Who among us has not been at least momentarily awed by an image or video of a whale breaking through the ocean’s surface, connecting the sea and the sky in such a glorious, mammalian, and utterly alien way – a glimpse, if only for a moment, into another dimension of the world?
Whales are some of the biggest and most majestic creatures on Earth, and scientists and conservationists say they are also climate heroes. During their lifetimes, they release enormous amounts of waste into the ocean that is rich in nitrogen, phosphorus, and other elements that nourish phytoplankton, which in turn release oxygen into the atmosphere while absorbing climate-warming carbon dioxide through photosynthesis.
What’s more, the substantial amount of carbon in their massive bodies remains out of the atmosphere for their entire lifetimes and even centuries after they die. Yet as Earth’s oceans warm, these climate heroes need more protection from changes in habitat that have diminished their food supply and otherwise threaten their survival.
Chris Johnson, a marine scientist and conservation strategist who leads the World Wildlife Fund Protecting Whales & Dolphins Initiative based in Melbourne, Australia, described his work with whales, their role in protecting the climate, and ways to help protect whale populations in a wide-ranging interview with Yale Climate Connections.
This interview has been lightly edited and condensed.
Yale Climate Connections: What first drew you to whales and this work? Was there a particular experience or realization that made you want to focus on them?
Chris Johnson: I am a bit of an “accidental scientist.” Growing up in New England, the sea was part of the culture, but I never felt the pull to become a marine biologist. I was more interested in creative work, studying music at college and later moving into technology in the mid- to late 1990s.
The turning point came in 1998, when I met Dr. Roger Payne. Roger helped the world understand that whales are intelligent, social beings with complex lives, and that their conservation matters. He was a big thinker who looked for creative solutions to some of the most challenging threats facing the ocean. That meeting changed the direction of my life and career.
YCC: Your organization has described whales as “wildlife climate heroes.” What are the main ways they help combat the effects of climate change?
Johnson: Whales help by keeping the ocean healthy and productive in several ways.
The first is nutrient recycling, often called the “whale pump.” Whales feed at depth or in productive feeding areas, then release urine and nutrient-rich fecal plumes nearer the surface. These contain nitrogen, phosphorus, iron, and other elements that can support the growth of phytoplankton – the microscopic organisms that form the base of marine food webs, produce much of the oxygen in the atmosphere, and absorb carbon dioxide through photosynthesis.
Whales also carry nutrients across the ocean during their long migrations. Many species move between high-latitude feeding grounds and lower-latitude breeding areas, connecting ecosystems that may be thousands of kilometers apart. Scientists sometimes call this the “great whale conveyor belt.”
Whales also accumulate carbon in their bodies during their lives. When a whale dies and its carcass sinks to the deep seafloor, a process known as a whale fall, some of that carbon may remain out of the atmosphere for centuries. The carcass also provides food and habitat for a succession of deep-sea animals and microbes. Whale falls are ecologically important, although their contribution to carbon storage at a global scale is modest and uncertain.
YCC: Are there certain whale species you might highlight either because they play especially important ecological roles?
Johnson: I’ll focus on great whales, although the science is still evolving. Blue and fin whales stand out because of their sheer size: blue whales, the largest animals ever to have lived, with fin whales as the second-largest whale. Their feeding and nutrient recycling may influence productivity across vast areas.
Sperm whales are the largest toothed whales and extraordinarily deep divers. They spend much of their lives foraging offshore for deep-water squid, moving nutrients between the deep ocean and the surface. They also live in a world shaped by sound, which makes them particularly sensitive to underwater noise pollution. Their complex social structures are changing how many of us think about culture in the ocean.
Humpback whales are a success story. Some populations have recovered strongly since the ban on commercial whaling. However, in the Southern Hemisphere, climate modeling suggests that climate-driven changes to Antarctic krill could place renewed pressure on humpback whale populations and potentially reverse some of that recovery by 2050.
