Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2, including only fast feedback processes. Equilibrium sensitivity,
including slower surface albedo feedbacks, is ~6°C for doubled CO2 for
the range of climate states between glacial conditions and icefree
Antarctica. Decreasing CO2 was the main cause of a cooling trend that
began 50 million years ago, large scale glaciation occurring when CO2
fell to 425±75 ppm, a level that will be exceeded within decades,
barring prompt policy changes. If humanity wishes to preserve a planet
similar to that on which civilization developed and to which life on
Earth is adapted, paleoclimate evidence and ongoing climate change
suggest that CO2 will need to be reduced from its current 385 ppm to
at most 350 ppm. The largest uncertainty in the target arises from
possible changes of non-CO2 forcings. An initial 350 ppm CO2 target
may be achievable by phasing out coal use except where CO2 is captured
and adopting agricultural and forestry practices that sequester
carbon. If the present overshoot of this target CO2 is not brief,
there is a possibility of seeding irreversible catastrophic effects.


Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...arbonemissions

On Apr 15, 9:57 am, Roger Coppock wrote:
Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2, including only fast feedback processes. Equilibrium sensitivity,
including slower surface albedo feedbacks, is ~6°C for doubled CO2 for
the range of climate states between glacial conditions and icefree
Antarctica. Decreasing CO2 was the main cause of a cooling trend that
began 50 million years ago, large scale glaciation occurring when CO2
fell to 425±75 ppm, a level that will be exceeded within decades,
barring prompt policy changes. If humanity wishes to preserve a planet
similar to that on which civilization developed and to which life on
Earth is adapted, paleoclimate evidence and ongoing climate change
suggest that CO2 will need to be reduced from its current 385 ppm to
at most 350 ppm. The largest uncertainty in the target arises from
possible changes of non-CO2 forcings. An initial 350 ppm CO2 target
may be achievable by phasing out coal use except where CO2 is captured
and adopting agricultural and forestry practices that sequester
carbon. If the present overshoot of this target CO2 is not brief,
there is a possibility of seeding irreversible catastrophic effects.

Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...techange.carbo...

But the Earth is showing signs of Cooling whilst Fossil CO2 is going
through the roof .

On Apr 15, 10:57*am, Roger Coppock wrote:
Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2, including only fast feedback processes. Equilibrium sensitivity,
including slower surface albedo feedbacks, is ~6°C for doubled CO2 for
the range of climate states between glacial conditions and icefree
Antarctica. Decreasing CO2 was the main cause of a cooling trend that
began 50 million years ago, large scale glaciation occurring when CO2
fell to 425±75 ppm, a level that will be exceeded within decades,
barring prompt policy changes. If humanity wishes to preserve a planet
similar to that on which civilization developed and to which life on
Earth is adapted, paleoclimate evidence and ongoing climate change
suggest that CO2 will need to be reduced from its current 385 ppm to
at most 350 ppm. The largest uncertainty in the target arises from
possible changes of non-CO2 forcings. An initial 350 ppm CO2 target
may be achievable by phasing out coal use except where CO2 is captured
and adopting agricultural and forestry practices that sequester
carbon. If the present overshoot of this target CO2 is not brief,
there is a possibility of seeding irreversible catastrophic effects.

Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...techange.carbo...

500 to 2000 seems pretty OK since this is what it has been since the
Jurassic (when modern animals and plants evolved)

On Apr 15, 8:55*pm, matt_sykes wrote:
On Apr 15, 10:57*am, Roger Coppock wrote:





Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2, including only fast feedback processes. Equilibrium sensitivity,
including slower surface albedo feedbacks, is ~6°C for doubled CO2 for
the range of climate states between glacial conditions and icefree
Antarctica. Decreasing CO2 was the main cause of a cooling trend that
began 50 million years ago, large scale glaciation occurring when CO2
fell to 425±75 ppm, a level that will be exceeded within decades,
barring prompt policy changes. If humanity wishes to preserve a planet
similar to that on which civilization developed and to which life on
Earth is adapted, paleoclimate evidence and ongoing climate change
suggest that CO2 will need to be reduced from its current 385 ppm to
at most 350 ppm. The largest uncertainty in the target arises from
possible changes of non-CO2 forcings. An initial 350 ppm CO2 target
may be achievable by phasing out coal use except where CO2 is captured
and adopting agricultural and forestry practices that sequester
carbon. If the present overshoot of this target CO2 is not brief,
there is a possibility of seeding irreversible catastrophic effects.

Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...techange.carbo...

500 to 2000 seems pretty OK since this is what it has been since the
Jurassic *(when modern animals and plants evolved)-


Nah ah ...

Toxic levels of carbon dioxide: According to occupational exposure and
controlled atmosphere research into CO2 toxicology, CO2 is hazardous
via direct toxicity at levels above 5%, concentrations not encountered
in nature [except perhaps at or near an active volcano or at water-
logged soils]. At these high levels there is risk of death from carbon
dioxide poisoning. At lower levels there may health effects and there
certainly are complaints of exposure at lower levels.

In the preceding section of this article, at CO2 POISONING SYMPTOMS we
discussed symptoms of carbon dioxide exposure. On specific
individuals, the effects of exposure to elevated levels of carbon
dioxide (CO2) vary by individual and with exposure level, and exposure
duration, ranging from drowsiness (perhaps at levels over 1000 ppm
continuous exposure) to the toxic effects listed just above.

...

The U.S. EPA CO2 exposure limits: The U.S. EPA recommends a maximum
concentration of Carbon dioxide CO2 of 1000 ppm (0.1%) for continuous
exposure.
ASHRAE standard 62-1989 recommends an indoor air ventilation standard
of 20 cfm per person of outdoor air or a CO2 level which is below
1000ppm.



http://www.inspect-ny.com/hazmat/CO2gashaz.htm

On Apr 15, 2:44*pm, Fran wrote:
On Apr 15, 8:55*pm, matt_sykes wrote:





On Apr 15, 10:57*am, Roger Coppock wrote:

Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2, including only fast feedback processes. Equilibrium sensitivity,
including slower surface albedo feedbacks, is ~6°C for doubled CO2 for
the range of climate states between glacial conditions and icefree
Antarctica. Decreasing CO2 was the main cause of a cooling trend that
began 50 million years ago, large scale glaciation occurring when CO2
fell to 425±75 ppm, a level that will be exceeded within decades,
barring prompt policy changes. If humanity wishes to preserve a planet
similar to that on which civilization developed and to which life on
Earth is adapted, paleoclimate evidence and ongoing climate change
suggest that CO2 will need to be reduced from its current 385 ppm to
at most 350 ppm. The largest uncertainty in the target arises from
possible changes of non-CO2 forcings. An initial 350 ppm CO2 target
may be achievable by phasing out coal use except where CO2 is captured
and adopting agricultural and forestry practices that sequester
carbon. If the present overshoot of this target CO2 is not brief,
there is a possibility of seeding irreversible catastrophic effects.

Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...techange.carbo....

500 to 2000 seems pretty OK since this is what it has been since the
Jurassic *(when modern animals and plants evolved)-

Nah ah ...

Toxic levels of carbon dioxide: According to occupational exposure and
controlled atmosphere research into CO2 toxicology, CO2 is hazardous
via direct toxicity at levels above 5%, concentrations not encountered
in nature [except perhaps at or near an active volcano or at water-
logged soils]. At these high levels there is risk of death from carbon
dioxide poisoning. At lower levels there may health effects and there
certainly are complaints of exposure at lower levels.

In the preceding section of this article, at CO2 POISONING SYMPTOMS we
discussed symptoms of carbon dioxide exposure. On specific
individuals, the effects of exposure to elevated levels of carbon
dioxide (CO2) vary by individual and with exposure level, and exposure
duration, ranging from drowsiness (perhaps at levels over 1000 ppm
continuous exposure) to the toxic effects listed just above.

...

The U.S. EPA CO2 exposure limits: The U.S. EPA recommends a maximum
concentration of Carbon dioxide CO2 of 1000 ppm (0.1%) for continuous
exposure.
ASHRAE standard 62-1989 recommends an indoor air ventilation standard
of 20 cfm per person of outdoor air or a CO2 level which is below
1000ppm.

http://www.inspect-ny.com/hazmat/CO2gashaz.htm- Hide quoted text -

- Show quoted text -



Agricultural workers in greenhouses work with CO2 generally at 5000
ppm as a maximum recomended level so your 1000 is from some other
source, perhaps for ill or old people in hospital?

