Been very busy of late and just spotted the thread has gone wild.
Rojo and Bio still talking bollocks – so no change there then.
This is bad, even by your disingenuous standards Rojo.
Which 'Peer Reviewed' journal published this graph? Even Michael Mann would be embarrassed to put this forward.
The 'Little Ice Age' has gone.
The 'Medieval Warm Period' has gone.
Have I been wrong these last few years?
A number of people have been emphasizing that changes in climate are not new – indeed they are the norm.
Quite true. The temperature of the Earth has remained stable for 4 billion years. It's only the last 14 years that it's changed in any way.
The climate has changed up and down many times before we arrived. It will change up and down many times after we have been well gone.
So - humans are fragile. The climate has changed many times without any human intervention. For billions of years, in fact.
Is it too simplistic of me to butt in here and say i think its scaremongering on a mass scale.
The fact that 'Climate Change' is nothing 'new'. It's been going for billions of years. It's been cooler than it is now. It's been warmer than it is now. When we're gone we know that it'll be cooler than it is now. We know it'll be warmer than it is now.
Trying to pretend that 'Change' is happening has always been ludicrous because the temperate, current climate for the last 10,000 years isn't anything "Special" or "Normal". It's just that the climate has been "About what it is" "Now".
For "Change" to be unusual, it would have had to have been stable forever. It's never been stable. Not ever. It's always gone warmer. It's always gone cooler. Way, way, way before mankind appeared. Catastrophic events have changed the climate and it's always bottomed out. Should a catastrophic event occur today then history shows us that it'll bottom out.
Maybe human activity is changing the CURRENT climate RIGHT NOW. But maybe it isn't. If it is then the push might be to get it back to this artificial normal that just corresponds roughly to human experience of climate - but perhaps that's not possible. It's moved around so much in 4 billion years that 'normal' is just whatever it is right now.
And some, like Rojo, who claim that we have never seen rises like the 20th century - the satanic influence of CO2.
The current situation is different because we know, with a degree of certainty that is so close to absolute that it makes little difference, that the current levels of climate change are accelerated way beyond natural trends. What we then need to do is explain why. The most likely hypothesis, again by a magnitude so large to be close to certainty, is that the greenhouse effect caused by human actions is to blame.
Let's have a quick look in the light of the graph you put up Rojo.
The following was published at the Foresight Institute and I will shamelessly plagiarize it.
http://www.foresight.org/nanodot/?p=3553J. Storrs Hall had some interesting graphs made from NOAA ice core data
(Alley, R.B. 2000. The Younger Dryas cold interval as viewed from central Greenland. Quaternary Science Reviews 19:213-226.)
We're going to look at the temperature record as read from this central Greenland ice core. It gives us about as close as we can come to a direct,
experimental measurement of temperature at that one spot for the past 50,000 years.
So what does it tell us about, say, the past 500 years? (the latter half of Rojo's fantasy)
It's Hockey Stick(ish) !!!! In fact, the “blade” continues up in the 20th century at least another half a degree.
Have I misjudged you RJ? The graph above does look a
little like yours.
But how long is the handle? How unprecedented is the current warming trend?
Rojo, Rojo, Rojo - there
was a Medieval Warm Period (in central Greenland at any rate). But we knew that — that’s when the Vikings were naming Greenland err, well,
Greenland. And the following Little Ice Age is what killed them off, and caused widespread crop failures.
But was the MWP itself unusual?
Well, no — over the period of recorded history, the average temperature was about equal to the height of the MWP. Rises not only as
high, but as
rapid, as the current hockey stick blade have been the rule, not the exception.
In fact for the entire Holocene — the period over which, by some odd coincidence, humanity developed agriculture and civilization — the temperature has been
higher than now, and the trend over the past 4000 years is a marked decline. From this perspective, it’s the LIA that was unusual, and the current warming trend simply represents a
return to the mean.
From the perspective of the Holocene as a whole, our current hockey stick is beginning to look pretty dinky. By far the possibility I would worry about, if I were the worrying sort, would be the return to an ice age — since interglacials, over the past half million years or so, have tended to last only 10,000 years or so. And Ice ages are not conducive to agriculture.
… and ice ages have a better claim on being the natural state of Earth’s climate than interglacials. This next graph, for the longest period, we have to go to an Antarctic core (Vostok):
In other words, we’re pretty lucky to be here during this rare, warm period in climate history. But the broader lesson is, climate doesn’t stand still. It doesn’t even stay on the relatively constrained range of the last 10,000 years for more than about 10,000 years at a time.
Does this mean that CO2 isn’t a greenhouse gas? No.
Does it mean that CO2 isn’t producing a warming? No.
The Physics of CO2 is straightforward enough – a doubling will give a rise of ~ 1 deg C.
Not the 3.5 deg C that warming alarmists would try to scare us with.
And before Bio trys to muddy the waters with claims that the MWP and LIA (so outrageously airbrushed out by Rojo) were NH only phenomena – there are a hundred or so papers showing the opposite – see
http://www.co2science.org/data/mwp/mwpp.php