Tag Archives: el nino

Maui

The Maui fires are awful. First of all, my sympathy for all the loss of life, property, and all the displacement and disruption people are experiencing. The Los Angeles Times has some coverage of factors that may have contributed to the disaster.

  • Rain shadow and seasonal dry conditions, which are normal
  • Severe drought on top of these conditions
  • Low humidity
  • High winds (gusts up to 80 mph) caused by a hurricane nearby, but not close enough to cause rainfall on the island
  • High ocean temperatures made even worse by El Nino this year

The severity and frequency of both drought and hurricanes have increased due to climate change, making this catastrophic combination of factors more likely to occur than it would have been in the past. The article also says cooler ocean temperatures in the past have tended to steer hurricanes away from Hawaii, and this is also less like to occur now than in the past. So all this is bad luck, but we humans have made our own bad luck to a certain extent.

El Nino and the blizzard of ’16

We kept hearing that it was the warmest winter ever, and then the blizzard came along and disproved it, right? Not exactly, according to NPR:

Scientists have been doing some forensic work to figure out what set this megastorm in motion. And they think they’ve found a trail that starts with the weather pattern called El Niño…

“A lot of climate change is actually going into the oceans,” he says.

He means the oceans are absorbing a lot of the extra heat from the atmosphere. That can alter their circulation, and where and when they release that heat back into the atmosphere.

“It’s changing the behavior of the oceans in a way that affects weather patterns around the globe,” Mann says.

paste clever title about Christmas and climate change here

We pretty much have to check in with Eric Holthaus over at Slate on the freak Christmas heat wave.

To be clear: Global warming wasn’t primarily to blame/thank for this weekend’s ridiculously warm weather. A record-breaking El Niño has shunted the jet stream far to the north, paving the way for warm air to shatter records. The lack of snow so far—that may change later on this winter—has also helped keep things warmer: Without snow on the ground, the feeble December sun can warm things up much more efficiently. Third on the list, bumping up temperatures by perhaps a couple of degrees, is global warming. (Though, recent science suggests super-strong El Niños like this one might become more common in the coming decades.) Blaming an exceptionally warm December day entirely on global warming is just as misplaced as senators seeking to use a snowball as proof against it. Climate change made this weekend’s warmth more likely, but it wasn’t the main driving force.

El Nino

Eric Holthaus continues his entertaining El Nino coverage in Slate:

El Niño means the tropical Pacific is warmer than normal, which improves the chances that typhoons will form. This week, a series of typhoons on both sides of the equator are helping to reinforce a big burst of westerly winds along the equator. These westerly wind bursts are a hallmark of El Niño, and help push subsurface warm water toward the coast of South America. If enough warm water butts up against Peru, the normal cold water ocean current there can get shut off, exacerbating the pattern.

Exactly how this all gets kicked off is an area of active research, but it’s clear that big El Niños need deviant trade winds to maintain the feedback loop. During especially strong El Niños, like this year’s promises to be, the trade winds can sometimes reverse direction—and this week’s off-the-charts wind surge is at record-strengthfor so early in an El Niño event. Since all this takes place in the tropical Pacific Ocean—the planet’s biggest bathtub—a fully mature El Niño has the power to shift rainfall odds worldwide and boost global temperatures. That’s exactly what’s happening this year.

Don’t worry, says Michelle L’Heureux at NOAA:

xWe are now nearing 1.5 degrees Celsius in the Niño-3.4 index for a 7-day or weekly average. Among the post-college age crowd who can remember it (yes, this officially means you’re old), the level of warmth in sea surface temperatures this time of year harkens back to 1997-98 El Niño, which ended up becoming a record strength event.

Are these weekly numbers impressive? Yes. But when a weekly value hits 1.5°C is El Niño instantly considered strong? I’d argue no. While a short-term (daily or weekly) number might be striking, it shouldn’t be used as an indicator of El Niño strength unless it is carefully placed into a larger context…

Weekly averages bounce around because… you know, weather. It is not unusual to see jumps of several tenths of a degree from week-to-week. This is because there are shorter-term changes in the ocean and atmospheric circulation that can be related to faster, non-ENSO phenomena, such as the Madden Julian Oscillation, which happens to be currently in place and isinfluencing the tropical Pacific. With short-term changes, we cannot be sure they reflect El Niño, which evolves more slowly.

