot of this upward trend in the long-term pattern can be explained just by dust storms and volcanoes,” he says. “About 70 percent of it is just being forced by the combination of dust and volcanoes, and about a quarter of it is just from the dust storms themselves.”
The result suggests that only about 30 percent of the observed Atlantic temperature increases are due to other factors, such as a warming climate. While not discounting the importance of global warming, Evan says this adjustment brings the estimate of global warming impact on Atlantic more into line with the smaller degree of ocean warming seen elsewhere, such as the Pacific.
“This makes sense, because we don’t really expect global warming to make the ocean [temperature] increase that fast,” he says.
Volcanoes are naturally unpredictable and thus difficult to include in climate models, Evan says, but newer climate models will need to include dust storms as a factor to accurately predict how ocean temperatures will change.
“We don’t really understand how dust is going to change in these climate projections, and changes in dust could have a really good effect or a really bad effect,” he says.
Satellite research of dust-storm activity is relatively young, and no one yet understands what drives dust variability from year to year. However, the fundamental role of the temperature of the tropical North Atlantic in hurricane formation and intensity means that this element will be critical to developing a better understanding of how the climate and storm patterns may change.
“Volcanoes and dust storms are really important if you want to understand changes over long periods of time,” Evan says. “If they have a huge effect on ocean temperature, they’re likely going to have a huge effect on hurricane variability as well.”
Source: University of Wisconsin-Madison (news : web)
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http://www.newscientist.com/article/dn11462-climate-change-a-guide-for-the-perplexed.html
“(From PhysOrg.com h/t to Leif Svalgaard) — The recent warming trend in the Atlantic Ocean is largely due to reductions in airborne dust and volcanic emissions during the past 30 years, according to a new study.”
If you take a look at the satellite photo that heads this piece,the wind dust blowing in a NW direction looks like a button mushroom in cross section.
This would suggest that the wind (made visible by the dust) is hitting an equal but opposite wall of wind that is limiting its penetration into the Atlantic.
Could this be a mechanism for African particulate reduction ?
Just to add my voice of support to a previous commentator to try to limit comments in this site to topics relevant to the thread and to science and to limit political comments to comic relief .
These comments apply to me as well as I have been guilty of drifting.
Bob Tisdale…
Thanks for your comment Bob. Have had a look at the graphs you provided. The thing is, I was thinking primarily of Pielke Srs comment on his weblog of 24th March, where he discusses the recent Loehle paper, comparing it to findings of his own posted on Feb 9.
On the Feb 9 posting, Pielke Sr compares Hansons own heat content change prediction to the actual data now in from Josh Willis (the revised “not quite so cold” data – heh!). The Willis figures basically show no change in ocean heat content since the experiment started (I think I read that correctley) which Peilke then compares to Hansons prediction of cumulative ‘heat’ per year they expected to find. Over the short term of the Argo data, Pielke notes that Hanson is now so far behind, cumulatively, that it would now take something massive to get him back on track.
Surely the Argo heat content change/trend has got to become the premier data set for tracking ocean heat content, and so GW, without the constant arguements about the deficiencies of the surface station data or satalites, which seems to have become a ‘choose your witness’ debate?
If the Argo’s are saying ‘no change’ then GW has definately stopped, and worse for the AGW camp, there is no ‘pipeline’ effect either.
I appeciate I’m seeing the ‘ocean’ as one temp and take your point that its diff depending where you look, but as an overall measure surely the Argo’s are indeed going to give us that elusive ‘average global temp’ that the other data sets are argued over?
Would appreciate your views on the Argo’s in general and Pielke Sr comments on thier data. Sorry if I’m being too simplistic, I’m no scientist at all. Just seems to me that the whole Argo experiment was designed to ‘prove’ GW via sea temps…….and its actually saying something different?
