In California, diversity is not just about embracing demographic change. It’s about protection against disasters, natural and manmade. California is a disaster-prone state, and when calamity strikes, diversity — of all kinds — keeps bad times from becoming even worse. The central insight into diversity as protection is biological: a diverse eco-system is more resilient because it has a much broader variety of ways to respond to stress and calamity. This insight applies not only in the forest but also in neighborhoods, government and industry. When an ecosystem loses its diversity, when the variety of trees and plants narrows, you get disasters that are more damaging than those we’ve seen before. That’s the story behind California’s mega-wildfires, —like the Soberanes Fire in the Big Sur area, now the costliest fire to fight in U.S. history. Instead of allowing smaller fires to thin and renew our lands, keeping them diverse, we’ve suppressed fires for decades. Now, when the calamities of climate change and drought are upon us, our lands lack protection. Something similar can happen when disasters strike neighborhoods. The most resilient communities are ones with people — of different ages, varied levels of education, and diverse sources of income. When the housing and foreclosure crisis struck California a decade ago, communities across the state got hurt. But the hardest hit were newer low- and middle-income communities inland whose residents conformed to a similar socio-economic profile. At the same time the housing crisis hit, a lack of diversity was making the economic catastrophe even worse in my own profession: journalism. Economic and technological changes (especially the rise of the Internet) were going to do damage to established newspapers and TV stations no matter what. But media outlets made things worse, by employing too many of the same kinds of people. At the papers where I spent my youth, including the L.A. Times, editors almost exclusively hired people with journalistic training, and were wary of technologists. And the near absence of racial and ethnic diversity in newsrooms meant that media outlets lacked community allies willing to support them when times got rough. So these vital civic institutions didn’t have the diversity of expertise and connection to protect against massive change in the business. When you think about all the ways a lack of diversity leaves us exposed to danger, the lesson should hit home. Diversity is not something to be celebrated or embraced as a virtuous luxury. It must be sought out and developed as a core strategy for survival. Unfortunately, California is so diverse that we’ve come to take our diversity for granted. The state’s racial and ethnic diversity is really a legacy of our parents and grandparents, who brought with them very different cultures and experiences. Today’s Californians are majority homegrown, so, despite our different shades, we are more homogenous than before. With immigration levels to California declining dramatically from previous decades, we need to think about renewing our population by attracting more people from around the world. In our old-line neighborhoods, we need to stop fighting affordable housing and new developments that bring badly needed diversity. And we need to stop obsessing about income inequality — which is really just diversity of income — and instead make sure that people with different incomes can afford to stay in California and live and work productively together. We must stop protecting our highly centralized system of state government, in which Sacramento makes regulatory and tax decisions for us all, and return real control to local governments so they can embrace very different destinies. And we should fight back against those who demand ideological purity in our politics and parties—and purge from the party those who dissent. Those who create political monocultures are making it possible for dangerous people to invade and take over political institutions (Ask your Republican friends—they’ll know what I’m talking about). In the meantime, get out there and become part of our diversity. Make new contacts not like you, move to a different neighborhood, and ignore all your like-minded friends on Facebook. You’re not just turning over a new leaf. You’re protecting the forest from a bigger fire. Joe Mathews writes the Connecting California column for Zócalo Public Square.