At a time when melting polar sea ice had many focus on which political power control the Arctic (using the Northwest Passage shipping lanes and the petroleum resources beneath the sea ice), Cortada planted a green flag and reclaimed it for nature. To do so, he developed Native Flags, a participatory eco-art project that engages others in planting a green flag and native tree in their homes to prevent the polar regions from melting. Reforestation sequesters carbon from the atmosphere, helping reduce greenhouse gases that warm the planet.