Exploring Antarctica: How Canadian science is helping decode climate change

Climate change is reshaping Earth’s oceans, and nowhere are the impacts more evident - or more consequential - than in Antarctica. Rising temperatures, melting ice, and shifting ocean currents are altering marine ecosystems in ways scientists are still trying to understand. But these changes don’t stop at the polar circle; they influence global sea levels, weather patterns, and biodiversity beyond Antarctica. Understanding these changes is one of the most pressing scientific challenges of our time. Could the key to understanding the Earth’s climate lie at the bottom of the world?

For scientists on board His Majesty’s Canadian Ship Margaret Brooke, finding the answer to this question meant setting sail to Antarctica on an extraordinary expedition. Made up entirely of Canadians, the Royal Canadian Navy ship hosted 15 scientists in the spring of 2025 from a variety of Canadian organizations and departments, including two from Fisheries and Oceans Canada (DFO). The two DFO scientists onboard were Dr. Sophia Johannessen, a research scientist and geochemical oceanographer, and Cynthia Wright, an aquatic science technician. Both women have spent decades studying the ocean’s chemistry and are trying to understand how climate change is altering it.

Why Antarctica? And why now?

While Antarctica may seem distant to those of us living in Canada, it plays a crucial role in regulating the Earth’s climate. “People think of Antarctica as remote,” says Johannessen, “but changes in the Antarctic ice and ocean affect the whole world —including Canada.”

Johannessen explains that the global ocean is a key buffer against global warming; it has absorbed more than 90% of the excess heat and about 25% of the carbon dioxide (CO₂) emitted by fossil fuel burning and human-caused land-use change. The Southern Ocean is especially important to CO₂ uptake, because it is very cold, and CO₂ dissolves more easily in cold water than in warm water. In addition, the Southern Ocean is one of only two places in the world (the other being in the northern North Atlantic Ocean) where surface water sinks all the way to the bottom of the ocean, locking away the absorbed CO₂ for hundreds of years. This process results in less CO₂ in the atmosphere and allows the surface water to absorb even more.

Luckily for scientists, the ocean floor contains layers of particles that have built up on top of each other for years. Through sediment core sampling, which involves pulling up cylinders of mud from the ocean floor, scientists can study the chemical makeup of these layers. “Each core is like a time capsule,” Johannessen says. “They offer clues about what’s been happening in the ocean for decades or even centuries. By analyzing these layers, scientists can figure out things like: How fast is sediment building up? What kind of organic material is ending up at the bottom? And how have ocean productivity and carbon storage changed over time?”

Secrets in the water

Wright points out that it’s also important to understand how different forms of carbon - like carbon dioxide, organic matter, and particles - are moving through the system right now. “With glaciers retreating, you have this massive amount of freshwater pouring into the ocean,” she says. “This creates a unique mixture where freshwater meets salty ocean. We want to understand how this terrestrial meltwater affects the carbon cycle from shore to open sea.”

To answer these questions, Wright operated a real-time electronic instrument, the CTD rosette sampler. This instrument measures conductivity, temperature, and depth, while the rosette allows water to be collected at specific depths. The science team then collected water samples from the rosette to study organic matter, nutrients, and other variables such as Environmental DNA (eDNA). By studying an area only about the size of a postage stamp, scientists can determine if the patterns seen in small bays and glaciers reflect broader regional changes. These samples help track how carbon spreads and settles, which will help researchers understand how climate change is influencing marine ecosystems—and how those changes might feed back into the climate system itself.

A joint effort

Scientists are hoping to answer a range of questions, including two key ones: Has climate change caused a change in phytoplankton growth—tiny, floating plants that form the base of the ocean food web? And is more organic matter from land ending up in the ocean due to melting glaciers and increased runoff?

If phytoplankton growth and land-runoff are increasing, that could mean more food for marine life—but also more carbon sinking to the ocean floor, potentially acting as a natural brake on climate change. It’s a complex puzzle, and the answers won’t come quickly. The samples collected will be analyzed back in Canada, with results expected months down the line. Even then, findings must go through a peer review process to allow other scientists to rigorously critique the work before it’s published. “It’s like piecing together a global climate story from one small corner of the world,” says Johannessen. “And while the work is meticulous and slow, it could hold answers that shape how we respond to the planet’s most urgent challenge.”

An experience of a lifetime

For both Johannessen and Wright, the mission left a lasting impression. “It was a privilege to be a part of this expedition and to experience Antarctica ,” Johannessen says. “The inhospitality of the environment juxtaposed against the fascinating science and beautiful icebergs was extraordinary. And, of course, the penguins were amazing!”

Wright reflects on the icebergs as well, saying, “Watching the Navy crew thread the needle through those iceberg alleys was unforgettable. The collaboration on the ship was seamless—everyone working together with focus and trust to make the mission a success.”

The data gathered from this voyage will feed into a broader understanding of climate change, carbon cycles, and the health of our oceans. It will take years before the full picture emerges, but the mission is already a testament to what Canada can achieve in polar science.

“We want Canadians to know,” says Wright, “that scientists care. We do this not for glory, but because we believe in protecting our planet and informing the decisions that shape our future.”

To watch exclusive footage from the mission, tune into CBC’s one-hour special program to join international climate correspondent Susan Ormiston and her crew as they document the mission alongside the scientists.