2012 Global Temperatures

[WeatherRusty]

You can plot the GISS data from here yourself and note the 0.05C per decade cooling trend since 2002 that I noted.

http://data.giss.nas.../SH.Ts dSST.txt

Its not going to show up very well on the graph you posted since your graph goes back to 1880. And I agree that short term trends can be unreliable and should be taken with caution. That is why I take the recent spike of warming in the arctic the last 10 years with caution as well.

9 of the 11 warmest years J-D on record for the SH occurred between 2001 and 2011 inclusive.

[ORH_wxman]

9 of the 11 warmest years J-D on record for the SH occurred between 2001 and 2011 inclusive.

Yes that would be expected with a nearly flat line (only slight cooling) from the warmest point on the running mean. The warmest southern hemisphere year on record was 2009 according to GISS. However, the #2, #3, #4, and #5 warmest on record all occurred from 1998-2005 which is what contributes to the flat or slight cooling trend starting from around the turn of the century .

[Snow_Miser]

The northern hemisphere warmth has been impressive. Though the southern hemisphere has more than made up for it to make 2011 colder than 2009 on a global scale through July. SH is running like 0.17-0.18C colder than 2009.

Yeah, SH had it's 23rd warmest July on record, which is quite impressive, and shows you how cool (relatively speaking) the SH has been during July 2012 compared to the past 30 years.

[Snow_Miser]

Why might this be the case? Perhaps expanding Southern Hemisphere sea ice extent around Antarctica has produced this outcome, even as the ice sheet (particularly in western Antarctica has experienced significant melting)?

Antarctica was quite cold compared to the 20th Century average in July 2012 according to GISS. Only the Antarctic Penninsula had above normal temperatures, which constitutes a very small portion of Antarctica.

It's interesting how the Arctic has generally been much warmer than Antarctica.

[Snow_Miser]

You are asking an awful lot from a radiative forcing only on the order of 0.06W-0.30W/m^2.

Observationally, the total radiative forcing from the sun has been estimated to be 7-8 times as large as the TSI Forcing over the course of a solar cycle. We can also expect that this amplification mechanism also applies to long term trends, and thus a significant portion of the warming is likely solar induced, depending on which TSI reconstruction is used.

Shaviv 2008, Marsden and Lingenfelter 2003, Kirkby and Laaksonen 2000, Svensmark and Friis-Christensen 1996, and Reis and Serrano 2009 find that (or cite papers that show) that an amplifying mechanism is needed to explain the total forcing during a solar cycle. It should be noted that the last paper claims that a decrease in Cloud Cover during a solar cycle leads to a 0.8-1.7 w/m^2 radiative forcing may be underestimating the Cloud Cover effects during a Solar Cycle, since the Cosmic Ray impact is with the Low Clouds, and Low Clouds cool the climate more than just Clouds overall (Usoskin et. al 2004).

It is well accepted that solar irradiance changes range by about 1 w/m^2 over the course of a solar cycle, so in order to translate this value, we need to account for the Earth's albedo and geometry. We first need to divide this value by 4 to account for the geometry of the Earth, (The Earth is a sphere) and multiply this value by 0.7 to account for the Earth's albedo.

This means that the irradiance forcing during the course of a Solar Cycle is around 0.18 w/m^2. Kirkby and Laaksonen and Reis and Serrano agree that the forcing from GCRs over the course of a solar cycle is approximately 1.2-1.3 w/m^2. This is a value that is much higher than just irradiance changes alone. To get the total forcing over the course of a solar cycle, we need to add the irradiance forcing onto the GCR forcing to get a mean value of around 1.43 w/m^2. It should be noted that the total forcing during the solar cycle, (~11 years) once this amplification mechanism is accounted for, is highly comparable to the Total Anthropogenic Forcing since 1750 (~1.6 w/m^2). To find out how much bigger the total solar forcing is compared to the irradiance forcing, we can divide the total solar forcing by the irradiance forcing to get the multiplying factor. This is nearly a factor of 8 larger than the TSI forcing alone, and the IPCC may be underestimating the total solar forcing by a factor of 8. In addition, we have various TSI proxies since the Maunder Minimum that are not in agreement with each other, so the TSI forcing from the IPCC may not be correct either.

