Is there any combination of 'natural' events that can be shown to be a better explanation than the AGW theory?

No, there's not. Let's examine the possible culprits:

Solar activity has remained unchanged on average for over 50 years.

http://www.mps.mpg.de/images/projekte/sun-climate/...

According to the Milankovitch cycles, the planet should be slowly cooling.

Natural oscillations like PDO, NAO, AO, etc. are exactly that - oscillations. They have no impact on global temperatures over the long-term. The PDO for example has had one positive and one negative cycle over the past 50 years.

Galactic cosmic rays have been shown to have little impact on cloud formation. There has also been no long-term trend in galactic cosmic ray flux on Earth, or in solar magnetic field strength.

http://www.ecohuddle.com/wiki/global-warming-and-c...

Cloudcover also has essentially no long-term trend. If anything it's increased over the past 50 years, which would cause cooling.

http://meteora.ucsd.edu/~jnorris/presentations/Cal...

As for CO2, it has the dominant radiative forcing right now. The amount in the atmosphere has increased 40% over the past 150 years, which can be traced to human activity through isotopic analysis. There are several key fingerprints of an enhanced greenhouse effect such as a cooling upper atmosphere, greater warming at the highest latitudes, greater warming at night than day and during winter than summer, etc.

If we were keeping score, it would be AGW: 100, Natural: 0. Believing global warming is being caused by some magical natural cycle which nobody can seem to identify requires a massive leap of blind faith. I'll take the scientific evidence, thank you very much.

*edit* Dent says "Go ahead give me a thumbs down and tell me why I'm wrong."

Okay, since you asked. You claim "In summary, I point to the sun as the leading cause of our insignificant warming." In summary of what? You presented zero evidence to support that claim, other than a graph of sunspot number, which has remained flat over the past 50 years.

http://solar-center.stanford.edu/sun-on-earth/600p...

You then fail to distinguish between climate and weather, and make a false claim about cloud formation. You ask "why could the models not see the cooler weather of the past 2 years?". 2009 was the second-hottest year on record.

That's where you're wrong. I also gave you a thumbs-down as requested. You're welcome.

*edit 2* What on Earth are you talking about, Dent? There was no peak in 1998 - not even of the 11-year solar cycle. Those peaks were in 1991 and 2002.

http://www.acrim.com/RESULTS/Earth%20Observatory/e...

I showed you the data, sunspot number has not increased in over 50 years. If you want to deny that, it's your own problem. That's why you're a denier.

http://en.wikipedia.org/wiki/File:Sunspot_Numbers....

http://en.wikipedia.org/wiki/File:Holocene_Tempera...

The first graph only goes back 400 years. But you will notice that it syncs with the second graph.

The second graph, is that of the Holocene epoch, which we are currently in. We are at the far left of it. Just 1500 years ago, it was as warm as it is today. 4000-7000 years ago, it was much warmer. As you can see, temperatures are not rising anymore dramatically than they have in the past. The global temperature is always in flux.

Your reference to Milankovitch cycles is trivial. And if AGW is keeping us out of an ice age, then more power to us!

http://en.wikipedia.org/wiki/File:Solar_Activity_P...

Another graph showing a rise in sunspot activity, which correlates with increasing temperatures.

Co2 concentrations have increased by 36% since 1832. Has the global temperature risen by 36%?

http://en.wikipedia.org/wiki/File:Instrumental_Tem... You be the judge.

In summary, I point to the sun as the leading cause of our insignificant warming.

Now on to your future consequenses. Computer models are used to forecast the weather, right? They are barely accurate over a span of 5 days. How can they possibly be accurate over 100 years?

Short range versus long range, yeah I heard it before. Then why could the models not see the cooler weather of the past 2 years, 10 years ago?

Cloud formation

AGW climate modelers for some reason assume that the clouds will fractionate. They give no reason for building their models like this.

Go ahead give me a thumbs down and tell me why I'm wrong.

Who is the denier now, Dana? Sunspot activity has increased over the past century, with a solar peak in 98'. Hmmm, 98' seems signifigant some how. Ah yes, the hottest year ever, in the past 100 years or so...

There are any number of natural events that can affect the climate, what deniers either forget of just don't know is that many of the same scientists who discovered or developed much of our knowledge on these are the same scientists who also worked out much of the GW theory.

We know with a high level of precision the Suns activity (for instance) for the last 35 years, this is how we know that Solar activity has certainly had little effect on the warming seen over that period.

Over much longer periods 10s of millions of years continental drift plays a fair part in long term climate change with much larger landmasses or no landmasses over Antarctica or the Arctic meaning much larger glaciers or only sea ice, having a marked effect on global climate. Some deniers try to talk about billions of years ago this is absolutely irrelevant given several different major variables being totally different like Solar output, atmospheric content and Biomass.

