California, widely considered the U.S. state that most promoted the American Dream, may turn into a nightmare this summer as a result of the worst drought in at least 15 years.

And a new academic study suggests there may be a direct connection between the persistent drought and climate change caused by burning fossil fuels.

The study shows that, beginning with unusually cold waters off Southeast Asia, a persistent high-pressure ridge, or dipole, built up late last year and anchored over the Gulf of Alaska, preventing usual levels of moisture from reaching the West Coast of North America.

Reviewing weather data and sea surface temperatures, the study also determined that the dipole generated a low-pressure ridge built up north of the Great Lakes, eventually resulting in so-called freezing Polar Vortex events in central Canada and the U.S.

Simon Wang, Assistant Professor of Climate at Utah State University, is the lead author of the study — Probable causes of the abnormal ridge accompanying the 2013–2014 California drought: ENSO precursor and anthropogenic warming footprint.

In an email interview, Wang told DeSmog the study results are important because “scientists have known for years that climate change impacts extreme events like drought, but had not been able to relate a single event to climate change or warming.”

Wang said the research provides quantitative evidence how the California drought and the polar vortex events are linked to the long-term change in climate, and the role of greenhouse gases.  

“Knowing this link helps people anticipate future extreme events, because the trend is going to continue and drought can get worse,” he said. “Simply put, there will be drought again and we need to be ready for it when it strikes.”

The dipole is linked to the recent cold water off Southeast Asia that act as a precursor to El Niño, which is an occasional and powerful event that warms the tropical Pacific and changes global weather systems.

The academic paper suggests that increased greenhouse gas loading in the atmosphere contributed to the dipole, the drought in California and the Polar Vortex events. It also said the study can be used to predict future puzzling weather events.

“The inference from this study is that the abnormal intensity of the winter ridge is traceable to human-induced warming but, more importantly, its development is potentially predicable,” the report concluded.

Wang said it is important to reduce carbon levels in the atmosphere because they can lead to increased intensity of drought and flooding.

“The reduction of carbon levels will help reduce the intensity of such events,” he said. “But the more pressing issue is mitigation like improving irrigation technology and solving water right issues; we could learn from how Australians have dealt with drought.”

Wang’s study likely won’t help California deal with its current drought — which is now covering the entire state — but it may help scientists, engineers, agrologists and firefighters plan for the future.

Described as the ninth largest economy of the world, California is the top agricultural producer in the U.S. at almost $45 billion. CBC has reported that Statistics Canada data shows that Canada imported food products worth $2.7 billion from the state last year.

The state’s already tiny snowpack is quickly melting, many of the major reservoirs are at extremely low levels and the ground is already caked dry. Governor Jerry Brown, fearful of an impending catastrophe, declared a state of emergency in mid-January.

Although the official start of summer is still more than six weeks away, cattle are already being moved out of state, farmers are wondering what to plant and where and consumers — in and outside of California — have been warned that higher food costs are on the way.

With more than 38 million people, the Golden State is clearly bracing for worse in the months to come.

In the meantime, Wang added he and other climate researchers will build on the study by continuing to “identify the pathways in which greenhouse gases modulate the weather/climate systems, hoping each of the puzzle can eventually lead to useful prediction and better preparation.”

Image Credit: Folsom lake drought. USGS image by David Pratt.