As a Titanic El Nino Begins to Fade, What Fresh Trouble Will a Record Warm World Bring?

Today the globe is feeling quite a bit of backlash from a human-warmed sea surface and atmosphere. As it ends up, Dr. Kevin Trenberth was right. Deep ocean warming set off by heat-trapping fossil fuel emissions and building up through the first two decades of the 21st Century did re-surge from the depths to haunt us in 2014, 2015 and 2016. In that wrenching global climate system shift to the hot side of natural variability, a titanic El Nino emerged. It was one of the top three strongest such events in the modern record. One that by NOAA’s measure appears to have tied the extreme event of 1998 at its peak intensity.

ONI sea surface temperature anomalies in Nino 3.4

(Sea surface temperature departure from average in the benchmark Nino 3.4 zone shows surface ocean heat anomalies for the 2015-2016 El Nino equaled peak 1997-1998 values. Image source: NOAA/CPC.)

Expected Heat, Drought, and Storms Together With a Few Ominous Surprises

This event did push the world into extreme warmth even as predicted related severe weather flared in some of the typical regions. Annual average global temperatures rocketed to about 1.06 C above 1880s baselines during 2015 even as monthly departures hit 1.2 to 1.3 C or more higher than the same benchmark during December and January.

Amidst this great upheaval of global heat, the world also experienced yet one more wave of freak droughts (this time over Northern South America, the Caribbean, large swaths of Africa and Southeast Asia), heat-related mass casualty events, floods, and strongest hurricanes on record. Arctic and global sea ice measures are once again plunging to new record lows. A global coral bleaching event, perhaps the worst such instance ever experienced, was also set in motion.

The predicted patterns and potential worse-case events (such as heatwave mass casualties, coral bleaching, and sea ice loss) were also contrasted by a number of surprises. The first and perhaps most ominous was the failure of El Nino to bust the California drought. Though the West Coast of the US did experience a number of storms, the pattern was more typical of normal Winter moisture for the Northwestern US even as drought continued throughout the Southwest.  Moisture instead tended to split fire-hose fashion — with storms either cycling northward into Alaska, the Aleutians, or the Bering Sea, or south over Southern Mexico or Central America, up across the Gulf and on out into a particularly severe storm zone forming in the North Atlantic.

30 day precipitation anomaly shows southwest drought continuing

(Over the last 30 days the southwest drought re-emerged as a blocking pattern again began to take hold over Western North America and the Eastern Pacific. Image source: NOAA/CPC.)

This continued loss of moisture for the US Southwest despite a record El Nino is particularly apparent in the Climate Prediction Center’s most recent precipitation anomaly measure for the last 30 days. Here we find that large parts of Central and Southern California have received just 10 to 50 percent of typical rainfall for this period. Coupled with 1-3 C above average temperatures for the month, this loss of rainfall during what would typically be California’s wettest period has come as a disappointment to many who were hoping a strong El Nino would help break the state out of a crippling drought. Now, the window for late Winter and early Spring rains is starting to close even as the blocking pattern appears to be strongly re-established in both the present weather pattern and in the forecast model runs.

But perhaps the biggest surprise coming from this El Nino year was a set of weather events in the North Atlantic that were likely more related to climate change. There, severe storms hammered a flood-beleaguered UK as a greatly distorted Jet Stream heaved Equatorial heat and moisture northward — rushing it up over a ridiculously warm and apparently backed-up Gulf Stream before slamming it on into a likely Greenland ice melt-outflow related cool pool. There the heat and moisture collided with cold to produce the epic storms that then vented their fury upon the UK.

Warm Arctic Storm

(December 29th saw temperatures rise above freezing at the North Pole — the first time temperatures have warmed so much for this high Arctic region so late in the year. Image source: Earth Nullschool.)

During one such event, a daisy chain of heavy-hitting North Atlantic lows hurled high winds, heavy rains and epic surf at the UK even as the meridional flow set up by these powerful beasts shoved above-freezing temperatures all the way to the North Pole during late December. Yet one more unprecedented and unexpected event during a record warm year. One that looks more like a human forced warming which has overcome the traditional influences of El Nino, rather than an El Nino related impact in itself.

