Travel brochures for Napa County almost universally feature the same images: a valley floor carpeted with vineyards, nestled between hillsides dotted with spreading valley oaks. As climate change brings hotter days — and more of them — to the county, these twin pillars of the landscape, grapevines and oak trees, are both challenged by it and central to local resilience strategies. A climate action plan has been in the works since 2011 but has yet to be adopted — a delay some local activists attribute to pushback from the powerful agriculture industry. Meanwhile, other entities are spearheading efforts to adapt to the new climate reality, centering on the county’s iconic flora. Efforts to support oaks continue. Hotter, drier weather will likely make Napa’s environment less hospitable to valley oaks, which require a lot of water and prefer cooler temperatures. “Oak sequester a tremendous amount of carbon, improving the soil’s ability to hold moisture, aiding groundwater recharge, while their huge canopies provide shade,” says the Resource Conservation District’s Frances Knapczyk. Of course, oak trees can only do so much to mitigate the local effects of climate change, and those effects — drought, heat, and wildfire — are creating an unnerving threat to the valley’s other iconic flora: grapevines. “Right now Napa is in a sweet spot for growing premium wine grapes,” says local climate activist Jim Wilson. “But it’s well known that in a couple of generations it won’t be.”
Cariad Hayes Thronson covers legal and political issues for Estuary News. She has served on the staffs of several national publications, including The American Lawyer. She is a long-time contributor to Estuary News, and some years ago served as its assistant editor. She lives in San Mateo with her husband and two children.