Global warming” may become one of those quaint cocktail party conversations of the past if three key climate drivers – cooling North Pacific sea surface temperatures, extremely low solar activity and increased volcanic eruptions – converge to form a “perfect storm” of plummeting temperatures that send our planet into a long-term cool-down lasting 20 or 30 years or longer.
“There are some wild cards that are different from what we saw when we came out of the last warm PDO [Pacific Decadal Oscillation] and entered its cool phase [1947 to 1976]. Now we have a very weak solar cycle and the possibility of increased volcanic activity. Together, they would create what I call the ‘Triple Crown of Cooling,’” says Accuweather meteorologist Joe Bastardi.
If all three climate-change ingredients come together, it would be a recipe for dangerously cold temperatures that would shorten the agricultural growing season in northern latitudes, crippling grain production in the wheat belts of the United States and Canada and triggering widespread food shortages and famine.
Cool Pacific Decadal Oscillation
The Pacific Decadal Oscillation refers to cyclical variations in sea surface temperatures that occur in the North Pacific Ocean. (The PDO is often described as a long-lived El Niño-like pattern.) PDO events usually persist for 20 to 30 years, alternating between warm and cool phases. During these long periods there are sometimes short-interval phase switches that can last several years.
From 1977 to 1998, during the height of “global warming,” North America was in the midst of a warm PDO. Since then, we have experienced several short-duration PDO fluctuations between cool and warm.
But the PDO has once again resumed its negative cool phase, and, as such, represents the first climate driver in the Triple Crown of Cooling. With the switch to a cool PDO, we’ve seen a change in the El Nino/Southern Oscillation (ENSO), which alternates between El Nino (warm phase) and La Nina (cool phase) every few years. The recent strong El Nino that began in July 2009 is now transitioning to a La Nina, a sign of cooler temperatures ahead.
“We’re definitely headed towards La Nina conditions before summer is over, and we’re looking at a moderate to strong La Nina by fall and winter, which, as these La Ninas tend to persist in the cold PDO for two years, should bring us cooler temperatures over the next few years,” predicts Joe D’Aleo, founder of the International Climate and Environmental Change Assessment Project (ICECAP) and the first director of meteorology at the Weather Channel.
He is not alone in his forecast. Bastardi also sees a La Nina just around the corner.
“I’ve been saying since February that we’ll transition to La Nina by the middle of the hurricane season. I think we’re already seeing the atmosphere going into a La Nina state in advance of water temperatures. This will have interesting implications down the road. La Nina will dramatically cool off everything later this year and into next year, and it is a signal for strong hurricane activity,” Bastardi predicts.
The difference in sea surface temperature between positive and negative PDO phases is not more than 1 to 2 degrees Celsius, but the affected area is huge. So the temperature changes can have a big impact on the climate in North America.
In fact, as Dr. Roy Spencer points out, the warm-phase PDO lasting from 1977 to 1988 might explain most of the warming we experienced in the late 20th century.
“This is because a change in weather circulation patterns can cause a small change in global-average cloudiness. And since clouds represent the single largest internal control on global temperatures (through their ability to reflect sunlight), a change in cloudiness associated with the PDO might explain most of the climate change we’ve seen in the last 100 years or more,” he writes.
Declining solar activity
Another real concern – and the second climate driver in the Triple Crown of Cooling – is the continued stretch of weak solar activity Earth is experiencing. We recently exited the longest solar minimum –12.7 years compared to the 11-year average – in 100 years. It was a historically inactive period in terms of sunspot numbers. During the minimum, which began in 2004, we have experienced 800 spotless days. A normal cycle averages 485 spotless days.
In 2008, we experienced 265 days without a sunspot, the fourth-highest number of spotless days since continuous daily observations began in 1849. In 2009, the trend continued, with 261 spotless days, ranking it among the top five blank-sun years. Only 1878, 1901 and 1913 (the record-holder with 311 days) recorded more spotless days.
In 2010, the sun continues to remain in a funk. There were 27 spotless days (according to Layman’s sunspot count) in April and, as of May 19, 12 days without a spot. Both months exhibited periods of inexplicably low solar activity during a time when the sun should be flexing its “solar muscle” and ramping up towards the next solar maximum.
Why are sunspot numbers important? Very simple: there is a strong correlation between sunspot activity and global temperature. During the Dalton Minimum (1790 - 1830) and Maunder Minimum (1645 -1715), two periods with very low sunspot activity, temperatures in the Northern Hemisphere plummeted.
During the Dalton Minimum, the abnormally cold weather destroyed crops in northern Europe, the northeastern United States and eastern Canada. Historian John D. Post called it “the last great subsistence crisis in the Western world.” The record cold intensified after the eruption of Mount Tambora in 1815, the largest volcanic eruption in more than 1,600 years (see details below).
