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It’s Here! A Mega el Niño Finally Reveals Itself (Part 1)


The Long Hot Year

So far, 2015 is shaping up to be an interesting year weather-wise. NOAA’s monthly climate update for August contained another long list of records. The July global average temperature was 0.81oC (1.46oF) warmer than the average for the entire 20th Century; it was the warmest July on record and the warmest month of any month on record. Global temperature records now span 136 years from 1880. The July average land temperature was just the 6th warmest July, but the July average ocean temperature, at 0.75oC (1.35oC) above average, was the warmest July on record, and the largest warm departure from average for any month ever. The oceans, in particular, are hot, and the tropical oceans are particularly hot.

The January to July period was the warmest such period on record, whether you looked at the average global temperature (+0.85oC, +1.53oF), the average land temperature (+1.34oC, +2.41oF), or the average ocean temperature (+0.62oC, +1.21oF). The full year 2015 remains on track to eclipse 2014 as the warmest year on record. Anyone who still doubts the world is warming needs to be able to explain why temperatures for the January to July period have been consistently above average since 1978. The world is not some Lake Woebegone (where all the children are above average).

Jan to July temperature anomaly NOAA NCDC
The extent to which average temperature for the 7-month period, January to July, have exceeded (red) or fallen below (blue) the long-term average for the 20th Century.
Figure courtesy of NOAA National Climate Data Center.

The exceptionally warm oceans got that way because of the slow-to-develop, but finally-here el Niño. As the months wore on, I confess I had begun to wonder if it would ever properly appear. I first talked about the possibility of a strong el Niño developing in April 2014. In July, I reported that NOAA was still speaking of “about a 70% chance of [an el Niño] starting in the next few months, and an 80% of [it] commencing by later this fall”, and by November, I was admitting that I had stuck my neck out and was now praying to the el Niño gods to please come, and help us avoid a cold and snowy winter like the previous year. We all know where that got me. The winter of 2014-15 was brutal in eastern North America, and the el Niño gods were nowhere to be seen.

NOAA for its part was putting out el Niño updates every month, and flipping through these in the archive it is interesting to observe how el Niño seemed to be gathering steam in April, 2014, but more or less stalled by June. The July report stated “At this time, the forecasters anticipate El Niño will peak at weak-to-moderate strength during the late fall and early winter”. By November they were expecting a weak el Niño to develop within a month or two and continue into spring 2015. Their expectations remained for an ever later and weak el Niño through February. In March 2015, the tone changed yet again. Now they anticipated it would develop and continue throughout 2015, although they expected it to remain weak and to have few impacts. The expectation of a weak event, possibly lasting throughout 2015 persisted until June, when NOAA reported “For the fall and early winter, the consensus of forecasters slightly favors a strong event” although they hastened to add that a weak event remained possible. Still they saw an 85% chance of it lasting through the northern 2015-16 winter. By August, NOAA was reporting a strong el Niño, peaking in late 2015 and continuing into the spring of 2016. Its pace has been very slow; it’s a year later than it should be in arriving, but it looks like it is definitely here. And now I am hoping that it will be strong enough this winter to give my region a mild winter instead of us experiencing, for the third year in a row, a winter made cold by a deeply depressed and stuck Jetstream – a situation favored by the melting Arctic.

The Many Ways in Which el Niño Affects our World

So, what is this el Niño going to do, now that it has arrived? El Niño is a recurrent climate pattern in which trade winds slow or even reverse, allowing warm equatorial water to build up in the eastern and central Pacific. This slows the pattern of upwelling of cooler, nutrient-rich waters in the eastern Pacific and reduces fishery yields along the Pacific coast of South America. In the western Pacific, el Niño reduces the rate at which warmer tropical waters move into the temperate zone. Along the way there are profound adjustments to the timing and location of the monsoons, and the generally warmer tropical oceans spawn more intense tropical storms. Catherine Gautier of UC Santa Barbara has provided a clear explanation of el Niño at The Conversation. She cautions that there is much scientists do not yet understand about el Niño, and how it may, or may not be altered by climate change.

While it is a tropical phenomenon primarily, a large el Niño can have geographically widespread effects. The 1997-8 el Niño, the largest on record, caused at least $35 billion in damage and 23,000 deaths globally. The Economist summarized as follows:

A Niño generally produces heavy rains, higher temperatures and cyclones in parts of South America and east Africa. South-East Asia and Australia could see drier weather than usual or drought. Some countries are already feeling its impact. Thailand is rationing water. The Peruvian government has declared a state of emergency because of heavy rain and mudslides. This Niño is partly to blame for drought in parts of Central America, Indonesia, the Philippines and Australia. The Panama Canal’s water levels are so low that officials there have limited traffic. Globally, its effects could be devastating. Some countries could see inflation, according to a recent University of Cambridge paper, thanks to disruptions to trade and harvests. Agricultural and economic havoc could fuel political conflict. Indeed, Columbia University’s Earth Institute found that Niños double the risk of civil wars across 90 tropical countries. Not all its effects are bad. One study shows that a Niño may reduce the number of tornadoes in the Midwest. It may also suppress hurricanes from forming in the Atlantic Ocean. Many in California, which is in its fourth year of a drought, are hoping the current Niño may shorten their dry spell. America’s Northeast may also see a milder winter.

Apart from their unnecessary anglicizing, calling it a Niño, instead of el Niño, that is pretty much correct.

