Persistent La Niña Is Back Again — And Driving Up Food Prices

By Stephen Leahy *

UXBRIDGE, Canada, Oct 11, 2011 (Tierramérica)

La Niña is back less than three months after the end of its last appearance, a particularly strong event that contributed to driving up global food prices.

The new La Niña will continue the largely dry conditions in important agricultural regions in Brazil and Argentina as well as the southern United States and hurt yields of soy and wheat, experts say.

“Multi-year La Niñas are not uncommon,” said Jeff Masters, co-founder and director of meteorology for Weather Underground, the web’s first commercial weather service.

“The last was between 1998 to 2001 with a few months of neutral conditions like this year,” Masters told Tierramérica.

La Niña and El Niño are, respectively, the cold and warm phases of the famous El Niño-Southern Oscillation (ENSO), a cyclical climate phenomenon that affects weather patterns around the world.

ENSO is part of the system that regulates heat in the eastern tropical Pacific Ocean and is driven by changes in surface ocean temperature and air pressure.

“ENSO is undoubtedly being affected by climate change,” said Masters.  Continue reading

The Great Groundhog’s Day Blizzard – Worst Winter Storm in 60 Years

Images Modis sat - January 31 at 10:30 a.m., 12:05 p.m., and 1:45 p.m. Eastern Time

This is what climate change looks like

One of the largest winter storms since the 1950s has hit 30 U.S. states from New Mexico to Maine and now into central and eastern Canada — +100 million people affected, hundreds of thousands without power. Chicago could get buried by more than 60 centimeters (2-ft) of snow — hundreds stranded already.

Climate change is certainly playing a role in this massive storm.

1. Warmer global temps means there is now four per cent more water vapour in the atmosphere which means heavier snowfalls.

2. There is also more energy in the climate system which makes storms more powerful.

3. Finally the melting of the Arctic sea ice is changing wind patterns in the polar regions bring colder, wetter winters to the eastern US  and western Europe scientists told me several months ago. (See my previous post East Coast Blizzard and Europe’s Snowmaggddon Reveal Fingerprints of Climate Change

Climate change loads the dice in favour of extreme events.

My latest article on this The Yin and Yang of Climate Extremes We Will See More of. — Stephen

Recent related articles:

Climate Change Could Be Worsening Effects of El Niño, La Niña

Arctic Melt Down Is Bringing Harder Winters and Permanently Altering Weather Patterns

Arctic Ice in Death Spiral, Thaws Permafrost — Risks Climate Catastrophe

Climate Change Could Be Worsening Effects of El Niño, La Niña

Global Warming Worsening Impacts; Creating New ENSO ‘Flavors’

By Stephen Leahy*

UXBRIDGE, Canada, Jan 11, 2011 (Tierramérica) 

The strongest La Niña weather system in 50 years has brought historic flooding to Australia and drought to Argentina, Brazil and Uruguay, driving up food prices.

Scientists now believe climate change is likely enhancing the impacts of the famous El Niño-Southern Oscillation (ENSO), a cyclical climate phenomenon that affects weather patterns around the world.

La Niña and El Niño are, respectively, the cold and warm phases of the ENSO cycle, and form part of the system that regulates heat in the eastern tropical Pacific Ocean.

Both accompany simultaneous changes in surface ocean temperature and air pressure.

In conditions defined by climatologists as “neutral,” high air pressure predominates in the eastern Pacific, while low pressure predominates in the west.

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The difference in pressure generates the trade winds, which blow east to west over the surface of the tropical Pacific, pushing the warm waters westward. The deeper, cooler waters then surface in the east, replacing the warm waters.

During episodes of La Niña, the differences in pressure are more marked, the trade winds blow more strongly, and the cold-water currents in the eastern Pacific intensify.

On the other hand, during El Niño, high surface air pressure in the western Pacific and lower pressure on the coasts of the Americas cause the trade winds to weaken or change direction, resulting in warmer water temperatures in the eastern Pacific.

“There has been a very rapid transition from El Niño to La Niña in 2010,” Kevin Trenberth, a senior climate scientist with the National Centre for Atmospheric Research (NCAR) in the central U.S. state of Colorado, told Tierramérica. Continue reading