Graeme M,

"...whether that matters depends on the extent to which CO2 has any effect on climate..."

http://www.academia.edu/1026105/The_significance_of_an_Early_Jurassic_Toarcian_carbon-isotope_excursion_in_Haida_Gwaii_Queen_Charlotte_Islands_British_Columbia_Canada

The above is beyond my limited knowledge for the most part, but I can glean some information...

"...Outgassing of volcanogenic CO2 from this eruption stated a prolonged period of global warming...that subsequently destabilised and released -5000Gt of methane hydrate from continental shelf sediments..."

Now before anybody jumps down my throat and accuses me of forecasting near-term catastrophe, I'm merely pointing out possible scenarios and processes over the "longer term" regarding climate.

Thanks for the lesson Robert. You're so good to me.

Just a few things you might like to amplify on in the next lesson. Are there only positive feedbacks from the melting? For example, if (and its a BIG if) the ocean temps rise at any measurable rate due to this far off Arctic melt, wouldn't that lead to more evaporation? Wouldn't that lead to more cloud? Wouldn't those cloud do the same job as the sea ice in reflecting the sunlight? Maybe they'd do a better job? Maybe they'd be like a negative feedback or don't such things exist in your version of the global climate system? Quite complex isn't it? Much more complex than the knee-jerk "melting is bad".

Oh, and if this arctic melt heats the oceans in summer, then wouldn't the winter re-icing re-extract that heat?

Oh, and talking of negative feedbacks, if the oceans were to heat somewhat due to the melting ice, would that lead to more evaporation and precipitation over the Antarctic where the snow would be sequestrated. Maybe that's why the loss of ice in the arctic is being offset by the gaining of ice in the Antarctic?

Wow this really is very complex. I can see your going to have to give me lots more lessons.

Of coarse, its very difficult to be definitive about clouds since, as Freeman Dyson said recently, the climate models are hopelessly bad a modeling them. My theory is that, since they are almost certainly negative feedback items, most of the consensus aren't interested in studying them.

But you already knew that, I'm sure.

mhaze,

"...Wouldn't those cloud do the same job as the sea ice in reflecting the sunlight?. Maybe they'd do a better job?..."

Yeah, unless they happen to be very thin low-lying clouds which let the sun through, but trap the heat near the surface.....which is what may have happened to Greenland last year.

http://www.noaanews.noaa.gov/stories2013/20130403_greenlandicemelt.html

Climate is such a complicated doohickey.

But pumping CO2 at the rate we are into the atmosphere is like setting the table for the Mad Hatter's Tea Party...(lets hope the invitations go astray:)

Poirot,

Yes its very true that clouds can be both positive and negative feeedback mediums due to all sorts of things like their height, thickness and/or colour. What is very poorly known is the extent of this and what conditions cause them to be one and not the other.

Increasingly, science is coming to realise that clouds are a much more important element in the climate than the models allow. Apparently the next IPCC report will accept that we know very little about these feedbacks, their extent and even their overall sign ie negative feedbacks may outweigh positive.

In the past, models treated clouds as a static item in the climate and didn't allow for the possibility that they change as temperatures change. But as the models have improved their handling of clouds (and this is only a small improvement) we have found that the predictions of warming has declined. So, as the models better handle clouds, they predict less warming.

" pumping CO2 at the rate we are into the atmosphere is like setting the table for the Mad Hatter's Tea Party.."

Previously, you mentioned a disaster that occurred in the Jurassic. At that time CO2 were at around 2500ppm. We are now at 400ppm and have centuries before we get anywhere near those levels. Since we started pumping all that CO2 in around 1850 we've increased the CO2 levels from 280ppm to 390ppm in a century and a half. We MIGHT get to 560ppm by 2100 but its doubtful. Think of it like this. Say you had 10000 smarties in a jar of which 3 are blue and the rest red. In 160yrs we've changed one of those red smarties to a blue one.

The amount of CO2 we are putting out is only of potential concern if the feedbacks are strongly positive. And we don't even know if they are positive at all.

Time to chill...if you'll forgive the expression.

MHaze,
<<Since we started pumping all that CO2 in around 1850 we've increased the CO2 levels from 280ppm to 390ppm in a century and a half. We MIGHT get to 560ppm by 2100 but its doubtful. Think of it like this. Say you had 10000 smarties in a jar of which 3 are blue and the rest red. In 160yrs we've changed one of those red smarties to a blue one.>>

LOL

They don’t like to hear such common-sense approaches. Besides the warmists are colour blind they can only see the blue ones.

Here's an epoch more similar to our own.

http://en.wikipedia.org/wiki/Pliocene_climate

http://en.wikipedia.org/wiki/File:Pliocene_megabiome.png

The more I read, the more I realise just how complex are the systems (astronomical, geological, biological, meteorological, etc) which drive climate on the planet....(actually now wishing I was a geologist :)

Btw, SPQR, which colour "smartie" are you?