Wednesday, December 4, 2013

An outreach triple-header

by Kim Cobb

Last month I had the privilege of speaking to three very different audiences about three very different topics in one week. Yes, it was a week of intensive outreach, in the classic definition of the word. But each opportunity presented a unique challenge:  How was I going to reach the audience members? Because it's not enough to reach out, by showing up with some powerpoint slides. You must grab their hands and pull them in, as hard as you can.

Tuesday, 10/12:  The first talk found me in front of 500+ girls, the entire middle and high school populations of the National Cathedral School in Washington DC. I was there as part of the Nifty Fifty program, which brings scientists and engineers into DC area schools as part of the USA Science and Engineering Festival held each spring. My goals were simple, if not ambitious:  help them to understand the key role for paleoclimate data in reducing climate uncertainties while telling my own personal story through lots of pretty pictures. My slides are here. They let out an audible gasp when I showed the aerial photo of Fanning. But I knew I had them when I put up my last slide - a photo of my four kids - to a loud and long "Awwwwwww". Yes, ladies, it can be done. And boy is it fun. When I ended my talk, almost every other hand in the middle school section shot up, bless their hearts. They were so hungry for information about the corals ("Do you kill them when you drill them?" No.), my personal journey ("When did you decide you wanted to become a scientist?" When I was 19.), and our collective future ("What is your position on fracking?" Next question please! - just kidding). The questions were insightful, and demonstrated a high level of engagement with our nation's toughest environmental challenges. The next time you feel depressed about the lack of comprehensive energy/climate policy, go talk to some kids. They get it.
Speaking at the National Cathedral School in Washington DC last month as part of the Nifty Fifty program.

Thursday:  Two days later, I participated in a panel on "Empowering Voices of Early Career Scientists" at the NSF-sponsored Gender Summit:  North America. [The day before, a NSF program manager had noted that I am decidedly not "early career" anymore, which means I'm academically, if not chronologically, over-the-hill!] My fellow panelists represented a range of highly accomplished women scientists from an assortment of fields and career levels, ranging from graduate students to Assistant Professors, each of whom had a unique and insightful perspective on early career issues for women. The overall message was clear:  while there are significant structural hurdles to women's advancement in academic research-intensive environments, you can achieve your goals with the right strategies and tools. Effective female mentors are key, as is a broader support network of peers and senior colleague/advocates. Women cannot wait for structural changes to "the system", but that does not mean that women shouldn't advocate tirelessly for such changes - especially once they attain a certain stature in their professional community. My GSNA slides are here. The most thought-provoking idea to come from the last plenary session, dedicated to fleshing out a "Road Map" towards gender equity, was the concept of including a diversity metric in the calculation of the US News and World Report's ranking of colleges and universities. The room erupted in applause at the suggestion. For better or for worse, administrators in higher ed are constantly seeking to move their institution up in this ranking. By including "diversity" in this calculation, diversity-related issues would begin to receive the attention they deserve in our nation's top institutions. My own department, at ~30% female faculty, would help to offset much lower ratios of female faculty in the engineering schools at Georgia Tech.

Sunday:  Back home in Atlanta, I delivered a presentation on sea level to members of the Trinity Presbyterian Church (slides here). It was the first time I had publicly presented on this topic, and it made for a really fun discussion at the end of the talk. The bottom line:  there is much we do not know about the effects of future warming, but sea level is already rising and will continue to rise at increasing rates. The official IPCC AR5 estimates for 21st century sea level rise (+0.3 to 1m; see the full Chapter 13) are overly-rosy in my opinion, given that sea level is currently rising at ~3.2mm/yr (equivalent to 0.3m by 2100). [Note:  The new IPCC AR5 estimates of sea level rise are dissected in a detailed post here, on RealClimate.] I'd say that +0.5m by 2100 is a minimum number to use in adaptation planning, which assumes that melting/sea level rise will scale with warming, with rates doubling to >6mm/yr likely by the end of the 21st century as global temperatures warm by an additional 2C or more. I think that +1m is a better number to plan around, because it allows for positive feedbacks in ice melting - feedbacks that have been documented by glaciologists (see Zwally et al., 2002 for a classic example). The audience was very receptive to this sobering news, and encouraged me to share this message more broadly. As a climate scientist communicator, however, I pointed out that sea level is one of the most certain, but most delayed, impacts of climate change - does the prospect of 3ft of sea level rise in the next 100 years really move hearts and minds? They answered "Yes!", impressed by the evidence that significant melting is already underway, and measurable as rising global sea levels. Their encouragement reminded me that the public definitely doesn't get to see enough raw climate-related data, presented with appropriate caveats. They don't want their climate information delivered in 20-second soundbytes on the evening news - they want to see the data themselves, and draw their own conclusions. Happy to oblige!

