WILL THE SUN'S DECLINE AFFECT CLIMATE CHANGE?

On Apr 24, 6:59*pm, Chris L Peterson wrote:
On Fri, 24 Apr 2009 18:07:40 -0500, "S. Caro" wrote:
Of course, I don't see why there is need for debate. *The IPCC
can just plug the numbers into their climate model and come up
with unequivocal proof that the declining sun will or will
not affect global warming.

The IPCC doesn't have any climate models. The IPCC is just the policy
forum for thousands of individual climate scientists and institutions,
which between them have developed a half dozen major models, and many
more variations.

All of the models consider solar irradiance (as a function of
wavelength) as a primary input. All show a reduction in global
temperature following an extended drop in irradiance. None, however,
show the drop during the Maunder Minimum producing as deep a temperature
drop as was observed during the Little Ice Age. It remains a question of
study if the problem is the models, or if the Little Ice Age was only
partly caused by a drop in irradiance. My money is on the latter. But in
any case, I doubt you'd find anybody who disagrees that a drop in solar
output lasting years (basically, we need to miss a couple of solar max
cycles) wouldn't result in a reduction in the rate global temperatures
are rising.
_________________________________________________

Chris L Peterson
Cloudbait Observatoryhttp://www.cloudbait.com

The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.

On Fri, 1 May 2009 18:36:57 -0700 (PDT), wrote:

The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.

I'd say that remains uncertain. Records are poor for the southern
hemisphere, but there are some good proxies suggesting it also saw some
cooling. Climate models also show cooling, but less than in the north.
It may well be that ocean currents in the north provided additional
cooling there. Certainly, the models (which don't predict changes in
ocean currents very effectively) don't predict as much cooling in Europe
and North America as was actually observed.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

wrote:

The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.

This study says it likely did exist in all the northern hemisphere and
possibly globally, but doubts the MWP was a warm as now.

The evidence currently available indicates that NH mean temperatures
during medieval times (950–1100) were indeed warm in a 2-kyr context
and even warmer in relation to the less sparse but still limited
evidence of widespread average cool conditions in the 17th century.
However, the evidence is not sufficient to support a conclusion that
hemispheric mean temperatures were as warm, or the extent of warm
regions as expansive, as those in the 20th century as a whole, during
any period in medieval times.

There are markedly fewer well-dated proxy records for the SH compared
to the NH, and consequently little evidence of how large-scale average
surface temperatures have changed over the past few thousand years

Earlier periods, around AD 700 and 1000, are reconstructed as
warmer than the estimated level in the 20th century, and may
have been as warm as the measured values in the last 20 years.
The paucity of SH proxy data also means that uncertainties
associated with hemispheric temperature estimates are much
greater than for the NH

On May 3, 12:00*pm, Jax wrote:
wrote:

The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.

This study says it likely did exist in all the northern hemisphere and
possibly globally, but doubts the MWP was a warm as now.

The evidence currently available indicates that NH mean temperatures
during medieval times (950–1100) were indeed warm in a 2-kyr context
and even warmer in relation to the less sparse but still limited
evidence of widespread average cool conditions in the 17th century.
However, the evidence is not sufficient to support a conclusion that
hemispheric mean temperatures were as warm, or the extent of warm
regions as expansive, as those in the 20th century as a whole, during
any period in medieval times.

There are markedly fewer well-dated proxy records for the SH compared
to the NH, and consequently little evidence of how large-scale average
surface temperatures have changed over the past few thousand years

Earlier periods, around AD 700 and 1000, are reconstructed as
warmer than the estimated level in the 20th century, and may
have been as warm as the measured values in the last 20 years.
The paucity of SH proxy data also means that uncertainties
associated with hemispheric temperature estimates are much
greater than for the NH

Actually papers by Bradley and Jones, 1993; Hughes and Diaz, 1994;
Crowley and Lowery, 2000; Grove and Switsur, 1994; Bradley,
1999;O'Brien et al., 1995; Wanner et al., 1995; Luterbacher et al.,
1999; Pfister, 1999; Salinger, 1995; Cook et al., 2000; Wang et al.,
1998a,b; Wang and Gong, 2000; Keigwin and Pickart ,1999 all draw a
different conclusion. Reading these papers suggest that cold
conditions appear to have been considerably more pronounced in
particular regions and reflect changes in atmospheric circulation. The
"Little Ice Age" appears to have been most clearly expressed in the
North Atlantic region as altered patterns of atmospheric circulation
consistent with the negative or enhanced easterly wind phase of the
NAO which implies both warm and cold anomalies over different regions
in the North Atlantic sector. What evidence is available at the
hemispheric scale for summer and annual mean conditions suggests
markedly different behaviour from the Northern Hemisphere. The only
obvious similarity is the unprecedented warmth of the late 20th
century.

wrote:
On May 3, 12:00 pm, Jax wrote:
wrote:

The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.
This study says it likely did exist in all the northern hemisphere and
possibly globally, but doubts the MWP was a warm as now.

