Hand drawn sketch of an artificial or mechanical tree for direct air capture of carbon dioxide, by Professor Klaus Lackner, Lenfest Center for Sustainable Energy, Columbia University, New York, 2010

This sketch was drawn by Professor Klaus Lackner during his time as Director of the Lenfest Center for Sustainable Energy, Columbia University, New York (2001-2014). Lackner is one of a small number of scientists who had championed direct air capture – the removing of carbon dioxide from atmospheric air – during the 1990s and 2000s. When he began developing prototype carbon collectors like this one, most people viewed carbon capture as science fiction, considered too complex to be economically feasible. By the early 2020s, many considered that there is no practical way in which the Earth’s temperature can be kept below 1.5 degrees without carbon capture technologies.

The sketch represents Lackner’s early mechanical tree concept. The imagined tree has a large ‘spatula’ design that contains ‘branches’ within two extended arms. Alongside this sketch is a person drawn for scale, as well as information pertaining to the expected collection rates and efficiency of such a design. The motivation for this early concept came from a school project undertaken by Professor Lackner’s daughter, in which she successfully demonstrated (via a shop bought fish tank pump) that carbon dioxide could be captured from the air through a reaction with sodium hydroxide. As put by Lackner, ‘I was surprised that Claire [his daughter] succeeded as easily as she did and that got me thinking. Obviously, I couldn’t use an aquarium pump to drive air through my system. I got sketching. The first drawing I made – which you have on display – ended up looking like a tuning fork, or a goal post, with Venetian blinds.’