Penn State researchers, in trying to unlock the mystery of climate change, have discovered that the tiniest insects could tell a lot about our future.
A recent study released by the Proceedings of the National Academy of Science found that a present and future increase in carbon dioxide and temperatures could have extreme implications on plant and insect life.
The cause of the current carbon dioxide increase is not debatable, Currano said.
"There is no doubt that humans are causing the increase in carbon dioxide or temperature increases," said Ellen Currano, a geoscience graduate student. "We absolutely caused this."
Currano worked alongside Peter Wilf, an associate professor of geoscience, and four other researchers for about five years before releasing the information on Feb. 11, she said.
The study focused on a warmer period about 59 to 54 million years ago, during which there was an abrupt increase in carbon dioxide and temperature, in an attempt to explain what is happening today, she said.
During this specific warming period, which is called the Paleocene-Eocene Thermal Maximum, researchers observed an increase of insects feeding on leaves when the temperature increased. From this, they concluded that as the amount of carbon dioxide nearly tripled and temperatures around the world increased anywhere from 3 to 10 degrees, insect feeding on leaves also increased rapidly.
The temperature increase can be attributed to the extreme amount of carbon dioxide in the atmosphere, much like the amount today, Currano said. She said her team is still exploring why there was such an increase 55 million years ago.
The increase in insect feeding is not so definitive, however. Currano said it's hard to determine whether there was an increase in feeding or an increase in the insect population.
"It's hard to tell in fossils the answer to those questions. We have the leaves and the insect damage is preserved; we can see there are more types of damage and more damage total," Currano said.
Richard Alley, professor of geoscience, said these carbon dioxide changes will effect biology now, as they did in the past with the insects, and that is what the study illustrates.
"We as humans are changing the atmosphere, and that is changing the climate. We have high confidence if we keep doing what we are doing we will change biology," Alley said. "We will look to the past to see when large climate changes happened, what happened to living things, but it is a different world. There weren't people stomping around then."
Alley also said the climate changes in the past probably weren't as fast and extreme as what humans have the ability to do, and this has affected biology in fairly strong ways.
"Essentially, this shows that when the climate changes and plants move, that points to processes happening. It's a response to the atmosphere," he said.
Currano said that, given the results of the study, the planet might experience future biological migration.
"The biggest thing we can expect is for the geographic ranges of insects to change as it gets warmer," she said. "Insect species from the tropics will be moving into Temperate Zone and possibly the Arctic -- so everything will be shifting northwards."
