Corals as climate archive: Are El Niños intensifying?

A storm is gathering. Most likely a very big one. El Niño is a natural climate phenomenon occurring every two to seven years, towards the end of the year, but it comes in various different strengths, depending on the prevailing conditions. El Niños are considered strong if the surface temperature of the water off the west coast of South America is more than 1.5 degrees Celsius above average. In July this year, the US National Oceanic and Atmospheric Administration (NOAA) was already observing temperature increases of greater than three degrees Celsius in the eastern and central Pacific. The German Meteorological Service believes this "could in all likelihood develop into one of the strongest El Niño events since records began.