Thursday, September 19, 2013

Lights! Camera! Science!

 Testing the hydraulic drill on land before taking it underwater.  photo by Jess Harrop, The Years Project
What follows is my attempt to share an amazing experience I had last month. It all started earlier this year, when I got a very cryptic message about a "high-profile project involving climate change." After several chats about the incredible things we can learn from corals, and months of detailed logistical planning, on August 11th I found myself on a plane to one of my long-time research sites, Christmas (Kiritimati) Island, with a film crew from Years of Living Dangerously. I thought I knew what I was in for. Little did I know... (in my defense, my mental preparation was severely crippled by the string of late nights I had been pulling in anticipation of a big NSF proposal deadline on 8/15).

Some will ask why in Newton's name would I volunteer for such an undertaking? After all, it is a highly risky proposition:  place myself and my science in the hands of Big Hollywood, where sound-bytes and bikinis have more market value than my life's work as a scientist. And I'm a woman scientist -- one who would feel the viewer's judgment of my scientific worth months before shooting began. Yep. There is no doubt that the safe thing would have been to stay in my lab, cranking on our research, letting its merits be judged by an international network of geeky peers. But I felt absolutely compelled to do this shoot, as a climate scientist who is deeply invested in science communication, and even more so as a woman in science (and mother to 4 small children). My thought process went something like this:  "Hell yes, you can wear a bikini and wield a monster hydraulic drill while SCUBA diving!" and "Hell yes, you can be a good, even great, scientist and actively embrace opportunities to communicate your science to the public!" Because folks, if we cannot tackle these needling cultural issues in science, then science will fail to achieve its rightful place in the public discourse. Besides, my mom once told me never to make an important decision based on fear, and so, I leapt.
They're coming! Run (or swim) for it! photo by Sanjayan

The Years crew consisted of Jake Kornbluth (Producer), Jess Harrop (Associate Producer), Sanjayan (Correspondent), Paul Atkins (Cinematographer), Matthew Berner (Second Camera), and Chris Wiecking (Sound). To say that these people were professionals is an understatement. Not only did they have a driving mission to capture the beauty and the guts of our science, but they managed to do so while I steadily ticked off my ambitious list of scientific goals for my short week there. There were the requisite re-takes (literally marked by one of those "clapper" things closing down with a snap, with people saying things like "Rolling, and... action"). It would send me into nervous chuckles every time - not helpful. There were "bloopers", including one that had me swallowing seawater from laughing so hard. The science team, comprised of myself, my student Pamela Grothe, and FIT postdoc Lauren Toth, was referred to as "the talent", which I could definitely get used to. And there were some real-time reviews of my acting:  "We are definitely not going to win any Oscars with this!" Acting, as it turns out, is hard! Harder than debugging Matlab code or repairing my mass spec. And as a classic Type A over-achiever, I don't take failure lightly. I wanted to look like Angelina Jolie and sound like Carl Sagan. I fell far short on both axes, I'm afraid. It certainly didn't help that I was stung by an invisible sea creature on the first day and did most of my interviews fighting back allergy-induced tears.