The evidence currently available indicates that NH mean temperatures
during medieval times (950–1100) were indeed warm in a 2-kyr context
and even warmer in relation to the less sparse but still limited
evidence of widespread average cool conditions in the 17th century.
However, the evidence is not sufficient to support a conclusion that
hemispheric mean temperatures were as warm, or the extent of warm
regions as expansive, as those in the 20th century as a whole, during
any period in medieval times.

There are markedly fewer well-dated proxy records for the SH compared
to the NH, and consequently little evidence of how large-scale average
surface temperatures have changed over the past few thousand years

Earlier periods, around AD 700 and 1000, are reconstructed as
warmer than the estimated level in the 20th century, and may
have been as warm as the measured values in the last 20 years.
The paucity of SH proxy data also means that uncertainties
associated with hemispheric temperature estimates are much
greater than for the NH

Actually papers by Bradley and Jones, 1993; Hughes and Diaz, 1994;
Crowley and Lowery, 2000; Grove and Switsur, 1994; Bradley,
1999;O'Brien et al., 1995; Wanner et al., 1995; Luterbacher et al.,
1999; Pfister, 1999; Salinger, 1995; Cook et al., 2000; Wang et al.,
1998a,b; Wang and Gong, 2000; Keigwin and Pickart ,1999 all draw a
different conclusion. Reading these papers suggest that cold
conditions appear to have been considerably more pronounced in
particular regions and reflect changes in atmospheric circulation. The
"Little Ice Age" appears to have been most clearly expressed in the
North Atlantic region as altered patterns of atmospheric circulation
consistent with the negative or enhanced easterly wind phase of the
NAO which implies both warm and cold anomalies over different regions
in the North Atlantic sector. What evidence is available at the
hemispheric scale for summer and annual mean conditions suggests
markedly different behaviour from the Northern Hemisphere. The only
obvious similarity is the unprecedented warmth of the late 20th
century.

You disagree with the 3500 scientists of the IPCC?

On May 3, 8:51*pm, Jax wrote:
wrote:
On May 3, 12:00 pm, Jax wrote:
wrote:

The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.
This study says it likely did exist in all the northern hemisphere and
possibly globally, but doubts the MWP was a warm as now.

The evidence currently available indicates that NH mean temperatures
during medieval times (950–1100) were indeed warm in a 2-kyr context
and even warmer in relation to the less sparse but still limited
evidence of widespread average cool conditions in the 17th century.
However, the evidence is not sufficient to support a conclusion that
hemispheric mean temperatures were as warm, or the extent of warm
regions as expansive, as those in the 20th century as a whole, during
any period in medieval times.

There are markedly fewer well-dated proxy records for the SH compared
to the NH, and consequently little evidence of how large-scale average
surface temperatures have changed over the past few thousand years

Earlier periods, around AD 700 and 1000, are reconstructed as
warmer than the estimated level in the 20th century, and may
have been as warm as the measured values in the last 20 years.
The paucity of SH proxy data also means that uncertainties
associated with hemispheric temperature estimates are much
greater than for the NH

Actually papers by Bradley and Jones, 1993; Hughes and Diaz, 1994;
Crowley and Lowery, 2000; Grove and Switsur, 1994; Bradley,
1999;O'Brien et al., 1995; Wanner et al., 1995; Luterbacher et al.,
1999; Pfister, 1999; Salinger, 1995; Cook et al., 2000; Wang et al.,
1998a,b; Wang and Gong, 2000; Keigwin and Pickart ,1999 all draw a
different conclusion. Reading these papers suggest that cold
conditions appear to have been considerably more pronounced in
particular regions and reflect changes in atmospheric circulation. The
"Little Ice Age" appears to have been most clearly expressed in the
North Atlantic region as altered patterns of atmospheric circulation
consistent with the negative or enhanced easterly wind phase of the
NAO which implies both warm and cold anomalies over different regions
in the North Atlantic sector. What evidence is available at the
hemispheric scale for summer and annual mean conditions suggests
markedly different behaviour from the Northern Hemisphere. The only
obvious similarity is the unprecedented warmth of the late 20th
century.

