Whales Keep Carbon out of the Atmosphere

 If conservation efforts pay off, whales could help islands meet their emissions reductions

• Blue Climate Solutions in Scientific American.

Unlikely heroes could play a starring role in helping the Pacific islands meet their climate commitments: whales.

Residents of the Pacific islands are keeping an anxious eye on the whales that populate their steadily warming waters. Many are concerned that climate change will take a toll on the marine mammals that are an integral part of the islands’ culture, as well as the base of a thriving eco-tourism industry.

Members of the scientific community are also worried, albeit for a different reason: Whales are crucial to ocean carbon absorption. As whale numbers dwindle, it could lead to increased greenhouse gases in the atmosphere, scientists say. But if conservation efforts pay off, whales could play a role in helping the islands meet the reductions to their nationally determined contributions (NDCs) of greenhouse gases framed in the Paris Agreement.

“The main takeaway here is that whales eat carbon, not fish,” said Angela Martin, project lead with Blue Climate Solutions and co-author of a recent report produced for the secretariat of the Pacific Regional Environment Programme that looked into the species’ role in carbon absorption.

“The deep ocean stores a lot of carbon, so it’s worth looking at the contribution of animals and help in conservation efforts,” she added.

Whales facilitate carbon absorption in two ways. On the one hand, their movements — especially when diving — tend to push nutrients from the bottom of the ocean to the surface, where they feed the phytoplankton and other marine flora that suck in carbon, as well as fish and other smaller animals. The other, explained Natalie Barefoot, executive director of Cet Law and co-author of the report, is by producing fecal plumes.

“In other words, pooing,” she said. “That also introduces nutrients that create marine plants in the area. These plants use photosynthesis, which absorbs carbon, thus enhancing the carbon capture process.”

But as waters steadily grow warmer, whales may not be able to survive in the region. It’s difficult to predict just how climate change will affect the species, said Barefoot, because they’re part of a complicated ecosystem with many interlinked species.

Climate threats are also coupled with human ones like overfishing. Broadly speaking, however, increased temperatures will likely create tough living conditions and drive more whales out of the waters around the islands.

“Temperature change may directly influence the distribution of whales, and then you have ocean acidification, which can affect the food chain and habitats of their prey. Whales are highly mobile creatures, so if climate change causes the prey to move, they will probably follow them. Then there’s the increased competition that comes about as surface temperatures change and species move to different habitats — all of a sudden, you have different species using the same area, so there’s more competition,” she said.

Then there’s the question of how climate pressures on humans could affect whale habitats. For instance, as shifting weather patterns affect food security, humans could start relying more on the ocean for food. There’s also the possibility that ship traffic will increase as melting ice opens up more routes across the ocean, leading to more pollution, garbage and noise.

That dynamic could create a cycle where warming waters harm the whales, in turn reducing the ocean’s ability to suck in carbon and leading to even more temperature increases.

‘Small islands with big oceans’

Scientists have made progress in terms of pinpointing exactly how much carbon whales keep out of the atmosphere; one study suggests that every year, sperm whales help sequester as much carbon as 694 acres of U.S. forests do. Another found that in Hawaii, the swimming motion of 80 whales can absorb the equivalent carbon of 208 acres of U.S. forests. But there’s still a huge degree of uncertainty here.

If scientists were to research this and calculate a concrete figure, it could have profound implications for the Pacific islands. That figure could be incorporated into the NDCs they’ve framed under the Paris Agreement and allow them to participate in voluntary carbon markets, said Martin.

Fakavae Taomia, permanent secretary for the office of the prime minister of Tuvalu, encouraged research into whales’ carbon absorption properties.

“[W]e are small islands with big oceans, now trying to meet our Nationally Determined Contributions under the Paris Agreement,” he said in a statement.

For residents of the islands, who consider the species to be an integral part of their identity, changes in whale populations could have cultural and economic consequences, as well. Whales play starring roles in local folklore and are believed to guide travelers who cross the ocean. They are also a huge tourism draw for the region; an entire industry has developed around whale-watching.

The whale-watching sector has grown by around 45 percent between 1998 and 2005. In 2005, it raked in around $21 billion in local economic benefits, a figure that is likely much higher today. But if the number of whales dwindles and sightings become rarer, all of that could change.

“One impact climate change could have is [to] introduce seasonal variances, which would mean that the whales’ migration seasons would become less predictable. This could stress tourism, particularly during shoulder season, when they’re coming and going,” said Barefoot.

Link to orgininal article on Scientifc American (11 Apr. 2017): https://www.scientificamerican.com/article/whales-keep-carbon-out-of-the-atmosphere/?platform=hootsuite