I will pick you up on one point, I don't think that understanding of the role of greenhouse gases in the atmosphere means that nothing else affects climate. They are going to be dominant on the timescale of a century or several decades but there are lots of processes that also alter regional and global climate on all timescales. These tend to be dominant over months and years up to say a decade.

Isn't that the point of the debate? Everyone now accepts that there are a whole host of climate drivers. There are some disagreements about what some of those are, but the biggest disagreements are over just how much influence any one driver has, the main bone of contention being whether CO2 is the major driver at present or if there is something else going on (solar variation seeming to be a main contender).

As I said, looking at the figures for CO2 I can see why the pro-AGW lobby are so concerned about it, and if they are correct about its effects on climate we are pretty much doomed because there is no way China is going to slow down, stop or reverse its massive coal-burning power station building programme (10 a week going up at one stage weren't there?)

It's all a bit lot worrying and I can see why so many people don;t want it to be true. I don;t want it to be true either.... but that is why I need to find out the answers to my questions. I never just accept what I'm told.

Another way to think about this is to remember that all of the natural cycles have been impacting climate for millenia and, to a reasonable extent, their effects can be demonstrated.  What is different now is that we are changing one of the key parameters (i.e. GHGs).  You may have seen my question elsewhere in this Forum as regards the sensitivity of the climate system to CO2 increases.   There seems to be a reasonable case that quite small changes in solar output have disproportionate effects on our climate system - IIRC the variation in solar is less than 0.5% between peak and trough.  In which case increasing CO2 by ca. 0.5% every year must be taking a risk with the climate system: it is a mistake to assume that the relationships are linear.  Sceptics tend to react to suggestions of tipping points or step changes but it is a fact of the natural world and IMHO we are tampering with a complex system without understanding the potential effects.

As for your comment about China, might I ask you to think about why has increased it's GHG emissions so much in the last 10-20 years?  Have a look at all the goods you buy and see where they are made.  We are responsible for a significant proportion of those emissions because we buy their manufactured goods. 

Sadly your comment "we are pretty much doomed" is about right.  It will require a complete re-engineering of our entire socio-economic systems and our assumptions about how we live on this planet - and that isn't going to happen pro-actively.  It will happen in response to any changes we inflict on our planet - whether that be climate change or wholesale degradation of the eco-system through pollution and loss of species.

However, I would suggest that the sun has to be our major climate driver - after all, it is our distance from the sun that enables the planet to have the life-sustaining temperatures it has in the first place. 0.5% variance of solar radiation could conceivably be a far bigger influence than 0.5% variance in the levels of a gas that only makes up, what, 0.04% of the atmosphere? I am not saying that is the case, but you can see how it looks to a great many people.

Of course, to put it in perspective you could start telling people exactly how big a flu virus is. They might realise, then, that tiny things can have a huge effect....

I like the last comment - I'll remember that one, thanks.   We had that discussion here some time back, i.e. how can something that is only ca 390 parts per million matter.....

As for your opening point, then yes clearly the sun is the major climate driver.  But this plays back to the previous point - the sun is a constant plus or minus 0.5%.  What has adding, so far, 110 parts per million, or 40%, to CO2 levels done to the balance in the system.  The issue is how this is manifesting itself and how that effect is measurable above the noise of the underlying climate variability. 

Yep the +- 0.5% solar would completely dwarf a +-0.5% change in CO2, but as Gandalf notes CO2 is 40% higher now than pre-industrial revolution.

I would think that the thing about natural cycles is that, with the exception of Milankovic cycles and things of that timescale, they oscillate on timescales long enough to affect "climate" trends (as Tom noted) but not long enough to actually change the direction of climate change, which was a fairly steady cooling over the last 6000 years (bar some up and down bumps eg MWP/LIA). I put climate in quote marks because our arbitrary definition of 30 years is short enough that the trend over that period could be affected by whatever natural cycles are doing.

I think the problem is that addition greenhouse forcing, caused by humans, is for life and beyond and not just for Christmas. If natural cycles conspire to cool the next 20 years, what happens when they conspire to warm the 20 after that, plus all the additional greenhouse warming?

Well then we are back to proportionality and timing.

If any AGW effect is only a very small proportion of natural variability then for at least 200 years all we will see is a very slight elevation of temperature throughout the natural cycle and since cold is worse for us than warmth the net outcome will be beneficial.

Then there is the issue as to what the practical effect of a slightly warmer world really is. If the only effect is to shift the jets a bit then absolute global temperature isn't of much significance anyway.

As we can see now, climate changes in specific regions arise primarily from changes in the air circulation above rather than from a change in absolute global temperature. The effect of the former is far far greater than the effect of the latter.

Since the natural air circulation changes are so big anyway any human effect is pretty insignificant and a tiny incremental change is unlikely to activate any tipping points when one bears in mind that the natural air circulation adjustments are so much greater anyway. Such adjustments are always negative to any forcing trend whether towards warming or cooling which is why the system is stable enough for the Earth to have retained liquid oceans for billions of years.

The UN estimates for global population stability (and then decline) have been brought forward to the mid 21st century because prosperous peoples always reproduce at slower than replacement rate so soon enough the population issue will go away of it's own accord. A managed decline in global population over the next 500 years is the most likely scenario.

That then just leaves resource and pollution pressure but technology and a free world can deal with that better than centrally directed authoritarianism would with its energy rationing via an artifically inflated global pricing mechanism.

