El Niño, More Rain Likely With Climate Change

El Niño may be back for a visit this year. The National Oceanic and Atmospheric Administration’s Climate Prediction Center released a statement Wednesday saying that current indicators point toward a possible El Niño warming trend for this coming summer or fall.

That could mean more rain for some areas on the Pacific Coast, and particularly for the rain-starved counties of Southern California.

But it could also mean further weather upsets in other regions of the country, as well. According to the CPC, there is a 50 percent chance that El Niño will develop, although current “atmospheric and oceanic conditions reflect ENSO-neutral,” which is climatologists' lingo for the calm before an El Niño or La Niña change. The fact that there has been a warming (not a cooling) trend in ocean waters recently suggests that the Northern Hemisphere can likely expect an onset of warmer conditions for the following winter. For hurricane-prone coastlines, that can mean a milder season, but the warm ocean currents can also herald other problems, such as reduced fishing in some areas that depend upon the nutrient-rich cool waters later in the year.

According to the CPC, in order for an El Niño to be forecast, eastern Pacific temps must be at least 0.5 C (32.9 F) degrees above the average temperature for three months in a row. Those three months of course, usually happen at the warmest time of the year in the Pacific, which is summer and early fall, but an extended increase usually impacts the weather conditions in various parts of the world, creating anomalies in South America and the Pacific Coast that influence farming and fishing industries.

The CPC’s “El Niño Watch” is also in keeping with the U.S. Global Change Research Program’s long-term forecasts, which suggest that there may be more days of extreme rainfall for many areas of the Northwest Hemisphere. The USGCRP’s 2009 report coalesced findings from a diverse source of research concerning past climate behavior, temperature trends and projections regarding anomalies in settings where human behavior was a consideration (such as through the elevation of fossil fuel-based pollution).

According to the report, some areas of the country (the Northwest, Northeast and Midwest in particular) can expect increasing rainfall due to global warming. That also means more potential stress on those areas that are subject to flooding in say, the Pacific Northwest.

“Observations show a consistent picture of surface warming and reduction in all components of the cryosphere (frozen areas, like the Arctic, Antarctic and glaciers)” says authors Peter Lemke et al in their supporting paper, Observations: Changes in Snow, Ice and Frozen Ground (Chapt. 4 of the report).  That surface warming not only means stress on the cryosphere, but more shifts in weather that undermine the critical snowpack that is needed to replenish watersheds through the spring and following summer.

So while drought-impacted areas like Southern California, Arizona and Texas may benefit from a few months of a possible El Niño anomaly this year, the long forecast, say says the USGCRP, points toward drier conditions for some and more time slogging through rainy days for those more accustomed to a colder, snowier winter.

Image of Stillaguamish River flooding, Washington State: Walter Siegmund