Joan Salwen is creating a food system that helps sustain the ecosystems that both humans and livestock depend on.

The amount of climate-warming gasses emitted each year by one cow is roughly equivalent to the amount emitted by a car — which makes the digestive systems of cattle the single largest source of greenhouse gas emissions for human activities for which there is no solution.

Joan Salwen has an innovative, natural solution: seaweed. When minimally processed and fed in small amounts to cattle, the natural oils in a variety of Asparagopsis taxiformis, an abundant red seaweed, stops the formation of methane and dramatically reduces the cow’s emissions.

Salwen’s company, Blue Ocean Barns, grows and sources this seaweed, and processes, markets, and certifies it as an additive for livestock feed. In trials, the additive has reduced methane emissions in cows by up to 90%.

Salwen’s work at Blue Ocean Barns brings her back to her agricultural roots. Growing up, Salwen had worked on a farm in rural Iowa her family had owned for generations. “Farmers can be heroes in slowing climate change,” Salwen says. “I do the work I do today as a nod to my ancestors, especially my grandfather, who made his living caring for land and animals. I also do this work for my children and future grandchildren. I firmly believe it is my generation’s responsibility to find climate solutions that will help secure their futures.”