For his thesis project at Delft University of Technology in the Netherlands, Riel Bassai designed a modular chair made with blocks of carbon-negative bio-HDPE to store atmospheric CO2.

Called Unito, the conceptual chair consists of forty two large blocks which are connected by smaller pieces that fit into square holes in each side of the cubes. If you grow tired of the chair, you can take it apart and build something else.

The blocks are made of bio—high density polyethylene (HDPE), which is a bioplastic that can store CO2. About one kilogram of organic carbon is stored in each block, chemically derived from 3 kilograms of atmospheric CO2 using renewable energy, giving the blocks a negative carbon footprint. Because the blocks last at least 100 years, the chair is a sustainable form of long term CO2 storage. Ultimately, the biopolymer can be recycled or stored in geological sinks.

The concept of Unito has been fabricated in various degrees, including two HDPE blocks on a 1:1 scale, including two connectors, a scaled wooden version, and a 1:1 geometric model made of MDF, aluminium and 3D printed components.

If we want to meet our 1.5˚C goals, the IPCC predicts we need to actively sequester 100 gigatonnes of greenhouse gasses by the end of the century. Unito is a speculative concept meant to spark conversation about how designers can address climate change by actively removing atmospheric CO2, while also making tangible what a kilogram of carbon actually is.

Images: Riel Bassai