As El Nino Fades, Equatorial Heat Tends to Move Pole-ward

Though we may see these two events — the failure of El Nino to provide heavy rains to the US West Coast, and the massive northward pulses of storms, heat and moisture hitting the North Atlantic — as unrelated, the twain patterns appear to be linked to an ongoing polar amplification. Overall, heat within the Arctic has tended to weaken the Northern Hemisphere Jet Stream over these two zones. And even during El Nino, when the Jet would have typically strengthened, we have continued to see high amplitude wave patterns forming over these regions.

But as El Nino weakens and the Equator cools, the Jet Stream would tend to slow even more. Such an atmospheric state would tend to further exaggerate already significant Jet Stream wave patterns — transferring still more low-Latitude heat poleward. In addition, the ocean gyres tend to speed up as El Nino fades or transitions to La Nina. The result is an amplified pulse of warmer waters emerging from southern Latitudes and entering the Arctic.

It’s for these combined reasons — tendency to amplify south to north atmospheric heat transfer into the Arctic post El Nino and tendency to flush warmer waters toward Arctic Ocean zones during the same period that it appears we are entering a high risk time for potential new sea ice melts and possible related Greenland land ice melts during 2016 and 2017.

Hot Blobs

(Northeastern Pacific Hot Blob remains at high intensity even as its size is predicted to expand through July. Meanwhile, very warm sea surface temperatures are predicted to remain in place off the Eastern Seaboard. The net effect of these two hot blobs may be to shove the Jet Stream far northward over North America during the summer of 2016 — potentially increasing the risk of widespread and potentially record heat and drought. Predicted very warm sea surfaces in the region of the Barents and Greenland seas — in excess of 3 C above average for a large region — is also cause for concern. This is not only due to risk for sea ice loss through this zone, but also due to its potential to set off blocking pattern and heat dome formation over Eastern Europe and Western Russia. Image source: NOAA/CFS.)

In addition, we are at serious risk of seeing the high amplitude blocks and wave patterns re-establish and persist, especially in the zone over Western North America were a related Northeastern Pacific Hot Blob is expected to restrengthen as El Nino fades. In fact, large regions of the US may fall under record to near record heat and drought this summer due to the combined influences of two very warm ocean zones surrounding her shores. Models now indicate a particular late spring drought risk for the Great Lakes region as well as an extended period of far above average temperatures for pretty much all of the Continental US during summer. Meanwhile, predicted above average spring-time precipitation for the Southwest appears less and less likely to emerge.

Finally, extreme above average sea surface temperatures are predicted to intensify over the Barents and Greenland seas through to end of Summer 2016. This is an area to watch. The added ocean heat would tend to pull the Jet Stream northward over Eastern Europe and Western Russia — generating risk of heatwaves and drought for this region even as Central Asia fell under risk of floods. Long range CFS precipitation and temperature model runs for Europe have not yet picked up this risk. However, given the intensity of heat predicted for Barents sea surfaces and the related tendency of warmth over oceans and in the far north to influence the formation of blocking patterns, heat domes, and high amplitude troughs, it’s worth keeping a weather eye on the situation.

El Nino to Weaken and Then Return; or is a Shift to La Nina Now Under Way?

Related to a polar and ocean warming-enhanced tendency to generate high amplitude Jet Stream waves — as well as associated persistent heatwaves, droughts, and floods — is the heat balance of the Equatorial Pacific. Strong El Ninos, or even a tendency to remain in or near an El Nino state, has historically aided in the breaking of new record global high temperatures when linking up to the greenhouse gas warming trend. Meanwhile, the shift toward La Nina has tended to enhance a range of global heating related issues including record rainfall events and large injections of heat toward the poles in the drop off from El Nino to La Nina.

