Yet another collection of uniformed rants by idiots who can't tell the difference between climate and weather.

Global warming doesn't mean that everything stays the same but just a little bit warmer - it means more extreme weather variations.

Like snow in Spring for example.

The SBS program the other night on the recent extremely cold winters in the UK gave an example of the way in which warming can result in colder weather. The colder winters were due to movement of cold arctic air masses south over Europe and the UK. This was due to a slowing down of the northern jet stream, which caused big meanders in its route (rather than a fast straight path). A meander south over the UK dragged colder air further south.

So why did the jet stream slow? Two possible reasons(probably inter-related):
1) The warming of the arctic (clearly evidenced by recent extreme melting of arctic ice) means that the temperature gradient from the North Pole to Equator is less and since the temperature gradient is what gives energy to the jet stream, a decreased gradient means a slower jet stream means more meanders in the jet stream means colder air pulled further south within meanders.

2) Excessive rain in Indonesia (ie the equatorial island complex) which affects the circum-Pacific air flow which affects the northern jet stream etc.

This is an example of how 'climate' (long-term pattern) and 'weather' (short-term events) can be related. The slowing down of the jet stream is a result of increased arctic warming, but the resulting meanders will be randomly placed year to year - one might form over the UK bringing an exceptional cold winter this year, but affect somewhere else (or nowhere else) next year.

Re the statement ' no warming since 1998'..

I've always been dubious of a single figure for temperature for the whole world. Maybe it seemed like a good idea at the time to make a hugely complex situation easy for people and politicians to understand.

But it is based on averaging records from extremely different local situations and is dependent on adequate coverage of weather stations, and consistency of recording between stations both now and in the past. The recent furore about the ABM rejigging past records demonstrates the difficulties.

But consider the example of the extreme cold winters in the UK and Europe. I bet there are a lot more weather stations there than say, central Africa. We didn't hear much about what was happening in Central Africa when it was snowing in Britain. Was it a bit warmer there than previously (and how long are the weather records there)? Did those records cancel out the colder records from Europe for that period so the average world temperature was stable? Even though the colder weather in Europe can be attributed to warming in the arctic?

I conclude that debates back and forth about warming/no warming at a global level since 1998 are a waste of time. The atmospheric system is so complex that the effects of added CO2 are unlikely to be characterised by a single figure. In any case the world doesn't work on nice neat trend lines. What's more likely is stepped change - where one steady state jumps suddenly to another. So a run of (apparent) little warming may be followed by a jump to a new plateau.

'morning wobbles and Cossomby,

Since you have not read or understood the five extracts I posted from the IPCC AR5 WG 1 report, I again refer you to this report above.

You will note that the IPCC in each and every statement, disagrees with you on severe weather issues.

That leaves you in the unenviable position of being at odds with the IPCC. You could write to them to complain or seek a position on the WG 1. Alternatively you could accept that the story they once gave you has now been acknowledged as wrong and that you have been ditched by the IPCC.

If you want to be the ones telling the IPCC that they are bastards for giving you the bum steer in the first place, be my guest.

Please share any responses you get with OLO?

Spindoc: your quotes from the IPCC were about cyclones and droughts.

The SBS program I quoted dealt with neither of those but with observed changes in the route of the jet stream, from a straight trajectory to a meandering one, which brought polar air further south in the large meanders. There is a direct and observable physical cause of the meanders, a decrease in the temperature gradient from the pole to the equator.

The IPCC may be correct in the lack of a correlation between more intense cyclones and global warming - so far.

My comments on the issue of a single figure for world temperature are all my own work (based on a background in stats.)

I have endeavoured to avoid the emotion involved in both pro- and anti- global warming camps (which you demonstrate) and just consider some aspects that I can analyse myself.

Even with a couple of degrees in science, it's impossible to take on board all the evidence and arguments without doing a huge amount of reading, and indeed research, but I do recognise just how immensely complicated the research is.

I guess it would be easier to be a layperson and just cherry-pick items to support pre-conceived views, either pro- or ante-.

I'm currently open-minded but there do seem to be a couple of evidence based events that are occurring - the warming of the arctic polar region, and the general decline of glaciers. (and yes, it is quite possible to have a warmer Arctic and increased Antarctic sea ice - but I don't need to explain that, there's plenty of info on line).