NOAA’s Climate Prediction Center issued an “El Niño Watch” today. This chart from NOAA makes clear why that is a big deal:
Global average surface temperatures during El Niño and La Niña years.
An El Niño in the second half of 2012 would make it quite likely that 2013 would be the hottest year on record. NASA had a long discussion of this very point in a January analysis, “Global Temperature in 2011, Trends, and Prospects.”
NASA explains that the apparent recent slowdown in global surface temperature rise is likely to prove “illusory”:
The cool La Niña phase of the cyclically variable Southern Oscillation of tropical temperatures has been dominant in the past three years, and the deepest solar minimum in the period of satellite data occurred over the past half dozen years. We conclude that the slowdown of warming is likely to prove illusory, with more rapid warming appearing over the next few years.
Of course, the warming never slowed down in the place where climate science predicted 90% of the heat would go in the first place — the oceans (as discussed here).
The El Niño Southern Oscillation (ENSO) doesn’t change the overall warming trend, but it is a short-term modulation, what NASA labels the largest contributor to the “natural dynamical variability” of the climate system. El Niño and La Niña are typically defined as sustained sea surface temperature anomalies (positive and negative respectively) greater than 0.5°C across the central tropical Pacific Ocean. You can read the basics about ENSO here.
NASA has some great charts to explain the impact of the solar minimum and ENSO on the recent warming trend:
What would an El Niño do in combination with this return to (almost) normalcy in total solar irradiance? NASA explained back in January:
So if there is an El Niño in the second half of the year, then a very warm 2013 seems the likely outcome. What are the chances of that?
The monthly ENSO diagnostic discussion from NOAA’s Climate Prediction Center (CPC) and the International Research Institute for Climate and Society (IRI), which included the “El Niño Watch,” explains:
Finally, the ENSO discussion concludes:
The CPC/IRI forecast calls for ENSO-neutral conditions through JAS, followed by an approximately 50% likelihood for El Niño during the remainder of the year (see CPC/IRI consensus forecast).
Stay tuned. The heat is on.
- Hottest Decade on Record Would Have Been Even Hotter But for Deep Oceans — Accelerated Warming May Be On Its Way