The cause for increased risk of major precipitation events is due to the fact that El Nino is providing a massive moisture bleed into the atmosphere at times of peak intensity. With the current El Nino topping out near record levels and with global temperatures at above 1 C higher than 1880s averages, global atmospheric moisture levels are hitting new record highs at this time. If global temperatures subsequently drop by around 0.1 to 0.2 C during a transition into La Nina (into a range about 0.9 to 0.8 C hotter than 1880s values) then the atmosphere will be unable to keep a larger portion of that extra moisture in suspension and it will fall out as precipitation — primarily wringing out where the major trough zones tend to set up. We should be very clear here in saying that the drought risk related to a global warming intensification of ridge and heat dome formation is not reduced during such instances — just that the risk of extreme precipitation events is enhanced.

Russian Heatwave Pakistan Floods Jet Stream

(During 2011, as the 2010 El Nino faded into La Nina conditions, a high amplitude wave in the Jet Stream set off record heat, drought and wildfires over Russia even as Pakistan was hit by a month-long deluge that was the worst rainfall event for the region in the last 1,000 years. La Nina’s tendency to wring excess water out of the atmosphere can enhance the risk for such events to occur in a warming climate state. Image source: NASA.)

As for risks to sea ice, we’ve provided some of the explanation above. However, it’s also worth noting that the mobility of heat poleward tends to be enhanced during the periods when El Nino drops off toward La Nina. During these times, Equatorial heat tends to propagate in wave fashion toward the Poles — especially toward the Northern Hemisphere Pole which has already lost its strong Jet Stream protection warding away warm air invasions.

These two factors are major issues when considering whether La Nina or an ENSO Nuetral state will appear post El Nino during 2016. But there is a third — rate of global temperature rise. Though the primary driver of global warming is a massive human fossil fuel emission, the response of the world ocean system can significantly wag the rate of atmospheric temperature increases on a decadal time scale. If the ocean tendency is for La Nina, this would tend to somewhat suppress the overall decadal rate of temperature increase — and we saw this during the 2000s. But if the ocean tendency is to produce El Ninos (in a switch to a positive Pacific Decadal Oscillation, as appears to be happening now), then the overall pace of global atmospheric temperature increase would tend to be enhanced.

La Nina Emerges

( IRI/CPC consensus model runs show a drop off to a weak La Nina by late in the year. However, CFS model runs [image below] have shown a tendency to predict a resurgence of El Nino conditions by Fall. Image source: NOAA/CPC.)

To this point we find that the official model forecast consensus published by NOAA (IRI/CPC figure above) shows a transition to ENSO neutral states by May, June, and July which then proceeds on to a very weak La Nina by Fall. In such a drop off, we would likely still see record global high temperatures during the period of 2016 (in the range of 1.03 to 1.15 C above 1880s values).

However, the late 2016 and 2017 tendency for temperatures to recede from new record highs would be somewhat enhanced (likely dropping below the 1 C above 1880s mark in 2017 or 2018 before again making a challenge to the 2015-2016 record with the potential formation of a new El Nino in the 3-5 year time-frame of 2019 through 2021). It’s worth noting that this scenario shows an increased risk of a stronger warm air pulse heading toward the Northern Polar zone together with added fuel for extreme precipitation events as global temperatures would tend to drop off more swiftly from late 2015 and early 2016 peaks.

El Nino Continues

(CFSv2 model run — shows El Nino continuing on through the end of 2016. Over recent months, the CFSv2 series has shown a high accuracy. However, NOAA’s current forecast preference is for the IRI model set predictions [previous image above]. Image source: NOAA/CPC.)

In contrast, the CFSv2 model forecast from NOAA (above image) shows El Nino only weakening through to July and then re-strengthening in the October-November time-frame. This CFS model scenario would result in higher atmospheric temperatures in 2016 — practically guaranteeing a lock on an unprecedented three back-to-back-to-back record warm years for 2014, 2015, and 2016. But such a scenario — implying that the Pacific Ocean had entered a new period of El Nino tendency — would also tend to keep atmospheric temperatures nearer to the newly established record highs.

