eddie

If we take the current Hadley figure then we need a daily average temperature of 16.8C+ to take us over the 69-90 average. I certainly wouldn't rule that out at this point. 17.9C required to beat the 1971-2000 average. Still possible but much less likely.

I can't think of any feedbacks that would stop all the sea ice from melting. Increased winter precipitation could perhaps slow down the melting of the polar ice cap itself. It will be interesting to see what effect all that extra open water will have on the weather patterns seen at such latitudes.

In my opinion people put far to much faith in the accuracy of current climate models. You just can not accurately model something you do not fully understand. In current climate models if a process isn't fully understood, and therefore can't be modelled based on an understanding of the actual physical processes involved, or is too complex to be modelled with current computing power then it is added to the model as a parameter. That parameter is essentially a number (or maybe a time series of numbers or whatever) that is made up to represent that process and fed into the model. That number is based on the best science available at the time. If the level of understanding of that science isn't great then neither is the accuracy of the number. Add in a load of these parameters and the scope for error is large. Since we have never seen (and I mean with accurate satellite measurements) the arctic melt before, our level understanding of how that happens and any feedback processes that might occur as a result is low. The same can probably be said for lots of other processes/cycles that affect climate such as ocean currents, El nino, solar variance, cosmic flux. These processes in climate model are really just a best guess. I really think the most accurate thing we can expect from climate models at the moment is 'The earth is going to get warmer if we release more CO2 and here is the range that the temperature could fall within'. When they start saying there is going to be X less rainfall in this region, Y more in this region, the antarctic ice will melt by Z it makes me laugh. Maybe in 10 or 20 years when the science and computing power has advanced considerably.

It does seem like every single factor needs to line up correctly to get a below average month these days. It would be lovely to come on to this forum and say 'Well given the synoptics that should have been an above average month but we came in 1C below'. It seems they invented the internet 30 years too late.

I should clarify my question really. What I should have asked is 'What is the optimum global tempererature for the human race?'. Temperatures obviously vary widely across the globe and seasons but there must be a global average temperature which gives the most ideal conditions in the most places. Are we at that temperature now or would a 1 or 2C drop be better (or even a 1C rise)? The second part of my question I was hoping would be answered with a more political slant. What might be a good global average temperature for one part of the planet might not be good for another (for example a temperature which gave more droughts in affrica might give better crop yields in the europe for example). If we could control the temperature of the earth then how could we decide what it shoud be?

These are things that I have always also wondered too. For example, if humans had suddenly stopped releasing greenhouse gases in 1900 then what would the temperatures profile of the 20th Century look like? I assume somebody must have already run this scenario through a climate model? What is the optimum temperature for the planet? If we had control over the global temperature then who would decide what it should be?

Back in early June I would have said there was 50% chance that we could see a year with every single month above average, we were getting above average months with what seemed like below average synoptics. That seems to be looking much less likely now. It looks like we are going to maintain the current CET of 15C, or perhaps a slight drop, until the 14th. It would then take a 2nd half CET of 17.8 to give us an above average month. I would say there is less than a 20% chance of an above average July now.

I voted option 2. I belive the IPCC are correct when they say that we are affecting the climate via GHG emissions but I am much less convinced they have got the numbers right. I just don't have enough faith in global climate models or the underlying assumption they use that climate is a completely unchaotic system and reacts to all external forcings (things like solar variation, cosmic rays etc.) in a similar unchaotic and linear way. I reckon that any future warming will not match what current Global Climate Models predict even if actual CO2 emission follow the one of the curves used in the various IPCC scenarios. (Although I suppose with the huge range of predictions from all the different models one of them will get somewhere close purely through chance.) This of course means that the future could be better or worse than predicted and doesn't change the fact we should do something to mitigate the effects of climate change.

Mild, dry and sunny is quite a tall order in winter. I would settle for dry.

The ice cap was still 0.5 - 1km less thick than it was today and sea levels were still 5 meters higher but it certainly is interesting research. If it takes a 5C increase to raise sea levels by 5 meters then perhaps we still have a chance to avert catastrophic sea level rises. I wonder if increased snow fall in the winter over the centre of the ice cap may have offset the summer melt somewhat?

Powerful telescopes aren't really required to count sunspots. In fact looking at the sun through a telescope is something you really really don't want to do. You just need a simple lense that can project the image of the sun on to a piece of paper. It's quite easy to count the spots.

When I went to Iceland there were loads of geothermal power stations. With so many active volcanoes I think it makes it a bit easier to get to the 'hot stuff' than it would be here though. Wind power is probably going to be the cheapest renewable energy source the UK has (I read somwhere we have 70% of Europe's wind power potential) but we will still need something for days when it's not that windy so perhaps geothermal power could fill that gap.

I don't think we will be able to reduce car ownership by enough to make much of a dent in CO2 emissions. Certainly not in the timescales required and when you factor in developing countries. I think the solution lies in cleaner cars rather than less cars. We need to build more wind, hydro electric, and nulcear power plants then everybody can drive clean electric cars.