I won't attempt to improve on the other excellent answers, I just want to pick up on one thing.

BravoZulu resurrects the discredited argument that extra CO2 can't make a difference, because it absorbs everything that it can in the first few tens of metres above the ground anyway. This argument shows a total misunderstanding of the physics of grey body radiation, and has been repudiated many times, all the way back to the 1959 Scientific American article that was one of the first to publicise the greenhouse gas issue. For fuller details, and a discussion of how the science has held up over the past more than 50 years, see

http://www.scientificamerican.com/article.cfm?id=c...

That's

http://www.scientificamerican.com/

article.cfm?id=carbon-dioxid

e-and-climate

YES. There have been five Ice Ages from which the earth recovered. Therefore GW has occurred five times in the past, and can be proved that man did not cause this GW, because man was not around for the first four and only cave man was around for the last. How can we say that man is causing GW now when it has happened five times in the past and man was not the cause. It is due to natural processes that we do not fully understand.

Every other known forcing mechanism has been examined. It is only after all other possible explanations have been accounted for that AGW emerges as a significant factor. The observed behavior in the earth's climate is not accounted for by the other "natural" events.

=====

Meadow F --

Ed Cook is not at CRU. He works at LDEO, where he has been the entire time I have known him (> 20 years). All that quote shows is that uncertainty is as much a part of science as it is real life - and that Ed is a smart and funny guy who speaks his mind.

So all you have shown is your own biased and careless research (based on the prejudiced cherry-picking of political activists), and ignorance of the subject matter and the epistemology of human knowledge.

CO2 is a greenhouse gas and if you believe the third grade level "science" of algore, it is a layer that is getting thicker. That infantile explanation is intentionally deceptive to non scientists. Reality is ignored by alarmist who are pushing an agenda and only see what they want to see. The reality is that CO2 only absorbs narrow bands that account for at most 8 percent of the thermal bandwidth. Most of the heat is absorbed in the first 10 meters and all of the radiation from the ground, which is what greenhouse warming is, is absorbed in the first few hundred meters. The only difference you get from increasing the level of CO2 is by reducing the distance that it absorbs to extinction all the frequencies it can. That is mitigated by Beer's law and especially convection which might reduce it to the point of complete irrelevance. Alarmists like to claim that the increased warmth will make more humidity and that will raise the temperature. That is actually idiotic because it pretends that warming from CO2 is different than warming from water vapor where there is obviously feedback mechanism in the form of clouds or other factors that prevent a run away warming from water vapor. Then they try to claim that CO2 reflect warmth. That doesn't matter in the slightest when it is absorbed to extinction as simple common sense would indicate. The only difference is slight warming from the compression of where it is absorbed to extinction. That is obviously far less than natural warming and cooling that happens all the time to the climate. The boring fact is there no evidence or rational theory supporting anything but a minor increase from humans but that doesn't mean it will be warmer in the future. It only means that it might be slightly warmer than it would have been. Anything else is irrational anti-scientific propaganda.

Nope.

Graphical illustration first, then the details. Black is the observed temperature, blue is what you'd predict using natural factors, pink is what happens when manmade factors are included. One of MANY proofs that cause the vast majority of scientists to agree this is mostly caused by us.

http://www.windows.ucar.edu/earth/climate/images/i...

One detailed scientific paper on exactly this point here (and, there are many others):

Meehl, G.A., W.M. Washington, C.A. Ammann, J.M. Arblaster, T.M.L. Wigleym and C. Tebaldi (2004). "Combinations of Natural and Anthropogenic Forcings in Twentieth-Century Climate". Journal of Climate 17: 3721-3727

"...then isn't there an obvious explanation? ... that the increase in CO2 is causing the warming?"

Well no. It's only an hypothesis......

and only time will tell how good a fit it is to reality.

"Is there any combination of 'natural' events that can be shown to be a better explanation than the AGW theory?"

no, unfortunately. we can see the anthropogenic actions taking over from natural events around the middle of the last century in this graph;

http://www.mps.mpg.de/images/projekte/sun-climate/...

its all in here;

http://svs.gsfc.nasa.gov/stories/greenhouse_200201...

"what is wrong with the AGW theory?"

the main areas of uncertainty are now the other way; action of soot, masking effect of ocean currents and decadal weather patterns, sudden non linear feedbacks (sorry cant not mention them)

"Nature has singled out four areas — regional climate forecasts, precipitation forecasts, aerosols and palaeoclimate data — that some say deserve greater open discussion, both within scientific circles and in the public sphere."

http://www.nature.com/news/2010/100120/full/463284...