Its demise was the most obvious sign of growing troubles and dimming expectations for a space that has spawned hundreds of startups over the last few years. A handful of other companies have shuttered, downsized, or pivoted in recent months as well. Venture investments have flagged. And the collective industry hasn’t made a whole lot more progress toward that billion-ton benchmark.The hype phase is over and the sector is sliding into the turbulent business trough that follows, warns Robert Höglund, cofounder of CDR.fyi, a public-benefit corporation that provides data and analysis on the carbon removal industry.