On Hansen on El Niño (sub. req.)
Super El Niño?
I blogged earlier today at work about the latest ENSO assessment from the Climate Prediction Center, and said this:
We’re at the point in the year where forecasting is hard, so the computer models used to try to get a handle on where this is headed are all over the map.
It’s the conventional wisdom the ENSO forecast community has been giving me for years, a sort of “pivot point” around this time of year when their forecast skill is weakest.
Then comes this draft paper from Jim Hansen and others:
We suggest that an El Nino is likely to originate in 2006 and that there is a good chance it will be a “super El Nino”, rivaling the 1983 and 1997-1998 El Ninos, which were successively labeled the “El Nino of the century” as they were of unprecedented strength in the previous 100 years.
(hat tip RP for the link to the Hansen piece)
Hansen goes on to “argue further that global warming has increased the likelihood of super El Ninos.'”
As it happens, I’ve been poking at this question as well because of the important relationship between ENSO and the climate here in the southwest. More/bigger (less/smaller) El Ninos means less (more) drought where I live. As Eric Guilyardi recently put it, “Predicting El Nino occurrence and amplitude… is a key societal need.”
The problem, as Hansen acknowledges, is that the global climate models are all over the map on this one.
Haiyan Teng and colleagues at NCAR just published a model intercomparison in GRL that looked, among other things, at the way a suite of global climate models handled ENSO under CO2 held constant at 2000 values.
In the present set of models, 9 out of 16 models show a committed El Nino-like response, while the rest have either a La Nina-like response or more uniform committed warming across the tropical Pacific. The reasons for these differing responses require further investigation.
That’s the paper that got me curious, which led me to Guilyardi’s paper in Climate Dynamics which also did a big model comparison. Again, the results tilted toward increased El Nino amplitude in a warmer climate, “though there is a considerable spread of El Nino behaviour among the models.”
I’m not a scientist, so I won’t try to evaluate Hansen’s claims, but were I a journalist trying to write about this and looking for the sweet spot where the bulk of the science lies, I’d have to explain to readers that Hansen is well to one side of it on both the question of what can be said now about what will happen in the coming year, and of what effect greenhouse warming might have on ENSO.
Imperial Valley
The reason I’ve been tinkering with the Salton Sea story is its (potential?) centrality to the story of climate variability and the allocation of the Colorado River’s water. (I say I’m writing a book about “drought,” but I’m really trying to deal with questions of how people here in the West have responded over the years to decadal-scale climate variability. “Drought” people get. “Decadal-scale climate variability” gets me that glazed eye look.)
In the first two decades of the 20th century, folks were trying to turn the desert of the Imperial Valley of southeast California into farmland. Great soil, great sunshine, no rain, but the relatively frequent rampaging of the Colorado River flooding them out. So while much of the impetus for damming the Colorado involved storage of water for droughts, the Imperial folks needed it dammed a) to give them a reliable flow of irrigation water rather than the Colorado’s huge fluctuations, and b) to keep them from getting flooded out by the Colorado’s huge fluctuations.
I was talking about all this over breakfast with Mom and Dad this morning at the Frontier, and Mom told me a story I’d not heard: when my grandparents were first married (John S. and Gertrude Berry, Mom’s parents), granddad’s first job was driving a produce truck in the Imperial Valley – in 1915, smack in the middle of the period I’m reading about.
I still don’t understand the extent to which what happened in the Imperial Valley is a result of climate variability (drought?), but it’s cool that granddad was there while all this was happening
Morning Ride
My two best riding buddies, Jaime and Steve, are doing the Phoenix Ironman Sunday, which I think is nutty. (Why get off a perfectly good bike and run 26 miles? Wouldn’t it be a lot quicker to just keep riding? I mean, I can understand why you have to swim the water bit, ’cause youre bike would get all rusty….) But I’ve nevertheless benefitted from their efforts, sucking their wheels for a lot of miles over the winter as they prepared. So this morning, their last ride before the race, I tagged along. Just a half hour in the foothills, serenaded by the squeek of new brake pads on their wacky carbon race wheels and a lot of pent up energy. At one point Jaime hit the gas on a little uphill and left me struggling trying to get onto his wheel. They’re good to go.
