Lethal Heating: 01/02/16

02/01/2016

Climate Chaos, Across the Map

New York Times - Justin Gillis

Clockwise from top left: Flooding in Straiton, Scotland, on Wednesday; haze in Kalimantan Province, Indonesia, in October; flooding in Horry County, S.C., in October; drought in South Australia in November. Credit Danny Lawson/Press Association, via AP; Haris Sadikin/Agence France-Presse — Getty Images; Janet Blackmon Morgan/The Sun News, via AP; David Gray/Reuter

What is going on with the weather?
With tornado outbreaks in the South, Christmas temperatures that sent trees into bloom in Central Park, drought in parts of Africa and historic floods drowning the old industrial cities of England, 2015 is closing with a string of weather anomalies all over the world.
The year, expected to be the hottest on record, may be over at midnight Thursday, but the trouble will not be. Rain in the central United States has been so heavy that major floods are beginning along the Mississippi River and are likely to intensify in coming weeks. California may lurch from drought to flood by late winter. Most serious, millions of people could be threatened by a developing food shortage in southern Africa.
Scientists say the most obvious suspect in the turmoil is the climate pattern called El Niño, in which the Pacific Ocean for the last few months has been dumping immense amounts of heat into the atmosphere. Because atmospheric waves can travel thousands of miles, the added heat and accompanying moisture have been playing havoc with the weather in many parts of the world.

The weather phenomenon known as El Niño can cause dramatic effects around the world. Henry Fountain explains where it comes from. By Henry Fountain, Aaron Byrd and Ben Laffin on Publish Date September 9, 2014.

But that natural pattern of variability is not the whole story. This El Niño, one of the strongest on record, comes atop a long-term heating of the planet caused by mankind's emissions of greenhouse gases. A large body of scientific evidence says those emissions are making certain kinds of extremes, such as heavy rainstorms and intense heat waves, more frequent.
Coincidence or not, every kind of trouble that the experts have been warning about for years seems to be occurring at once.

Waiting out the flood Wednesday in Dumfries, Scotland, after heavy rain. Credit Andy Buchanan/Agence France-Presse — Getty Images

"As scientists, it's a little humbling that we've kind of been saying this for 20 years now, and it's not until people notice daffodils coming out in December that they start to say, 'Maybe they're right,' " said Myles R. Allen, a climate scientist at Oxford University in Britain.
Dr. Allen's group, in collaboration with American and Dutch researchers, recently completed a report calculating that extreme rainstorms in the British Isles in December had become about 40 percent more likely as a consequence of human emissions. That document — inspired by a storm in early December that dumped stupendous rains, including 13 inches on one town in 24 hours — was barely finished when the skies opened up again.
Emergency crews have since been scrambling to rescue people from flooded homes in Leeds, York and other cities. A dispute has erupted in Parliament about whether Britain is doing enough to prepare for a changing climate.
Dr. Allen does not believe that El Niño had much to do with the British flooding, based on historical evidence that the influence of the Pacific Ocean anomaly is fairly weak in that part of the world. In the Western Hemisphere, the strong El Niño is likely a bigger part of the explanation for the strange winter weather.

Cutting grass in South Africa, which is experiencing its worst drought since 1994. Credit Joao Silva/The New York Times

The northern tier of the United States is often warm during El Niño years, and indeed, weather forecasters months ago predicted such a pattern for this winter. But they did not go so far as to forecast that the temperature in Central Park on the day before Christmas would hit 72 degrees.
Likewise, past evidence suggests that an El Niño can cause the fall tornado season in the Gulf Coast states to extend into December, as happened this year, with deadly consequences in states like Texas and Mississippi.

Many parts of England and Scotland are experiencing damage from severe flooding brought on by Storm Frank. REUTERS on Publish Date December 31, 2015.

Matthew Rosencrans, head of forecast operations for the federal government's Climate Prediction Center in College Park, Md., said that the El Niño was not the only natural factor at work. This winter, a climate pattern called the Arctic Oscillation is also keeping cold air bottled up in the high north, allowing heat and moisture to accumulate in the middle latitudes. That may be a factor in the recent heavy rains in states like Georgia and South Carolina, as well as in some of the other weather extremes, he said.
Scientists do not quite understand the connections, if any, between El Niño and variations in the Arctic Oscillation. They also do not fully understand how the combined effects of El Niño and human-induced warming are likely to play out over the coming decades.
Although El Niños occur every three to seven years, most of them are of moderate intensity. They form when the westward trade winds in the Pacific weaken, or even reverse direction. That shift leads to a dramatic warming of the surface waters in the eastern Pacific.
"Clouds and storms follow the warm water, pumping heat and moisture high into the overlying atmosphere," as NASA recently explained. "These changes alter jet stream paths and affect storm tracks all over the world."
The current El Niño is only the third powerful El Niño to have occurred in the era of satellites and other sophisticated weather observations. It is a small data set from which to try to draw broad conclusions, and experts said they would likely be working for months or years to understand what role El Niño and other factors played in the weather extremes of 2015.
It is already clear, though, that the year will be the hottest ever recorded at the surface of the planet, surpassing 2014 by a considerable margin. That is a function both of the short-term heat from the El Niño and the long-term warming from human emissions. In both the Atlantic and Pacific, the unusually warm ocean surface is throwing extra moisture into the air, said Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research in Boulder, Colo.
Storms over land can draw moisture from as far as 2,000 miles away, he said, so the warm ocean is likely influencing such events as the heavy rain in the Southeast, as well as the record number of strong hurricanes and typhoons that occurred this year in the Pacific basin, with devastating consequences for island nations like Vanuatu.
"The warmth means there is more fuel for these weather systems to feed upon," Dr. Trenberth said. "This is the sort of thing we will see more as we go decades into the future."

