The ENSO cycle is very much natural and have been in play long enough for the entire eco-system of Australia to have evolved around it. So about 40 million years at least. However, what is significant is that in recent years the La Nina years have not brought about high levels of rainfall or cold weather. In Australia in the last 70 years the beginning of winter has shifted back about 6 weeks, so winter keeps starting later and later, but the spring rainfall doesn't increase so the loss of rainfall isn't offset by extra rainfall after winter, and winter's have been almost repeatedly dry.

So it would seem the warming ocean (as demonstrated by the moving fish "stocks") is responsible.

Basically it's not in dispute that the Earth's climate is changing and becoming warmer, what is in dispute by some is whether or not it's anthropogenic.

Believe it or not I've actually read people claiming solar activity is responsible, despite the fact there has been no change in the sun's activity for over 400 years! Yes, some people are that low and morally bankrupt.

ummm Zippi62, once the heating of Earth reaches 4 degrees celcius there will be a runaway effect.

Nice neutral question, just like most of your posts.

Lol OM, Sou has a good post on that topic as well. [1]

The laughable part about the Global Warming alarmism from the environmental zealots (IP CC and their climate scientist cohorts) is that an El Nino coupled with existing GHG levels "may" kick up the heat (Global mean temperature) and the "runaway greenhouse effect" may kick in.

They don't actually say it, but they get awfully close to it:

http://www.bloomberg.com/news/2014-04-15...

It's even more laughable that they even try to implicate a runaway effect. Science already knows that is highly unlikely, but it doesn't stop Bloomberg from giving this press release. ROTFLMAO!!!!!

Bob Tisdale has three good posts on this topic. Here is the third one with links to the previous two near the end: http://bobtisdale.wordpress.com/2014/04/...

Kano asks an interesting question here:

https://answers.yahoo.com/question/index?qid=20140414193247AA5qe3t

...that alerts me to my less than precise understanding of historical El Nino and La Nina events and how they relate to more recent events. While I can google PDO calendars, I am looking for commentary and opinions about the impact of these events on global average temperatures and the significance of mankind's activities related to El Nino and La Nina events. Not to step on the secondary part of Kano's question and ask for replies here rather than in his question, but he asks if El Ninos and La Ninas should be "discounted in the temperature trend or included as part of AGW?"

I'm not sure if my request for commentary about mankind's influence on PDO gets any closer to the underlying matter that Kano seems to address in his secondary question but he seems to be suggesting that one of the issues he is seeing is whether El Nino and La Nina events are entirely natural events or being influenced by mankind, and therefore need to be accounted for in a certain way. My secondary question would be, from the standpoint of climate science, how is this considered?

While I remain neutral on most matters related to AGW and rarely ask questions, in part because sometimes it seems as if the answers should be self-evident to someone like me, in this particular instance I am asking for a little more guidance insofar as how these events fit into the bigger picture.