Our home in space

some remarks on global heating and ocean acidity

Guy Ottewell

A change to cooling?

Some were saying that since there was a peak in 1998 the planet must have reverted to a cooling trend. But this was an instance of a shorter-term jag.
    There are two oceanic phenomena, called “El Niño” and “La Niña”, that add to or subtract from the general trend. They bring warm and cool currents, respectively, to the eastern Pacific and have world-wide effects on weather. The 1998 El Niño was the strongest on record and added to global heating. It was followed by a La Niña that brought some cooling. Another El Niño began in mid 2009 and continued into 2010.
    Even though this El Niño was far weaker than the 1998 one, 2010 looks like exceeding the 1998 record: 14.58° C was the prediction (Dec. 10, 2009) of the United Kingdom's Met Office, which gave it a more than 90% probability, not a certainty, because the El Niño could end sooner or volcanic eruptions could have their usual cooling effect. But the prediction is apparently becoming true.