Under the CFSv2 scenario, we may expect annual average global temperatures to rise as high as 1.08 to 1.2 C above 1880s values during 2016 (a very extreme departure and one uncomfortably close to the 1.5 C warming mark). These extreme values would, perhaps, recede to around between 0.9 and 1.1 C during 2017 so long as the second El Nino pulse did not remain in place for too long. However, if the bounce back toward El Nino conditions was strong enough in late 2016, there would be an outside chance that the globe may experience not 3, but an absolutely obnoxious 4 back-to-back record warm years.

NASA temperature trend

(During 2015 global annual temperature rocketed to above 1 C hotter than 1880s values. There’s at least an even chance that 2016 will be hotter still. Considering the considerable heating tendency imposed by a fossil fuel-forced warming of the world, how much worse can it get during the 21st Century’s second decade? Image source: NASA GISS.)

Meanwhile, the warm air pulse heading toward the poles may be somewhat muted under this scenario. A statement that should be qualified by the fact that we’ve already seen a substantial amount of El Nino heat heading poleward during the present event. In addition, potentially heavy rainfall events may not receive the added oomph of a decent global temperature drop to wring out more moisture. A statement that requires the further qualification that overall atmospheric moisture loading is enhanced by rising global temperatures — so comparatively less heavy rainfall is a relative term here.

At this time, NOAA favors a transition to La Nina forecast stating:

“A transition to ENSO-neutral is likely during late Northern Hemisphere spring or early summer 2016, with a possible transition to La Nina conditions by fall.”

However, it’s worth re-iterating that the CFSv2 model forecasts have been quite accurate in predicting the path of the current record El Nino to date.

Links:

NOAA/CPC

NASA GISS

Hothouse Mass Casualty Event Strike Eqypt

Southern Hemisphere’s Strongest Storm on Record

Punishing Four Season Storm Grips US

A Monster Arctic Melt Season May Have Already Begun

Deep Ocean Warming is Coming Back to Haunt Us

Warm Arctic Storm to Unfreeze the North Pole

More Signs of Gulf Stream Slowdown as Floods Devastate Cumbria England

Deconstruction of Asia’s Wild Weather

Hat tip to Caroline

 

Even a Monster El Nino Can’t Beat the Southwest Drought

For those who follow weather, it’s a rather strange and disturbing story.

A powerful Pacific Ocean storm forms about 500 miles south of the Aleutian Islands. Heavily laden with rains, strong winds, and trailing a long squall line, the system takes aim at the US West Coast. It’s a burly beast of a thing. Pumped up by an enormous bleed of moisture rising off of one of the mightiest El Ninos ever seen. An instance of extreme Equatorial heat that’s been firing off since October.

Another Pacific Storm Deflected

(Another Pacific Storm is deflected northward by increasingly persistent high pressure systems as the US Southwest swelters under unseasonable warmth. GFS climate reanalysis by Climate Reanalyzer shows this disturbing weather pattern again and again in the February forecast. In short, it doesn’t look like the California Drought is going to end anytime soon. Image source: Climate Reanalyzer.)

The towering El Nino-fed storm clouds chug east, steaming along toward what appears to be an inexorable collision with California, Oregon, and Washington. But, at the last moment, the storm slams into a heavy pile of atmospheric heat. Warm air building over the US Southwest and nearby ocean zones has shoved the upper air steering current called the Jet Stream pole-ward. The great storm is sucked up into this atmospheric train, delivering its rains along an arc from Washington State on northward.

And so the seemingly impossible has happened. A powerful El Nino’s rains and snows — usually bound directly for California, Oregon and Washington — have been diverted by a new kind of atmospheric pattern associated with climate change.

El Nino’s Rains Gone or Just Taking a Break?

Ever since late January, strong ridges have tended to develop over Western North America. By February 4th, the National Weather Service (NWS) had begun to report on the pattern — describing  it as El Nino taking a 5-10 day break. But the ‘break’ had already begun to show up on January 26th — about ten days prior to the February 4 NWS announcement. And now, on February 10, we’ve seen two full weeks of warm, dry weather settling in over California and the US Southwest. Meanwhile, long range model forecasts indicate that the ‘break’ from El Nino conditions will continue through at least February 16th.