The critically endangered North Atlantic right whale is a cautionary story. As ocean warming changes the distribution of their prey in the Gulf of Maine, the whales have moved into areas where they face greater risks from ship strikes and fishing-gear entanglement in the gulf of the St. Lawrence River. Climate change is amplifying exposure to existing human threats.
YCC: What are the main challenges facing whales?
Johnson: Climate change is altering the ocean conditions that have shaped whale behavior and movement over time.
For many species, the most immediate effects are impacts to their prey. As waters warm, currents shift, sea ice declines, and marine heat waves intensify, prey may move or become less predictable. Whales may have to travel farther, spend longer searching for food, or change the timing of their migrations. This is particularly important for baleen whales, which must build large energy reserves during relatively short feeding seasons. A female’s ability to reproduce is closely linked to how successfully she feeds.
Entanglement in fishing gear remains one of the most serious global threats to whales, dolphins, and porpoises. Fisheries bycatch kills an estimated 300,000 cetaceans each year, but this estimate is now more than 20 years old. The true scale is difficult to assess because monitoring and reporting remain limited across many fisheries.
Other pressures have not gone away. Ship strikes, underwater noise, chemical and plastic pollution, poorly planned offshore development, and, in some places, commercial whaling continue to affect whale populations.
I am most concerned about the cumulative impact of these pressures. A whale might cope with one stressor, but reduced prey, increased noise, growing entanglement risks, and ship traffic together can gradually erode its resilience and health.
YCC: Given everything we’re learning about whales’ role in ocean ecosystems, what kinds of conservation efforts or solutions are most important right now? What can people do to help whales?
Johnson: Whale conservation needs to work at the scale of the animals’ lives and range. We need to treat the ocean as one system and work to strengthen its ecological connectivity.
A whale moves thousands of kilometers across their critical habitats. We call these connected habitats and migratory pathways “blue corridors.” They can extend across national waters and the high seas, often overlapping with growing impacts from shipping, fishing, pollution, and climate change.
Much of our work involves mapping these habitats and migratory journeys so they can be considered by governments, policymakers, and industry as areas for improved ocean management and protection. We created BlueCorridors.org as a mega collaboration to make this evidence easier to access and easier to take action.
Many of the solutions are already available. Slower ship speeds in high-risk areas can reduce the likelihood and severity of vessel strikes. Changes to fishing gear and practices, such as “on demand” or ropeless systems, can help reduce entanglement. Well-designed protected and managed areas can safeguard important habitats, while quieter shipping and other noise-reduction measures can help whales communicate, navigate, and feed. Strong climate action is also essential. We need to move to a low-carbon future to protect the prey and habitats whales depend on.
We know that whale recovery is possible if we make this a global priority. The global moratorium on commercial whaling allowed some populations to recover, including humpback whales, but there is much work to be done.
On an individual level, people can support strong ocean and climate policies, choose sustainable seafood, reduce their use of plastic, and ask questions about how fishing practices impact marine wildlife. They can also support communities and organizations developing whale-safe solutions, reduce pollution, and follow responsible whale-watching guidance. These actions are especially valuable when they build wider political and market support for change.
YCC: After all the time you’ve spent studying and working to protect whales, what do you most hope people understand about them?
Johnson: I hope people understand that whales are important indicators of ocean health and inspiring icons of the wonder of life on Earth.
Do whales need us? Whales have been around longer, much longer, than us. They thrived long before commercial whaling and other human pressures turned their ocean into a complex obstacle course. Today, they need us to manage our impact on the ocean better.
Do we need whales? Absolutely. We depend on the healthy, resilient ocean that whales, other marine life, and ecological processes help sustain. A world with thriving whales is richer and healthier for future generations. By protecting whales and their blue corridors, we also protect something essential – something greater than ourselves.
This article first appeared on Yale Climate Connections and is republished here under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.![]("https://i0.wp.com/yaleclimateconnections.org/wp-content/uploads/2020/10/ycc-favicon.png?resize=100%2C100&ssl=1")
