Global warming 'no big deal,' geologist says

Randy Metcalf Arizona Daily Wildcat Geologist Judith Parrish stands on the UA Mall yesterday. Parrish believes the "world will not end" because of global warming. She said that it will cause problems but since the effects will happen over time, people will adapt.

Barring an unpredictable catastrophic event, climatic change over the next century will happen slowly enough that humans will be able to adapt to it, said Judith Parrish, a global climate expert.

Parrish recently authored a book on methods of studying climate during the Cretaceous period, which took place 113 to 65 million years ago when the Earth's poles were about 50 degrees hotter than they are today.

In a lecture two weeks ago, Malcolm Hughes, director of the UA tree-ring research lab, predicted that sea levels will rise and more hurricanes will sweep across the Earth in the next century because of global warming.

The combination of climatic forces could have disastrous consequences for island nations and coastal cities, Steve Leavitt, another UA tree-ring scientist, said yesterday. Where and when certain food crops can be planted will also be affected by warming.

Parrish doesn't view global warming's effects as urgent problems.

"We'll just move - none of that is going to wipe out the human race," she said. "I think humans are infinitely adaptable and whatever happens - we'll adjust."

Houston and New Orleans are both below sea level and spend money to pump water out of the cities, Parrish said. Money for such projects is limited, which means people will be forced to think about where they choose to live.

"It (rising sea level) is disruptive in the sense that people will have to move, but people have to move all the time anyway," Parrish said.

As far as scientists can predict, Parrish said climate changes over the next century will be incremental. The "little catastrophes" like flooding are merely an inconvenience for humankind.

Josh Cohn, a Student Environmental Action Coalition representative, said he is worried about the social issues stemming from global warming.

"If oceans get larger and land space gets smaller, the Earth is not going to stop spinning," Cohn said. "Unfortunately, civilization doesn't function on a geologic time scale."

He did not think scientists have an "altruistic obligation" to solve social problems caused by global warming.

"The biggest responsibility lies with our government at all levels," Cohn said.

If the government decides to limit greenhouse gas emissions, then scientists could certainly play a role in preventing the global warming trend by researching new and efficient ways of producing energy, Cohn said.

Parrish was unconvinced that such legislation would be useful.

"There is social disruption involved in that (cutting fossil-fuel emissions)," Parrish said. "And we would be avoiding something that may not even happen."

While there is debate in the scientific community whether global warming is caused by human action, Hughes' latest research indicates the relatively huge temperature leap in the last century is related to human burning of fossil fuels.

The planet has seen temperatures far warmer than those that would result from global warming in the next century, Parrish said. Diversity of life was high 100 million years ago in the Cretaceous period, and temperatures at the poles were about 50 degrees Fahrenheit.

In the Paleozoic period, carbon dioxide levels were 10 to 12 times higher than they are today, and life flourished as reptiles and vertebrates were evolving, Parrish said.

Concern about global warming stems from the rate at which the temperature is increasing, not how hot it will get. Parrish said scientists know of no natural mechanism that could put carbon dioxide into the atmosphere as quickly as humans do.

But even at the current rates of emissions, climate change will probably be slow, Parrish said.

However, "there is always the possibility that there will be some catastrophic change that we can't predict," like sudden glacial melt, she said.

Disasters can happen as "climatic thresholds" are crossed. Climate tends to change slowly in the face of events like the increase of carbon dioxide in the atmosphere. Sometimes the equilibrium of a climatic system suddenly shifts and the rate of change dramatically increases. It is difficult for scientists to predict when climatic thresholds are being approached.

"We don't want to be caught off guard by something that could be disastrous," Leavitt said.

It will be to scientists' advantage to figure out in advance how global warming will influence civilization, he said. Geologists are trained to understand the planet and use computer models to predict climatic events over the next century.

As predictions are proven right or wrong, researchers can tune their models of the Earth and make new predictions about the effects of global warming and other events.

Whether global warming is a scientist's problem, Leavitt expects to learn from the planet as it heats up.

"We'll be forced to learn," he said. "We don't have a choice."

Sarah Spivack can be reached via e-mail at Sarah.Spivack@wildcat.arizona.edu.