Wood Ice Seed for Sea Ice Generation

The Arctic Ocean is predicted to lose all summer sea ice as early as 2030, even if carbon emissions are drastically cut ^1,2 . Neglecting the sea ice retreating could lead to the catastrophic point of no return as the polar weather pattern would fall into a vicious cycle of sea ice loss and rising sea surface temperature. Here, we propose an environmentally responsible Ice-Wood that has the unique capability to induce and accelerate ice formation even under adverse ambient conditions. Ice-Wood is prepared directly from natural wood through a subtractive process that entails partial lignin removal and surface carbonization. Once floating on the water, its 0.911 albedo and 0.941 mid-infrared emittance consistently induce and maintain a temperature drop from the sea surface that offers a sub-freezing platform. With 1.5 cm thickness, Ice-Wood is optically equivalent to snow-covered or multi-year sea ice (thickness > 1 m). Meanwhile, its inherent hierarchical microchannels along with 6% surface carbonization spontaneously draw seawater upwards, promoting further ice accumulation. Additionally, Ice-Wood can efficiently drain solar-absorbing melt ponds (albedo as low as 0.2 to 0.4), thereby restoring ice cap albedo and slowing the ice melting. During our field validation in open ponds, the proof-of-concept prototype maintained at up to 7.1-8.7 °C sub-ambient temperature that triggered earlier and faster ice formation while the passive cooling effect better preserves ice against environmental factors of solar irradiation, temperature rise, and wind. The proposed strategy can inspire further investigation into scalable and broad ice regeneration acts, particularly in coastal zones experiencing rapid ice retreat.