Anyway, it is unlikely we will ever get to 1000 since plant growth
will explode.

chemist wrote:
On Apr 15, 9:57 am, Roger Coppock wrote:
Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2, including only fast feedback processes. Equilibrium sensitivity,
including slower surface albedo feedbacks, is ~6°C for doubled CO2
for the range of climate states between glacial conditions and
icefree Antarctica. Decreasing CO2 was the main cause of a cooling
trend that began 50 million years ago, large scale glaciation
occurring when CO2 fell to 425±75 ppm, a level that will be exceeded
within decades, barring prompt policy changes. If humanity wishes to
preserve a planet similar to that on which civilization developed
and to which life on Earth is adapted, paleoclimate evidence and
ongoing climate change suggest that CO2 will need to be reduced from
its current 385 ppm to at most 350 ppm. The largest uncertainty in
the target arises from possible changes of non-CO2 forcings. An
initial 350 ppm CO2 target may be achievable by phasing out coal use
except where CO2 is captured and adopting agricultural and forestry
practices that sequester carbon. If the present overshoot of this
target CO2 is not brief, there is a possibility of seeding
irreversible catastrophic effects.

Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...techange.carbo...

But the Earth is showing signs of Cooling whilst Fossil CO2 is going
through the roof .

Welcome to La Nina, lying idiot.

matt_sykes wrote:
On Apr 15, 2:44 pm, Fran wrote:
On Apr 15, 8:55 pm, matt_sykes wrote:





On Apr 15, 10:57 am, Roger Coppock wrote:

Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2, including only fast feedback processes. Equilibrium
sensitivity, including slower surface albedo feedbacks, is ~6°C
for doubled CO2 for the range of climate states between glacial
conditions and icefree Antarctica. Decreasing CO2 was the main
cause of a cooling trend that began 50 million years ago, large
scale glaciation occurring when CO2 fell to 425±75 ppm, a level
that will be exceeded within decades, barring prompt policy
changes. If humanity wishes to preserve a planet similar to that
on which civilization developed and to which life on Earth is
adapted, paleoclimate evidence and ongoing climate change suggest
that CO2 will need to be reduced from its current 385 ppm to at
most 350 ppm. The largest uncertainty in the target arises from
possible changes of non-CO2 forcings. An initial 350 ppm CO2
target may be achievable by phasing out coal use except where CO2
is captured and adopting agricultural and forestry practices that
sequester carbon. If the present overshoot of this target CO2 is
not brief, there is a possibility of seeding irreversible
catastrophic effects.

Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...techange.carbo...

500 to 2000 seems pretty OK since this is what it has been since the
Jurassic (when modern animals and plants evolved)-

Nah ah ...

Toxic levels of carbon dioxide: According to occupational exposure
and controlled atmosphere research into CO2 toxicology, CO2 is
hazardous via direct toxicity at levels above 5%, concentrations not
encountered in nature [except perhaps at or near an active volcano
or at water- logged soils]. At these high levels there is risk of
death from carbon dioxide poisoning. At lower levels there may
health effects and there certainly are complaints of exposure at
lower levels.

In the preceding section of this article, at CO2 POISONING SYMPTOMS
we discussed symptoms of carbon dioxide exposure. On specific
individuals, the effects of exposure to elevated levels of carbon
dioxide (CO2) vary by individual and with exposure level, and
exposure duration, ranging from drowsiness (perhaps at levels over
1000 ppm continuous exposure) to the toxic effects listed just above.

...

The U.S. EPA CO2 exposure limits: The U.S. EPA recommends a maximum
concentration of Carbon dioxide CO2 of 1000 ppm (0.1%) for continuous
exposure.
ASHRAE standard 62-1989 recommends an indoor air ventilation standard
of 20 cfm per person of outdoor air or a CO2 level which is below
1000ppm.

http://www.inspect-ny.com/hazmat/CO2gashaz.htm- Hide quoted text -

- Show quoted text -



Agricultural workers in greenhouses work with CO2 generally at 5000
ppm as a maximum recomended level

..for an 8 hour day.


so your 1000 is from some other
source, perhaps for ill or old people in hospital?

