Science

5 ideas to fight climate change through better land use

Growing more crops in the shade of the forest and fertilizing crops with plant-based charcoal are some of the ways we can fight climate change by using land more sustainably, says the co-author of a new UN-backed climate report.

More sustainable food production and forestry could cut emissions and store carbon

Workers turn soil containing biochar in a corn field at the Villa Carmen Biological Station in Peru in December 2014. The addition of biochar can both store carbon in the soil and act as fertilizer. (Enrique Castro-Mendivil/Reuters)

Growing more crops in the shade of the forest, fertilizing crops with charcoal, and using trade policies to ensure imported food is grown without damaging landscapes and widening deserts overseas are some of the ways we can fight climate change by using land more sustainably, says the co-author of a new UN-backed climate report.

"I think there's lots of opportunities to make these changes, and it's not too late," said Margot Hurlbert, co-ordinating co-author for Chapter 7 of the Intergovernmental Panel on Climate Change report, released Thursday.

The report focused on the links between climate change and land use. It noted that climate change is putting extra pressure on forests, farmland and other landscapes that are already strained or threatened by human activities like farming and forestry. 

At the same time, it found that reducing greenhouse gas emissions from land use and food production is crucial to keeping global warming below 2 C — the international target set by the Paris Agreement to avoid the worst effects of climate change.

Officials from the local Water Conservancy Bureau walk on the fringe of a desert, which has been planted with grass to prevent desertification, in China's Gansu province in 2010. Climate change can exacerbate problems like desertification, a new IPCC report finds. (Stringer/Reuters)

Hurlbert, a University of Regina professor and Canada Research Chair in climate change, energy and sustainability policy, was in charge of the chapter titled "Risk management and decision making in relation to sustainable development."

In a conversation with CBC News, she highlighted some of the land use strategies that can help fight climate change and, in some cases, adapt to it too.

1. Agroforestry

Hurlbert describes agroforestry as "having forests that agricultural producers are also farming and living in." 

That could include growing crops under a forest canopy, as with shade-grown coffee, interspersing fruit trees such as mangos with field-grown crops like vegetables, or dispersing fields through a forest, as is done in some countries.

"In Canada, that's actually kind of a foreign concept," she said. But she suggested it's something we should learn more about.

According to the IPCC report, agroforesty can reduce erosion. It can also sequester carbon in the trees and boost biodiversity by providing habitat for plants and animals.

The report highlights policies to encourage it in Costa Rica, where landowners get paid for agroforestry.

Protected by trees left for shade and to break the wind and avoid erosion, coffee plants blanket a hillside in Camaca, Brazil in April 2000. Agroforestry is listed as one solution to land use problems related to climate change. (Douglas Engle/Associated Press)

In Canada, one kind of agroforestry that's sometimes used is shelter belts — the planting of rows of trees to protect crops, livestock, roads and buildings from conditions like wind and snow.

According to Agriculture and Agri-Food Canada, that can boost crop yields, reduce the amount of feed required by animals such as cattle, and reduce energy use from heating.

Hurlbert said Canada used to have incentives for farmers to grow shelter belts, and could look at bringing them back.

2. Biochar

Biochar is a special kind of charcoal that's produced by controlled burning of plant matter such as agricultural residues or wood waste. 

"That actually makes it into something that can be used as a fertilizer and store carbon in the ground," Hurlbert said, noting that it's an alternative to nitrogen-based fertilizers that can degrade soils if over-applied.

The IPCC report says biochar even has the potential to reverse soil degradation, but suggests it works better in the tropics than in temperate regions.

American volunteer Heather Nobert cools biochar extracted from an oven in Pilcopata, Peru in December 2014. (Enrique Castro-Mendivil/Reuters)

3. Producing more wood

Sustainable forest management that produces harvested wood products can store carbon over the long term and substitute for more emissions-intensive materials such as concrete, metal or plastics, the IPCC report found. 

In Canada, solid wood products accounted for 44 per cent of forestry's economic impact in 2013, while pulp and paper accounted for 36 per cent, Natural Resources Canada reports.

Hurlbert suggests encouraging the forest industry to shift that balance in favour of wood products.

Sustainable forest management that produces harvested wood products can store carbon over the long term, the IPCC report found.  (Reuters)

4. Thinking outside the plot

There is lots of land on a farm beyond the actual fields where crops are growing, and those can potentially store a lot of carbon, Hurlbert said. They include ponds and wetlands that form in gullies and forested areas that farmers could be encouraged to retain. 

She suggests starting to track and recognize practices in agriculture that reduce greenhouse gas emissions and encouraging them, and to start "thinking about our food and our farms and our landscapes in a more holistic manner."

5. Sustainable sourcing

Of course, most of the land use problems cited in the new report — such as desertification, land degradation, clearing and burning of forests, and over-harvesting of fuel wood — are mostly happening outside Canada.

But that doesn't mean there's nothing we can do about it.

Hurlbert says there are many sustainability certifications that exist now that allow governments, organizations and consumers to source food and wood products that have been sustainably produced in relation to land, climate and people's livelihoods.

Canada can also wield influence through its own use of trade conditions and policies, she adds: "Countries who want to have food security often have to ensure that they have access to other food markets like the Canadian suppliers in order to ensure their food security when they have a drought event."

Of course, while these ideas will make a difference, the fundamental solution to problems involving land use and climate, is the one we've been talking about all along, Hurlbert says: "Reducing greenhouse gas emissions is the proactive policy, because if we get that right, then it reduces the strain on land."

ABOUT THE AUTHOR

Emily Chung

Science, Climate, Environment Reporter

Emily Chung covers science, the environment and climate for CBC News. She has previously worked as a digital journalist for CBC Ottawa and as an occasional producer at CBC's Quirks & Quarks. She has a PhD in chemistry from the University of British Columbia. In 2019, she was part of the team that won a Digital Publishing Award for best newsletter for "What on Earth." You can email story ideas to emily.chung@cbc.ca.