I for one find it interesting that this topic, “Dust study suggests only 30% of Atlantic temp increase due to warming climate”, is adjoined to “Ocean iron fertilization CO2 sequestration experiment a blooming failure”. It is the dust, and the iron oxides contained in that dust, blowing off of North Africa that provides the iron that fertilizes the Mid-Atlantic ocean. Upwelling at the poles is the other major source.
–Mike Ramsey
1/ Quoting the article above: Evan says this adjustment brings the estimate of global warming impact on (the) Atlantic more into line with the smaller degree of ocean warming seen elsewhere, such as the Pacific. “This makes sense, because we don’t really expect global warming to make the ocean (temperature) increase that fast,” he says. In other words, this paper provides some more support for man-made global warming. 2/ What goes up must come down. Warmer temperatures mean more evaporation. So there will be more precipitation, somewhere else. And increased stream flows. 3/ I t takes 30 years of weather to establish climate. Yet it seems appropriate to point out that these conditions may become the norm, in the expected future climate.
@Francis
It really doesn’t matter what happens, the AGW hypothesis is unfalsifiable as everything is claimed to be man caused.
wouldn’t the reduces volcanic activity also have increased temepratures of the other oceans ?
@Dale Rainwater AGW is very falsifiable. Just demonstrate that there is something else more primary than CO2, in forcing the increasing temperatures over the past 30 years. Think hockey stick, and be careful about cyclical explanations.It suggests that, regardless of what was forcing then; there is something new, now.
I keep looking at that picture. Notice the green edge in the water around the landform? Could that be a plankton bloom lining the shoreline? If this kind of bloom feeds the ocean, I would imagine that toxic blooms occur as well. In the past, efforts have been made to eradicate toxic blooms. The kind of plankton that are toxic are a very small percentage of all the plankton species. However, under the right conditions, even nontoxic plankton can kill marine life by starving it of oxygen. But even when that happens, the dead marine life may be a necessary part of the cycle. Why are we so opposed to dead and decaying matter? My grandma searched high and low for the stuff to put in her corn hills. Her motto: a dead fish in every hill of corn.
The other thing that seems to get people’s attention is when a species dies back. We do that all the time to plants. It invigorates new growth. And we think nothing of it. But if an animal species goes through this possibly natural cycle, humans are put on the chopping block without much further serious conversation about the cause. And God forbid someone says it is natural. We humans don’t like things dying.
Pamela you might want to look at my most recent posts on the Iron Fertilization thread.
“But if an animal species goes through this possibly natural cycle, humans are put on the chopping block without much further serious conversation about the cause.”
Address the causes of those….and in this case….homo sapiens are defintiely on the chopping block.
This is coming from a republican, bush-voting (please do not hold that against me) HAWK.
:~)
CHRIS
Norfolk, VA
“But if an animal species goes through this possibly natural cycle, humans are put on the chopping block without much further serious conversation about the cause.”
A serious conversation about the cause of 99% decline of large predatory sharks in the busy north-west Atlantic? Any Chinese-Tiawanese connection here?
How are these number part of the possibly “natural” cycle?
Correction: “numbers”
Many sharks clean up dead and dying marine life. That’s why chumming works so well. If the natural cycle is for marine life to slowly die down during the waning moments of the warm phase of oceanic oscillations, to spring back to life when upwelling starts the cycle again, it would make sense that the top of the food chain would be the last to see a decline themselves. Your correlation is statistically weak but that does not mean that you could be right. I think it would be wise to look at all possible reasons for shark decline. If other fish counts do not follow fish catch and instead mirror oceanic oscillation, wouldn’t it be worth while to see if this is true for shark as well?
I meant to say “but that does not mean that you are wrong.”
Statistically WEAK…..in WHAT universe, Pamela???
99% decline in the northwest Atlantic. Functionally EXTINCT in the Mediterranean.
How is that statistically “weak”….in any way shape or form…in ANY known or unkown universe??
Give me one SHRED of evidence to the contrary.
