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Joellen Russell: Master climate modeler
By Stephanie Doster | January 7, 2008
Joellen Russell’s tool of the trade is a crystal ball of sorts.
A master climate modeler at The University of Arizona (UA), the assistant professor of geosciences plugs differing climate change scenarios into a supercomputer and draws on observational records to simulate future conditions on Earth, from Arizona and the Amazon to Australia and the Antarctic.
“The only way to get a glimpse of how things might change is to run one of these climate models,” Russell said.
One of Russell’s jobs at the UA is setting up and running a climate modeling center in the Computer Center on Highland Avenue. Only she runs these particular models, which require 120 to 150 processors running together, on a very fast machine. To run the models, the university last year bought a state-of-the-art super computer similar to, yet smaller than, one used at the National Oceanic and Atmospheric Administration (NOAA), which is funding two of Russell’s current projects that use the computer.
One of those projects involves figuring out how warming, ice-melt, and ongoing shifts in the Southern Hemisphere westerly winds will affect the biogeochemistry of the Southern Ocean. The project builds on one in which Russell—with her Biogeochemical Dynamics Laboratory—and a team of NOAA scientists developed a model that accurately simulates the Southern Ocean circulation and these westerly winds, which have moved poleward in both hemispheres in the last thirty years. Their model showed that the Southern Ocean may slow the rate of global warming by taking up significantly more heat and carbon dioxide, a greenhouse gas, than previously thought.
Russell is part of another NOAA project to model and study the acidification of the planet’s oceans. The oceans soak up atmospheric carbon dioxide, which forms carbonic acid when dissolved in sea water. As humans continue to burn fossil fuels, the oceans are taking up excess carbon dioxide, which is boosting acid levels. That increased acidity is threatening corals because it dissolves the calcium carbonate in their skeletons.
Russell is working on a model to predict when the Great Barrier Reef will dissolve under various conditions.
“This (acidification) has got a lot of people very concerned in the oceanographic community because we’ve never seen anything like this before. There’s nothing in the marine record over the last sixty million years that looks anything like this,” Russell said.
Russell is also analyzing models for the World Wildlife Fund to study how sea ice is changing and how those changes will affect the Antarctic’s Adélie and emperor penguins. Scientists say the Earth already has warmed 0.9 degrees Celsius since the late 1800s. Russell’s preliminary results show that when the models hit an additional 1.1 degrees C of warming—most likely during this century—the ice on which the penguins depend to rest, feed, and raise their young will be significantly thinner and the birds will be forced closer to the shoreline. That could limit their food availability and significantly influence reproduction rates, Russell said.
If humans don’t curb greenhouse gas emissions, she said, the future could be grim for penguins, polyps, and people alike.
“It is scary, absolutely. On the other hand, knowledge is power,” Russell said. “If we can communicate our results clearly enough to stakeholders, maybe we can get people interested in changing this outcome.”
Moving to land, Russell is working with Scott Saleska, a UA assistant professor of ecology and evolutionary biology, to look at what is in store for the Amazon forests. The model Russell is using depicts a drought-stricken scene in which savanna encroaches on Amazon forests. Those forests make up an enormous storehouse of carbon; without the trees, that carbon would go into the atmosphere as carbon dioxide, significantly accelerating climate change.
But Russell isn’t always peering into the future. Reaching into the past, Russell and experts from the UA’s Laboratory of Tree-Ring Research are comparing a land model with paleoclimate data derived from tree rings to determine whether the model captures the right size and extent of drought.
“We do paleomodeling because we have had some very large shifts in climate before—like megadroughts—that we want to make sure the climate models can reproduce,” Russell said. “We need to make sure that we can predict an even unpredictable event like that, so we’re verifying the model and making sure that we’ve got these large swings that used to happen.”
As the name of her lab—the Biogeochemical Dynamics Laboratory—suggests, Russell’s job encompasses the interactions between chemistry—particularly carbon dioxide—and biology, from the phytoplankton in the ocean to the trees on land, and geology, in the form of fossil fuels.
“Working with these models shows how interrelated everything is. They are very complicated, but they are the coolest things since sliced bread,” Russell said. “I love my work.”