doubling of El Nino

Nature Climate Change says El Nino frequency could double due to climate change. The result: “severely disrupted global weather patterns, affecting ecosystems4, 5, agriculture6, tropical cyclones, drought, bushfires, floods and other extreme weather events worldwide3, 7, 8, 9

El Niño events are a prominent feature of climate variability with global climatic impacts. The 1997/98 episode, often referred to as ‘the climate event of the twentieth century’1, 2, and the 1982/83 extreme El Niño3, featured a pronounced eastward extension of the west Pacific warm pool and development of atmospheric convection, and hence a huge rainfall increase, in the usually cold and dry equatorial eastern Pacific. Such a massive reorganization of atmospheric convection, which we define as an extreme El Niño, severely disrupted global weather patterns, affecting ecosystems4, 5, agriculture6, tropical cyclones, drought, bushfires, floods and other extreme weather events worldwide3, 7, 8, 9. Potential future changes in such extreme El Niño occurrences could have profound socio-economic consequences. Here we present climate modelling evidence for a doubling in the occurrences in the future in response to greenhouse warming. We estimate the change by aggregating results from climate models in the Coupled Model Intercomparison Project phases 3 (CMIP3; ref. 10) and 5 (CMIP5; ref. 11) multi-model databases, and a perturbed physics ensemble12. The increased frequency arises from a projected surface warming over the eastern equatorial Pacific that occurs faster than in the surrounding ocean waters13, 14, facilitating more occurrences of atmospheric convection in the eastern equatorial region.

El Nino

More El Nino coverage from Slate. It’s going to be the strongest since 1998! or 2010! or ever!

First off, it’s rapidly intensifying. El Niño is about self-reinforcing feedbacks between the ocean and the atmosphere, and from all accounts, this one has its foot on the accelerator pedal.

If it continues, the impacts will be felt around the globe—here’s my detailed rundown of what to expect. Among them: drought in Australia, Southeast Asia, and perhaps India, with flooding in Peru and Southern California.

Slate’s top-notch oceanography coverage

Slate manages to make oceanography and climate change interesting. I think they sensationalize a bit, which is unnecessary because the story is compelling on its own merits. But I don’t see this kind of coverage anywhere else and I enjoy it. You could spend a month drilling down to all the links they provide. An excerpt:

The news comes amid increasingly confident forecasts that there will be a strengthening El Niño for the remainder of 2015, which could spark a litany of impacts worldwide, not the least of which is the more efficient transport of heat from the oceans to the atmosphere. That liberated heat from the Pacific Ocean should boost global temperatures to never-before-recorded levels, making 2015 the warmest year ever measured…

Besides El Niño, a more worrying, longer-term trend is also taking shape. The Pacific Decadal Oscillation (PDO) is a decades-long periodic warming of the Pacific Ocean that tends to favor bursts of accelerated global warming. As I wrote last October, the Pacific appears to be in the midst of a shift into a new warm phase that could last 20 years or so.

The PDO—or, “the blob” as it’s been referred to recently—is starting to freak out some scientists. There are emerging signs of a major shift in the Pacific Ocean’s food chain, including a dearth of plankton, tropical fish sightings near Alaska, and thousands of starving sea lion pups stranded on the California coast. As Earth’s largest ocean, what happens in the Pacific affects the weather virtually planet-wide, and that means an “imminent” jump in global warming may have already begun—spurred on by the PDO.

El Nino

El Nino has officially arrived, according to Slate, and might be a particularly long and strong one.

El Niño transfers huge amounts of heat from the oceans to the atmosphere, and there are hints that this El Niño, combined with the already very warm global oceans, could bring about a new phase in global warming. An associated slow-moving indicator of Pacific Ocean temperatures, called the Pacific Decadal Oscillation, reached record levels in December and January. A persistently strong PDO is associated with cold winters in the East and drought in California—we’ve had both in abundance this year. Should the PDO stay strong, it’ll essentially join forces with El Niño and increase the odds that 2015 will rank as the warmest year on record globally. Last fall I wrote that a PDO signal like we’re currently seeing could kick off a surge of global warming over the next five to 10 years.

I don’t have the expertise to say whether this article is sensationalized or not, but it is interesting reading.

By the way, Slate, “The Slatest” is okay, but some of us are still waiting for you to bring back “Today’s Papers”, which was the greatest news summary ever because it would compare and contrast how different media outlets were covering the same story, way back before the Internet was even a thing. I haven’t seen anything like it since. It was “fair and balanced” indeed, and the world got a bit dumber the day it went away. So bring it back, please!