For two years running , California’s wildfires have sent plumes of smoke across Silicon Valley. So far, that hasn't spurred much tech innovation aimed at addressing extreme-weather disasters associated with climate change. It's true that tech companies from enterprise software-maker Salesforce to financial-technology firm Stripe have pushed to dramatically reduce their climate impact. Individual investors and small investment firms have stepped in to fund emerging efforts around cleantech — a term used broadly to describe technology that looks to manage human impact on the environment. And the catastrophic Australian wildfires have spurred additional interest. But among startups who provide much of tech innovation, things are still moving slowly. That's partly a lingering hangover from a cleantech investment bust almost a decade ago.