In an attempt to curb the increasing impacts of climate change, California has taken a leadership role on the geopolitical stage. The state has signed international climate agreements independent of the United States and created a market-based cap and trade system that incentivizes lower greenhouse gas emissions and forest offsets. And its renewable energy production target is one of the highest in the world.

The state’s ambitious 2015 clean energy law mandates that 50 percent of the state’s electricity come from renewable energy sources by 2030. To meet this goal, California must double its current renewable generation capacity in less than 15 years—relying mostly on solar, wind and geothermal power. The state is also innovating, rolling out rooftop solar in cities, increasing the grid’s capacity to store energy from intermittent renewable sources and increasing energy efficiency.

California’s commitment to reducing emissions speaks to the urgency of the situation, says Louis Blumberg, California climate change director for The Nature Conservancy.

“It’s very important that we reduce greenhouse gas emissions as quickly and as significantly as possible,” he says.

But that doesn’t mean the state should act rashly. The first green energy rush, spurred by federal stimulus spending, was an all-out land grab in the desert. Without a plan to balance clean energy and desert conservation, government agencies approved the construction of large-scale solar power facilities right next to Joshua Tree National Park and the Mojave National Preserve. These power plants use up thousands of acres of land, dramatically changing these iconic vistas and harming some of the oldest living plants and animals on earth. Poor planning also caused project delays, increased costs and spurred litigation.

California has a big appetite for energy, but there’s a better way to meet the state’s needs. The Nature Conservancy, in partnership with government agencies, is using scientific assessments to map the state—and the entire Southwest—identifying millions of acres where solar power plants could be built without disrupting critical habitat and pristine desert land. With this data in hand, California doesn’t need to make the painful trade-off between renewable energy and conservation.

Read on to learn how The Nature Conservancy’s science and unlikely partnerships with utility powerhouses is fueling California’s clean energy future.

The 2009 federal economic recovery package was hailed as a “green stimulus,” earmarking roughly $80 billion for renewable energy development. From tax credits to loan guarantees, The American Recovery and Reinvestment Act offered incentives that spurred solar energy investments. And all eyes quickly turned to California’s deserts.

It makes sense—solar power feeds on sunlight. And the desert has plenty of that. It’s also big, with vast flat expanses, and mostly uninhabited. Or so one might think.

In reality, the desert houses some of the oldest plants and wildlife on earth. It’s also home to some of the country’s most iconic national parks, preserves and wilderness areas. But in the rush to invest in green energy, the federal government allowed companies to build solar facilities near protected areas, jeopardizing some of the desert’s most ecologically valuable lands.

For example, Ivanpah, a $2.2 billion concentrating solar plant, was built in an area of high ecological value in the California desert—near protected wilderness and the Mojave National Preserve. Ivanpah Valley was home to a large number of threatened desert tortoises, the California state reptile. The tortoises were displaced by construction of the massive power plant and their habitat was destroyed.

Ivanpah is just one example of a renewable energy facility that was proposed in a location with many conflicts. In 2010, applications for renewable energy facilities covered more than 1 million acres of public land in California’s deserts, many proposed in places that would have tremendous impacts on the desert’s fragile ecosystem.

Seeing that the desert was on a collision course that would put California’s clean energy, climate and desert conservation goals at risk, The Nature Conservancy focused on research to find a better way forward. To help the federal government strike the right balance between green energy demands and the needs of nature, The Conservancy came to the table with data-driven analyses of two critical areas: the Mojave and Sonoran Deserts.

These landscape-level ecological assessments provided detailed maps that highlight previously disturbed areas where development can occur with fewer potential impacts to nature. They also highlighted areas of high conservation value—those that need to be left undeveloped. Using hard data and scientific assessments, The Nature Conservancy has helped identify more than 1 million acres that may be developed for solar and wind projects across California with a lower impact to nature.

Mapping disturbed areas in the desert had never been attempted, but The Nature Conservancy recognized that this data could be useful to finding solutions for clean energy and nature. Unlike other ecosystems, where restoration can be accomplished quickly by planting seeds and adding water, the desert is very slow to recover from disturbance. In fact, the tank tracks made by General Patton’s troops while they trained for World War II are still visible to this day. With ecological recovery in the desert measured in decades or centuries, as opposed to years, The Nature Conservancy recognized that siting renewable energy facilities in places where desert vegetation had been removed and the soils disturbed would cause much less impact.

To streamline the proposal process, federal agencies used The Conservancy’s disturbance mapping to designate zones where developers could apply for permits that were in areas of lower ecological impact—and they used The Conservancy’s ecological mapping to identify areas that should not be developed at all. This will help avoid another ecological crisis as the state works to provide 50 percent of the state’s electricity from renewable sources by 2030

“This approach to developing a vision for both renewable energy and conservation is something that can be replicated in other states and in other countries as they are setting renewable energy mandates,” says Erica Brand, director of The Nature Conservancy’s California Energy Program.

The Nature Conservancy also evaluated the economic effects of building in areas with a lower environmental impact. This analysis found that there’s a minimal cost increase for consumers (less than 2 percent) that comes with avoiding high-value land. Plus, building in low-conflict areas help developers avoid costly permitting delays and public controversies.