Take Haigh 2003 which finds a 3-4 w/m^2 increase in TSI since the Maunder Minimum. TSI insolation changes need to be divided by 4 and multiplied by 0.7 for the reasons stated above. When you do so, you get a TSI forcing of 0.61 w/m^2 since the Little Ice Age. The Maunder Minimum roughly ended during the same time that the IPCC's total radiative forcings started, so comparing the direct and indirect Solar Forcing to the anthropogenic forcing is reasonable. If TSI alone were the solar forcing, we would have a problem, since the net anthropogenic forcing is larger than the TSI forcing by a factor of 2.6. However, when we include the amplification from the indirect solar forcing, we can find that the Anthropogenic Forcing is dwarfed by a much larger solar forcing. When we multiply the TSI forcing by a factor of 8 to account for an amplification mechanism, we get a total solar forcing of nearly 5 w/m^2 (4.88 w/m^2). This is significantly larger than the anthropogenic forcing during the same timeframe by over a factor of 3. We get a solar contribution of around 75% to the warming observed since the Little Ice Age. This is highly significant.

The temperature has increased by roughly a Degree C since the LIA, so we can also roughly calculate the sensitivity of the Climate based off of this rough analysis. Since a combined forcing of 6.5 w/m^2 from solar and anthropogenic causes created a 1 Degree C increase in temperatures, we can use the 6.5 w/m^2 as a constant. The 3.7 w/m^2 forcing for a doubling of CO2 gives you about a 0.57 Degree C response, which is significantly smaller than the IPCC climate sensitivity.

The role of natural internal climatic variability also needs to be considered as another significant contributing factor to the recent warming episode, and if it is, the sensitivity to CO2 may go down even further.

[Snow_Miser]

All I'm saying is that I want to see what actually transpires over the next 5-6 years or so before giving up on solar being a bigger influence (via BOTH direct and indirect influences). Admittedly, I would have liked to have seen 2012 not be as warm globally as has been the case to assume a larger solar influence. So, I do think that the odds of a larger solar influence than many assume have fallen from what I thought around 2010 or so. However, I still think it is too early to eliminate that possibilty and I want to see what happens to global temp.'s, say, through 2017-8. One thing that is puzzling me about the current warming is how it is northern hem. centered and how much cooler the southern hem. has been relative to the northern in recent years. It has been more like hemispheric warming than global warming recently. Why is that? Do we know the answer? Could the behavior of the southern hem. be a harbinger of things to come in the northern hem. with regard to the current grand solar min.?

The beginning of the year was quite cold relatively speaking... with the El Nino warming things up somewhat, it hasn't been quite as cool on the GISS, with last month finishing as the 13th warmest Globally, but we are still below the 15 year average for 2012. As Will (ORH_wxman) mentioned earlier, if this El Nino remains weak (which it likely will) and we go into a La Nina, we may see some pretty low readings a year or two from now.

The impact of cumulative low solar activity over the next 30 or so years rather than one low solar cycle will ultimately determine the role of the sun in Climate Change IMO.

[donsutherland1]

In his paper, Shaviv writes:

Three independent data sets consistently show that the oceans absorb and emit an order of magnitude more heat than could be expected from just the variations in the total solar irradiance.

We thus conclude that the apparent oceanic flux variations must be the result of a large amount of heat of an external forcing, which periodically enters and leaves the oceans without being amplified by the atmosphere nor by an internal oceanic mode. This implies that the sun affects climate through a mechanism other than TSI variations.

Several quick points:

1. Shaviv correctly notes that the oceans absorb/emit far more heat than can be explained by solar irradiance.

2. Shaviv speculates that the discrepancy between TSI and the actual heat is due to some mechanism that amplifies solar forcing.