Upper 60s to upper 80s California and Arizona

(Temperatures in the upper 60s to upper 80s is predicted for a large sections of California and Arizona on Tuesday, February 16th. It’s the kind of hot, dry air that brings back memories of recent years when formations of strong, ridiculously resilient ridges pushed California into one of its worst drought episodes on record. Image source: Climate Reanalyzer.)

It’s all just terrible timing. First, California snow packs during December and January began to recover due to strong, El Nino associated, storm systems barreling in. However, now during what should be the peak of the Southwestern rainy season, we have what could be a month long pause in storms hitting the region. It’s as if the rainy season is being hollowed out. And not just any rainy season — a strong El Nino rainy season which should have been far, far rainier than most.

Last week, Climate Central and Peter Gleick — a climate expert at Pacific Institue — made the following warning:

seven days of sustained warmth could melt as much as 30 percent of California’s snowpack. The hot, dry weather is exactly what baked in exceptional drought in California over the past four years. Some signs indicate the heat is driven in large part by climate change, but the role of the ridiculously resilient ridge is still an area of active investigation.

Well, by tomorrow seven days will have come and gone. But the end to the anomalous warm, dry spell is still nowhere in sight.

California Drought Really Hasn’t Budged

Meanwhile, a four-year-long California drought appears to be making a strong run at year five. In fact, if you look at the US Drought Monitor, you’ll find that a large swath of the West is currently suffering under moderate to exceptional drought conditions.

West Still Suffering From Drought

(Severe Drought remains in place over the US West. El Nino appears to have lost at least some of its ability to deliver heavy rains as an intensifying regime of human-forced warming pushes typical weather patterns further and further off-kilter. All bad news for an area that has been suffering from one severe drought after another since the early 2000s. Image source: Drought Monitor.)

Quite frankly, it’s insane that we’re still seeing these conditions during a monster El Nino. These droughts should be rolling back as the storm track intensifies and hurls severe weather at the US West Coast. But that’s not what’s happening. At least not consistently. Instead, we keep getting these extreme ridge patterns in the Jet Stream over western North America. We keep getting these very warm, very dry spells of weather during the wet season. And now, we have California Snowpack melting away in February of all times.

A Ridge-Trough Pattern That’s All-Too Likely Related To A Human-Forced Warming of the Arctic

The fact that these weather patterns emerged after the warmest January and lowest sea ice extents on record for the Arctic is a point that should not be missed by weather and climate analysts. It appears that what we are seeing is yet more evidence that polar amplification is driving a consistent high amplitude bulge in the Jet Stream over Western North America together with severe periods of warmth, dryness and snowpack melt during Winter. The hot side of a dipole pattern that is also setting up more extreme storm potentials as cold air is driven out of the Arctic along a deep trough over the Eastern US, slams into a record hot Gulf Stream, and then sets off a series of atmospheric bombs along a storm track running all the way across the North Atlantic and into Western Europe. Yet more evidence that what happens in the Arctic doesn’t stay in the Arctic.

Links:

Climate Reanalyzer

Drought Monitor

Hot, Dry Weather Could Cut California Snowpack

Polar Amplification vs A Godzilla El Nino

NWS: El Nino Taking a 5-10 Day Break

Arctic Sea Ice Death Spiral Continues

BBC: Storm Imogen Takes Aim at UK

Hat Tip to DT Lange

Hat Tip to Andy in San Diego

Hat Tip to Colorado Bob

 

 

Century of Water Shortage Ahead? Lake Mead Drops Below Rationing Line For First Time in Its History.

1075 feet. That’s the water level Lake Mead must stay above before mandatory multi-state water rationing goes into effect. A level just 25 feet above the highest intake pipe used to supply cities across the Desert Southwest. Last night water levels at the key national water storage facility fell below that hard line to 1074.99 feet — a record low never before seen in all of its history.

lake meade water levels

(Lake Meade water levels hit below the 1075 hard line yesterday, the lowest level ever recorded. Image source: Lake Mead Water Data.)

