Here's a scary thought: What if California's dry spell lasts several more years?

That's the scenario examined in a new study from the Public Policy Institute of California titled: "What If California’s Drought Continues?"

Researchers found that two to three more years of below average rainfall would likely cause serious problems for many low-income rural communities and endanger certain birds, fish and forests.

"Emergency programs will need to be significantly expanded to get drinking water to rural residents and to prevent major losses of waterbirds and extinctions of numerous native fish species, including most salmon runs," the authors noted in the study.

Researchers with PPIC looked at current trends to predict how a prolonged drought would likely play out.

Cities and farms will be okay

The good news is that cities and suburbs have adapted well to the drought so far, and would likely continue to manage with less water for several years to come.

"That’s not by chance," said Ellen Hanak, Director of PPIC's Water Policy Center. "That’s really a reflection of the fact that there has been a lot of investment in building drought resilience since the last major drought that California had.”

Specifically, urban and suburban water managers have increased their water storage capacity by a factor of 13 to 14 since the early '90s, Hanak said.

Water districts have also spent money to improve conservation efforts and to expand their ability to share water when times get tough.

California's farmers have also felt the pinch of the drought, but they have adapted too.

Despite receiving only about half the surface water normally allotted to agriculture, the sector overall is still going strong, losing only about 4 percent in revenue because of the drought.

Farmers made up the loss of surface water by letting some fields go fallow and by pumping more and more ground water.

Rural communities in danger

The study found that a prolonged drought would likely be much worse for low-income communities in places like the Central Valley.

That's because many residents there rely on local, shallow wells that are about to — or have already — run out of water.

As of July this year, more than 2,000 wells have run dry, and as farmers continue to pump groundwater for crops, the situation will get worse, the study noted.

"Particulate air pollution from a combination of heat, dust, and fires has also increased in the San Joaquin Valley, likely exacerbating asthma and other health problems," the authors added.

So far, the state and federal governments have chipped in about $110 million to help supply water to these towns, sometimes trucking in bottles or large containers.

PPIC's Ellen Hanak says much more money and long term solutions will be needed if the drought persists.

Wildlife on the brink of extinction

Worse yet is the fate some fish and fowl might see if the rains do not return.

Ellen Hanak says the combination of drought and record heat has put many native ecosystems in crisis. That's because low flows of water and high heat in rivers and streams can be a deadly duo for many animals.

In particular, her team identified 18 species of fish across the state that are at high risk of going extinct if severe drought continues.

“That’s most salmon runs, it’s a number of trout species as well as some other fish," Hanak said.

Many of the 5 million water birds that fly through California every year are also in trouble.

These birds, like ducks, geese and herons, need wetlands to rest and feed in during periods of migration. As the state has dried out, so have many of these protected wetlands.

As birds crowd into the shriveling lakes, rivers and swamps left, they are at higher risk for running out of food or spreading deadly diseases.

Hanak says much more effort is needed to conserve and create new wetlands to prevent a mass die-off of waterbirds.

A glimpse into the future

The PPIC study calls the current dry spell a "drought of the future" because it is the type the state is likely to see more of as the planet warms from green house gas emissions.

In fact, in a study published Thursday from Columbia University’s Lamont-Doherty Earth Observatory, researchers found that increased temperatures related to global warming have likely already played a role in exacerbating California's drought.

“A lot of people think that the amount of rain that falls out the sky is the only thing that matters,” said lead author and bioclimatologist A. Park Williams in a statement. “But warming changes the baseline amount of water that’s available to us, because it sends water back into the sky.”

As the planet heats up, more water evaporates from lakes, rivers and the soil, leading to drier conditions over all.

Williams estimates that around 15 to 20 percent of the severity of the current drought has been caused by global warming.

Some are hoping a strong El Niño will bring much needed rain to the state, but forecasters say even with a rainy winter, it will likely take years for California to fully recover from the drought.