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Extreme Times: World's Weather Is On A Weird Track That Will Continue Into 2016

Fairfax - Peter Hannam

What's El Nino got in store for 2016? The giant 2015 El Nino in the Pacific is at or nearing its peak, but it will be months before the world's weather engine takes the heat off Australia.

If Santa really did reside at the North Pole, he could probably have doffed his thick coat for a few hours this week to dig his sled out of the slush.
Despite being shrouded in darkness since early October, the top of this world recorded temperatures that appear to have been above freezing point for about six hours on Wednesday, thanks to a huge storm that steered tropical warmth into the high latitudes.
The Arctic has long been observed as warming at about twice the rate as elsewhere on Earth, but the 30-plus degrees Celsius jump above the average for this time of year was a stunning reading polar temperatures briefly above cities like Chicago in the US and Vienna in Austria far to the south.

Arctic heat caps off a record hot year for planet Earth. Photo: Leigh Henningham

Such events made descriptors such as "unprecedented" or "record" almost the bywords for 2015 when it came to weather.
The combination of an epic El Niño in the Pacific overlaying the background warming unleased mostly by humans' combustion of fossil fuels jolted the concept of what "normal" conditions mean. It also sets up 2016 for more wild weather.
Even before December brought record heatwaves to regions as diverse as Victoria, the High Arctic and almost all of the eastern US, major meteorological agencies had heralded 2015 as the hottest year for the planet since reliable data gathering began 136 years ago.
The call was an easy one to make. By November, year-to-date temperatures were more than 0.1 degree higher than the previous hottest year – set just one year earlier in 2014 – with the gap widening, according to the US National Oceanic and Atmospheric Administration [NOAA]:

Of 1630 months tallied by NOAA since 1880, seven of the 10 most usually hot months occurred in 2015 alone.

When the latest data is assessed, it may reveal December to be the first month with a temperature reading a full one degree above the 20th-century average. Last October fell just shy with a 0.99-degree anomaly, NOAA says.
Climatologists have scant doubt which way the climate is changing. In Australia since 2000, for instance, record hot days have been 12 times more common than record cold ones, research published in September showed. 2015 will probably be among the five warmest years for Australia since records began in 1910.
Those trends – and evidence of increasing extreme weather, such as worsening fire risks in southern Australia – were the reason why almost 200 nations agreed last month at the Paris climate summit to try to keep temperature increases "well below two degrees" compared with pre-industrial levels. We are roughly half way there.
Governments, including Australia's, also backed carbon neutrality – balancing emissions of greenhouse gases to the amounts being sequestered – by the latter half of this century, a pact that will need much more ambitious climate action to limit coal and other fossil fuel use than now being offered.
The global temperature gauge certainly got a kick-along this past year from the monster El Niño in the Pacific, which rivals the 1997-98 event as the most intense on record, and has a big influence on worldwide weather.
Even so, temperatures have been creeping higher for decades, whether it is an El Niño year (red) or its reverse, La Niña (blue), as shown in this NOAA chart:

During El Niños, the typical westward-blowing equatorial winds stall or reverse. Along with a build-up of heat in the central and eastern Pacific, rainfall patterns also shift eastwards away from Asia.
The current El Niño is marked by unusually warm waters covering about 16 million square kilometres, an area bigger than twice the size of Australia and larger than the 1997-98 record event.

Nearing peak?

The 2015-16 version is also showing "no signs of waning", NASA said this week. Australia's Bureau of Meteorology, though, estimates the event is near its peak but says models indicate the unusual heat won't break up until May or later.

Wenju Cai, a CSIRO research scientist who studies how climate change will affect El Niños in the future, says a lengthy breakdown of the event means 2016 could set annual global heat records for a third year in a row.
"It's the release of heat from the ocean that is going to make us hotter," Cai tells Fairfax Media.
Parts of the Northern Hemisphere might welcome a little extra warmth – although less so if it's accompanied by more storms and floods as lately seen in the UK. But in Australia, the extra heat "is coinciding with our peak" in summer, Cai says.
Forests and grasslands have already turned crisp across much of Victoria and elsewhere in southern Australia, prompting fears of a "Black January" if significant rainfall doesn't arrive to add moisture and disperse the heat.
In 2015, south-west Western Australia and parts of inland Queensland, South Australia and much of Victoria and Tasmania had very much below-average rainfall, the bureau said.