IMO, the second point is where Shaviv makes an error. He assumes that something is amplifying the solar forcing.

What he is actually coming across is the anthropogenic forcing. If one accounts for that forcing, the energy imbalance is completely explained (Hansen, et al., "Earth's energy imbalance and implications, December 2011). Hence, one need not speculate on the existence of an unknown amplifying mechanism(s) to explain the discrepancy when one can calculate the radiative forcing attributable to an identified forcing and fully account for that discrepancy.

[Snow_Miser]

In his paper, Shaviv writes:

Three independent data sets consistently show that the oceans absorb and emit an order of magnitude more heat than could be expected from just the variations in the total solar irradiance.

We thus conclude that the apparent oceanic flux variations must be the result of a large amount of heat of an external forcing, which periodically enters and leaves the oceans without being amplified by the atmosphere nor by an internal oceanic mode. This implies that the sun affects climate through a mechanism other than TSI variations.

Several quick points:

1. Shaviv correctly notes that the oceans absorb/emit far more heat than can be explained by solar irradiance.

2. Shaviv speculates that the discrepancy between TSI and the actual heat is due to some mechanism that amplifies solar forcing.

IMO, the second point is where Shaviv makes an error. He assumes that something is amplifying the solar forcing.

What he is actually coming across is the anthropogenic forcing. If one accounts for that forcing, the energy imbalance is completely explained (Hansen, et al., "Earth's energy imbalance and implications, December 2011). Hence, one need not speculate on the existence of an unknown amplifying mechanism(s) to explain the discrepancy when one can calculate the radiative forcing attributable to an identified forcing and fully account for that discrepancy.

That doesn't seem like a likely possibility Don.

The cooling influence being 7-8 times larger than the cooling influence by the TSI Forcing during the downside of a solar cycle can not be explained by the positive forcing from anthropogenic sources.

In addition, Shaviv detrended the data, so any long trend upward in forcing would be eliminated, and the natural oscillation of the 11 year solar forcing would be much more obvious.

I would also be extremely skeptical of the Hansen et al. 2011 paper for a few reasons:

1) A paper by Lean and Kopp in 2011 found a lower value for TSI than previously expected, which eliminates the Energy Imbalance.

2) Hansen et. al are measuring changes in hundreths of a degree in the ocean, a value that should have considerable uncertainty, considering that there is one Argo buoy in the ocean for every 165,000 cubic kilometers of water. Errors can accumulate quickly.

[donsutherland1]

Antarctica was quite cold compared to the 20th Century average in July 2012 according to GISS. Only the Antarctic Penninsula had above normal temperatures, which constitutes a very small portion of Antarctica.

It's interesting how the Arctic has generally been much warmer than Antarctica.

I was referring to the 2000s as a whole, not just July 2012. July 2012 was cool across a large part of Antarctica, portion of South America, and part of Australia. The GISS map and NCEP-NCAR map are in good agreement.

The July 2012 outcome reflects what one would expect to see from the thermal bipolar see-saw (warm in Greenland and opposite in Antarctica, except for the western Atlantic portion of Greenland). Of course, the see-saw is not a one-month phenomenon. It plays out over a long time span and it is sort of reflected in the much slower warming relative to the Arctic that is shown on the climate models in the last IPCC report.

[donsutherland1]

That doesn't seem like a likely possibility Don.

Hansen took a compromise between two datasets on OHC. One shouldn't hold the Hansen's numbers to precision, as some margin of error almost certainly exists. However, what is important is that the energy imbalance can be reconciled without having to resort to speculation of "missing energy." The paper might not be perfect, but it is reasonable and, IMO, more reasonable than earlier papers that can't account for a significant portion of the energy imbalance and assume missing energy.

