Companies that suck planet-heating emissions from thin air — a process often decried as too costly and little more than science fiction — say they are gaining wider interest from governments and investors to help fix a "code red" climate change crisis.

Three top direct-air-capture firms — Climeworks, Carbon Engineering and Global Thermostat — said they are increasingly hopeful governments could provide incentives to develop the fledgling industry, modeled on subsidies for solar power or electric cars.

Swiss-based Climeworks opened the world's largest direct-air-capture plant in early September in Iceland.