In the meantime….you would do yourself a big favor to watch the movie Sharkwater.
An award-winning masterpiece just from its sheer beauty…its content sends it over the edge.
I DARE you to try to force the ivory tower theories after you have watched.
I dare you.
How can you possibly even attempt to refute.?
You and I have JOKED about the AGW blah blah ad infinitum.
But, in light of the egregious overfishing in the past few hundred years by homo sapiens…our overfishing in the past few hundred DOES NOT QUALIFY US AS BEING PART OF THE NATURAL CYCLE THAT HAS OCCURRED FOR THE PAST FEW HUNDRED MILLION….
And I would challenge you to respond, point-by-point to my posts on the iron fertilization thread.
Pamela…you would appreciate the deadpan approach….
Thanks.
Chris
“But if an animal species goes through this possibly natural cycle, humans are put on the chopping block without much further serious conversation about the cause. And God forbid someone says it is natural. We humans don’t like things dying.”
Natural cycles are one thing. Those natural cycles have been around in the oceans, like some of its native habitat, for a few hundred million years’ time.
How just a few hundred years of anthropogenic “forcing” of valuable marine species could be included in the equation as part of the “natural” cycle, is beyond me.
As I said in previous posts and will say again. This is not an either/or situation.
I will say it again: This is not an either/or situation. It is very, very, complex problem, as complex as the very food web that graces the ocean.
Now….we can not really do anything about the natural oscillations. We can just study them and learn to adapt to them. It would be silly to think science will ever be good enough change the the pressure values of the NAO to suit ones liking….or adjust the ENSO events so that more rain falls on California.
But we CAN at least TRY to reverse some of the problems we HAVE created (or at least exacerbated), whichever the case may be.
As you can tell, I chose my screen name for a reason, as species destruction may be one of those reversible problems.
Please take time to watch the whole film. But the clip is here http://www.sharkwater.com
Chris
Norfolk, VA
I assign your position statistically weak because two things occurred at the same time, once, leading you to assign causation (shark population decline and tonnage taken). The Sun’s sleepy stage has been tagged by some as the cause agent for cooling because cooling occurred during some sleepy stages in the past. The statistical correlation is weak but that doesn’t stop some from assigning causation anyway. Fish counts have notoriously been attached to tonnage take from the oceans. Why? Because of a now and then coupling. But when statistical analysis was done, fish counts correlated much higher to oceanic oscillations than to tonnage taken from the sea. You have not provided links to journaled studies of shark counts. I prefer those over movies. Do you want links to studies of fish counts?
How a 90% to 99% decline of some species could be called “statistically weak” is as perplexing as the declines themselves!
As far as some links and quotes, here you go for starters.
And on a side note, you (and your students), would benefit from seeing Sharkwater. Besides being a beautiful work, it is loaded with good information. There is a reason it received numerous international film awards. http://www.sharkwater.com
http://www.sciencemag.org/cgi/content/abstract/315/5820/1846?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=myers+shark&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT
and this quote:
“Impacts of chronic overfishing are evident in population depletions worldwide, yet indirect ecosystem effects induced by predator removal from oceanic food webs remain unpredictable. As abundances of all 11 great sharks that consume other elasmobranchs (rays, skates, and small sharks) fell over the past 35 years, 12 of 14 of these prey species increased in coastal northwest Atlantic ecosystems. Effects of this community restructuring have cascaded downward from the cownose ray, whose enhanced predation on its bay scallop prey was sufficient to terminate a century-long scallop fishery. Analogous top-down effects may be a predictable consequence of eliminating entire functional groups of predators.”
And also….
http://www3.interscience.wiley.com/journal/118811165/abstract?CRETRY=1&SRETRY=0
And I would invite you to head over to the Iron Fertilization thread and see my posts starting at 11:58:33 and following.
Please read carefully what is said there….and take a few minutes to read the links as well.
Thanks.
Chris
Norfolk, VA