Abstract
[Opinion] This aims to begin deliberation about investing in negative emissions technologies (NETs) by suggesting that the investment could be responsive to two particular values: need and efficiency—and that these values point us towards taking different actions. For negative emissions technologies, I suggest, we face a Need-Efficiency Tradeoff, i.e. a “NET effect”. This tradeoff also highlights several contrasts: responding to need focuses on regional and short-term moral considerations; responding to efficiency focuses on global and long-term moral considerations. [Open access]