A La Niña cannot erase decades of warming

From a post by John Bruno on Skeptical Science:

Former TV weather guy Art Horn has a post up at Pajamas Media about the current La Niña. He mixes some reasonable and accurate observations with several important misconceptions and misstatements about weather, oceanography and climate change.

Mr. Horn correctly points out that we are in the midst of a strong La Niña phase of the El Niño Southern Oscillation (ENSO) cycle. We entered the current La Niña when the last El Niño ended in April/May (or a month or so later based on NOAA's Multivariate ENSO Index). As a result, equatorial Pacific Sea Surface Temperatures (SSTs) are currently about 1.4 C cooler than average.

As Art says, the switch from El Niño to La Niña was abrupt, as can be seen in the rapid change from negative to a positive Southern Oscillation Index (SOI) . . .

The Southern Oscillation Index (as plotted by the Australian Government Bureau of Meteorology above) is based on the measured air pressure difference between Tahiti and Darwin. Sustained positive values are associated with stronger Pacific trade winds and are indicative of La Niña.

Record high temperatures during La Niña
Art then goes on to make a number of errors in his analysis of the relevance of this La Niña, and ENSO in general, for anthropogenic climate change. Although his wording is a bit vague, he seems to suggest that a La Niña can somehow erase anthropogenic heat accumulation:

"strong La Nina events drop the Earth’s average temperature around one degree Fahrenheit" "The most recent La Nina developed in the spring of 2007, and persisted until the early summer of 2008. The global average temperature fell one degree Fahrenheit in that period of time, equal to all of the warming of the last 100 years!"