The Nature Conservancy’s approach has been so comprehensive, balanced and useful that both the U.S. Department of Interior and the U.S. Department of Energy adopted it in 2012 as part of the Western Solar Energy Program, which covers 100 million acres in the Southwest.

But it wasn’t just us. In order for The Nature Conservancy’s data to inform public policy, industry, other environmental and conservation NGOs, and government players—including the U.S. Fish and Wildlife Service, the California Energy Commission and power company representatives—had to see the value in using the science and creating a new approach.

The Nature Conservancy collaborated with multiple partners that brought a wide range of perspectives and expertise to develop policy recommendations. In addition, The Conservancy incorporated considerations that were important to others into our ecological assessments. For example, the disturbance mapping that The Conservancy conducted included technical criteria identified by developers, such as the appropriate slope and solar radiation needed for economically feasible solar development. In this way, The Conservancy helped create a collective vision for clean energy and conservation.

“The Conservancy has a great reputation for really doing their homework and using the best available science for coming up with assessments and analysis,” says Diane Ross Leech, director of environmental policy, Pacific Gas & Electric (PG&E). “With The Conservancy’s help, PG&E can provide clean, renewable energy for our customers, while also protecting the fragile desert.”

The desert tortoise has roamed the Mojave for millions of years—even before the region was a desert. Over millennia, the tortoise has adapted to thrive in one of the planet’s harshest environments.

“The desert tortoise is a true arid land denizen,” says Sophie Parker, Ph.D., senior scientist for The Nature Conservancy. “It survives in the desert by growing slowly and digging burrows to escape the heat.”

One thing it can’t handle is rapid change. Human activity in the desert has caused the tortoise to be placed on the California and Federal Endangered Species List. Its status is threatened, just one notch below endangered. How the renewable energy industry grows within the Mojave Desert could determine the future of the desert tortoise—and hundreds of other native species.

Underneath the barren surface, desert soils support a miniature garden of lichen, algae, moss and microorganisms. This biological soil crust can take decades to form—and some individual plants have been around for thousands of years. So, once industry moves into an area and disturbs the soil, the ecosystem will never be the same.

“It can take decades to restore that land—if it’s even possible to restore it at all,” says Erica Brand, director of The Nature Conservancy’s California Energy Program. “So once it’s converted, it will stay that way for a very long time, if not forever.”

To help California move toward a clean energy future while also protecting this unique desert ecosystem, The Nature Conservancy completed an in-depth ecoregional assessment in 2010. The goal was to analyze the conservation value of the entire Mojave Desert—all 32 million acres. Previous assessments had focused on critical conservation areas, known as portfolio sites, but a complete assessment to characterize the value of land within the ecoregion had never been done before.

“We wanted a better understanding of the threats to biodiversity,” says Dr. Parker. “And we wanted to develop a long-term vision of what conservation success would look like.”

Using information about the presence of plants and animals across the landscape, as well as data on roads and properties that had been previously disturbed or developed, the assessment placed land into four categories, each with a different conservation value. “Ecologically core” and “intact” areas were a priority to protect while “moderately degraded” and “highly converted” land could be developed with a lower environmental impact.

One factor the study considered was the location of desert seeps and springs. Underneath the desert’s surface are groundwater aquifers containing water that predates the last ice age. Many unique plants and animals, some of which are endemic to the Mojave, depend on this water, which bubbles to the surface in seeps and springs. But today, a lot of this water also is pumped and used by people—and some of it goes toward the operation and maintenance of solar facilities.

“If too much water is taken from this system, the recharge may not be high enough to replace the groundwater,” Dr. Parker says. “If the aquifer becomes overdrafted, you can have land subsidence, where the land actually falls in and constricts the aquifers. That means there could be less space to store water in the future.”

While the assessment found that 86 percent of the Mojave retains high conservation value, there were also hundreds of thousands of acres that had already been disturbed.

The takeaway for policymakers was clear: It’s possible to meet aggressive renewable energy goals using land with lower conservation value—leaving the desert connected and intact from the Salton Sea to Death Valley.

“Because we did our analysis before the planning processes were fully underway, we have the ability to help guide policy and decision-making,” Dr. Parker says.

This influence can be seen in the Desert Renewable Energy Conservation Plan (DRECP). The first phase, which was approved by the Bureau of Land Management in September, will guide land use decisions for 10.8 million acres of public land. It sets aside 388,000 acres, more than 600 square miles, as renewable energy development focus areas—and 6.5 million acres for conservation. The designations were informed by The Conservancy’s ecological assessments done in the Sonoran and Mojave Deserts.

The DRECP also safeguards the desert’s groundwater by protecting the rare places where groundwater surfaces as springs, seeps and wetlands. It promises a network of connected, intact lands and water sources, stitching together already protected parks and preserves like Joshua Tree, Death Valley and the Mojave National Preserve.

“The DRECP ensures we address one issue without creating another,” Brand says. “It’s a science-based, collaborative road map for siting renewable energy on public lands in places that will have less ecological impact—so we can address the causes of climate change while still protecting the desert.”