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A few years ago, on a ranch in the small Marin town of Nicasio, a series of events led to an important environmental discovery. Scientists found that a single application of compost on rangeland helps plants suck carbon from the air and store it in the ground. Compost on less than three acres can offset carbon emissions from four diesel truck trips from San Francisco to Washington, D.C. If compost were applied to the millions of acres of rangeland in California, the effect would be monumental.

Everyone knows about the California Gold Rush – the massive migration of fortune seekers to the hills of the former Spanish colony in the late 1840s and 1850s. During the same period, however, there was another rush to California with a more lasting effect – farmers seeking fertile land and a mild climate. Those included the ill-fated Donner Party, but many thousands more. Many who came for the gold also learned that more durable fortunes were to be found in farming, such as my cousin, Hugh Glenn, the “wheat king of California” for whom Glenn County is named.

As drought-stricken residents of Los Angeles’s hottest neighborhoods replace thirsty lawns with native plants, pavers and bare soil, new research has shown how their local climates could begin tipping back in the direction of their desert-like origins. In a region beset this year by drought and powerful heat waves, the widespread adoption of drought-proof landscaping is expected to bring warmer days — and much cooler nights. Overall, experts say the changes would help to protect residents from heat waves, which are being made worse by global warming.

California’s top water guzzlers — the people who use tens of thousands of gallons more than their neighbors to keep lawns bright green during serious droughts — could soon be hit with higher water bills and their names made public if the drought continues. A law signed late Monday by Gov. Jerry Brown requires retail urban water suppliers with more than 3,000 customers to put in place rules that define “excessive water use” and impose them during drought emergencies.

Five years into a drought, California is facing essential decisions about its water future. It’s implementing new groundwater law, weighing the pros and cons of a large infrastructure project for water supply and beefing up its data collection. But there’s more to do. Water Deeply asked four experts who work in different arenas of California water issues what they think should be California’s biggest policy priority to address in the next year. Here’s what they had to say.