The weather this year has been all over the place and it is undeniably related to el Niño. Christmas on the East coast this year was spent BBQ-ing in tank tops and shorts. Meanwhile California is getting feet of snow- a stark contrast to last season’s drought throughout the region. Why is the weather so sporadic and seemingly unpredictable? The atmospheric and oceanic pressure systems that correlate to el niño lead to warmer temperatures in the Northeast, drier temperatures in the Midwest, and more precipitation than average in the South and the West.
With that being said, there is another ongoing natural phenomenon known as the Pacific Decadal Oscillation. The long story short is that we are currently in a strong positive phase of PDO which means that it exaggerates the weather trends of el niño. The last fifteen year period of PDO has been a negative or cooling trend and subsequently has delayed the visible side of climate change with relatively standard surface temperatures. However, with warmer temperatures in the Pacific and a positive PDO, climate change and warmer earth surface temperatures will likely be visible. According to Gerald Meehl, a climate scientist at the National Center for Atmospheric Research in Boulder, Colorado, “If [PDO] transitions back into positive, we’d see a resumption in these more rapid rates of global warming”.
This is leading up to be one of the strongest el niño’s on record and has the potential to create a decadal shift in weather. The last el niño close to this strength was the 1997 season. Although this shift is not guaranteed, the odds are 2:1 for a twenty year warm period of sea surface temperatures. With the combination of el niño and a positive PDO it is common for weather events to become much more exaggerated and extreme. The only thing we can do at this point is sit back, relax, and wait for the weather to run its course and see if it was as close to expert predictions as we’d hoped.