NATURAL VARIABILITY: A record in coral suggests that climate change may be making El Niño and La Niña sea-surface temperature patterns more variable.
Image: Wikimedia Commons/NOAA
Predicting the behavior of the El Niño weather cycle is a challenge for forecasters and climate scientists, and the stakes are high.
El Niño and its counterpart La Niña, driven by changes in sea-surface temperatures in the tropical Pacific Ocean, can have major effects on weather conditions hundreds and thousands of miles away. Studies have linked catastrophic floods, droughts, disease outbreaks, wildfires and even social unrest to the weather cycle, known as the El Niño-Southern Oscillation.
Yet scientists have struggled to understand whether climate change is altering that cycle. Climate models have produced conflicting results, and reliable instrumental records of ENSO events begin in the early 20th century.
Now a new study, which builds on prior efforts to reconstruct El Niño's past behavior by examining coral growth, suggests that El Niño and La Niña events have become more variable and intense over the past several decades.
"We kind of answered the question, is El Niño changing with respect to recent natural variability?" said Kim Cobb, the Georgia Institute of Technology climate scientist who led the research published yesterday in the journal Science. "The answer is yes, tentatively so."
The 7,000-year portrait painted by the corals she examined suggests El Niño may get stronger as the level of carbon dioxide in the atmosphere climbs, Cobb said.
But researchers will need to do more work -- including a concerted effort to fill gaps in the record of El Niño's past behavior -- to prove that connection, for now a tentative one, she said.
"It could be thrown out," Cobb said. "But whatever the result, we will have confidence with more data."
Coral cores tell the story
The new analysis is based on samples that Cobb describes as a data "down payment," tripling the amount of coral-core data available from the past 7,000 years.
Cobb and her colleagues extracted 17 cores from fossilized corals on two tiny islands, Christmas and Fanning, in the Line Islands archipelago in the central Pacific Ocean.
Researchers painstakingly examined each core millimeter by millimeter, using radioactive dating to determine the age of each sample.
To determine how temperature and precipitation had changed during each coral's lifetime, the scientists tracked variations in the ratio of two oxygen isotopes, O-18 and O-16. During warm, rainy El Niño periods, the coral that grows has less O-18. During cool, drier La Niña events, new coral has more O-18.
Cobbling together the data from those 17 coral samples -- each covering a period 20 to 80 years long -- allowed the scientists to reconstruct the ENSO cycle thousands of years into the past.
The results show that the variability and strength of the ENSO cycle was greater during the 20th century than at most points in the 7,000-year fossil record -- but the episode is not unprecedented, the scientists said, pointing to a similar period during the early 17th century.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500
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12 Comments
Add CommentI only hope we can adapt to our changing climate. We cannot keep pumping billions of tons of CO2 into the atmosphere each year without consequence.
Reply | Report Abuse | Link to this@krohleder, the problem is that our adaption to the changing climate is based on the ability of many other plants, animals and microorganisms to adapt. The science shows that it will be a challenge. What we have seen from other mass extinctions is that mega fauna tend to go extinct when there is a collapse in the food chain caused by the mass die-off of micro fauna. Just imagine what would happen if we lost pollinators or plankton. Our food supply would collapse, and most of us with it.
Reply | Report Abuse | Link to this@RSchmidt, I Agree the challenge is very big and it may already be too late. I try to be optimistic but not much is really being done.
Reply | Report Abuse | Link to thisOur planet became hospitable for the human life form only by accident and circumstances then dictated that it would only remain hospitable for a brief period. Humans still have quite a bit of time left before normal earth temperatures and conditions make living here unbearable again. In the meantime, the human species should forget about trying to place blame for a naturally occurring situation and enjoy life on a pretty decent planet. Of course, human behavior here, being what it has evolved into, won't allow for any extended periods of enjoyment.
Reply | Report Abuse | Link to this@littleredtop, "In the meantime, the human species should forget about trying to place blame for a naturally occurring situation" or we could choose not to listen to idiots such as yourself and instead try to understand the problem and find a solution.
Reply | Report Abuse | Link to thisSigns are mounting of a pending cooling period. If it eventuates the AGW proponents will adapt. Adapt their theory that is. Inevitably more research funding will be required to enable the old theory to be shoehorned into the new reality.
Reply | Report Abuse | Link to thisThe Dr. David Viner moment we’ve all been waiting for…a new snow record
http://wattsupwiththat.com/
It is interesting that the above site, sneered at by so may on his site, has so many climate scientists who debate issues on its pages.
The article that follows is very interesting too. Pity SCIAM does not follow real climate science. : Neutrons and the 1970s cooling period
"The cycle of Pacific Ocean surface water warming and cooling has become more variable in recent decades, suggesting El Niño may strengthen under climate change"
Reply | Report Abuse | Link to thisAlernatively, the (real) factors causing El Ninos are also causing an increase in global warming.
The only solution will be to relocate.
Reply | Report Abuse | Link to thisThis was an unsatisfying article. No mechanism was even suggested as to how global warming was affecting El Nino/La Nina behavior.
Reply | Report Abuse | Link to thisThis article, as with all Alrmist articles misses a key point, without which it is nothing more than a random collection of electrons.
Reply | Report Abuse | Link to thisThe issue that Alarmists must provide clarity on is:
Please explain the exact mechanism,limits, physics and experimental data confirming the heat trapping amplifying mechanism CO2 creates. ALL researchers and modelers (yes even IPCC ones) know that CO2 is a weak greenhouse gas. They also know that a doubling of CO2 cannot by itself trap much more heat than it already has.
Some amplifier circuit between CO2 and some other greenhouse effect is needed to boost CO2's effects.
The problem is that NO RESEARCHER has yet identified, isolated, explained in detail or experimentally demonstrated precisely what this supposed amplifier is. The computer models ALL use one and assume that it is correct, but it may all be imaginary.
If the amplifier is non-existent, CO2-fixated Alarmism is nothing more than the maddening of a crowd.
If you know of research that demonstrates (not computer models) the CO2 amplifier, please post it. If you yourself have data that demonstrates it, please publish it and get your Nobel Prize. Seriously... we need this issue cleaned up.
I give up we're all gonna die. Who's with me???? What, no followers? But my message is so inspiring.
Reply | Report Abuse | Link to thisInteresting study that again supports the theory that we are seeing signifcant change in climate cycles in the last century. Further work in this area will show how pronounced this change is and may provide pointers to what we can expect as change intensifies in the coming decades. Scientists are very clever in finding evidence in the most obscure places.
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