You disagree with the 3500 scientists of the IPCC?

Actually the papers listed and the text is a summary FROM THE IPCC
report, so I guess that means I agree with the 3500 scientists who
contributed

wrote:
On May 3, 8:51 pm, Jax wrote:
wrote:
On May 3, 12:00 pm, Jax wrote:
wrote:
The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.
This study says it likely did exist in all the northern hemisphere and
possibly globally, but doubts the MWP was a warm as now.
The evidence currently available indicates that NH mean temperatures
during medieval times (950–1100) were indeed warm in a 2-kyr context
and even warmer in relation to the less sparse but still limited
evidence of widespread average cool conditions in the 17th century.
However, the evidence is not sufficient to support a conclusion that
hemispheric mean temperatures were as warm, or the extent of warm
regions as expansive, as those in the 20th century as a whole, during
any period in medieval times.
There are markedly fewer well-dated proxy records for the SH compared
to the NH, and consequently little evidence of how large-scale average
surface temperatures have changed over the past few thousand years
Earlier periods, around AD 700 and 1000, are reconstructed as
warmer than the estimated level in the 20th century, and may
have been as warm as the measured values in the last 20 years.
The paucity of SH proxy data also means that uncertainties
associated with hemispheric temperature estimates are much
greater than for the NH
Actually papers by Bradley and Jones, 1993; Hughes and Diaz, 1994;
Crowley and Lowery, 2000; Grove and Switsur, 1994; Bradley,
1999;O'Brien et al., 1995; Wanner et al., 1995; Luterbacher et al.,
1999; Pfister, 1999; Salinger, 1995; Cook et al., 2000; Wang et al.,
1998a,b; Wang and Gong, 2000; Keigwin and Pickart ,1999 all draw a
different conclusion. Reading these papers suggest that cold
conditions appear to have been considerably more pronounced in
particular regions and reflect changes in atmospheric circulation. The
"Little Ice Age" appears to have been most clearly expressed in the
North Atlantic region as altered patterns of atmospheric circulation
consistent with the negative or enhanced easterly wind phase of the
NAO which implies both warm and cold anomalies over different regions
in the North Atlantic sector. What evidence is available at the
hemispheric scale for summer and annual mean conditions suggests
markedly different behaviour from the Northern Hemisphere. The only
obvious similarity is the unprecedented warmth of the late 20th
century.
You disagree with the 3500 scientists of the IPCC?

Actually the papers listed and the text is a summary FROM THE IPCC
report, so I guess that means I agree with the 3500 scientists who
contributed

Which IPCC report?

wrote:
On May 3, 8:51 pm, Jax wrote:
wrote:
On May 3, 12:00 pm, Jax wrote:
wrote:
The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.
This study says it likely did exist in all the northern hemisphere and
possibly globally, but doubts the MWP was a warm as now.
The evidence currently available indicates that NH mean temperatures
during medieval times (950–1100) were indeed warm in a 2-kyr context
and even warmer in relation to the less sparse but still limited
evidence of widespread average cool conditions in the 17th century.
However, the evidence is not sufficient to support a conclusion that
hemispheric mean temperatures were as warm, or the extent of warm
regions as expansive, as those in the 20th century as a whole, during
any period in medieval times.
There are markedly fewer well-dated proxy records for the SH compared
to the NH, and consequently little evidence of how large-scale average
surface temperatures have changed over the past few thousand years
Earlier periods, around AD 700 and 1000, are reconstructed as
warmer than the estimated level in the 20th century, and may
have been as warm as the measured values in the last 20 years.
The paucity of SH proxy data also means that uncertainties
associated with hemispheric temperature estimates are much
greater than for the NH
Actually papers by Bradley and Jones, 1993; Hughes and Diaz, 1994;
Crowley and Lowery, 2000; Grove and Switsur, 1994; Bradley,
1999;O'Brien et al., 1995; Wanner et al., 1995; Luterbacher et al.,
1999; Pfister, 1999; Salinger, 1995; Cook et al., 2000; Wang et al.,
1998a,b; Wang and Gong, 2000; Keigwin and Pickart ,1999 all draw a
different conclusion. Reading these papers suggest that cold
conditions appear to have been considerably more pronounced in
particular regions and reflect changes in atmospheric circulation. The
"Little Ice Age" appears to have been most clearly expressed in the
North Atlantic region as altered patterns of atmospheric circulation
consistent with the negative or enhanced easterly wind phase of the
NAO which implies both warm and cold anomalies over different regions
in the North Atlantic sector. What evidence is available at the
hemispheric scale for summer and annual mean conditions suggests
markedly different behaviour from the Northern Hemisphere. The only
obvious similarity is the unprecedented warmth of the late 20th
century.
You disagree with the 3500 scientists of the IPCC?