The Smell of Cheerios in the Morning
Cyclists notice the wind, perhaps like pilots or kite fliers, probably more the most other folks. On my favorite rides, I know where all the flagpoles are – especially early, near my house, which I need to use to get my bearings. There’s the humongous US flag at the big freeway interchange in the center of town, and another on the motel where the bike path crosses Menaul Blvd.
They took down the flags at the Kwik-E-Mart up on Montgomery (sigh), but the big gravel operation north of Rennaissance Center faithfully flies is patriotism and gives me a good north side reading.
But my favorite wind vane is a bit more subtle.
Up at the north end of my morning ride is a factory that makes breakfast cereal. If there’s a headwind, you can smell the baking sugar treats before you get there. The stronger the headwind, the earlier you smell them. I love the smell of baking Cheerios in the morning. It smells like …. cycling.
Climate’s Ebb and Flow
A nice bit of business from Anjali Nayar’s NYTimes profile of Gavin Schmidt:
“The climate is like the city,” he said as he gestured at the scene around him.
The city is made up of millions of people making individual decisions: when to wake in the morning, what time to go to work, where to go on vacation. Yet many things about the city can be predicted. On weekdays, the subways will be more crowded at 8:30 a.m. than at midday. The government knows roughly how many jobs there will be next year.
“It is the same thing with the climate,” Dr. Schmidt said. “We don’t have to worry about every little detail of the weather to understand what is going on at the global scale, just like we don’t have to worry about every person to understand how a city works.”
Relative Entropy
Climate model fidelity and projections of climate change:
Relative entropy, which is a measure of the difference between two probability distributions, has been calculated for the simulations of the climate of the 20th century from 13 climate models and the observed surface air temperature during the past 100 years. This quantity is used as a measure of model fidelity: a small value of relative entropy indicates that a given model’s distribution is close to the observed. It is found that there is an inverse relationship between relative entropy and the sensitivity of the model to doubling of the concentration of CO2. The models that have lower values of relative entropy, hence have higher fidelity in simulating the present climate, produce higher values of global warming for a doubling of CO2. This suggests that the projected global warming due to increasing CO2 is likely to be closer to the highest projected estimates among the current generation of climate models.
Shukla et al., Geophys. Res. Lett., 33, L07702, doi:10.1029/2005GL025579
And More Stuff I Wrote Elsewhere
Blast to Simulate Nuke Explosion (sub. req.):
Pentagon researchers plan to set off a simulated nuclear blast in the Nevada desert in June as part of their search for a better way to destroy buried enemy bunkers, according to federal documents.
A Defense Nuclear Threat Reduction Agency spokeswoman would neither confirm nor deny the nuclear connection Friday, saying only that conventional mining explosives would be used in for the massive blast.
But a Pentagon budget request is explicit about its purpose: to “improve the warfighter’s confidence in selecting the smallest nuclear yield necessary to destroy underground facilities while minimizing collateral damage.”
Stuff I Wrote Elsewhere
N.M. Scientists Mimic Global Warming to Study Long-Term Effects (sub. req.):
As if Earth isn’t warming fast enough, Jim Elliott wants to speed things up.
To do it, Elliott has fashioned what look like 20 oversized bed frames on a remote patch of desert south of Belen to create an extra bit of global warming on a very small scale.
Elliott is the self-described “blue-collar scientist”— the guy who knows how to use tools— on a team trying to answer a deceptively simple question: What will happen here as our planet warms?
Scientists no longer question whether Earth is warming, and few doubt that the stuff coming out of our tailpipes is the primary cause. Much research today is focused on what will happen as a result.
Later….
Led by University of New Mexico scientist Joe Fargione, they are building contraptions to impose global warming conditions on a patch of desert to see how plants growing here respond.
Spread across 400 square miles, the Sevilleta is an ideal laboratory for the research, spanning the sort of ecological boundaries where change is most apparent.
In the case of Fargione’s research, the important boundary is the northern edge of the creosote’s range. That boundary has been creeping northward, and warmer temperatures are one possible explanation because of creosote’s sensitivity to winter freezes.
The scientists want to see if creosote will have an edge in a warming world. They also want to know whether the mix of grasses on the site will change to favor those more comfortable in warmer weather.