El Niño and La Niña

What is the "El Niño" event?

Full name: El Niño-Southern Oscillation (ENSO). The warm phase of ENSO.
(Source for this inof and that which follows): http://en.wikipedia.org/wiki/ENSO

It is a global coupled ocean-atmosphere phenomenon. El Niño and La Niña are important temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. The name El Niño, from Spanish for "the little boy", refers to the Christ child, because the phenomenon is usually noticed around Christmas time in the Pacific Ocean off the west coast of South America. La Niña, means "the little girl".

ENSO is associated with floods, droughts, and other disturbances in a range of locations around the world.

Because El Niño's warm pool feeds thunderstorms above, it creates increased rainfall across the east-central and eastern Pacific Ocean.

The effects of El Niño in South America are direct and stronger than in North America. An El Niño is associated with warm and very wet summers (December-February) along the coasts of northern Peru and Ecuador, causing major flooding whenever the event is strong or extreme. The effects during the months of February, March and April may become critical. Southern Brazil and northern Argentina also experience wetter than normal conditions but mainly during the spring and early summer. ... Drier and hotter weather occurs in parts of the Amazon River Basin, Colombia and Central America.

What is the "La Niña" event?

La Niña is the name for the cold phase of ENSO, during which the cold pool in the eastern Pacific intensifies and the trade winds strengthen.

Financial implications:

Economic: Flooding: danger of loss to life and property.

Global warming and ENSO:

ENSO is a natural part of the Earth's climate, an important concern is whether its intensity or frequency may change as a result of global warming.

ANOTHER TAKE ON THIS: Source extracted: http://environment.about.com/od/globalwarming/a/elninolanina.htm

How is Global Warming Related to El Niño and La Niña?

Some scientists believe that the increased intensity and frequency—now every two to three years—of El Niño and La Niña events in recent decades is due to warmer ocean temperatures resulting from global warming. In a 1998 report, scientists from NOAA explained that higher global temperatures might be increasing evaporation from land and adding moisture to the air, thus intensifying the storms and floods associated with El Niño.


Another take on what’s happening is from Kevin Trenberth, a climatologist at the Colorado-based US National Center for Atmospheric Research. Trenberth believes that the Southern Oscillation may be functioning like a pressure release valve for the tropics. With global warming driving temperatures higher, ocean currents and weather systems might not be able to release all the extra heat getting pumped into the tropical seas; as such, an El Niño occurs to help expel the excess heat.

My thoughts on this: I can't see global warming, whatever the cause, not playing a role in the ENSO phenomenon. The climate systems now are all so "globalised" that an imbalance in one aspect may certainly cause a shift in another.

ENSO and Human Security - Here's a "fact sheet" from an event:

Guyana and La Niña in 2005

http://www.usaid.gov/our_work/humanitarian_assistance/disaster_assistance/countries/guyana/fy2005/guyana_fl_fs02_02-08-2005.pdf

Environmental Change and South America: Water

Questions and answers - Worldbank article

1/ Climate change - how it affects the design of (new) water resource infrastructure.

Fact: Climate change will impact the water resource systems of the world.
Explanation: For example, reservoir designs for water storage have been based on a water
system assumed to be driven by historic climate conditions. If the climate changes, river or other water source runoffs will either increase or decrease in a way that could be different from what has generally been observed over previous decades. This means that costs will be required to adapt the reservoirs to these changes. If there is less water flow, then there is less water supply and may this may economic damage and other hardship. Increased water flow, on the other hand, may cause flooding.

Bottom line: South America could experience a range of runoff changes depending on
whether and how climate change affects precipitation and temperature patterns over the continent. Models for South America suggest a greater climate sensitivity to changes in precipitation than temperature.

My note: The expenses to cater for water infrastructure design changes are quite large for developing countries but they should be considered as an investment in the future. The degree of impact from climate change may be uncertain but the change itself is a reality that needs to be addressed and whose impacts are already being felt. Farming communities in some countries find it hard to plan crop planting because the weather systems have altered unpredictably from historic patterns making it difficult to plan for hydrologic needs.

Source extracted: http://siteresources.worldbank.org/INTLACINSPANISH/Resources/SDWP_Future_Climate.pdf

Intro.

The objective of this blog is to compile information on environmental change and what it means for human security around the globe. It is a huge topic but I will try to keep it tight and as objective as possible. My interest in this field arises from having seen first hand and read about the effects of climate change on farming communities in South America and the rest of the world. That does not mean that the impact on farming will be central to this blog, but it will be one aspect of it. After all, food supply is key to human survival and security.