Actually the papers listed and the text is a summary FROM THE IPCC
report, so I guess that means I agree with the 3500 scientists who
contributed


Your comments come directly from the Third Assessment Report of the IPCC
in 2001. The report I listed is from the Fourth Assessment Report of
the IPCC in 2007. The 2007 report used more recent temperature
reconstructions including Esper et al. (2002), Bradley et al. (2003a),
Jones and Mann (2004), D’Arrigo et al. (2006). The IPCC concluded the
warmest period prior to the 20th century very likely occurred between
950 and 1100...The evidence currently available indicates that NH mean
temperatures during medieval times (950–1100) were indeed warm in a
2-kyr context and even warmer in relation to the less sparse but still
limited evidence of widespread average cool conditions in the 17th
century (Osborn and Briff a, 2006). Wiki MWP

On May 5, 7:53*am, Jax wrote:
wrote:
On May 3, 8:51 pm, Jax wrote:
wrote:
On May 3, 12:00 pm, Jax wrote:
wrote:
The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.
This study says it likely did exist in all the northern hemisphere and
possibly globally, but doubts the MWP was a warm as now.
The evidence currently available indicates that NH mean temperatures
during medieval times (950–1100) were indeed warm in a 2-kyr context
and even warmer in relation to the less sparse but still limited
evidence of widespread average cool conditions in the 17th century.
However, the evidence is not sufficient to support a conclusion that
hemispheric mean temperatures were as warm, or the extent of warm
regions as expansive, as those in the 20th century as a whole, during
any period in medieval times.
There are markedly fewer well-dated proxy records for the SH compared
to the NH, and consequently little evidence of how large-scale average
surface temperatures have changed over the past few thousand years
Earlier periods, around AD 700 and 1000, are reconstructed as
warmer than the estimated level in the 20th century, and may
have been as warm as the measured values in the last 20 years.
The paucity of SH proxy data also means that uncertainties
associated with hemispheric temperature estimates are much
greater than for the NH
Actually papers by Bradley and Jones, 1993; Hughes and Diaz, 1994;
Crowley and Lowery, 2000; Grove and Switsur, 1994; Bradley,
1999;O'Brien et al., 1995; Wanner et al., 1995; Luterbacher et al.,
1999; Pfister, 1999; Salinger, 1995; Cook et al., 2000; Wang et al.,
1998a,b; Wang and Gong, 2000; Keigwin and Pickart ,1999 all draw a
different conclusion. Reading these papers suggest that cold
conditions appear to have been considerably more pronounced in
particular regions and reflect changes in atmospheric circulation. The
"Little Ice Age" appears to have been most clearly expressed in the
North Atlantic region as altered patterns of atmospheric circulation
consistent with the negative or enhanced easterly wind phase of the
NAO which implies both warm and cold anomalies over different regions
in the North Atlantic sector. What evidence is available at the
hemispheric scale for summer and annual mean conditions suggests
markedly different behaviour from the Northern Hemisphere. The only
obvious similarity is the unprecedented warmth of the late 20th
century.
You disagree with the 3500 scientists of the IPCC?

Actually the papers listed and the text is a summary FROM THE IPCC
report, so I guess that means I agree with the 3500 scientists who
contributed

Your comments come directly from the Third Assessment Report of the IPCC
in 2001. *The report I listed is from the Fourth Assessment Report of
the IPCC in 2007. The 2007 report used more recent temperature
reconstructions including Esper et al. (2002), Bradley et al. (2003a),
Jones and Mann (2004), D’Arrigo et al. (2006). The IPCC concluded the
warmest period prior to the 20th century very likely occurred between
950 and 1100...The evidence currently available indicates that NH mean
temperatures during medieval times (950–1100) were indeed warm in a
2-kyr context and even warmer in relation to the less sparse but still
limited evidence of widespread average cool conditions in the 17th
century (Osborn and Briff a, 2006). Wiki MWP

