This article expands upon the notion of ideology as a material phenomenon, usually in the form of institutionalized, taken-for-granted practices. It draws on Herbert Marcuse and related thinkers to conceptualize technological solutions to environmental problems as materialized ideological responses to social-ecological contradictions, which, by concealing these contradictions, reproduce existing social conditions. This article outlines a method of technology assessment as ideology critique that draws attention to: (1) the social determinants of the given technology; (2) whether the technology conceals or masks (...) social-ecological contradictions; (3) whether the technology reproduces existing social conditions; and (4) whether the technology may be used for more rational or emancipatory ends in different social conditions. The examples of solar geoengineering and agricultural biotechnology are examined and it is found that, in each case, these technological solutions conceal social-ecological contradictions and support the current economic system and those benefiting from it, while precluding other alternatives. (shrink)