From El Niño to La Niña: Man before beast

Extreme weather conditions are predicted on a global scale as experts come to terms with the latest details emerging from the La Niña event, climate-changing ocean temperature alterations which follow El Niño and affect vast swathes of our planet on an intercontinental scale.

42003.jpegThe World Meteorological Organization, the UN's weather agency, warned yesterday that the weather pattern known as La Niña (The Girl, in Spanish), will probably continue and strengthen over the forthcoming four to six month period and is likely to bring prolonged extreme weather conditions to diverse areas of the planet, namely flood and drought cycles and extreme high or low temperatures.

The warning from the WMO was stark: "Almost all forecast models predict continuation and possible further strengthening of this La Niña episode for the next four to six months". The present cycle developed after the end of El Niño in April, the first signs appearing in June and July.

La Niña characteristically follows El Niño (The Boy). Whereas the latter brings higher ocean currents, La Niña creates unusually cooler water temperatures. Both La Niña and El Niño can last for a year or more and impact weather cycles and climate changes across the globe, as knock-on effects kick in, the result of interaction between oceanic and atmospheric aspects of current events.

La Niña typically brings increased rainfall to the Western equatorial Pacific region, Indonesia and the Philippines. South America and Southern Africa usually experience higher than average precipitation in December to February while South-Eastern Australia experiences the same in June to August.

Coupled with this, unusually low temperatures are felt in December to February in South-Eastern Africa, Japan, Southern Alaska, Western and Central Canada and South-Eastern Brazil and in  June-August, cooler temperatures are registered in India, SE Asia, the South American West Coast, the Gulf of Guinea, the northern part of South America and Central America.

Conversely, higher than normal temperatures are felt in the Gulf Coast of the USA in December to February. Coastal Ecuador, NW Peru and Eastern Africa usually experience drought in December to February, Southern Brazil and Argentina in June to August.

The WMO also warned that the present La Niña may differ in its effects from previous phenomena. The situation at present is moderate to strong La Niña conditions in the Pacific, with water temperatures 1.5C cooler than average and subsurface conditions between 2 to 6C below. This La Niña, warns the WMO, presents strong ocean-atmosphere coupling.

If we thought weather conditions and climate change were already extreme, we may be in for a very unusual winter.

Source: WMO

Timothy Bancroft-Hinchey




Author`s name Timothy Bancroft-Hinchey