If one looks back 200 years the technological changes have been incredible and the pace of it keeps quickening.

If we have more trhan 200 years without a significant human induced climate effect then the whole AGW scare is an irrelevant and dangerous distraction which could actually delay our progress towards a long term sustainable relationship with the world.

Just compare Soviet style tower blocks to the leafy suburbs around London to see what authoritarian solutions lead to.

And compare the potentially permanently damaged industrial regions of China to the reclaimed coal spoil heaps of South Wales or the English Potteries where the first industrialisation occurred.

We really do not need the panicky behaviour of environmentalism with its lack of belief in humanity's ability to progress in a positive direction.

History has already proved them wrong in their pessimism time and time again.

Free and prosperous peoples always do the right thing eventually. We and the planet are as one. We are part of Gaia. We can only be free and prosperous with cheap energy however derived.

Let Earth's people be free subject only to a minimal level of top down regulation to prevent a limited range of short term abuses of the environment.

AGW's impacts may 'appear small' thus far but if you spotted a crack in a dam you wouldn't discount it would you? The inertia in the climate system is another 'unknown' (just like the feedbacks?) but we know to expect it. Once the 'inertia' is overcome then change (IMHO) will be rapid.

Are we not seeing such 'extremes' over the past 7 years? In the area we are told to look for the greatest 'extremes' (the Arctic) do we not see those extremes even greater?

Stephen, rather than re-typing chunks of your post I will respond in bold against each as necessary:

http://www.sciencedaily.com/releases/2011/02/110216132100.htm

Another 'oh dear' moment? Seems we're goosed if we stop emmisions right now (even without the imputs from the permafrost) but when we add in what nature has in store for us....well....

It appears that a certain amount of warming is now 'locked in', but that should not be used as an excuse for inaction. By taking collective and immediate action (unlikely to happen) we could still reduce the magnitude of the warming.

I recall having my comments rubbished by the usual suspects when I suggested that there were risks that the outlook could be worse than the IPCC predictions because positive feedbacks were as likely as negative ones.

This is the second time this week I have seen reference to the effects of melting permafrost and similar risks. I had always thought that the deposits locked up at the bottom of the oceans were safe until temperatures had risen significantly but I hadn't considered shallow oceans where quite modest warming may penetrate to the ocean floor.

I've had 'ding dong's' with folk purporting to be actively researching the clathrates and their 'release'. The deep deposits have both temp and pressure in their favour and so you'd need a mechanical reason to destabilise them (landslides down the continental shelf promoted by earthquakes/tsunamis).

When I mention the ones in the shallow shelf sea off Siberia it generally falls a little silent and the conversation is dragged back to the continental shelf (generally at the edge of delta's like the Nile or Amazon) and the shallow shelf sea permafrosts/clathrites are ignored .

 To me this means the rush to study the losses now occuring along the Siberian coast are 'off the table' for folk seeking to reassure folk that our methane hydrates are beyond the reach of global warming...

As it is bubbling to the surface over a wide area I'm not sure how, but it would certainly be preferable to leaving it to escape into the air.

As I understand it methane, although around 20-25 times more potent than CO2,  turns into CO2 (plus water) in the atmosphere over time.

I know but just look where we are heading. 

Titanic

Deckchairs

And the band played on

http://www.youtube.com/watch?v=2J6RvaesGCM

It seems we are there already.
We're doomed captain.

Doomed.

(Saxon brings back memories.)

I do not believe this is your nature.

Things are improving and will continue to do so,out of neccessity.

We can mine methane clathrates but certainly this would only be done in areas where it is economically viable. Mining and burning the methane as a fossil fuel would be preferable to letting it escape into the atmosphere as methane is the more potent GHG, as noted in this thread. This is one reason that gas is burnt off when it comes up with oil on rigs. Of course the folly of that plan is that the gas is pretty useful, but it was actually cheaper for the oil companies to burn it than to process and transport it for sale! Hopefully that is changing as gas becomes a more valuable commodity.

However I think it might be best to leave the clathrates where they are and implement other measures to try and keep global warming to a minimum.

BTW I seem to recall the timescale for methane breakdown into CO2 + water is something like 7-10 years.

Something to look at.

Stu, I read somewhere that Methane has a half-life of 7 years, so 50% after 7 years, 75% after 14 years etc.

Sorry, AIMSIR, I am indeed inclined to that view.

We are doing nothing absolutely nothing meaningful to reduce GHG emissions.  To do so requires dramatic changes to the way we live and consume on this planet.  The problem we have created so far has been created by a relatively small proportion of the global population.  With time more of that population is becoming wealthier and producing more GHGs.  With each passing year we are adding more heads to the population, further exacerbating the problem.

Things will only improve in response to a major crisis, whatever form that takes.  My bet on the likely candidate is, as stated elsewhere declining crop yields caused by more variable and extreme weather and declining water supplies in key areas. 

I expect to see new record global temperatures being set this decade and increasingly hard evidence that the climate is being destabilised. 

The $64,000 question is how much bad news there has to be before everyone accepts that it is happening and accepts the increasingly urgent and significant measures needed. Which leads to your final sentence - yes, things will improve out of necessity.  But it might be analogous to trying to bale water out of a sinking boat with a teaspoon....

(Chin up and straighten those shoulders old chap)

There are great strides being made into alternatives these days.agw or not.

Necessity is the mother of invention.