Development is rapidly eating up open space in Dublin.

Thousands of acres of green open space in the East Bay are in danger of being gobbled up by suburban housing tracts.

A steady gale whipped the long, spring grass, sending waves streaking across the hills near Mount Diablo. “I’ve always loved that view—right there,” said Michael Amorosa, who had come to a stop while walking along Empire Mine Road, a bike path and trail that bisects a suburban wilderness near Antioch on the east slope of the mountain. Amorosa looked west at the peak’s summit as it was momentarily framed between the slopes of two sublimely green hills.

Amorosa has lived in Antioch for 31 of his 47 years. Throughout his childhood, he tromped through the open spaces here. “We had all sorts of Huck Finn-type adventures out there,” he recalled. He hopes his son and his daughter will be able to walk through these same hills when they’re adults.

But Amorosa’s wish might never come true. Almost 3,000 unspoiled acres here—open space known as the Sand Creek Focus Area—have been targeted for conversion into suburban neighborhoods, packed with 4,000 homes. Two of the projects, Aviano Farms and The Vineyards at Sand Creek, are already approved and will fill 1,200 houses with residents. Another proposed project, tentatively sized at about 1,300 homes, has been euphemistically named The Ranch by the real estate firm Richland Communities.

“The Ranch would pave over 551 acres of real working ranchland,” said Joel Devalcourt, who works with Greenbelt Alliance, an environmental group that strives to stop suburban sprawl and promote construction of new homes in developed urban areas, especially those near transit centers, a type of development called infill or smart growth. Devalcourt is working closely with Amorosa and his neighborhood group—the Antioch Community to Save Sand Creek—to stop the projects.

Their battle is just one of many that have escalated across the East Bay as developers continue to gravitate toward oak-studded real estate, much of it still home to such iconic wildlife as golden eagles and mountain lions. The region’s human population is expanding rapidly, and throughout the Bay Area nearly 300,000 undeveloped acres are at risk of being lost to suburban sprawl over the next 30 years, according to a recent analysis by Greenbelt Alliance. Developers particularly covet the hills east and south of Mount Diablo. In total, more than 60,000 acres in Contra Costa County and another 30,000 in Alameda County are threatened.

Already, much of the East Bay has been transformed from pasture, orchard, wetland, and oak woodland into vast suburbs. And with every acre that is graded and paved, imperiled species,  including the San Joaquin kit fox, the Alameda whipsnake, the burrowing owl, and the California red-legged frog, lose critical habitat they will never regain.

But those aren’t the only impacts associated with building more homes in the Bay Area’s rural hinterlands. Most residents of these new housing tracts will have to drive private vehicles to and from their homes. And as most locals know, East Bay roadways simply can’t accommodate more vehicles during rush hour.

“The traffic will only get worse as they build up more open space,” warned Jim Gibbon, an environmental architect and a smart-growth advocate with the Sierra Club’s San Francisco Bay chapter. Additional suburban sprawl and thousands more vehicles on area roads will also worsen the region’s greenhouse gas emissions, thereby making it tougher for California to meet its climate change goals.

Backers of the pending projects say the demand for more housing merits the conversion of green space into new homes. “It’s a response to Antioch’s need for housing,” said Aaron Ross-Swain, Bay Area director for Richland Communities. Ross-Swain also argued that not everyone wants to live in apartment buildings or condo complexes in dense urban areas. The Ranch, he said, will fulfill people’s desire for traditional single-family homes in a suburban-style setting.

Although The Ranch and the other projects of the Sand Creek Focus Area would be on land technically zoned for development, many residents want to see the area remain open space. Community meetings addressing how to use the land here have drawn loud protests against development. Elected officials, including Antioch’s Mayor Pro Tem Lamar Thorpe and Contra Costa County Supervisor Candace Andersen, have also questioned the wisdom of building more new homes on land that is miles from the nearest transit station—a perfect recipe for worsening traffic.

In fact, county and regional planners have determined in recent analyses that the East Bay has enough available acreage within established urban landscapes—including in Oakland and many sites along BART lines—to completely absorb the region’s expected population growth.

“We just did an urban limit line update, and we found there’s sufficient buildable land within the developed areas,” said Andersen, who believes the social value of the East Bay’s open space and agricultural land exceeds its value as real estate.

Devalcourt agrees and insists that sacrificing undeveloped  open space to new homes is unnecessary. “We don’t need  to make a deal with the sprawl devil,” he said.

The farthest reaches of the East Bay experienced a massive housing boom in the early 2000s, with Brentwood becoming the fastest growing town in California. Huge areas  of open space were sacrificed to the explosion, and over a period of 15 years, Brentwood grew  from a quiet community of 6,000 people to a small city of more than 50,000.

The subprime mortgage crisis and the Great Recession put the building boom on hold, but now another one is underway as throngs of people scramble to find places to live in the Bay Area. This time around, Brentwood’s neighbor to the south has become one of the most targeted areas to settle. “Dublin is getting gobbled up,” Devalcourt said.