But where I fell short, Christmas Island delivered in all its glory. A whole rainbow of blues and greens danced above water, and a vibrant reef ecosystem dazzled as a backdrop to our underwater drilling shoot. With the corals doing much of the talking, I told the story of the 1997/98 El Nino event, and tropical Pacific climate changes of the past and future, and sea level rise. And for the first time ever, I took a (forced) day off in the field, as we went bird-watching and manta-swimming in search of your basic tropical paradise glamour footage. Now it was my turn to see Sanjayan's face light up, and to learn more about the non-carbonate-excreting creatures on Christmas. Our week culminated in a feast
My birthday cake. Ko rabwa! (photo by L. Toth)
complete with sashimi (expected), a truly amazing chocolate birthday cake (very unexpected), a band of drummers who played several hundred PVC pipes with used flipflops (ah-may-zing), and an impromptu dance session that I truly hope has already been deleted from the raw footage.

So what did I learn? One clear take-away:  it's the people, stupid. Separated from our wireless devices (most notably smartphones and, in my case, kids), and confined on a remote tropical island for a whole week, we got to know each other quite well. While every fieldtrip yields scores of new samples to feed the mass specs, the friendships I made on this one were truly unique. And in a way, that's what the Years Project is all about:  climate change as a story told by real people, from one human to another.

Another obvious lesson:  damn I love my job! It's not an exaggeration to say that I am obsessed with corals, and the Line Islands, and climate change, so the combination typically sends me into a veritable frenzy. It's always great to share that passion with my students on-site, but this time, in front of the cameras, I felt both the burden and the privilege of being the public face of the corals that have revealed so much about climate change in this region, and the island that has offered up these precious time capsules.

I certainly gave it my all. For science, for women, for Christmas Island, for the planet.
Diving the "Coral Gardens". photo by Lauren Toth

Wednesday, September 11, 2013

The hunt is on – fossil coral collecting on Kiritimati Island

By Pamela Grothe

Coral rubble field on Christmas Island


That is “hello” on Kiritimati (Christmas) Island, one of only three words I learned during my two-week field trip to this special place last month. Luckily, my science was a bit more productive than my Gilbertese lessons!

First off, I must thank Showtime and the Years of Living Dangerously crew for putting on this trip. Even though the primary focus was filming the wonderful science Kim does and all she has learned about climate change from Christmas Island corals, it provided me the opportunity to explore my own science goals, collect my own samples, and learn valuable fieldwork skills. It really was a trip of a lifetime, and even though I’m sure I’ll have more trips to come, this first one will always be extra memorable.

Before diving straight into the field trip itself, I think it is important to convey the science questions I am after. My overall goal is to reconstruct climate change in the central tropical Pacific over the last 6,000 years. This includes understanding changes in mean climate on different timescales (i.e. 100-yr and 1000-yr) and variations in the El Nino Southern Oscillation phenomenon, such as the intensity and frequency of El Nino events. More importantly though, is to convey to you WHY this is important. This region experiences a high-degree of natural variability in the climate system on decade-long timescales. This makes it hard for us to observe what recent changes in climate are caused by human-induced warming since instrumental data in this region only go back to the mid 20th century. In addition, future climate projections, especially for El Nino events, are not well constrained, despite having major global consequences on temperature and precipitation patterns. Additional climate data beyond the instrumental record would help us assess what current changes are due to human-induced warming and better assess model predictions for future climate changes.

Fossil coral rubble specimen - Porites
This is why we have turned to the corals, as they have proven to be reliable records for changes temperature and precipitation at a monthly resolution. These records provide us an opportunity to understand the background climate state of the central tropical Pacific and how it has changed during periods in the past. And if you recall from my earlier posts, I am trying a new ensemble method where I will be using hundreds of short fossil coral segments of ~10yr-long records, or “rubble” to reconstruct these climate changes.

With that being said, my time on Kiritimati Island was spent fossil hunting for Porites fossil corals! My previous work on dating provided a map with the distribution of ages of fossil coral on the island. This was extremely useful in determining where to focus my efforts.

My first objective was to collect samples on the leeward side of the island where most of the coral date to several thousand years old. Here, the corals are scattered around town, in piles in people’s yards, and even piled high in rock walls. This was exciting because it afforded us the opportunity to talk to the locals (before stealing coral out of their yards), play with pigs (OK, I wasn’t really a fan of the pigs, especially when it was standing on top of my backpack), and reconstruct rock walls after removing beautiful samples from them (I felt bad removing corals from their well constructed walls that I felt the need to replace them). Also, these samples are generally much larger, so through much effort of hauling rocks around the island, we took the samples back to Dive Kiribati and drilled them into 3-inch cores – this was by far my favorite task!

