Tuesday night Assistant Professor of Earth and Environmental Science Dana Royer spoke at the First Church of Christ about global temperature change and the methods used to detect it. The talk was part of one of the Jonah Center for Earth and Art’s monthly meetings.

Royer presented a general background on CO2 atmospheric patterns and their direct correlation to global temperature change. He showed graphs of temperature change and CO2 atmospheric levels dating back 650,000 years.

“There is a correlation of temperature peaks and drops in the temperature graph …corresponding to CO2 levels,” Royer said. “There is strong geological evidence for a strong CO2 relation to temperature; as CO2 levels go up, temperature goes up.”

In response to one attendee’s question, he described the most common method used to detect CO2 levels from the last 650,000 years, ice core analysis. To determine CO2 levels, ice cores from the arctic are dug out of the ground up to two miles deep. Air bubbles trapped in the cores are then analyzed to discover atmospheric gas levels.

“If you release these bubbles, you can actually measure the amount of CO2 in this ‘old air,’” Royer said.

Royer described his field of work, which involves the analysis of plant fossils. These fossils can be used to determine what the temperature was like millions of years ago. He described the method he uses, which involves counting the number of pores on the surface of leaves. The concentration and number of pores has a direct correlation with atmospheric CO2 levels.

“The surfaces of leaves are covered with a waxy substance called a cuticle that prevents them from drying out…[the leaf] has these pores that lets CO2 enter,” Royer said.

According to Royer, leaves develop more of these pores, called stomata, when CO2 levels rise.

“If you look at how tightly packed these pores, stomata, are, it correlates with CO2 levels in the atmosphere,” he said.

He referenced the work he did in the Florida Panther Refuge and in the Bighorn Basin in Wyoming. One of the species Royer focused on was the Ginkgo biloba.

“Comparing Ginkgo fossils to the present-day species…the same species haven’t changed much in approximately the last 70 million years,” he said.

Royer shared the “hockey stick graph,” a graph commonly cited by the United States Environmental Protection Agency that depicts temperature data from the last 1000 years. While the recent sharp rise in temperature has been caused by human gas emissions, Royer said that it was important to look at broader temperature trends.

“The level of CO2 today is higher than it has been in the last 25 million years…but most CO2 levels in earth’s history have actually been higher than they are today,” Royer said. “We have to look at [times] in earth’s history where earth was warmer…this is when looking at periods even further in earth’s history can be beneficial.”

Although he noted that the future of global climate change is a highly debated topic, Royer said that the environment was ultimately a self-regulating system. Any changes that are too drastic, including those in human emissions output, could have large-term impacts that are not immediately apparent.

“It’s like when you’re in a canoe: you push it, and it regulates itself back again,” Royer said. “You tip and you tip, but if you just tip a little too much, the effects are devastating. Knowing where that tipping point is can be very, very difficult.”

The Jonah Center for Earth and Art is an organization of community members that meets monthly to discuss environmental issues. People from the greater Middletown area attended Royer’s speech. Mrs. Robert E. Cumming from East Haddam said she found Royer’s presentation very informative and easy to understand.

“I think his presentation was spectacular,” Cumming said. “He’s so young, and he knows so much!”