[Isotherm]

Sunspot activity over the 11-year period is not as important as solar cycle length, and when there are many, consecutive long solar cycles, there is a cumulative impact on global temperatures. Two to three cycles with a length of 11.5-12 years is much more impactful than only one cycle of 12 years. However, if there is a cycle with 12 year length, it's highly likely that the ensuing solar cycles will also be long ones. We've seen this occur repeatedly over the past few centuries, and it may happen again between now and 2050, with 2-4 long solar cycles of decreased sunspot activity. The global temperature response I guess is debatable (but so is the AGW effect on temp); however, I believe it to be about +0.8C to +1.0C temp variation from cycle length of less than 10 years to over 12 years.

The following paper is a good read:

http://www.tmgnow.com/repository/solar/lassen1.html

[Isotherm]

Sunspot activity over the 11-year period is not as important as solar cycle length, and when there are many, consecutive long solar cycles, there is a cumulative impact on global temperatures. Two to three cycles with a length of 11.5-12 years is much more impactful than only one cycle of 12 years. However, if there is a cycle with 12 year length, it's highly likely that the ensuing solar cycles will also be long ones. We've seen this occur repeatedly over the past few centuries, and it may happen again between now and 2050, with 2-4 long solar cycles of decreased sunspot activity. The global temperature response I guess is debatable (but so is the AGW effect on temp); however, I believe it to be about +0.8C to +1.0C temp variation from cycle length of less than 10 years to over 12 years.

The following paper is a good read:

http://www.tmgnow.co...ar/lassen1.html

Just to clarify, I do attribute some of the temperature variation to anthropogenic influences, but I think the cumulative effect of long solar cycles is often underrated. The next couple decades will be an interesting test concerning whether natural or anthropogenic factors have a stronger impact on global temp fluctuation.

[Isotherm]

The decade of the 70s was warmer than the 60s, the 80s warmer than the 70s, the 90s warmer than the 80s, the 00s warmer than the 90s.

Do you expect that trend to not continue because of the factors you mention?

I do expect that the 2010s will likely continue leveling and will feature a cooling trend from the 2000s. I'm not confident enough to compare it to the 90s/80s/70s but I believe the 2010s will be a cooler decade globally than the 2000s, yes.

The temp trend upward slowed significantly over the past decade, and most of that period was prior to the introduction of natural cooling factors like the PDO, solar output, etc.

[Snow_Miser]

Hansen took a compromise between two datasets on OHC. One shouldn't hold the Hansen's numbers to precision, as some margin of error almost certainly exists. However, what is important is that the energy imbalance can be reconciled without having to resort to speculation of "missing energy." The paper might not be perfect, but it is reasonable and, IMO, more reasonable than earlier papers that can't account for a significant portion of the energy imbalance and assume missing energy.

If the readings are off just by a few hundreths of a degree, then there would be no Energy Imbalance.

Again, may I stress that there is one ARGO sensor for every 160,000 square kilometers of ocean.

That is why all OHC datasets (including a recently deleted UKEN3 dataset) should be taken with a grain of salt.

That would present a very high error margin in my book, since many complicated processes take place in the ocean that the ARGO sensors may not be measuring.

[tacoman25]

I was referring to the 2000s as a whole, not just July 2012. July 2012 was cool across a large part of Antarctica, portion of South America, and part of Australia. The GISS map and NCEP-NCAR map are in good agreement.

The July 2012 outcome reflects what one would expect to see from the thermal bipolar see-saw (warm in Greenland and opposite in Antarctica, except for the western Atlantic portion of Greenland). Of course, the see-saw is not a one-month phenomenon. It plays out over a long time span and it is sort of reflected in the much slower warming relative to the Arctic that is shown on the climate models in the last IPCC report.

Don, have you ever taken the time to compare the GISS surface maps with the satellite temperature maps? The interesting thing is that the temperature anomalies usually match quite well across most of the earth, suggesting a high correlation between surface temps and LT temps. However, there are often a few areas where GISS is notably warmer than the satellite maps, and that is enough to create warmer anomalies (aside from the baseline differences).