Nope, see 'continuous exposure'.



Anyway, it is unlikely we will ever get to 1000 since plant growth
will explode.

Which doesn't change the fact that once again, Matt Sykes has been caught
lying outright.

On Apr 15, 1:57*am, Roger Coppock wrote:
Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2,

Ludicrous speculation. No such data exists. These AGW whackjobs
can't distintinguish between data and their overactive imaginations.


including only fast feedback processes. Equilibrium sensitivity,
including slower surface albedo feedbacks, is ~6°C for doubled CO2 for
the range of climate states between glacial conditions and icefree
Antarctica. Decreasing CO2 was the main cause of a cooling trend that
began 50 million years ago,

Plainly false.


large scale glaciation occurring when CO2
fell to 425±75 ppm, a level that will be exceeded within decades,
barring prompt policy changes. If humanity wishes to preserve a planet
similar to that on which civilization developed and to which life on
Earth is adapted, paleoclimate evidence and ongoing climate change
suggest that CO2 will need to be reduced from its current 385 ppm to
at most 350 ppm. The largest uncertainty in the target arises from
possible changes of non-CO2 forcings. An initial 350 ppm CO2 target
may be achievable by phasing out coal use except where CO2 is captured
and adopting agricultural and forestry practices that sequester
carbon. If the present overshoot of this target CO2 is not brief,
there is a possibility of seeding irreversible catastrophic effects.

It's unfortunate you cannot provide us links to your imagination.


Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...techange.carbo...

wrote:
On Apr 15, 1:57 am, Roger Coppock wrote:
Target Atmospheric CO2: Where Should Humanity Aim?

James Hansen, Makiko Sato, Pushker Kharecha, David Beerling,
Valerie Masson-Delmotte, Mark Pagani, Maureen Raymo, Dana L. Royer,
James C. Zachos

Paleoclimate data show that climate sensitivity is ~3°C for doubled
CO2,

Ludicrous speculation. No such data exists. These AGW whackjobs
can't distintinguish between data and their overactive imaginations.

translation: droool




including only fast feedback processes. Equilibrium sensitivity,
including slower surface albedo feedbacks, is ~6°C for doubled CO2
for the range of climate states between glacial conditions and
icefree Antarctica. Decreasing CO2 was the main cause of a cooling
trend that began 50 million years ago,

Plainly false.

translation: droool





large scale glaciation occurring when CO2
fell to 425±75 ppm, a level that will be exceeded within decades,
barring prompt policy changes. If humanity wishes to preserve a
planet similar to that on which civilization developed and to which
life on Earth is adapted, paleoclimate evidence and ongoing climate
change suggest that CO2 will need to be reduced from its current 385
ppm to at most 350 ppm. The largest uncertainty in the target arises
from possible changes of non-CO2 forcings. An initial 350 ppm CO2
target may be achievable by phasing out coal use except where CO2 is
captured and adopting agricultural and forestry practices that
sequester carbon. If the present overshoot of this target CO2 is not
brief, there is a possibility of seeding irreversible catastrophic
effects.

It's unfortunate you cannot provide us links to your imagination.

translation: droool




Please see:

http://arxiv.org/pdf/0804.1126

For supporting materal see:

http://arxiv.org/pdf/0804.1135

For an article in the popular press, please see:

http://www.guardian.co.uk/environmen...techange.carbo...

On Apr 15, 7:00*am, matt_sykes wrote:
[ . . . ][
Agricultural workers in greenhouses work with CO2 generally at 5000
ppm as a maximum recomended level so your 1000 is from some other
source, perhaps for ill or old people in hospital?

In San Diego two greenhouse workers died from CO2.
Port workers packing stuff in dry ice also died.
Now, CalOSHA keeps a close watch on CO2 concentrations
at workplaces.


Anyway, it is unlikely we will ever get to 1000 since plant growth
will explode.

How tragic! You actually expect a miracle that will
save us from our greenhouse gas emissions.