Collecting fossil coral from the local's property means getting up close and personal with the pigs!
Full pile of large rubble to drill!
And there's still more.
Full day of drilling fossil coral -
showing off my longest core.
Example of the clear ridge lines of coral rubble
My second objective was to target the open ridge fields on the windward side of the island, where the ages are distributed from the last century near the shoreline to just over 1000 years in the ridges farther back from the shore. My work on the age distribution of these ridges is only in its infancy, so the goal was to map out the ridges in more detail and collect samples from each of the ridges and from multiple sites that I can date. This area is really unbelievable in the magnitude of fossil coral and with precise age distribution maps we can really create a focused sampling plan for each time we come back.

Out on the rubble field collecting fossil coral

All in all, I collected several hundred samples and brought back almost half for dating (either the samples themselves or chips from them). A super productive trip I’d say! In addition, I have come away with an appreciation for each sample I collected – the painstaking work of searching for and lugging rocks around on a tropical island with limited shade is not easy! And THANK YOU Lauren Toth for all your help in doing this!

With that, I say goodbye – Tiabo!

Kim and I posing for an underwater shot.

Friday, September 6, 2013

muchas gracias ICP

by Stacy Carolin
The transit bus to the airport has pulled away from Hotel Melia in Sitges (“sit-ches”), Spain, closing out the eventful 5-day International Conference on Paleoceanography (ICP11). ICP is a triennial conference that targets the ocean and climate community, and this year was its 30-year anniversary. The conference encompasses five broad scientific sessions, one per day, with each consisting of five invited 30-minute oral presentations plus one key-note 45-minute oral presentation in the morning, followed by a 2-hour poster session in the afternoon. 497 scientific posters were presented, of which 200+ were presented by students.

For the week I was our Cobb Lab ICP “pseudo-ocean" rep, happily permitted to squeeze in my stalagmite hydroclimate record to a paleocean conference. I roomed with two Caltech friends in Hostal Termes, located in the center of “downtown” Sitges and minutes from the beach front. We began each morning with a lovely croissant breakfast at a cute nearby bakery followed by a beautiful 20-minute walk, either through town or along the Mediterranean coast, to the Hotel Melia conference venue. With the $1000+ cost of international flights and somewhat weak dollar-to-euro exchange, the ratio of American to European scientists at the conference was small, and you could usually separate out the two quite easily based on the level of penny-pinching. I personally was quite proud of my cost-effective "juggling multiple budget-airlines" scheme to get to Europe. All was well and good on my stop-and-go trek through Canada-Iceland-UK-Spain until the poster baggage took its own trip out to Sweden. Better luck next time.

This was my first time presenting a science poster, and also my first international conference. As always, especially fun to spend time within another culture, and luckily the Sitges community enjoys late dinners (restaurants don’t even open until after 8:30pm), which allowed some time to explore the coastal town after a full day of conference (9:00am – 6:45pm). Although I still heavily favor presenting orally (my dancer-side has a never-ending love with center stage), poster presenting does provide its own distinctive merits, most notably the allowance of extended one-on-one conversation with particularly interested scientists. Also, after multiple discussions, the overall shared interest and reoccuring questions surrounding my current work became very apparent, which was useful to recognize as we move forward toward paper publishing.

Thanks to all for helping make the trip so memorable! And a shout out to the ICP Organizing Committee for their incredible job with putting everything together so seamlessly.

Editor's note:  Stacy won a prize for her poster at ICP. Great job!

Sunday, June 16, 2013

Dating (and Re-Dating) Coral Rubble

by Pamela Grothe

I’m back at it, dating more coral rubble, but this time using the U-series method. Last time I left off I had just finished dating many of the coral rubble using the fast-screen radiocarbon dating method. In all, I ended up dating 36 pieces of rubble from Christmas Island, 28 corals from the Palmyra collection, and 20 different coral from the Line Islands that were previously dated by U-series.