The issue is not what the temperatures were like, but where the
temperature anomalies occurred. If the temperature anomalies occurred
in both hemispheres and in all locations (with the usual caveats about
regional effects) then there would support for a factor that has a
global influence, like the Sun. In this case there is little evidence
to indicate a global effect, rather the papers you note document the
existence, but they do not show it in a global context. As the TAR
states that "the only obvious similarity is the unprecedented warmth
of the late 20th century."

wrote:
On May 5, 7:53 am, Jax wrote:
wrote:
On May 3, 8:51 pm, Jax wrote:
wrote:
On May 3, 12:00 pm, Jax wrote:
wrote:
The little ice age/medieval warm periods were not global phenomenon,
rather they were limited in scope to Europe. The data points to
changes in ocean circulation patterns in the north Atlantic fro why
there were shifts in the climate.
This study says it likely did exist in all the northern hemisphere and
possibly globally, but doubts the MWP was a warm as now.
The evidence currently available indicates that NH mean temperatures
during medieval times (950–1100) were indeed warm in a 2-kyr context
and even warmer in relation to the less sparse but still limited
evidence of widespread average cool conditions in the 17th century.
However, the evidence is not sufficient to support a conclusion that
hemispheric mean temperatures were as warm, or the extent of warm
regions as expansive, as those in the 20th century as a whole, during
any period in medieval times.
There are markedly fewer well-dated proxy records for the SH compared
to the NH, and consequently little evidence of how large-scale average
surface temperatures have changed over the past few thousand years
Earlier periods, around AD 700 and 1000, are reconstructed as
warmer than the estimated level in the 20th century, and may
have been as warm as the measured values in the last 20 years.
The paucity of SH proxy data also means that uncertainties
associated with hemispheric temperature estimates are much
greater than for the NH
Actually papers by Bradley and Jones, 1993; Hughes and Diaz, 1994;
Crowley and Lowery, 2000; Grove and Switsur, 1994; Bradley,
1999;O'Brien et al., 1995; Wanner et al., 1995; Luterbacher et al.,
1999; Pfister, 1999; Salinger, 1995; Cook et al., 2000; Wang et al.,
1998a,b; Wang and Gong, 2000; Keigwin and Pickart ,1999 all draw a
different conclusion. Reading these papers suggest that cold
conditions appear to have been considerably more pronounced in
particular regions and reflect changes in atmospheric circulation. The
"Little Ice Age" appears to have been most clearly expressed in the
North Atlantic region as altered patterns of atmospheric circulation
consistent with the negative or enhanced easterly wind phase of the
NAO which implies both warm and cold anomalies over different regions
in the North Atlantic sector. What evidence is available at the
hemispheric scale for summer and annual mean conditions suggests
markedly different behaviour from the Northern Hemisphere. The only
obvious similarity is the unprecedented warmth of the late 20th
century.
You disagree with the 3500 scientists of the IPCC?
Actually the papers listed and the text is a summary FROM THE IPCC
report, so I guess that means I agree with the 3500 scientists who
contributed
Your comments come directly from the Third Assessment Report of the IPCC
in 2001. The report I listed is from the Fourth Assessment Report of
the IPCC in 2007. The 2007 report used more recent temperature
reconstructions including Esper et al. (2002), Bradley et al. (2003a),
Jones and Mann (2004), D’Arrigo et al. (2006). The IPCC concluded the
warmest period prior to the 20th century very likely occurred between
950 and 1100...The evidence currently available indicates that NH mean
temperatures during medieval times (950–1100) were indeed warm in a
2-kyr context and even warmer in relation to the less sparse but still
limited evidence of widespread average cool conditions in the 17th
century (Osborn and Briff a, 2006). Wiki MWP

The issue is not what the temperatures were like, but where the
temperature anomalies occurred. If the temperature anomalies occurred
in both hemispheres and in all locations (with the usual caveats about
regional effects) then there would support for a factor that has a
global influence, like the Sun. In this case there is little evidence
to indicate a global effect, rather the papers you note document the
existence, but they do not show it in a global context. As the TAR
states that "the only obvious similarity is the unprecedented warmth
of the late 20th century."

The newer report,FAR, states the warming was more widespread in the NH
than just regionally as previously thought, and without more SH data,
global cannot be ruled either way. The warmth of the late 20th century
is irrelevant to your statement the MWP/LIA were only local to EU.
We're not discussing whether the MWP was warmer than today, which FAR
says it's doubtful.