Wavering weather causes climate concerns

Linh Le, a first-year finance major from Garden City, Kansas, is used to the high-hitting winds of the Great Plains, not wearing crop tops in the middle of a Pittsburgh winter.

“I expected it to be much colder moving up north, but based on what the locals say, the last couple winters have been a lot warmer than usual,” Le said.

Pittsburgh is generally known for its tough winters — on average, winter temperatures are about 31 degrees, and the city averages 42 inches of snow annually. Although mid-winter temperature spikes can occur in Pittsburgh, it’s unlikely for temperatures in winter months to climb to the high 60s, which was the case a few weeks ago. In February, the average temperature was nine degrees higher than normal. But this month, Pittsburgh’s daily temperature averaged 33 degrees — 15 degrees colder than last year’s average of 48.

With recent temperatures still in flux — including the winter switching from spring to winter over the course of a day — students and faculty alike are addressing climate change and delving into their research to learn more about the effects of global warming.

“With climate change becoming a bigger issue, I think it’s extremely important to start the conversation about how we in the next generation can help improve the earth we live on,” Le said.

The faculty in the department of geology and environmental science at Pitt regularly conducts research to find out how and why the climate is changing by observing human interaction with the environment.

Josef P. Werne, director of Pitt’s Graduate Studies program and a biogeochemistry professor, tackles climate-related issues with his students in his classes. He teaches geochemistry, the study of the chemical composition of the earth, and paleoclimatology, the study of the past climate.

Part of Werne’s research involves reconstructing past climate conditions by observing the geologic makeup of materials in the ground.

“When looking in lake sediments, you’re moving further back in time to reconstruct various climate parameters and the environmental responses to those changing climate parameters,” Werne said.

For example, during the Mesozoic Era — the time of the dinosaurs — scientists know the climate was hot, humid and dry because of the rocks and minerals found in the ground.

When discussing climate change, Werne said it’s important to recognize the difference between climate and weather: climate is how the atmosphere changes over a long period of time, and weather is how the atmosphere changes over a short period of time. The day-to-day or week-to-week fluctuations shouldn’t be cause drastic concern, Werne said.

“One warm week or month or year doesn’t prove anything,” he said. “In order to really look at whether or not there’s change in climate, you need to have many warm years in a row, relative to many previous years in a row.”

According to NASA, two-thirds of global warming, which started around the 1880s, has occurred since 1975 at a rate of 32 degrees per decade.

Werne also highlighted the connection between climate change and El Niño, a Pacific Ocean climate cycle that happens every two to seven years and impacts global weather patterns.

During an El Niño, warm water that is normally pushed toward the western half of the Pacific Ocean travels to the east from California to Chile, causing rain and storms. The global temperatures rise since the warmer ocean waters release heat into the atmosphere.
Each new El Niño is warmer than the last, as a result of changing climate, Werne said.

According to the U.S. Environmental Protection Agency, from 1901 to 2015, sea water temperature rose at an average rate of 0.13 degrees per decade and have caused an increase in ocean heat levels.

“This [El Niño winter] is the warmest one, and it’s a big one, so it affects us more strongly,” Werne said. “Part of the reason why it’s a big one is because of the changing climate systems as things warm.”

Brian Thomas, a hydrologist and assistant professor from the geology and environmental science department, studies the influence of humans on the water cycles — the process in which water goes from vapor in the atmosphere to rain to vapor again. He also studies the behavior of groundwater by using remote sensing devices and models.

“The major component [of the research] is understanding how the climate is going to change in the future, to be able to understand the sustainable use of groundwater and surface water in those systems,” Thomas said.

Because climate change can lead to wetter or drier seasons, it affects the water cycle from the atmosphere to earth — meaning we might not have water when we need it.

“If we don’t manage water systems well, we’re not only impacting the environment but also the efficiency of energy being used,” Thomas said.

Thomas also said if steps aren’t taken to decrease climate change, its effect on the weather year-round will only increase, no matter what season it is.

“So we’re probably going to see warmer temperature spikes in the summer than we have seen in the previous years,” Thomas said. “We may also see colder spikes because [the climate change] variability is increasing.”