According to a recent study co-researched by a Western University professor and former grad student, the Pacific Ocean's response to greenhouse gases could extend California's drought for centuries.
The study, which was published on Friday in the journal Nature Scientific Reports, looked at how natural climatic forces contributed to periods of aridity in California during the past 10,000 years. The study shows that greenhouse gas has recently become one of those forces that causes warming.
Glen MacDonald from UCLA led the study, along with Professor Katrina Moser from Western University and her former graduate student Amy Bloom, tracked California's historic climate and water conditions by taking a sediment core in the Sierra Nevada mountains. The researchers also correlated their findings with other studies of California's climate history, and cross-referenced these the Pacific Ocean's temperature history.
The researchers ultimately discovered that periods of increased "radiative forcing," caused by greenhouse gases, could produce drought-like conditions that could last indefinitely. These conditions were reportedly closely tied to prolonged changes in Pacific Ocean surface temperatures.
"Radiative forcing in the past appears to have had catastrophic effects in extending droughts," says MacDonald, who is an international authority on drought and climate change. "When you have arid periods that persist for 60 years, as we did in the 12th century, or for millennia, as we did from 6,000 to 1,000 BCE, that's not really a 'drought.' That aridity is the new normal."
Moser adds that as long as prolonged aridity in California continues, it "will have far-reaching effects across the United States, into Canada and beyond."