As this year's boreal summer monsoon draws to a close interest automatically centers around forecasts for next summer's monsoon and the likelihood of possibly another El Niño event. This brings about the question of historical El Niños and when I googled for the same I came up with this interesting site - Historical El Niño Events. I am familiar with the European medieval warming period Medieval Warming Period but my current question deals with the period from 1790 AD to 1799 AD as mentioned in the first link. It appears apart from the year 1798 all other years were El Niño years and that would appear to be a extraordinary period. My question is
Are there any references from paleoclimatology that talk of the atmosphere during that period ? Are those confirmed El Niño events ?