Companies producing everyday gases like nitrogen and oxygen are among the world’s largest electricity consumers, responsible for 2% of carbon emissions in China and the U.S. Despite their massive climate footprint, firms such as Linde, Air Liquide, and Air Products have largely escaped public scrutiny.

The University of California, San Diego, is among a growing number of colleges requiring all undergraduates to take courses on climate change, reflecting a shift in higher education toward preparing students in every field to understand and respond to the global climate crisis.