Climate Change Oceans in crisis

As ocean currents warm and hotter winds become more intense, the rate at which glaciers shed icebergs is accelerating, adding new water to the ocean and raising the sea level.

Among all global climate threats, one major life source is already in a state of crisis.

Ocean and atmospheric warming are collapsing polar ice caps and threatening the marine ecosystems, but scientists have said it is not too late to save what ocean life is left. Research into current and historic levels of greenhouse gasses, rising atmospheric and ocean temperature, melting glaciers and rising sea levels is ongoing at Texas A&M and on research ships around the globe.

A&M is home to a “library of Earth history.” The International Ocean Discovery Program Gulf Coast Core Repository holds over 100 km of IODP’s sediment and rock cores from around the world’s oceans.

“Much of what we know about Earth’s past climates comes from deep sea sediment cores drilled by [the] International Ocean Discovery Program, which is partly based at Texas A&M,” said Trevor Williams, Ph.D., expedition project manager and staff scientist. IODP is an international research collaboration that coordinates seagoing expeditions to study the history of the Earth recorded in sediments and rocks beneath the ocean floor.

“These marine sediments contain a record of the processes, mechanisms, long-term changes and impacts of natural climate variability on timescales from annual to hundreds of millions of years,” Williams said. Investigations include past warm climates under higher CO2 levels than today, and the stability of Antarctic ice and resulting sea level change, Williams said.

Scientists from all over the globe use samples from the repository to investigate climate conditions from the Earth’s past. Current research is also about the Earth’s future.

As fossil fuels, oil and gas are burned to produce energy, carbon dioxide is released into the atmosphere, said Kathryn Shamberger, an assistant professor in chemical oceanography at A&M. Those emissions trigger a series of reactions within the ocean, she explained.

“We’re putting a nice warm blanket around the atmosphere,” Shamberger said. “It’s keeping heat in, and that heat warms up the atmosphere. That warms up the ocean, too.”

The result is melting polar ice caps in Antarctica and Greenland, home to well over 500 glaciers. Since the last Antarctic summer, measurements show melting of glaciers Thwaites and Pine Island —– roughly the size of nine U.S. coastal states from Maine to Maryland —– caused a 4-foot rise in sea levels due to underlying warm water.

As temperatures rise and warm the ocean, waters beneath the glaciers provide enough heat to crack and break off ice from the glaciers, said Alejandro Orsi, oceanography professor at A&M. Glaciers inevitably melt, generating a rise in sea levels that threatens anyone and everything along the coast, Orsi said.

“More heat is going toward the ice in the last four or five decades,” said Orsi, who has spent much of his time in Antarctica studying the ocean currents. “If you have a glass of water, and you have an ice cube in it, and the cube melts, the level of the water doesn’t change. If you put an additional ice cube, and another, and another, the level of the water is going to go up.”

If all 483 glaciers in Greenland melt, sea levels would rise an additional 21 feet, Orsi noted. Even a single glacier melting in Antarctica would raise sea levels 27 feet, more than all of the Greenland glaciers combined. If all of Antarctica were to melt, the sea level would rise 120-150 feet.

With 80 percent of the world’s population living within 50 miles of the coast – and most oil refineries within 30 miles of the coast – Orsi said he is worried about sea levels if carbon dioxide emissions continue.

“Ice records show that when sea level rises it has occurred within 100 years,” Orsi said. “If the sea level goes up, you have to move all of those [people and refineries] uphill. Then, thinking is 100 years enough time to move and change everything?

We have to say that we don’t have a chance,” Orsi said.

Ice cap melts are only one threat; warming ocean and atmosphere temperatures put entire ecosystems at risk, A&M atmospheric sciences professor Andrew Dessler said.

“As humans add carbon dioxide in the atmosphere, some of the carbon goes into the ocean and converts to carbonic acid, which leads to the acidification of the ocean,” Dressler said.

Greenhouse gases like carbon dioxide and methane naturally travel back and forth between the atmosphere and ocean, explained Shamberger. As more of these gases are added to the atmosphere, more are added to the ocean, causing the acidity levels of the ocean to rise. Shamberger said there has been about a 30 percent increase in the ocean’s acidity since the start of fossil fuel burning.

“Marine organisms do not like this,” Shamberger said, citing phytoplankton, mussels, clams and fish. “Life in general is very sensitive to changes in acidification levels.”

Coral reefs are particularly sensitive to ocean acidification. Reefs maintain the ocean ecosystem by supporting thousands of marine organisms important for fisheries, pharmaceuticals and ocean diversity, Shamberger said.

“Coral reefs are having a harder and harder time building and maintaining that 3-dimensional reef structure,” Shamberger said. “There’s a lot of coastal communities where the reef actually buffers the coast from waves and storms.”

If coral reefs are unable to survive, Shamberger said coastal communities will be less protected from storms. The corresponding huge decline in tourism also would devastate economies of small island nations.

The effects on Arctic ice caps and ocean acidity levels are irreversible changes, Orsi said, but there is still more that can be done to combat further damage to the planet.

“We’re already locked in to warming and acidification,” Shamberger said. “The main thing to do is switch from fossil fuels to renewable energy.”

Some fear the switch is impossible, but Shamberger said even small changes make a drastic difference, and the A&M campus is a great place to start.

“Texas A&M is actually a really unique place in that we can make a significant difference in saving energy and reducing CO2 emissions by doing small things,” Shamberger said. “If everyone on campus does the small things like switching light bulbs to LEDs that would actually make a big difference because our campus is so large.”

As scientists continue to research the best ways to combat climate change, understanding the full scope of the issue can be challenging.

“We are starting to better understand how the ocean, and the ice and the atmosphere interact,” Orsi said. “It’s one of the most exciting science problems that we have.”


This story is a collaboration between The Battalion and upperclassmen in Texas A&M's journalism degree. To see the online copy of the Climate Change extra print edition, click here.

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