Land and Sea

“Poor agricultural practices can cause soil erosion and soil pollution,” says James Campbell, a research associate with the Research Centre for Carbon Solutions at Heriot-Watt University in Edinburgh, Scotland.

“A decrease in soil quality leads to more fertilizer, pesticide, and fungicide use. Poor agricultural practices can also lead to polluted soils containing heavy metals and microplastics. All of these can make their way to the sea, via rivers, and cause substantial harm,” says Campbell.

About 33 percent of the Earth’s soil is degraded, largely due to agriculture, and more than 90 percent faces the same fate by 2050, according to the United Nations (UN) Food and Agriculture Organization. But more than just the future of food production is thrown into jeopardy by this fact. So, too, is the planet’s ability to sustain any kind of life at all.

Soil stores carbon, helping to regulate the planet’s temperature. When it’s degraded, all that stored carbon gets released back into the atmosphere, making it one of the biggest contributors to climate change.

The availability of critical resources, such as water, are also affected by soil and land degradation. The UN figures that half of humanity is already feeling the effects of changes to Earth’s land surfaces, losing about US$40 trillion of ecosystem services—that’s about half the global gross domestic product of 2021. Land degradation is also considered the single greatest cause of terrestrial biodiversity loss.

The connection between soil health and our oceans

Land and soil degradation also affects our oceans. After all, carbon dioxide (CO2) being released through activities such as tilling or clear-cutting forests to make way for food production has to go somewhere. It goes into the Earth’s other carbon sink: oceans. And when CO2 dissolves in seawater, it becomes carbonic acid, raising the acidity of the ocean.

Ocean acidification is devastating for underwater ecosystems. Also known as “osteoporosis of the sea,” it decreases carbonate in seawater, which is used by shellfish, coral, and crustaceans to build their shells, reefs, and skeletons.

“This means that gradually, [lobsters] may have softening of their shell, and that will cause them to be more affected by things like parasites and other issues,” Vasseur says.

The impacts of biodiversity loss

It would be easy to think that if lobster populations dwindle or disappear because of parasites penetrating weak shells, humans will still be okay as a species. After all, there are other fish and crustaceans in the sea. The reality is that every time a species struggles to survive, or vanishes altogether, the sustainability of the ecosystem to which it belongs—and, ultimately, the whole planet—deteriorates, Vasseur explains.

As oceans acidify and warm up with rising global temperatures, species such as lobster or even cod, which thrive in the colder temperatures of the North Atlantic Ocean, move farther north into other ecosystems in search of the frigid waters they need to survive.

“The other issue is that you’ll have a change in the species where the cod used to live with more bottom feeders, and those that are capable of surviving in warmer temperatures or lower oxygen levels,” Vasseur says. “You’ll also have invasive species like the green crab, which we now have on the Atlantic coast and can survive better than some of our more sensitive species.”

That not only changes the look of our oceans but also the health of our economies, she adds. Functional ecosystems are essential for human survival, but many are already in peril because of human causes.

A 2020 UN report on biodiversity and ecosystem services estimated that a quarter of all terrestrial, freshwater, and marine vertebrates and invertebrates and plants are threatened with extinction, and many of those have only decades left before they’re gone forever.

Individual actions can affect the future

It’s a bleak prognosis, but if we want to change course, we can start by thinking more critically about the impact of our individual actions, including those decisions we make at the grocery store, Vasseur notes.

“We have to think about the ethical component of what we’re doing. We don’t think about ethics much these days. We tend to just think, ‘Oh yeah, I can do this.’ We don’t tend to think of the next generation,” she says. “But everything is connected to everything. Each time you take a step, you have an impact on something.”

What you can do to protect biodiversity

Buy local

Buying food grown close to home limits the distance it travels from farm to plate. Shorter transportation distances generally mean less carbon dioxide is emitted into the atmosphere. If you want to do one better, buy directly from farmers, especially those using organic and regenerative production methods, at the farm stand or through a community-supported agriculture (CSA) program.

Avoid using chemicals at home 

This includes fertilizers, insecticides, and pesticides on lawns or in gardens, which are harmful to humans, insects, birds, fish, and pets.

Swap the lawn for native plant species

To decrease the amount of mowing, watering, and even fertilizing required to keep your lawn lush, start switching out grass for vegetation that grows naturally where you are. Native species are adapted to the local environment where they grow, which means they require less maintenance and fewer resources than other plants. They also create natural habitat for local wildlife.

Keep Fluffy indoors 

Cats are cute but they are stealthy hunters, posing a threat to birds, small animals, and reptiles that call your yard or neighbourhood home. Keeping cats inside could help save as many as 200 million birds in Canada. If Fluffy is desperate to get out, dress him up in a collar with a bell to alert prey to his presence.

Source: Government of Canada

A forecast for healthier soils and oceans

Enhanced weathering sounds like fancy meteorology but it’s actually a carbon-capture technology using natural remedies to improve soil health and protect it from erosion. It can also increase ocean alkalinity to combat acidification.

James Campbell, a research associate with the Research Centre for Carbon Solutions at Heriot-Watt University in Edinburgh, Scotland, and other scientists are intensively studying enhanced weathering techniques. These include using rock dust to remineralize soil or depositing rock particles in the ocean to speed up and mimic a natural chemical reaction that occurs in the atmosphere to remove acidic carbon dioxide.

“There are also other soil remediation approaches under investigation, such as the addition of biochar,” Campbell says. “One of our students is investigating combining enhanced weathering and biochar additions to the soil, and there are some very positive preliminary results. Soil biodiversity improves, carbon is removed from the air, and crop yields and crop quality increase.”

This article was originally published in the April 2024 issue of alive magazine.