A Switch from What to Why
Climate Modeling Gets Another Look
Climate modeling in exploration is an idea whose time has come and gone -- and may have come again, according to Eric J. Barron.
“Twenty to 25 years ago there was a lot of active interest in physics-based models of atmospheric and ocean movement,” Barron said.
Because ocean motion affects sedimentation, the hope was that simulations of upwelling might point to source rock origins.
Success at the time was “moderate,” said Barron, dean of the Jackson School of Geosciences at the University of Texas, Austin.
“Since then our ability to do simulations has exploded,” he said.
“We are seeing sufficient advances in how to look at specific time periods and basins ... at features a geologist would be interested in and at a scale to be more useful,” Barron said.
Barron, who last month was named to a special AAPG committee dealing with global climate issues, discussed these and other ideas in a paper titled “Is It Time for a Rebirth in the Geologic Applications of Climate Model?” at the recent AAPG Annual Convention in Long Beach, Calif.
Modeling pioneers had to make assumptions from limited data, he said.
“The grid spacing was quite coarse, so application was limited on basins,” he said. “Now, the spatial resolution is much greater.”
The Great Debate
Models also play a major role in today’s debate over global climate change, an issue in which AAPG obviously has a “keen interest,” he said.
“The geologic record is a window on how the earth can change,” he said.
Simulations also help show how sensitive the planet is, he said, and storms provide one example.
“In the past, we might have thought about how a storm would cross the early Atlantic ... but not look at the effect of hurricanes on shelf structures,” he said.
“Also, there’s a difference in how we see how these storms function.
“Both are of interest ... in petroleum exploration and in the global warming discussion,” Barron said.
Just as the geologic record provides data for climate models, computer simulations can enhance understanding of geologic processes, he said.
“It helps us interpret the geologic record better.”
For example, he said, in studying pollen from an extinct plant species modeling might help researchers determine why the species occurred where it did and why it disappeared.
“Looking at the geometry of the continents and the sun along with the fossil record, we may say, ‘Wow, that’s arid conditions.’
“The simulation may show wet spots in winter and hot, dry summers -- precipitation times,” he said.
In his paper, Barron said climate models have been applied to geological problems in two tracks:
- The first emphasizes explanations of climate changes to understand periods of warmth or glaciation. The research focuses on the forcing functions that govern past climates, incorporating key climate feedbacks and matching the suite of thermal indicators.
- The second track focuses on reconstructing environmental conditions during specific periods, using the geologic record as a key indicator of those conditions.
Both tracks are of interest in exploration and global warming research, he said.
“We were doing a lot of comparisons to geologic data. Barron said. “Then we started to switch to ‘why?’ and spent less time marrying the wealth of geologic data to the models.
“The second track has much more promise (in exploration) than before,” he added.
Modelers are adding a broader range of physical variables, he said.
“In the ‘80s, we really didn’t do much with vegetation on the surface of the earth. We simply ‘painted,’ if you will, areas green,” he said. “Today the (modeled) vegetation begins to change with the simulations.”
While the core of researchers pursuing these areas today are in academia, the finer scale at which simulations can model climate-related geologic changes holds renewed promise for the petroleum industry, he said.
Noting that his paper for the annual meeting was an invited talk, Barron said “I believe they sense there are some added approaches here.”