Hi all,

Hoping Christmas was kind and of good cheer for you all.

I have only just sat down to start viewing the rest of David Archer's lectures my next being number 22.

I spent part of Christmas eve discussing cloud base heights with a pilot who was convinced temperature not pressure was the driver for condensation. With my new found knowledge I was able to beg to differ and he finally conceded the point. If nothing else David has provided the opportunity for one-up-man-ship over a few beers, always satisfying.

As much as these lectures have informed me I, like I suspect many others, ultimately take the perspective from which we view the GW predictions by what is happening locally.

We are told that the earth has cooled over the last few years however early this year my state of Victoria had numerous maximum temperature records tumble.

Now three days ago two towns to my north, Swan Hill and Bendigo eclipsed their December overnight minimums by 5 degrees. That bears repeating, 5 bloody degrees. Another three also broke records.

In the face of these there is no way I can be complacent about the issue and have got to the point where I need good solid reasons why CO2 is not the driver of temperature increases to shift my thinking.

If these records turn out to be a statistical blimp then well and good but to say no action is needed I think is taking a very optimistic view. But for now I am being presented with a well researched, scientifically supported, peer reviewed argument of why I should be concerned, and I am.

csteele,

I agree, that was my conclusion too. I think it's time we as a species started to look at the way we do things.

Some of the reading I've been doing of late is into Nuke power. However, Common reasoning there seems to be a worry too they're advocating big reactor technology that requires lots of fresh water. Indicating that we need to build them near permanent water... Given the predictions re water shortages, rising sea levels, storm surges, wild weather etc. cynically, I would ask where would that be exactly?

Add to that we are still going to have additional waste to deal with be it nuke waste or radioactive dead bits of a reactor.

But anyway at least maybe Santa will be grounded because of the polluting vapour trails and rein deer poo on every roof...I did leave some big "doggy bags" on the roof this year. Have a good one. Cheers

csteele, you're confusing climate and weather.

In the first place we have good Australian temperature records going back in most cases less than 60 years. So "records" aren't particularly compelling evidence of anything in that context because your dataset is not significant.

But anyway you have to look at the magnitude. How does a +0.6 degree maximum increase in global temperature translate into +5.0 degree increase? What you experienced was an unusual weather pattern that channelled hot air from the interior into your area over a prolonged period. Which is what caused your temperature record. It's probably just averagely hot at the source of your hot air.

But even if it was a global phenomenon (which it isn't this year) it is a non-sequitur to go from that to saying the reason for the temperature increase had to be CO2. Why not any of a number of other potential forcings, including ones that are known, such as the fact that solar activity has been higher in the late 20th Century than for quite some time, or ones that haven't been discovered yet?

We know that it has been hotter in the last 10,000 years than now. The fact that CO2 could not be implicated then suggests that the "only CO2" thesis is negatived. Which doesn't mean CO2 doesn't play a part.

Dear GrahamY,

I will be the first to acknowledge the weather patterns over Victoria have me a little spooked.

Even after examining the evidence I initially took some of the climate change predictions with a grain of salt but over the last decade the change in weather has continued to tick the required boxes in my state for me to give them some real credence.

When you lose a large number of your fellow Victorians in weather conditions that exceeded what I experienced during Ash Wednesday a certain focussing of the mind occurs.

This decade has been quite warm in itself and for some December overnight minimums to exceed previous records by 5 degrees certainly got my antenna twitching. I'm afraid I can not dismiss it as easily as you seem to be able to do. One or two degrees maybe but by FIVE?

We seem to have taken different paths on the issue since by your own admission you have become less concerned about the possible impacts of rising CO2 and temperatures while I have become more so. It is part of the reason for me doing more research.

I have been recently playing with some of the Cape Otway Lighthouse temperature figures. My area of interest is overnight minimum temps as I see them as less solar dictated than maximums. These records go back nearly 130 years and from the location would have little to no urban heat effect.

It can be found through this link.

http://www.bom.gov.au/climate/data/weather-data.shtml

Just type in Apollo Bay and it will come up in the selections. Try running the min temps and graph them off.

I find the data both 'significant' and 'compelling'.

I am more than willing to explore other potential forcings and had looked at solar activity earlier but was not particularly convinced. If you have a link or two I could examine I would be interested.

C, this is the graph for the one you are looking at http://tinyurl.com/yjxepey. Doesn't look too alarming to me. But I'm also not sure why you would prefer it to the mean maximum, which is http://tinyurl.com/yzkk7kk and shows a sharp decline in temperature since the end of the 19th Century. This graph of highest temperature is also interesting http://tinyurl.com/yzkf749. I've used excel to fit a trend line to the mean max data and it is down since the 1800s, and even since the beginning of the 20th C.

This seems to be the pattern with a lot of the long-term remote weather stations in Australia, and is a measurement issue which further clouds the issue of correlation in climate science. Suggests that the Urban Heat Island effect is not properly corrected for.

As for solar forcings Plimer's book gathers together a lot of references to papers which support solar forcings and I'm happy to trawl the footnotes when I get a chance and give you some references, but I want to finish the book first. The sun has to be the only source of global warming, so most of what we experience has to be solar driven. Which makes me wonder again why you would be trying to eliminate it by choosing minimum temperatures (although you can't eliminate it anyway).

While I'm finishing Plimer you could check out Svensmark's work, which provides an amplification mechanism for solar forcings. Although as it depends on clouds and Plimer also points out that there has been warming on other planets lately, there are probably other mechanisms at work as well.

C, just doing my morning reading. Another mechanism for amplifying solar activity http://insciences.org/article.php?article_id=8012. This one relies on cosmic rays and their effect on ozone. The amount of cosmic rays reaching the earth is affected by solar winds. Come across anything else new I'll lob it in here.