[donsutherland1]

If the readings are off just by a few hundreths of a degree, then there would be no Energy Imbalance.

Again, may I stress that there is one ARGO sensor for every 160,000 square kilometers of ocean.

That is why all OHC datasets (including a recently deleted UKEN3 dataset) should be taken with a grain of salt.

That would present a very high error margin in my book, since many complicated processes take place in the ocean that the ARGO sensors may not be measuring.

The graphs from the NODC site (on which Levitus's 2012 paper was based) show a steady upward trend over the long-term. The 2003-11 period is too short to be statistically robust. The above chart also excludes the impact of sub-700m oceanic heat content.

http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/heat_content55-07.png

http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/heat_content2000m.png

[Snow_Miser]

Don, have you ever taken the time to compare the GISS surface maps with the satellite temperature maps? The interesting thing is that the temperature anomalies usually match quite well across most of the earth, suggesting a high correlation between surface temps and LT temps. However, there are often a few areas where GISS is notably warmer than the satellite maps, and that is enough to create warmer anomalies (aside from the baseline differences).

I actually think that GISS for this past month is cooler than the satellites.

[donsutherland1]

Don, have you ever taken the time to compare the GISS surface maps with the satellite temperature maps? The interesting thing is that the temperature anomalies usually match quite well across most of the earth, suggesting a high correlation between surface temps and LT temps. However, there are often a few areas where GISS is notably warmer than the satellite maps, and that is enough to create warmer anomalies (aside from the baseline differences).

I've seen the differences. The literature has also noted that the lower troposphere has been warming more slowly than the surface. That might help explain the difference between surface temperatures and satellite measures of the lower tropospheric temperatures. I'm not sure that one should expect lower tropospheric trends to be much closer to surface trends than they are. The NCDC dataset is also fairly consistent with GISS, albeit with some minor differences when one uses a common base period. The BEST project's own dataset is also reasonably consistent. Therefore, I believe the GISS dataset provides a reasonable, even if imperfect, idea of surface temperature trends. Of course, things could change with later data, especially if one or more of the datasets diverge.

[Snow_Miser]

The graphs from the NODC site (on which Levitus's 2012 paper was based) show a steady upward trend over the long-term. The 2003-11 period is too short to be statistically robust. The above chart also excludes the impact of sub-700m oceanic heat content.

http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/heat_content55-07.png

Quick question.

Hansen's assessment of the temperatures and heat content of the upper ocean from 2005-2011 is considered to be adequate, but a trend from 2003-2012 is not, because it is too short of a timeframe? Am I missing something here?

Our deep ocean data is extremely poor, and should be taken with an even larger grain of salt than the 0-700 m OHC datasets.

[nzucker]

Quick question.

Hansen's assessment of the temperatures and heat content of the upper ocean from 2005-2011 is considered to be adequate, but a trend from 2003-2012 is not, because it is too short of a timeframe? Am I missing something here?

Our deep ocean data is extremely poor, and should be taken with an even larger grain of salt than the 0-700 m OHC datasets.

The Schuckmann deep OHC data, however, does account for much of the "missing energy," I believe.

[ORH_wxman]

I actually think that GISS for this past month is cooler than the satellites.

GISS has been actually cooler than UAH in the past 1-2 years narrowing their divergence pre-2010...to the point now where GISS' trend is smaller than UAH in the past 10+ years...GISS has a -0.02C per decade since the start of '02 while UAH is +0.02C per decade....the difference is statistically insignificant, however. But the fact they have converged over the past couple years makes them fairly reliable in the longer run.

At one point a couple years ago, I believe the trend was about +0.14C per decade for UAH and +0.17C per decade for GISS starting in 1979 when UAH began its records and the recent trends have made the figures now +0.136C per decade and +0.153C per decade respectively....less than 0.02C per decade difference now.

[donsutherland1]

Quick question.

Hansen's assessment of the temperatures and heat content of the upper ocean from 2005-2011 is considered to be adequate, but a trend from 2003-2012 is not, because it is too short of a timeframe? Am I missing something here?

