The current El Niño Southern Oscillation event and what it means.

The theme of this blog has importance as we are currently in the midst of the third global bleaching event, related to one of the strongest ENSO events we have ever seen. Unfortunately, as a result of the ongoing nature of this issue, no academic papers have been published, however there is a wide array of news articles and videos that draw alarm to this current event.

Before I start discussing these aspects, the National Oceanic and Atmospheric Administration has been updating a blog almost every fortnight following this year’s ENSO. It provides good meaningful empirical analysis of the event but does so in an informal and digestible tone making it both extremely interesting and accessible. Furthermore, the blog has different contributors whom post about its wide varying impacts from effects on drought in Australia to the snow we can expect this winter in the UK. (update: looks like the snow didn't turn up after all!)

Looking at their most recent post providing an October update, we can get a good understanding of how the current el Niño has been following the trajectory that the 1997 event had. Looking at Figure 1 we can see that the 2015 El Niño is now reaching its peak in the coming months but that also it has been slightly more moderate than that of the 1997 El Niño. The September 3-month average sea surface temperature was 1.5 above normal, third behind September 1987 (1.6) and 1997 (1.7). Regardless, the impacts of this event are to be catastrophic to coral reef colonies as though 18 years on from the 1997 event, a large amount of these destroyed reefs still haven’t recovered.

Figure 1. NOAA publication of SST's of the tropical Pacific

The NOAA were the first to declare the third bleaching event, their article further shows the potential projected threats of this El Niño event on coral reefs around the world. High SST’s are already causing bleaching in Hawaii but NOAA confirm that the same stressful conditions being seen in the pacific will spread to the Caribbean and Australasia very soon, potentially extending past new year (figure 2).  

“we are losing huge areas of coral across the U.S., as well as internationally. What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it’s likely to last well into 2016.” 

Mark Eakin NOAA

Figure 2. NOAA forecasted Coral Reef bleaching

The concerns about the length of time these coral reefs are to undergo stress is related to the fact that short term bleaching isn’t entirely detrimental as corals can respond, unlike prolonged long term bleaching where this isn’t possible as total degradation and erosion ensues. Most importantly however as with the interest of this blog, it will mean fewer habitats for fish and other marine life, including ecologically and economically important species.

Also, for a quick decent summary article on the current global bleaching event please refer to the one published by the New Scientist.