If water levels remain below the 1075 foot mark through January of 2016, then a multi-state rationing will go into effect (with most acute impacts for Arizona and Nevada). A rationing that will have serious consequences for desert cities across the Southwest, cities like Las Vegas which rely on Lake Mead for so much of their water.

Despite Lake Mead hitting the 1075 hard line, it appears that rationing may be forestalled through 2016. It’s a silver lining of all the severe summer storms that have rolled through the Colorado River Basin this spring and summer — pumping up water flows to Lake Mead and Lake Powell. A flush of much needed moisture that will, hopefully, prevent water rationing from going into effect during 2016. But prospects for the future, despite this temporary respite, are starting to look a bit grim.

Risk of Future Megadrought

The trend set in place by a human-forced warming of the Desert Southwest has resulted in an increasing number of dry years. The added heat forces water to evaporate more rapidly. So even when it does rain an average amount, moisture levels still fall. The result is not only an increase in single year droughts, but an increased risk of decadal droughts (called megadroughts).

As the years progress and more of the impacts of human-forced global warming become apparent, the drought impacts and severe drought risks are only expected to rise. For according to a recent Cornell University report (2014) the chance of a 10 year drought for the US Southwest under a moderate warming scenario (RCP 4.5) is 50% this century (greater for states like Texas, Oklahoma, New Mexico, Arizona, and Nevada — see graphic below). The chances of a 30 year drought range from 20-50 percent depending on the severity of the human greenhouse gas emission.

Megadrought risk

(Risk of an individual State experiencing a 10 year or longer drought as a result of global warming due to human fossil fuel emissions over the course of the next century. Note that Lake Meade watershed states show the highest risk for periods of terrible drying. Image source: Southwest May Face Megadrought this Century.)

Toby Ault, lead author of last year’s Cornell Paper noted:

“For the southwestern U.S., I’m not optimistic about avoiding real megadroughts. As we add greenhouse gases into the atmosphere – and we haven’t put the brakes on stopping this – we are weighting the dice for megadrought conditions.”

For reference, the current historic California drought is, so far, a four-year affair. So, as difficult and damaging as that drought has been, a 10 year or a thirty year drought may be seem comparatively unimaginable by today’s standards. In other words, though it’s been rather dry for the U.S. West over the past 15 years, an impact likely already worsened by human-caused climate change, we haven’t seen anything yet.

Early Warning and A Call For Necessary Action

In addition to increasing drying and severe drought risks, growing cities throughout the U.S. West have put greater and greater strains on water stores like Lake Mead. As a result of the combined human-forced drought and increased water consumption, levels at Lake Mead have been dropping since 1999. Back then, water levels averaged around 1200 feet. And since that time we’ve seen an average 8 foot drop each year.

It’s a trend that, unless it changes, will almost certainly mean water rationing in 2017, 2018 or 2019, if not 2016.  Water resource officials are notably concerned. Water-policy manager Drew Beckwith of Western Resource Advocates noted in USA TODAY:

“This is the check-engine light. It really does (make critical) the fact that we have to start changing.”

And that’s absolutely true. We need to change how we manage and use water in the US Southwest and we need to do absolutely everything we can to prevent as much future warming as possible to reduce the risk and intensity of the future megadroughts that are a likely upshot of human-forced warming. The crossing of the 1075 line for Lake Mead yesterday should thus be viewed as a climate change shot across the bow. If we want to husband our resources wisely, we need to look both toward conservation and toward making certain conditions do not spiral beyond even the ability of responsible resource management to make a difference. That’s the basic lesson of climate change — there are simply some conditions that are impossible to adapt to. And the goal of every rational person should be to do everything possible to prevent and reduce the intensity of those conditions. The water security of the U.S. Southwest depends on it.

Links:

Lake Mead Water Data

Lake Mead Sinks to Record Low Risking Water Shortage

Water Level in Lake Mead Drops to Warning Mark

Southwest May Face Megadrought This Century

Hat Tip to Andy in San Diego

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