La Niña next?

The El Niño's demise, though, is unlikely to usher in a new period of climate calm.

As Agus Santoso, a senior researcher at the University of NSW-based Climate Change Research Centre, notes, "extreme La Niñas tend to follow extreme El Niños".
As the climate warms further, "this kind of sequence will happen more", Santoso says. "It's very bad news."
During La Niña years, the world's weather engine flips back to the western Pacific, with rainfall patterns shifting with it. Indonesia, South Pacific and parts of Australia that were relatively dry in 2015 may get excessive amounts of rain in the next year or so.
A comparatively quiet tropical cyclone season for this summer for Australia may revert to a relatively active one in 2016-17.
Research published by Santoso and Cai in 2015 indicates that while the number of El Niños and La Niñas may not alter with climate change, the frequency of the extreme version of such events affecting Australia is likely to quadruple this century if greenhouse gas emissions remain on a rising trajectory.
While "the power of nature is huge" and human activity may not trigger El Niños or La Niñas themselves, the rising atmospheric concentration of carbon dioxide, methane and other heat-trapping gases will make a difference, Cai says.
"In a warming world, the atmosphere can store more water," Cai says. "When conditions for rain are there, it will come down much more vigorously because you have more water."
The climate will become less recognisable to today's population as shifts in the world's weather engine in the Pacific "move further or faster, and stay longer", he says.

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El Niño: Why Predictable Climate Event Still Has The Scientists Guessing

The Guardian - Tim Radford

Blister of sea surface heat in Pacific Ocean can set off devastating drought, storms and rainfall around the globe – or just fade away

False-colour images provided by Nasa compare Pacific Ocean water temperatures from the El Niño in 1997 (right) and the current El Niño. Photograph: AP

El Niño is one of the most predictable climate events on the planet, according to the US National Oceanic and Atmospheric Administration, but it also has a way of keeping climate scientists guessing.
In March the oceanographers predicted the current event could be the weakest on record, but in August the same agency warned it could be the strongest.
Right now it still looks strong, says Nasa's Jet Propulsion Laboratory (JPL) in Pasadena, California. Using satellite data, meteorologists keep a steady watch on El Niño because it can play out demurely, or it can bring catastrophe. It has been linked to drought and harvest failures on the African continent, devastating fires in the normally moist rainforests of the Indonesian archipelago, both drought and flood in Australia, damaging floods in the Americas, and unusually mild winters in Europe.
This month, tens of thousands of people have been forced to flee their homes in the border areas of Paraguay, Uruguay, Brazil and Argentina due to severe flooding in the wake of heavy summer rains brought on by El Niño. Paraguay's national emergencies office has said the flooding is "directly influenced by the El Niño phenomenon, which has intensified the frequency and intensity of rains".
El Niño is a blister of sea surface heat that every few years floats eastwards across the tropical Pacific Ocean. It was given its name by the fishermen of Peru, who called it "the Child" because they became aware of it around the Christmas season, as the fish catches failed. The shift of warm seas leaves the western Pacific cooler, and both temperature shifts seem to play out in disruption of global weather patterns.
The last great El Niño, in 1997-98, helped make 1998 the then warmest year on record – that too was accompanied by a series of devastating events around the world, among them ice storms in North America, floods on the west coasts of the Americas and forest fires in Borneo. It also delayed the monsoon rains in India, warmed tropical waters so severely that coral reefs started to "bleach" and die, and signalled a record-breaking season of typhoons and tropical cyclones in the eastern Pacific.
Although researchers are fairly sure that climate change as a consequence of the combustion of fossil fuels, and the release of greenhouse gases, could make El Niño more frequent, or more devastating, or both, it remains a natural, cyclic event. Climate historians have linked it, with sometimes faltering levels of confidence, to historic events, among them the epidemic of Spanish influenza that claimed millions of lives in 1918 and even the Biblical plagues of Egypt linked to the story of Moses.
Sometimes oceanographers watch an El Niño develop, and then fade gently. And sometimes it develops powerfully, with consequences for the rest of the globe. Oxfam has already warned that this time millions could face famine as a consequence.
However, as the rains fail in Africa, Californians – still in the grip of a prolonged and damaging drought – may see a silver lining. In 1997 and1998 storms slammed into the US west coast, crossed the mountains, drenched Texas and even hit Florida. This time, El Niño may be seen as bringing relief.
"The water story for much of the American west over most of the past decade has been dominated by punishing drought," said JPL climatologist Bill Patzert. "Reservoir levels have fallen to record or near-record lows, while groundwater tables have dropped dangerously in many areas. Now we're preparing to see the flip side of nature's water cycle – the arrival of steady, heavy rains and snowfall."
What a heat bubble on the eastern Pacific – where the much warmer water means that a great stretch of ocean is actually up to 25cm higher than the cooler waters north and south of it – means for the UK is much less certain. "There are a number of factors that affect winter conditions in Britain," the Met Office said earlier this year. "The increase in risk of a colder winter this year from the developing El Niño is currently considered small."

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