To recall, back in March I was dating corals with known U-series ages using the rapid screening radiocarbon method. Of the 20 different control corals, we found three corals with large differences between the two different types of ages, where two different corals disagreed by 1,000 years and one coral by about 3,000 years! However, the other 17 corals seemed to behave fairly well, at least within error of the radiocarbon fast screening age (which can end up being a couple hundred of years in either direction because of the large error in the rapid screening method itself and in addition the uncertainty in the calibrated age correction). This is a little unnerving considering all paleo-applications rely on the accuracy of the dates. Which date is telling us the truth? Why are they so different? Were samples mislabeled or did something happen geochemically to cause one or both of these dating methods to misbehave?

Before I move on to addressing these questions, first I want to present a first glance of the age distribution of the coral rubble on Christmas Island (based on the fast-screen radiocarbon dates). To our initial surprise, they are YOUNG! Many came back post-bomb, meaning they are younger than 1950. And others are only a couple hundred years old. Only a few were older than a thousand years old, and most of those were from larger fossil coral that the team drilled from people's lawns (with permission of course), not the rubble. At first I was a bit disappointed because I am really interested in nailing down mean tropical Pacific climate through the Holocene (really anything older than the last thousand years). However, this collection has taught us a few things and could be useful in filling critical gaps in the central tropical Pacific climate during that last Millennium, such as the Little Ice Age (~1500-1800AD) and the Medieval Climate Anomaly (~900-1200AD).

Map of age distributions for Christmas Island fossil coral rubble.
The oldest rubble samples come from further back in the rubble piles. It makes intuitive sense that younger coral rubble would be closer to the shore since they are most likely washed up storm deposits. This will guide our next sampling trip (in August perhaps?? Stay tuned!), focusing on grabbing samples from the back ridges and grabbing samples further down in the rubble pile to try and find several thousand year old samples.

That said, the existing coral rubble dates are all radiocarbon dates, which may contain some biases when applied to this type of material. This is why I am now at the University of Minnesota performing U-Th dating on the radiocarbon-dated coral rubble. U-Th dates have much smaller age errors than radiocarbon dates and there are fewer problems with this method so we generally trust them more. First, I am interested in if the corals that dated post-1950 are really that young (they do look pristine under the microscope!). One problem with Christmas Island and radiocarbon dating is that in the mid-1900’s thermonuclear bomb testing occurred on the island (YIKES!), which could theoretically make the corals “hot”, or in other words add a ton of radiocarbon to them, making them date "young" using the radiocarbon method. We don’t really notice this in any of our control dates but we can’t say for sure if it hasn’t randomly affected certain corals. Another problem we have to consider is that the samples for dating were taken within 2 cm of the exposed coral surface. The next time we visit our large coral archive at Christmas Island, we will sample in the interior of the rubble sample, just in case.

So here I am, at the University of Minnesota for my second two-week dating excursion and I’m sure with many more to come since dating is a heavy part of my research. I will be dating 48 corals with the U-series dating method, 3 of which are the coral with large discrepancies between radiocarbon and U-series dates, 23 of the Christmas coral rubble samples that were dated with the radiocarbon method, 2 samples from Palmyra whose radiocarbon dates fell near the Medieval Climate Anomaly, and 16 additional corals of unknown age from the Christmas Island rubble collection. All of these dates are being performed in Dr. Larry Edward’s lab with lots of help from Dr. Hai Cheng.

My goal is to really nail down these issues so that I can leverage both dating methods in order to get as many dates as I can, quickly and accurately, for my paleoclimate reconstruction work.

Stay tuned next week when I’ll go into more details about the U-series dating method for corals.  In the meantime you can brush up on your U-series dating from Stacy’s blog post last year (A Lesson on Dating...)!

Until then, CHEERS!