A quick question for you oldies on here; before 1990 what was the basline against which temperatures were measured? Also, who chooses when these baseline periods get changed? When we get to 2011 will we start using the 1981 to 2010 mean or does this have to be decided by the 'mean' police?

I wouldn't want to move closer to my work because that would mean moving to a crap area that looks rubbish and has a high crime rate. When I do move house (hopefully later in the year) I will consider what public transport is available but it really won't be that hight up my list of 'things I want from my new house'. I did sell my 20mpg car and get a 40mpg car (That cost me thousands of pounds which I definitely won't recoup in fuel costs) and when this one finally breaks I will buy an even more economical one but that's really the limit of what I will do unless public transport is transformed. I would loose 1.5-2 hours from my day switching to the bus. If I work out how much I earn per hour then multiply that by 2 hours then that is how much more expensive per day driving would have to be for me to stop using my car.

I drive. It's about 12 miles and takes between 20 and 25 minutes.

Thanks for that Roger. Based on your research, when would expect the three cycles you mentioned to coincide again?

I thought I would resurrect this topic because it's one I find so facinating. The yearly CET for 1740 was 6.84C which is the coldest in the entire series. What I find even more amazing though is that this exceptionally cold year followed the 12th, 13th, 14th, 15th and 17th warmest 10 year periods recorded. It makes me wonder if we could still see the odd exceptional winter even despite global warming. What could produce such a cold year and massive change? I would love to see the synoptic and SST anomaly charts. Such a shame they didn't have satellites back then!

I'm going for 14.2C. I think June is going to be quite unsettled and rainy, like May, and with temperatures not far above the 1971-2000 Average.

The London scheme does seem to work and it also doesn't use satellite tracking. I certainly don't have anything against charging people to enter cities to cut congestion. It's really the surveillance that worries me. We also shouldn't forget that London has the best public transport system in the UK. The same cannot be said for other cities in the UK. As with all efforts to get people out of their cars there has to be an alternative or it just becomes another tax.

That's a good question! Firstly I think congestion and CO2 reduction need to be treated as two separate issues. If you look at how the road pricing is going to work, people who drive 100+ miles along the motorway to work could potentially pay less road tax than somebody who drives 5 miles on more congested roads. Over a year who emits more C02? I also have no faith whatsover that the government could possibly deliver an IT system so huge that it would dwarf anything that has gone before without cocking it up. Just look at how badly almost every single government IT project in the past few years has been implemented (Google "NHS IT problems"). I have no doubt that they would make 1000s of people lives miserable via incorrect charging and fines levied. Remember that this money will come straight out of your bank account when you drive and it would be down to YOU to prove you didn't make that 1000 mile journey around the centre of Manchester or wherever. I just think it's going to be horribly flawed and be of no benefit to reducing CO2 emissions.

This government seems determined to set up all the surveillence tools and laws that would be required for a dictator to keep absolute power with no chance of any resistance or protest should, god forbid, one manage to get into office. Detention without trial for 'terrorists', email snooping, the power for The Council to come and snoop around your home and now plans to track every move you make when you leave your door? Our civil liberties are being gradually eroded away and somehow they always seem to use the arguments that it is 'for our own benefit and safety' and 'if you are law abiding you have nothing to fear'. Well that just great but what happens when the colour of your skin, beliefs or religion suddenly become against the law and there is no way of hiding and no way of resisting without being discovered and locked away without trial? You are probably all now thinking I'm one of those people that wears a tinfoil hat to stop the mind rays but you don't have to look far back into history to see that bad people do get elected (Germany anyone?). How many Jews would be left now if Hitler had all the surveillence measures that we have in this country? I wish people would start to wake up and see that civil liberties are very hard to get back once they are taken away. This is one step too far.

That's quite a brave prediction given the warming we have seen recently! You have to go back to 1991 for a June colder that that.

You have to understand how incredibly rare C14 is. You just can't compare a doubing in the amount of C02 with a doubling of C14. If CO2 levels were at 380ppm then only 0.038% of the atmosphere would be C02. Now 0.038% sounds like a small number but in reality 0.038% of the atmosphere is a physically significant amount of gas that is measured in billions of tons. The total amount of C14 in the atmosphere is just a few tons. Even if you doubled it again there would just not enough of it about to have any physical effect on the atmosphere. The figure I gave of 138 meters in a year is a worse case, all the energy transferred to moving the earth in one direction scenario which simply wouldn't happen. I guess in reality you might move the earth a couple of meters a year but given that the distance from the earth to the sun varies by 500,000,000 meters each year anyway it's really a negligible amount. I imagine that coronal mass ejections and other miscellaneous stuff hitting the earth have a far bigger impact on our planet's orbit each year than any nuclear test. I will have a dig around and see if I can find any research about it though.

Wow did I really guess 9.9? June-Dec would all have to come in 1C below the 1971-2000 average for me to win now. I think a yearly CET of over 11C is looking very likely indeed.