Our deep ocean data is extremely poor, and should be taken with an even larger grain of salt than the 0-700 m OHC datasets.

There are some differences:

1. Hansen was not saying that the 2005-2011 period was representative of trends in OHC. To do so would run into the same issues concerning statistical robustness.

2. Hansen was attempting to measure the impact of the solar minimum on the earth's energy imbalance. That's where this short period comes into play. The period, itself, is not necessarily representative of the long-term and Hansen's only point was that during the short period, the energy imbalance persisted. The continuing existence of that energy imbalance suggests that the observed warming is not largely a solar-driven outcome.

Finally, I agree that there is uncertainty with the OHC measurements, particularly the deeper ones. As far as I know, the uncertainty has not been found to be so great that the data are unusable.

[Snow_Miser]

The Schuckmann deep OHC data, however, does account for much of the "missing energy," I believe.

If you look at the Tisdake graph I posted a page ago, you can see that this featured a dip in OHC at around 2005.. Conveniently, the Von Schuckmann OHC chart on Skeptical Science begins at this dip in OHC on the NODC dataset maximizing any possible increase during this time period.

The fact of the matter is that our deep ocean data is so poor that it should be taken with a grain of salt, regardless if it accounts for any missing energy or not.

[Snow_Miser]

There are some differences:

1. Hansen was not saying that the 2005-2011 period was representative of trends in OHC. To do so would run into the same issues concerning statistical robustness.

2. Hansen was attempting to measure the impact of the solar minimum on the earth's energy imbalance. That's where this short period comes into play. The period, itself, is not necessarily representative of the long-term and Hansen's only point was that during the short period, the energy imbalance persisted. The continuing existence of that energy imbalance suggests that the observed warming is not largely a solar-driven outcome.

Finally, I agree that there is uncertainty with the OHC measurements, particularly the deeper ones. As far as I know, the uncertainty has not been found to be so great that the data are unusable.

I got the impression from the paper that they were using OHC as a metric for whether the Earth was still in an energy imbalance or not. They were determining this from an ARGO dataset which measures changes in the water temperature of the upper ocean.

As I said, that is assuming that the data is right. The fact that there is 1 Argo sensor for every 160000 square kilometers of water is a reason for skepticism about the accuracy of the dataset, since many things could be happening in the ocean that the ARGO sensor many kilometers away may not be aware of, as the ocean contains many complicated processes that take place there. Errors can accumulate, and we could actually be left without an imbalance at all.

I never claimed that the deep ocean data should be thrown away, I'm simply saying that no definite conclusions should be made with a dataset that has reasonable uncertainty.

[Snow_Miser]

GISS has been actually cooler than UAH in the past 1-2 years narrowing their divergence pre-2010...to the point now where GISS' trend is smaller than UAH in the past 10+ years...GISS has a -0.02C per decade since the start of '02 while UAH is +0.02C per decade....the difference is statistically insignificant, however. But the fact they have converged over the past couple years makes them fairly reliable in the longer run.

At one point a couple years ago, I believe the trend was about +0.14C per decade for UAH and +0.17C per decade for GISS starting in 1979 when UAH began its records and the recent trends have made the figures now +0.136C per decade and +0.153C per decade respectively....less than 0.02C per decade difference now.

Such an occurrence makes me a little more skeptical about a few papers which claimed that half of the warming trend on the surface temperature datasets was due to the urbanization bias, since GISS is running cooler than UAH now, and the temperature trends are now about roughly the same.

[tacoman25]

GISS has been actually cooler than UAH in the past 1-2 years narrowing their divergence pre-2010...to the point now where GISS' trend is smaller than UAH in the past 10+ years...GISS has a -0.02C per decade since the start of '02 while UAH is +0.02C per decade....the difference is statistically insignificant, however. But the fact they have converged over the past couple years makes them fairly reliable in the longer run.