Sunday, June 9, 2013

Take It to Print

by Stacy Carolin
We have a paper out (!) And all that text will likely cause a little headache, so I’ve condensed it down to the important talking points –in common tongue-- to bring to the dinner table tonight: 

The author examining a fallen stalagmite. Credit:  Syria Lejau

The new published record was created from stalagmites collected in Gunung Mulu National Park on the island of Borneo, which sits on the equator in the western Pacific. Variability in the isotopic chemistry of the rainwater over our site is directly related to variability in the rainfall amount in the region (see lab-colleague Jessica Moerman's recent study in EPSL). Stalagmites form from rainwater that drips through soil and limestone into cave chambers, and the isotopic chemistry in the rainwater is captured and maintained in the calcite formations over tens of thousands of years. The four stalagmites used in this study grew during most of earth's last ice age (100,000 years ago to 15,000 years ago), and reveal how rainfall amount over Borneo changed (or did not change) in response to various atmospheric and oceanic changes, both global and local, during this period.

Points (1)-(5) on published
Figure 2 --click for larger
(1) Ice-age-cycle global temperature and CO2 variations did not greatly influence rainfall amount over Borneo -- Like the Chinese stalagmite records, the 100,000-year-long Borneo record does not have a "sawtooth" shape famously characteristic in the global temperature, atmospheric CO2, and sea level records spanning several ice age cycles. We conclude then that on these multi-thousand-year timescales, those variables are not directly influencing rainfall amounts over Borneo.

(2) Abrupt sea level drop / sunda shelf exposure did not cause a synchronous shift toward dry (or wet) conditions in Borneo -- Sunda Shelf emergence (shallow continental shelf connecting Borneo to Southeast Asia) has been implicated in shaping western tropical Pacific rainfall amount in previous studies, but we find little correlation between the Borneo records and an index of Sunda Shelf exposure over the last 100,000 years. For example, significant variations in the Borneo records during the earlier glacial interval (90,000-70,000 years ago) bear little resemblance to reconstructed sea level changes, most notably ~76,000-71,000 years ago, when a 60 meter drop in sea level almost doubled the size of the exposed shelf without any corresponding shift in rainfall amount.

(3) Rainfall variability over Borneo closely followed solar radiation cycles over the equator (seasonal solar energy flux increase = rainfall amount increase, and vice versa) -- The Borneo records suggest that solar precessional cycles (meaning change in solar energy flux over the equator due to cyclical change in the orientation of earth's tilted axis) may be the dominant source of Borneo rainfall amount variability on thousand-year timescales. For example, today the tilted axis points the northern hemisphere toward the sun (northern hemisphere summer) when the earth is furthest from the sun in its elliptical orbit, while 12,000 years ago the tilted axis pointed the southern hemisphere toward the sun (northern hemisphere winter) when the earth was furthest from the sun in its elliptical orbit. These cyclical changes on thousand-year timescales vary the seasonal amount of solar energy over Borneo, which the records suggest in turn do drive changes in the amount of rainfall over Borneo.

(4) The Borneo record’s lack of many abrupt climate shifts that are present in almost all northern hemisphere records implies a selective response of Borneo rainfall to high-latitude abrupt climate change forcing -- The dominant paradigm to explain the famous global millennial-scale climate shifts first discovered in the Greenland ice cores is that they are driven from the North Atlantic region, either from weakening of the Atlantic ocean circulation or from a dramatic albedo change due to sea ice cover, which in turn shifts the northern hemisphere to cooler/drier conditions and makes the southern hemisphere warmer/wetter. The absence of several of these abrupt climate change signals in the Borneo record represents a clear challenge to our understanding of how the tropical Pacific is involved in the mechanism(s) that forced abrupt climate change during earth’s last glacial state.

(5) The largest millennial-scale anomaly in the 100,000-year Borneo record is coincident with the Toba super eruption -- The Toba eruption was the largest volcanic eruption in the past 2.5 million years and climate responses to the eruption are uncertain. Many anthropologists believe that the volcanic winter following the super-eruption decimated most “modern human” populations at that time, and caused a bottleneck in human evolution. The abrupt shift toward dry conditions over Borneo (within age error of the volcanic eruption) that then lasted for a millennium is interestingly mirrored in the Chinese stalagmite record. Further studies are needed to determine if these events are at all related.

Thanks to Kim, Jess, Jessica, Syria, Jenny, and all the rest for helping put this beast together, from field to print! What an experience!