COLLEGE STATION –Another year of drought, or even five to ten years more drought? The first is highly likely, and the second, though harder to predict, a strong possibility, according to Dr. John Nielsen-Gammon, state climatologist.
Regarding the drought continuing through this winter and spring, everyone is watching what appears to be a new La Niña developing, Nielsen-Gammon said.
But a strong Pacific Ocean La Niña is not the only phenomenon that affects Texas droughts, he said. Scientists now believe that Atlantic Ocean temperature oscillations also play a role in long-term droughts such as the one that hammered Texas and the Midwest in the middle of the last century.
Climatologists have found a strong correlation between Pacific Ocean surface temperatures and some events like the Dust Bowl drought. But the drought of the 1950s, which rivaled the current drought, did not show up in the computer simulations correlated with Pacific Ocean La Niña events. The simulations did find, however, that patterns that strongly suggested warmer-than-average North Atlantic sea-surface temperatures also contributed to droughts in parts of North America, Texas included, according to Nielsen-Gammon.
“Compared to the trend, the north Atlantic is warm in the 1940s and ‘50s, cool in the 1970s and ‘80s, and warm since 1995,” he said. “A cool North Atlantic implies a wet North America, amplifying the response to an El Niño.”
According to similar study, drought in Texas has been overwhelmingly more frequent when there is a negative Pacific Ocean La Niña event and a warm North Atlantic, such as was in place during the 1950s.
All this may seem a bit esoteric to any but professional climatologist, Nielson-Gammon said, particularly as there is currently no proven way of forecasting long-term ocean variability in the Pacific or North Atlantic.
“We do know that the current temperature patterns are not a death sentence for non-stop drought,” Nielson-Gammon writes in his blog, The Climate Abyss. ”But we have heightened drought susceptibility during this period, and, according to some studies, the effect of La Niña is likely to be amplified. … So this coming year looks very likely to be another dry one, and consequently it is very likely that next summer will have water shortages and drought problems even more severe than this summer.”
And what about the long-term picture?
“At this point, all I can say is that we’re in a period of frequent Texas drought until further notice,” he said. “This period, with both the Pacific and Atlantic working against us, might be over in a couple of years, or it might last another 15 or 20 years. It seems likely to last another decade.”