Say goodbye to El Niño, and a wary hello to La Niña
There's no easy way to say this, so I'm just going to come right out with it. I hope you're sitting down:
El Niño is dead, having slipped into a coma about a month ago, it was taken off life support by the Climate Prediction Center on Thursday.
I know you had grown used to us in the media citing El Niño as one of the weirdest weather events, and using this GIF, but we're going to have to put this back in digital storage for a while, until the next El Niño emerges in about five to seven years.
The demise of El Niño means that instead of milder than average ocean waters in the tropical Pacific Ocean, there are now near-average to below average sea surface temperatures there.
Officially, the tropical Pacific Ocean is now in what is known as an "ENSO-neutral" state, otherwise known as "La Nada."
See the impact of El Niño in California
This means there is neither an El Niño or La Niña, but this interlude is unlikely to last long.
The Climate Prediction Center says the cool phase of ENSO (the acronym stands for El Niño-Southern Oscillation) will likely kick in by the fall, which would influence the weather around the world throughout the rest of 2016.
Before considering those implications, though, here's a recap of the 2015-16 El Niño, which was by some measures the most intense on record.
A hotter, more extreme planet
By altering the exchange of heat between the ocean and atmosphere, and releasing heat into the middle and upper atmosphere at a strategic location above the vast Pacific Ocean, the El Niño contributed to a host of extreme weather events around the world.
In Indonesia, for example, a drought tied to El Niño combined with illegal agricultural burning practices to produce a massive calamity in the fall of 2015. Forest fires numbering into the six figures, took place in carbon-rich peatlands. The acrid smoke caused air quality to deteriorate to dangerous levels from Singapore to Vietnam as thousands of fires burned for months.
Peatlands around the world are a critical storage area for carbon dioxide, with most of it sequestered into the saturated soil. When peatlands are dried and burned, which can be cheaper than clearing land with heavy equipment, they release the carbon that took centuries to accumulate, emitting in a geological instant the global warming gases that nature had painstakingly deposited over many hundreds of years.
According to one initial calculation, the fires released more carbon in a two-month period than the entire country of Germany did in an entire year.
Without the El Niño-related drought, it's unlikely the 2015-16 fire season would have been nearly as destructive.
Coral reefs pushed beyond the brink
The El Niño conspired with the global warming-driven buildup in ocean heat to cause the third global coral bleaching event on record, with reefs from the Great Barrier Reef of Australia to ecological treasures in Kiribati, Hawaii and the Bahamas all seeing damage or coral death.
Coral bleaching occurs when coral expels the algae, known as zooxanthellae, that lives in its tissue, giving it color and nutrients. This action, caused by stresses such as increased water temperature and pollution, leaves the coral skeleton exposed, making it more susceptible to heat stress, disease and pollution.
Bleached corals can recover if the ocean waters cool or pollutants diminish. However, they can die if the stressors last too long.
During the bleaching event, ocean temperatures exceeded tolerable levels for most reef communities in the northern third of the Great Barrier Reef for at least eight months, reaching as much as 4 degrees Celsius, or 7.2 degrees Fahrenheit, above average.
Largest carbon dioxide jump on record
During El Niño years, the planet often sees a larger jump in planet-warming carbon dioxide, because of weather pattern changes and how ecosystems respond to them.
This year took that trend to another level, though, when the annual growth of atmospheric carbon dioxide hit its highest mark in 56 years of record-keeping.
Carbon dioxide concentrations measured at the Mauna Loa Laboratory in Hawaii rose by 3.05 parts per million (ppm) during 2015, and most likely permanently passed the symbolic milestone of 400 ppm.
For perspective, the amount of carbon dioxide in the air at the start of the industrial revolution was about 280 ppm.
"Carbon dioxide levels are increasing faster than they have in hundreds of thousands of years," said Pieter Tans, a NOAA scientist specializing in greenhouse gases, in a statement. "It's explosive compared to natural processes."
According to NOAA, the last time the Earth experienced such a sustained carbon dioxide increase was between 17,000 and 11,000 years ago, when carbon dioxide levels increased by 80 ppm. Today's rate of increase is 200 times faster, Tans said.
The record warm waters of the Pacific Ocean contributed to a record high number of Category 4 and 5 tropical cyclones worldwide.
Hurricane Patricia, for example, took advantage of deep, warm waters in the eastern Pacific in October to strengthen into the strongest storm yet measured by the National Hurricane Center in that ocean basin. The monster storm had winds of 215 miles per hour, with higher gusts, at its peak.
In February, Tropical Cyclone Winston, another Category 5 storm, hit Fiji, devastating parts of the island nation.
What will La Niña bring?
La Niña tends to be correlated with above average hurricane seasons in the Atlantic Ocean, a below average season in the eastern Pacific, and a drier than average winter in parts of the West.
This is not good news for California, which did not get nearly enough rain from its El Niño winter to squelch its epic drought.
If the La Niña event is particularly intense, it could curb global average temperatures enough to end the streak of warmest years on record, but only temporarily.
El Niño and La Niña act as breaks and accelerators to a climate system that is cruising to a warmer, more extreme future. They can temporarily modulate the rate of warming, but only dramatic cuts in greenhouse gas emissions will alter the long-term trend.