In Quebec's hydropower-rich grid, lettuce grown under indoor lights can match the carbon footprint of heads shipped from California fields—a finding that upends the assumption that local always means greener. A new McGill-led study reveals that the climate impact of controlled-environment urban agriculture hinges almost entirely on where electricity comes from, not where food is grown.
Researchers partnered with a commercial container farm in Montreal and tracked a full year of operational data: lighting, climate control, water use, crop yields. Lead author Estefany Cabanillas and her team then modeled how that same system would perform across all 13 Canadian provinces and territories, plugging in each region's electricity mix. The contrast was stark. In Quebec, where hydropower dominates the grid, indoor lettuce production holds its own against conventional farming—even in summer, when fresh lettuce grows outdoors naturally. But in Alberta, where fossil fuels power the grid, the energy demands of artificial lighting and climate control can multiply emissions many times over.
"Where your electricity comes from can matter more than food miles," Cabanillas said, challenging the deeply held conviction that proximity equals sustainability. That insight matters as cities worldwide bet on vertical farms and container agriculture as solutions to food insecurity and urban sprawl.
The tension is real. Indoor systems demand far more energy than conventional farming but use far less land and water. As climate change strains farmland and water supplies, that trade-off becomes increasingly significant. The researchers note that controlled-environment agriculture could prove vital for remote northern communities in Canada, where fresh produce travels long distances and supply chains remain fragile. Consistent access to affordable lettuce matters when the alternative is either scarcity or shipped-in goods with their own carbon and financial costs.
Previous studies, mostly single-location analyses in places like the Netherlands, had painted indoor farming as climate-heavy—sometimes several times more emissions-intensive than conventional agriculture. This McGill research takes a continental view, revealing nuance that single-site studies miss. The answer to "When does indoor farming reduce environmental impact?" is not "always" or "never" but "it depends on your power grid."
For cities investing in indoor farms, the implication is clear: pair these systems with renewable electricity, and they become genuinely low-carbon. Build them in coal-dependent regions, and they become emissions liabilities dressed up as innovation. The technology itself is neutral; the grid is destiny.
As the urgency around food security grows—driven by climate volatility, population growth, and unequal access—this research suggests that indoor agriculture has a real role to play, but only when harnessed alongside the energy transition. It's a reminder that sustainability is rarely about single solutions. It's about systems thinking: knowing your electricity source, measuring land and water saved, understanding where your food travels from, and building infrastructure that reflects actual climate realities, not wishful thinking.