At one point a couple years ago, I believe the trend was about +0.14C per decade for UAH and +0.17C per decade for GISS starting in 1979 when UAH began its records and the recent trends have made the figures now +0.136C per decade and +0.153C per decade respectively....less than 0.02C per decade difference now.

Well, I believe GISS set a new global temp record in 2010 while UAH didn't. It seems that since 1998, it has been ENSO neutral or Ninos where GISS has been warmer than UAH: see especially 2005, 2007, 2009 and 2010.

Regardless, while UAH has warmed some in comparison RSS has cooled...so the satellite LT temps remain cooler than GISS surface overall.

[Snow_Miser]

Well, I believe GISS set a new global temp record in 2010 while UAH didn't. It seems that since 1998, it has been ENSO neutral or Ninos where GISS has been warmer than UAH: see especially 2005, 2007, 2009 and 2010.

Regardless, while UAH has warmed some in comparison RSS has cooled...so the satellite LT temps remain cooler than GISS surface overall.

I believe that GISS has 2010 tied with 2005 for the warmest year on record.

[ORH_wxman]

Well, I believe GISS set a new global temp record in 2010 while UAH didn't. It seems that since 1998, it has been ENSO neutral or Ninos where GISS has been warmer than UAH: see especially 2005, 2007, 2009 and 2010.

Regardless, while UAH has warmed some in comparison RSS has cooled...so the satellite LT temps remain cooler than GISS surface overall.

I believe the lack of arctic data is making the cooling trend on RSS and Hadcrut3 too strong. That said, there are still some divergences and UAH/GISS are not perfect by any stretch. Even outside of the arctic there are issues.

I don't think any of the issues though would drastically change the temperature data set. It could change it by a few hundreths per decade which is statistically significant, but not a whole new complexion when analyzing the temperature record. Like the Watts paper for example...if that got peer reviewed after adding in TOBs and a few other tweaks (which it would need to do to get published)...it might lower the trend from 1979 on the surface from around 0.16C per decade to maybe 0.12C or so. That would be a significant change, but not an overwhelimg one where we need to reassess the entire temperature data set. RSS is 0.133C per decade since '79 and UAH is 0.135C per decade.

It would be tough to prove much lower than 0.12C per decade on the sfc I would think.

[donsutherland1]

FWIW, looking at the recent "slow" increase in global temperatures, I believe the full impact of rising atmospheric CO2 is being held partially at bay due to the flip in the PDO.

I constructed a simple linear model based on 30-year trends in:

1) The PDO (leading oceanic cycle, fairly predictable cycle)

2) Atmospheric CO2 concentration

Given the relatively flat TSI and its negligible impact on the coefficient of determination, I excluded TSI.

I then took numbers for the PDO based on the previous shift to a PDO- (the 30-year moving average would be around +0.05 in 2020 and -0.40 in 2030). I also assumed that the 30-year moving average for atmospheric CO2 would increase by 14 PPM per decade and 16 PPM per decade (a little slower than that for the last decade on the basis that there would be some relative increase in usage of renewable energy). The 16 PPM figure is probably the more realistic one (slow innovation/slow adoption of renewable energy).

I ran the numbers for the 2011-20 and 2021-30 decades. All the temperature data was based on GISS (land and ocean anomalies).

For context:

2001-10: +0.546°C Actual outcome for reference

Warmest year: +0.63°C, 2010

Here are the numbers I came up with:

Historic PDO Decline:

Scenario 1: 30-Year Moving Average for CO2 rises by 14 PPM/decade:

2011-2020: +0.531°C

2021-2030: +0.664°C

Scenario 2: 30-Year Moving Average for CO2 rises by 16 PPM/decade:

2011-2020: +0.582°C

2021-2030: +0.715°C

Aggressive PDO Decline:

If one were more aggressive with the PDO, and assumed figures of -0.15 and -0.75 (deeper than the last PDO-), the data would be a little cooler, but the 2021-2030 period would be notably warmer than the 2001-10 timeframe:

Scenario 1: 30-Year Moving Average for CO2 rises by 14 PPM/decade:

2011-2020: +0.527°C

2021-2030: +0.661°C

Scenario 2: 30-Year Moving Average for CO2 rises by 16 PPM/decade:

2011-2020: +0.578°C

2021-2030: +0.711°C

All said, consistent with the literature, the impact of the anthropogenic forcing is likely to increase over time relative to other forcings and oceanic cycles. The shift in the PDO cycle might be blunting some of the warming at present, but that could be a short-lived mitigating effect. My very simple model points to that outcome. The far more robust climate models used by IPCC also point to that outcome. Finally, the increase from 2001-10 to 2021-30 is faster than the observed 0.06°C/decade increase during the 2001-10 period but slower than the +0.17°C/decade increase seen over the past 30 years. The rate of increase during the 2021-30 period is closer to the 30-year rate, suggesting that whatever (PDO?) was holding back the rate of increase had largely lost its ability to do so.

[Snow_Miser]

FWIW, looking at the recent "slow" increase in global temperatures, I believe the full impact of rising atmospheric CO2 is being held partially at bay due to the flip in the PDO.

I constructed a simple linear model based on 30-year trends in:

1) The PDO (leading oceanic forcing, fairly predictable cycle)

2) Atmospheric CO2 concentration

Given the relatively flat TSI and its negligible impact on the coefficient of determination, I excluded TSI.

I then took numbers for the PDO based on the previous shift to a PDO- (the 30-year moving average would be around +0.05 in 2020 and -0.40 in 2030). I also assumed that the 30-year moving average for atmospheric CO2 would increase by 14 PPM per decade and 16 PPM per decade (a little slower than that for the last decade on the basis that there would be some relative increase in usage of renewable energy).

I ran the numbers for the 2011-20 and 2021-30 decades. All the temperature data was based on GISS (land and ocean anomalies).

For context:

2001-10: +0.546°C Actual outcome for reference

Warmest year: +0.63°C, 2010

Here are the numbers I came up with:

Historic PDO Decline:

Scenario 1: 30-Year Moving Average for CO2 rises by 14 PPM/decade:

2011-2020: +0.531°C

2021-2030: +0.664°C

Scenario 2: 30-Year Moving Average for CO2 rises by 16 PPM/decade:

2011-2020: +0.582°C

2021-2030: +0.715°C

Aggressive PDO Decline:

If one were more aggressive with the PDO, and assumed figures of -0.15 and -0.75 (deeper than the last PDO-), the data would be a little cooler, but the 2021-2030 period would be notably warmer than the 2001-10 timeframe:

Scenario 1: 30-Year Moving Average for CO2 rises by 14 PPM/decade:

2011-2020: +0.527°C

2021-2030: +0.661°C

Scenario 2: 30-Year Moving Average for CO2 rises by 16 PPM/decade:

2011-2020: +0.578°C

2021-2030: +0.711°C

All said, consistent with the literature, the impact of the anthropogenic forcing is likely to increase over time relative to other forcings and oceanic cycles. The shift in the PDO cycle might be blunting some of the warming at present, but that could be a short-lived mitigating effect. My very simple model points to that outcome. The far more robust climate models used by IPCC also point to that outcome. Finally, the increase from 2001-10 to 2021-30 is faster than the observed 0.06°C/decade increase during the 2001-10 period but slower than the +0.17°C/decade increase seen over the past 30 years. The rate of increase during the 2021-30 period is closer to the 30-year rate, suggesting that whatever (PDO?) was holding back the rate of increase had largely lost its ability to do so.

You are forgetting about the total solar forcing actually being 7-8 times larger than the irradiance forcing that I posted about a page ago.

You also agree with Isotherm to a degree that the -PDO has had a significant reason for why Globak temperatures have plateued for 10 or so years now, which is interesting, given your different views on solar variability impacts on climate change.