CO2 levels at Mauna Loa passed 400 ppm for the first time yesterday, 13th
May. See:

http://www.esrl.noaa.gov/gmd/ccgg/trends/weekly.html

It is probably the highest value that has occurred there since the start of
the Ice Age. In other words, it is now certain that the Greenland and west
Antarctic ice sheets will disappear, raising sea levels by over 10m. It is
not a matter of whether but when. Moreover, the Arctic sea ice will
disappear first, but the consequences of that are unknown, except that the
melting of the Greenland ice sheet will surely accelerate :-(

Cheers, Alastair.

On Tuesday, May 14, 2013 7:57:45 PM UTC+1, Alastair wrote:

It is now certain that the Greenland and west Antarctic ice sheets will disappear, raising sea levels by over 10m. It is not a matter of whether but when. Moreover, the Arctic sea ice will disappear first, but the consequences of that are unknown, except that the melting of the Greenland ice sheet will surely accelerate.

A bit of an over-reaction Alastair, almost Al Goresque!

:-)

Steve

"Steve Jackson" wrote in message
...
On Tuesday, May 14, 2013 7:57:45 PM UTC+1, Alastair wrote:

It is now certain that the Greenland and west Antarctic ice sheets will
disappear, raising sea levels by over 10m. It is not a matter of whether
but when. Moreover, the Arctic sea ice will disappear first, but the
consequences of that are unknown, except that the melting of the
Greenland ice sheet will surely accelerate.

A bit of an over-reaction Alastair, almost Al Goresque!

Only detailing the facts :-(

Al Gore chose the 100 k yr cycles as the most dramatic illustration of the
correlation between CO2 and temperature, but there is also a less obvious
correlation going back 600 M yrs. See:
http://www.geologywales.co.uk/storms...zoic_royer.jpg

Now we have raised CO2 to 400 ppm we have sent the climate back 2 M yrs to
before the northern ice existed and Mankind strode the planet.

But there is a greater danger. Here you can see another chart of temperature
against CO2 over the last 600 M yrs
http://deforestation.geologist-1011....mperatures.png
where the temperature makes step changes. That is my concern. Will CO2 pass
a tipping point where after a period of stability the global temperature
then jumps into a new extreme state.

Cheers, Alastair.

On Wed, 15 May 2013 10:18:42 +0100, "Alastair McDonald"
wrote:
..
..
..

But there is a greater danger. Here you can see another chart of temperature
against CO2 over the last 600 M yrs
http://deforestation.geologist-1011....mperatures.png
where the temperature makes step changes. That is my concern. Will CO2 pass
a tipping point where after a period of stability the global temperature
then jumps into a new extreme state.

What is causing the the leveling around 22C when the CO2 level
reaches very roughly 1000 ppm or higher? Why don't further increases
rise the temperature any higher?
Is it all snow/ice gone therefore no possibility to further reduce the
reflection of solar energy into space by white surfaces?

Bjørn Sørheim

On Wednesday, 15 May 2013 07:48:51 UTC+12, Steve Jackson wrote:
A bit of an over-reaction Alastair, almost Al Goresque! :-) Steve

Oh really?

On Tuesday, May 14, 2013 7:57:45 PM UTC+1, Alastair wrote:


In other words, it is now certain that the Greenland and west

Antarctic ice sheets will disappear, raising sea levels by over 10m. It is

not a matter of whether but when.



Cheers, Alastair.

Where on Earth do you get that from?

"Bjørn Sørheim" wrote in message
...
On Wed, 15 May 2013 10:18:42 +0100, "Alastair McDonald"
wrote:
.
.
.

But there is a greater danger. Here you can see another chart of
temperature
against CO2 over the last 600 M yrs
http://deforestation.geologist-1011....mperatures.png
where the temperature makes step changes. That is my concern. Will CO2
pass
a tipping point where after a period of stability the global temperature
then jumps into a new extreme state.

What is causing the the leveling around 22C when the CO2 level
reaches very roughly 1000 ppm or higher? Why don't further increases
rise the temperature any higher?
Is it all snow/ice gone therefore no possibility to further reduce the
reflection of solar energy into space by white surfaces?

Bjørn Sørheim


Where did you read that global temperatures would reach 22C at 1000 ppm
concentration of carbon dioxide (cCO2), and then go no higher even if cCO2
continued to increase? I have not heard that before.

However, the CO2 band is saturated, which should mean that if cCO2 increases
then no more heat will be trapped. In fact the band is made up of a series
of lines and although each line is saturated when cCO2 increases the lines
become broader and the space between the lines becomes narrower so more heat
IS trapped. Eventually the spaces all become filled in and the more heat is
only trapped at the edges of the band.

There has just been a paper published in Weather, the monthly magazine of
the UK Royal Meteorological Society, where they showed that a weak CO2 band
in the IR window would become effective at about 10,000 ppm cCO2.
http://onlinelibrary.wiley.com/doi/1....2072/abstract
But that is another story.

I can't comment much further without knowing your sources, which, even if
you could only give me a clue, I would be very interested in investigating.

Cheers, Alastair.