During the 70-year Maunder Minimum, astronomers at the time counted only a few dozen sunspots per year, thousands fewer than usual. As sunspots vanished, temperatures fell. The River Thames in London froze, sea ice was reported along the coasts of southeast England, and ice floes blocked many harbors. Agricultural production nose-dived as growing seasons became shorter, leading to lower crop yields, food shortages and famine.
If the low levels of solar activity during the past three years continue through the current solar cycle (Solar Cycle 24), which is expected to peak in 2013, we could be facing a severe temperature decline within the next five to eight years as Earth’s climate begins to respond to the drop-off in solar activity.
“The sun is behaving very quietly – like it did in the late 1700s during the transition from Solar Cycle 4 to Solar Cycle 5 – which was the start of the Dalton Minimum,” D’Aleo says. If the official sunspot number reaches only 40 or 50 – a low number indicating very weak solar energy levels – during the next solar maximum, we could be facing much lower global temperatures down the road.”
Even NASA solar physicist David Hathaway has said this is “the quietest sun we've seen in almost a century.”
"Since the Space Age began in the 1950s, solar activity has been generally high," Hathaway told NASA Science News. "Five of the ten most intense solar cycles on record have occurred in the last 50 years. We're just not used to this kind of deep calm."
Although the eruption of Iceland’s Mount Eyjafjallajokull volcano continues to raise havoc with air travel, it remains a relatively minor event by volcanic standards. Much of its ash cloud has stayed out of the stratosphere, where it would reflect sunlight, bringing cooler temperatures to the northern hemisphere.
Unfortunately, there is a very real chance Eyjafjallajokull’s much larger neighbor, the Katla volcano, could blow its top, creating the third-climate driver in the Triple Crown of Cooling. If Katla does erupt, it would send global temperatures into a nosedive, with a big assist from the cool PDO and a slumbering sun.
The Katla caldera measures 42 square miles and has a magma chamber with a volume of around 2.4 cubic miles, enough to produce a Volcanic Explosivity Index (VEI) level-six eruption – an event ten times larger than Mount St. Helens.
Katla erupts about every 70 years or so, most recently in 1918, often in tandem with neighboring Eyjafjallajokull, which is not a good sign.
According to Bastardi, “The Katla volcano in Iceland is a game changer. If it erupts and sends plumes of ash and SO2 into the stratosphere, any cooling caused by the oceanic cycles would be strengthened and amplified.”
Iceland’s President Olafur Grimsson says the eruption of Eyjafjallajoekull volcano is only a "small rehearsal.”
“The time for Katla to erupt is coming close . . . I don't say if, but I say when Katla will erupt,” Grimsson predicts. And when Katla finally erupts it will “create for a long period, extraordinary damage to modern advanced society.”
Not a very encouraging outlook. Yet major eruptions throughout history bear witness to the deadly impact of volcanoes.
The Tambora eruption in 1815, the largest in 1,600 years, sent the earth’s climate into a deep freeze, triggering “the year without a summer.” Columnist Art Horn, writing in the Energy Tribune, describes the impact:
“During early June of 1815, a foot of snow fell on Quebec City. In July and August, lake and river ice were observed as far south as Pennsylvania. Frost killed crops across New England with resulting famine. During the brutal winter of 1816/17, the temperature fell to -32 in New York City.”
And Katla, with its large magma chamber, would register high on the Volcanic Explosivity Index, if it were to erupt. When it unleashed its fury in the 1700s, the volcano sent temperatures into a tailspin in North America.
As Gary Hufford, a scientist with the Alaska Region of the National Weather Service, observes:
"The Mississippi River froze just north of New Orleans and the East Coast, especially New England, had an extremely cold winter.
"Katla could cause some serious weather changes. It depends on the duration of the eruption, and how high the ash gets blasted into the stratosphere.”
Global cooling: a life-threatening event
With the PDO now in its cool phase, solar activity the weakest in more than 100 years, and the prospect of a major climate-cooling volcanic eruption, actions to limit CO2 emissions should be shelved and preparations made for an extended period of global cooling that would pose far more danger to humankind than any real or imagined warming predicted by today’s climate models.
Says D’Aleo: “Cold is far more threatening than the little extra warmth we experienced from 1977 to 1998 during the recent warm PDO. According to NASA, crop yield decreased 30 percent, and there was a 10 percent decrease in arable land during that period, which helped us feed many millions more of the earth’s population. A cooling down to Dalton Minimum temperatures or worse would lead to shortened growing seasons and large-scale crop failures. Food shortages would make worse the fact that more people die from cold than heat.”
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