Saturday, December 12, 2015

El Niño 2015 is already setting records



by Scott Sutherland :

1. Record Air Quality Alerts for Beijing

In the final days of November and into the first few days of December 2015, a thick blanket of smog descended over regions of eastern China, including the capital city of Beijing. 

The choking mix of air pollution got so bad that officials issued a rare Orange Alert for air quality in the city. This was the worst air quality episode of the year for China, until just a few days later, when pollution returned with level even higher, prompting Beijing to issue its first ever Red Alert.

Smog is not a consequence of climate change, but rather is a result of the fossil fuel burning that contributes to global warming. So, these rare Orange and Red Alerts in Beijing also act as warnings about exactly how much coal and oil we are still burning. 

At the same time, however, there is some indication that smog episodes - especially over cities - will get even worse as rising temperatures cause more stagnant air patterns and fewer, but more extreme rainfall events.

Given that an estimated 7 million people die prematurely due to air pollution each year, according to the World Health Organization (WHO), reductions in carbon emissions will not only help curb climate change, but will also have a direct impact on human life expectancy.

2. "Historic" Deluge over Eastern India

Just as December kicked off, the east coast of India, which had already been soaked by a very active monsoon season so far, suffered a sudden, extreme deluge of rainfall.


The once-in-one-hundred-years flooding touched off by this intense burst of rainfall claimed over 250 lives and displaced thousands of people.

According to NASA's Earth Observatory:

Meteorologists in India and abroad attributed the rains to a super-charged northeast monsoon. In the winter, prevailing winds blow from northeast to southwest across the country, which tends to have a drying effect in most places, particularly inland. But those northeasterly winds also blow over the warm waters of the Bay of Bengal, where they evaporate a great deal of moisture from the sea and dump it over southern and eastern India. Coastal eastern India receives 50 to 60 percent of its yearly rainfall during this winter monsoon. 
In 2015, this pattern was amplified by record-warm seas and by the long-distance effects of El Niño. The city of Chennai recorded 1218.6 millimeters (47.98 inches) of rain in November 2015, according to Weather Underground blogger Bob Henson. India’s meteorological department noted that rainfall was 50 to 90 percent above normal in the eastern states. Then 345 millimeters (13.58 inches) more fell on Chennai in the December 1–2 storm, which was fueled by a low-pressure system offshore.

With sea surface temperatures on the rise, and a warmer atmosphere that can typically hold more moisture, these events are expected to become more common in the future.


3. Massive Flooding in the UK from Desmond

Storm Desmond pummeled the British Isles this past weekend, leaving major flooding in its wake.

According to The Telegraph, the UK Environment Agency issued a total of 16 severe flood warnings, indicating a danger to life, plus 55 flood warnings and 28 flood alerts, some of which were still in effect as of Tuesday.

"The rainfall experienced in many parts of the north west of the UK is thought to have been exceptional and early provisional rainfall statistics indicate many places have seen totals widely over 180 to 200 mm in the Lake District," the Met Office said. "It is thought very locally event totals may be in excess of 300 mm locally."

The Telegraph reported tens of thousands of homes and businesses without power due to the storm and flooding, with hundreds displaced and three deaths were attributed to the storm.

According to the Telegraph:

The Met Office warned that "all the evidence" suggests climate change played a role in the floods, with chief scientist Dame Julia Slingo describing the extreme weather conditions as "extraordinary."

Concerns about flooding with climate change are not just about rising sea levels. As extreme storms become more "the norm" with climate change, flooding events are expected to become more common along with them.

4. Extreme Snowfall in Iceland

Even though the name implies a certain common relationship with wintry weather, Iceland can still set some surprising records for snowfall.

On December 2, Iceland's capital city of Reykjavik received a dumping of 42.5 cm of snow - the highest amount of snowfall in December ever seen - beating out the previous record of 33 cm on Dec 29, 2011.

It certainly makes for some pretty scenery, but there's a cost to all this. 

A warmer atmosphere is capable of holding more moisture. With global temperatures creeping upward - likely reaching around 1oC above pre-industrial times this year - this means more moisture available to any storms that develop. 

We are certainly not going to see the last of below-freezing temperatures during the colder months of the year, especially in locations like Iceland and Canada. Slightly warmer storms - as long as they don't go so high as to melt all the snow into rain - will, therefore, tend to dump more snow on us than storms did in the past.

5. El Niño Breaks Records and Challenges Top Spot

El Niño 2015 is already setting records.

It boosted the eastern and central Pacific hurricane seasons, producing the strongest hurricane ever seen and the most active season in the central Pacific ever as well.

Scientists tracking sea surface temperatures along the pattern noted that this El Niño reached the greatest intensity in the central Pacific since record-keeping began. As of the week of November 11, temperatures in the Niño 3.4 region reached 3.0oC above normal for the first time, then peaked at +3.1oC the week after and dropped back down to +3.0oC in the last week of November. Although this was prior to the start of the climate talks in Paris, temperatures in the central Pacific remain at 2.9oC above normal as of the week of December 2, which still exceeds the +2.8oC record set back in late November of 1997.

Along with these records, this El Niño also reached the highest monthly temperature departure on record, at 2.35oC above the November monthly average, even beating out November 1997.

Just this past week, NOAA updated their three-month Oceanic Niño Index (ONI) to reflect the latest readings. From September to November, the Niño 3.4 region reached an average temperature anomaly of +2.0oC - the second highest ever for that period. Even though this El Niño may have already reached its peak, the next ONI value (Oct-Nov-Dec) will most certainly be even higher, possibly even matching or exceeding the 1997 record of +2.3oC.

El Niño isn't caused by climate change. It's a natural pattern that has probably been going on since Earth had an atmosphere and a Pacific Ocean. However, the already warmer ocean temperatures being observed around the globe are exacerbating this year's El Niño pattern. A continued rise in ocean temperatures may set up a pattern of more extreme El Niño events as a result, thus coaxing out even more records in the future.

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