1. Global warming is not the same thing as climate change. The increasing concentration of atmospheric CO2 and other greenhouse gases causes the Earth as a whole to retain more heat. That's global warming. Climate change is mostly a *consequence* of global warming; climate change is not the principal cause of global warming and it's not the same thing as global warming.

2. Another way of saying "the Earth as a whole retains more heat" is "the overall average temperature of the Earth's oceans and atmosphere increases". But this does *not* mean that all of the atmosphere and all of the oceans are everywhere getting warmer all of the time. There are local variations, and variations which can last for years. La Nina is one example. La Nina temporarily exposes cold deep ocean water which absorbs much of the global warming heat that would otherwise go into the atmosphere. This temporarily slows or stops the temperature rise of the atmosphere. When La Nina stops, the flow of heat into the deep ocean slows down, and heating of the atmosphere resumes. Lay people commonly think that atmospheric temperature increase is the only signal of global warming, so when global average atmospheric temperature holds steady or drops they mistake it as a sign that global warming has stopped or that it never existed.

(Obviously this leaves out a lot of detail. An ounce of imprecision saves a ton of explanation.)

bobclive, there's a great summary of the relationship between warming and El Nino in this RealClimate post (see the last 3 paragraphs, plus this follow-up post). So you're right that this is still an area of really active research. However, note that the question is how El Nino responds to warming, not to CO2.

Changes in the last couple of decades have caused the frequency of El Nino to increase (now coming every two years instead of the average rate of 7 years as in the past) and the La Nina phenomena has almost DISAPPEARED,this same time period also corresponds to a RISE in global temperatures of 0.5C in the last three decades.

It is suggested that these are a periodic oscillation related to the oceanic distribution of tropical heat. Although a significant natural influence on interannual weather, the temperature effects of the cycle smooth out over years and decades, that might have been the case when they occurred about every 7 years prior to the 1970`s, but not when they occur every TWO years as there is very little time for the temperature to normalise over that short period.

The Met Office Hadley Centre Coupled4 Model (HadCM2) has suggested than an increase in carbon dioxide in the atmosphere will indeed increase the frequency and intensity of El Niños. However, the third version of that model (HadCM3) does NOT show this; it predicts LITTLE or NO change in how El Niños occur.

It appears CO2 is NOT the cause.

Your comment on 'the human signal is emerging from the natural noise' is absolutely right, but the main media organizations are playing it like humans are the ONLY cause of the warming when in fact we are not the only cause. The media ignores facts like La Nina for instance and also ignores severe weather events of the past 100 years, always implying that severe weather today has never happened before, or saying that Hurrican Katrina 'proves' global warming, when in fact (according to the National Hurricane Center), Katrina was only a cat 3 when it hit New Orleans and there were numerous more powerful hurricanes in the past 100 years, including the cat 4 Galveston storm of 1900. We have to look at the big picture for sure, but past weather events have to be included in that discussion, as well as short-term cooling caused by La Nina.

I think Nature will always play a role in climate change, in feedbacks, positive or negative. We don't know all the answers yet and that's why billions are still spent on climate research even though according to some, the 'debate is over'. Research and debate is never over in science.

If EDF's more scientifically oriented news and articles would make the national network news, such as your comments above, instead of the blatant alarmism that so many in the media hype, we'd be much farther along in getting the needed caps on emissions that we should impose. Alarmism tends to cause bad short-term policy, like the corn-based ethanol fiasco, which is actually causing MORE global warming, not less (see this weeks' TIME magazine, for instance).

Sorry about the long rant, but I feel strongly about telling people ALL the facts of climate change, including the temporary La Nina cooling effect and the fact that we've had stormy weather, including heat waves, in the past, not just today.

It's important to keep time scales in mind. Short-term variation (a couple of years), both up and down, is normal. But the longer term trend (over decades) is clearly up. That upward trend is the influence of all the extra greenhouse gases we're producing – the human signal is emerging from the natural noise.

http://news.bbc.co.uk/2/hi/science/nature/7329799.stm

The UN WMO goes on to state that they forecast a new record warm year will be observed within 5 years.

My question and concern regarding this is why the IPCC and the papers they reviewed didn't take these natural ocean warm and cool periods into account? Or did they? I'm sure the public is getting more confused all the time since the media has been saying over and over that the planet is warming, all caused my humans. Now a natural force, La Nina, comes along and slows this warming, so in many people's mind this means that humans may not be playing as big a role in climate change as has been hyped.

It is a waste of critical time to sit around denying the validity of global warming or thinking that we can't have an effect as individuals and must wait on our governments to take action or blame the business world for causing the problem. They will follow us where we go since we are their bread and butter. The actions of one individual combined with the actions of many other individuals will be revolutionary in its effect.