The International Business Times has just reported on the concerns in East Africa, where additional rainfall will be welcome because of the current drought, but flooding and damage to crops and livestock could prove economically difficult as well as dangerous for people. The expectation is for heavier than usual rainfall through the October to December period, and with a real risk of flooding. One African concern is that el Niño seems to be becoming less predictable in timing and effects (this one’s delayed birth is a good example of that). It is possible that climate change is somehow affecting the underlying causal mechanism. A less predictable phenomenon is a more risky one.

In North America, el Niño usually delivers greater rainfall and more violent storms along the west coast, coupled with milder winters that extend into the interior and potentially as far as the north east. This one seems likely to be large enough to provide for milder winters through to eastern North America, but the details of what it does may be complicated by the presence of the “blob”, a British Columbia-sized mass of warm water that has been sitting in the north-east Pacific for the last several months, and may well cause el Niño’s effects to be modified towards a drier, milder winter in western Canada. While that may sound like good news to those thin-blooded tropical Canadians who live in Vancouver, this would lead directly to lower snow pack and less available water in both BC and Alberta rivers in the coming year. A number of people in California are cautioning correctly that while it may bring more rain, it will not ‘repair’ the current drought, and that the rain may well be intense enough to lead to floods, mudslides and other problems, especially given that so much of the land has been denuded by fire.

While some in California wait for the rain el Niño will bring, others know things could get really ugly. Cartoon © Paul Duginski/Los Angeles Times

Back in the tropics, of course, the biggest problems likely to be caused by el Niño are a change in the incidence of severe storms and another bout of coral bleaching. NOAA’s ENSO Diagnostic Discussion for 10th September predicts a strong el Niño that will likely lead to reduced hurricane activity in the Atlantic and enhanced hurricane/cyclone activity in the Pacific. The fact that three category 4 hurricanes were simultaneously present in the Pacific over the Aug 29-30 weekend is a sign of what may come. Named Ignacio, Kilo, and Jimena, they are believed to be the first trio of storms this big, ever to co-occur in that ocean since records have been kept. Each missed Hawaii, but only just.

Kilo, Ignacio and Jimena, three category 4 hurricanes simultaneously present near Hawaii.
Image courtesy NOAA, graphics © Los Angeles Times.

Step Right Up – Behold The Third Circumtropical Bleaching Event

Reef scientists are now concerned that we may now be seeing the third circumtropical bleaching event ever, surpassing the one in 2010, and possibly surpassing that worst ever event in 1997-8. (To those new to this blog who have somehow escaped learning what mass coral bleaching is all about, read my book, read a host of other books, blogs, and media articles; it is one of the primary ways in which we are hastening the disappearance of coral reefs on this planet.) NOAA’s Climate Prediction Center provided an update on the developing el Niño on 7th September in which was included an extremely angry red graphic describing the anticipated pattern of sea surface temperatures through to next May. The darker the red color on this graphic, the warmer the SST. The graphic covers only the Pacific basin, but it clearly shows the Hawaiian chain surrounded by red in the images reflecting the September to November, and the October to December periods. Guess what is happening right now in the Hawaiian Islands?
el Nino 2015 issued 7 Sept NOAA

The outlook for sea surface temperature in the Pacific basin from September 2015 through to May 2016. The scale represents departure from average climatic conditions so darkest red means water 3oC warmer than usual for that time of year and location. Notice the Hawaiian Islands, top center, surrounded by red in the first two graphics, and the Great Barrier Reef, surrounded by orange to red in the last three. Image courtesy NOAA Climate Prediction Center.

NOAA scientists estimate that bleaching over the past year has affected 12% of the world’s coral reefs. In December 2014, The Guardian reported that bleaching had begun in North Pacific sites, including the Northern Marianas Islands, Guam, the Republic of the Marshall Islands, Hawaii, Kiribati and Florida. Bleaching had shifted south with the seasons and the Solomon Islands, Vanuatu, Tuvalu, Fiji and the Samoas had been hit hard by warm waters in the first months of 2015. Now it has returned north; bleaching has occurred in the Tubbataha Reefs Natural Park, a 97,030 ha MPA in the Philippines, and Hawaii is currently being hit quite hard. University of Hawaii scientists have provided reports of extensive bleaching in the remote Papahanaumokuakea reserve in the leeward Hawaiian chain. Bleaching is now being reported along the coastline from the Ahihi Kinau Natural Area Reserve in South Maui to Kapalua Bay in West Maui and off Molokini, and among other sites around the main Hawaiian Islands. In the Caribbean, the Cayman Islands and several other Caribbean locations are under a level one bleaching alert. NOAA expects renewed bleaching in the South Pacific and into the Indian Ocean as the season progresses through the northern fall, and is predicting an overall loss of 6% of coral reefs globally once this bleaching episode is finished.

While humans do not cause el Niño, our emissions of CO2 have so raised sea surface temperatures that el Niños are now sufficiently warmed to stress corals and cause bleaching. Those same emissions are causing ocean acidification which leads to reduced capacity by organisms such as corals to build their calcium carbonate skeletons. These two effects are additive on reefs, reducing the amount of coral available to build new reef, and slowing the rate at which new reef can be built by the corals that remain.
NOAA bleached coral2

If too many reefs start to look like this, there will not be many reefs around by mid-century.
Photo courtesy NOAA.

Part Two, which deals with how to protect our coral reefs, will come shortly.

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