Temperatures in Alaska reached 90 degrees on the Fourth of July, CNN reported. This broke a 50-year record high previously set on June 14, 1969. Uncommon high temperatures cause problems for local ecology.
According to CNN, last month was the warmest June on record in Alaska, averaging 60.5 degrees, which is more than 5 degrees higher than usual in the typically chilly climate. Reporters captured images of dozens of dead seals that washed up on the coastline due to the irregular warmth—just one example of the damage a local ecology can suffer from increasing temperatures in its climate.
Climate and Local Wildlife: The Special Relationship
“The timing of [natural] events and the life history of organisms is clearly linked and integrated,” said Dr. Eric G. Strauss, Presidential Professor in Ecology at Loyola Marymount University in Los Angeles. “In fact, animal migrations are often timed to coincide with food availability along the way. If these systems are not in sync, then both the migratory species and the species they prey upon can have dire consequences.”
Dr. Strauss mentioned the relationship between the red knot, a migratory shore bird, and its prey species, the eggs of the horseshoe crab. He said that every year, more than a million red knots stop at the Delaware Bay to feed on horseshoe crab eggs before continuing on their migration routes. “This area is a critical stopover point for what will be a nonstop push northward to the arctic breeding grounds for these birds,” he said. “Many of these birds flew in from great distances, such as Tierra del Fuego at the very tip of South America.”
Recently, human fishing of the horseshoe crab has decreased its population, but it’s far from the only problem. “If you couple this to climate change, which is altering the breeding and wintering grounds for the red knot and gobbling up coastal habitat for the horseshoe crab, we can see the makings of an ecological disaster that are driven both by the anthropogenic activity of human fishing in the near geospatial domain, but also because of overall climate change, [which is] exacerbating the problem,” Dr. Strauss said.
Unfortunately, the red knot and the horseshoe crab are only one of countless examples of climate change affecting an area’s ecology and its wildlife population.
Hadley Cells and the Atmosphere
In order to look at the Earth’s climate, we have to consider the role played by the Hadley cell. “With Hadley cells, we understand that the circulation of air dominated the climate on Earth,” Dr. Strauss said. “Heat produced in one part of the Earth gets moved around because of the overall global circulation of air currents. Solar heating at the equator, which has the most direct angle to receive solar energy, heats up, causes the air to expand and travel up in latitude, and then ultimately diverges at the poles. The notion that warm air rises and cool air falls—this rising of warm air becomes an available energy source that animals can use.” But what is a Hadley cell and what is its role in our understanding of climate change and climate change’s effects on animal life in places like Anchorage?
“In the middle of the 18th century, George Hadley proposed an idea of a simple single cell of convection, air rising and cooling in a circular manner,” Dr. Strauss said. “Later on, this model was improved by William Ferrel, who proposed a three-cell model in 1865, and this model divides the circulation of each hemisphere into three distinct cells. This heat driven by these cells circulates air between the tropics and and subtropics—we call that the Hadley cell.” After the Hadley cell, Dr. Strauss explained, there’s a Ferrel cell of air current that circulates in the mid-latitudes and finally a Polar cell.
“Each consists of one belt of rising air that moves up, cools, and then sinks, and then warm air moving up again and back where it originally rose—these three cells work together like the cogs of a wheel,” Dr. Strauss said. Together, the three cells of air movement drive everything from a global atmosphere of heat around the Earth to localized climates of tropical rain belts, subtropical deserts, and the jet stream.
Many factors influence ecologies around the world. The record highs in Alaska this month may owe to climate change, which not only makes for unseasonable warmth in the greater Anchorage area, but also tampers with the relationship between predator and prey species. Climatologists often hope to understand minutiae of this complex web with components like Hadley cells, which can point them in the right direction of what’s happening with local wildlife and can provide an expectation for what is to come.
Dr. Eric G. Strauss contributed to this article. Dr. Strauss is a Presidential Professor in Ecology at Loyola Marymount University in Los Angeles. He received his undergraduate education at Emerson College and earned his Ph.D. from Tufts University.