Global Average Temperature 2024

[chubbs]

1 hour ago, nflwxman said:

Been several years since I've posted here, but between the recent trends in global temperature, and increased rate of growth in levels of CO2 measured, it's clear we are not in for a good 2030 - 2045 as a species.

Mass migration that climate scientists predicted is already happening and clearly causing the geopolitical stresses. Amazing that the media has not acknowledged the truth of that prediction from nearly 20 years ago.

Good to see you post again. Congrats on the call you made during the hiatus for 0.2C/decade warming. May end up low, but at least you were in the right neighborhood, unlike the rest of us.

 

[Typhoon Tip]

53 minutes ago, GaWx said:

 Indeed. Here’s Jan of 2025 using 1951-80 as the base: note how much of the US lower 48 was cold (well predicted several weeks in advance by Euro Weeklies by the way) and that it was the largest cold area on the globe:

Is that real tho ?

I mean I don't doubt that it is but I just went over to NASA's interactive page that runs the map request for GHCNv4 Tv5 and it says it's not available for Jan 2025

Do you have another link ?

[GaWx]

1 hour ago, Typhoon Tip said:

Is that real tho ?

I mean I don't doubt that it is but I just went over to NASA's interactive page that runs the map request for GHCNv4 Tv5 and it says it's not available for Jan 2025

Do you have another link ?

I don’t have another link.

[chubbs]

5 hours ago, Typhoon Tip said:

Is that real tho ?

I mean I don't doubt that it is but I just went over to NASA's interactive page that runs the map request for GHCNv4 Tv5 and it says it's not available for Jan 2025

Do you have another link ?

Here's a link. If you dig on website you can find all the details. This is usually the first estimate using GHCN to come out each month.

https://moyhu.blogspot.com/

[chubbs]

Ceres net radiation updated through last November. Net radiation continues to bottom out, consistent with transition to la nina, as nino warmth is radiated to space. Have to go back to 2009/10 for nino-related dip as large as current. However, this cycle is bottoming out at elevated level similar to recent dips, so would expect rapid warming to continue.

[Typhoon Tip]

https://phys.org/news/2025-02-earth-15c-global-limit-major.html

[bdgwx]

On 2/16/2025 at 8:26 AM, chubbs said:

However, this cycle is bottoming out at elevated level similar to recent dips, so would expect rapid warming to continue.

The fact that the bottom is around 1 W.m-2 is concerning. Some estimates of sensitivity put us at 1 C per W.m-2. That means there could be 1 C of warming still in the pipeline without any additional forcing. Yikes.

[HailMan06]

1 hour ago, bdgwx said:

The fact that the bottom is around 1 W.m-2 is concerning. Some estimates of sensitivity put us at 1 C per W.m-2. That means there could be 1 C of warming still in the pipeline without any additional forcing. Yikes.

Which would theoretically mean that we will reach equilibrium at ~2.5C above the preindustrial level even if we stopped emitting all GHG’s today. Also assuming no carbon sequestration or geo engineering.

[bluewave]

Another piece of the puzzle as to why global temperatures have been rising so quickly recently.

 

 

[bdgwx]

[Hansen et al. 2025] - Global Warming Has Accelerated

2024 comes to end with Hansen (and cohorts) calling it. Global warming has accelerated.

Those who track my posts know that I'm more pragmatic and conservative in general in regard to global warming perhaps even to the point that some might call me a skeptic though that would obviously mischaracterize my position. I just simply take a more middle-of-the-road IPCC style position. And I've said before that I'm currently Team Mann on this particular topic. However, I've also said that my conservative position is becoming more untenable by the year. I'm still not quite ready to switch over to Team Hansen, but I have to admit he has taken the lead in the debate...at least for now.

Are you Team Mann or Team Hansen?

[Typhoon Tip]

It’s all way worse already than science is aware. 

Put it this way … the state of the science is about as aware of how bad it already really is, as they were in 2022 that 2023 would observe the global heat explosion …

 

[chubbs]

12 hours ago, bdgwx said:

[Hansen et al. 2025] - Global Warming Has Accelerated

2024 comes to end with Hansen (and cohorts) calling it. Global warming has accelerated.

Those who track my posts know that I'm more pragmatic and conservative in general in regard to global warming perhaps even to the point that some might call me a skeptic though that would obviously mischaracterize my position. I just simply take a more middle-of-the-road IPCC style position. And I've said before that I'm currently Team Mann on this particular topic. However, I've also said that my conservative position is becoming more untenable by the year. I'm still not quite ready to switch over to Team Hansen, but I have to admit he has taken the lead in the debate...at least for now.

Are you Team Mann or Team Hansen?

An interesting question. Stepping back don't think that Team Mann or Hanson are that far apart. They are still on Team Climate Science. Saw a chart recently, but can't recall where, so can't post, that showed that Hanson's yellow cone overlay the CMIP6 projections, i.e., acceleration is expected due to an increase in forcing. However, think that the Mann/IPCC team is losing unfortunately. As I will explain below.

Hanson is right that aerosols are key for untangling our recent climate history. The chart below taken from a recent Climate Brink blog (link below) illustrates this. Aerosols have been masking the effects of CO2 and other GHG. There have been 3 broad GHG and aerosol forcing regimes (dates rough): 1) Pre-1970 where aerosols increased at roughly the same pace as GHG and masked almost all GHG warming, 2) 1970-2014 where aerosol emissions stabilized due to increasing clean air regulation allowing a steady rise in net man-made forcing (GHG+aerosols) as GHG continued to increase and 3) The last decade or so with decreasing aerosols which unmasked GHG in the atmosphere causing the rate of forcing to increase. We are now getting the effect of new GHG as they are emitted, plus the old GHG that had been masked. Temperatures have tracked forcing (warming rates and dates rough): 1) Before 1970 - stable, 2) 1970-2014: steady 0.18 increase, 3) Post 2014: 0.25+ per decade. 

Of course the regimes didn't change as suddenly and other factors have played a role as described in the Hanson paper: sun, volcanoes, shipping rules, etc. Hanson is also right that an increasing aerosol effect implies higher climate sensitivity when using recently observed temperatures to estimate climate sensitivity.  However, there are other ways of estimating climate sensitivity, i.e, Hanson is underestimating the uncertainty in ECS. I don't see enough evidence that climate sensitivity is at the high end. What has happened though is the low end has been lost, ECS is not under 3, recent science and the acceleration in temperatures make that clear. My personal range is 3-4C per CO2 doubling.

More important than climate sensitivity, it is clear that policy and emissions aren't following any IPCC scenario; and, with the election of Trump aren't likely to in the near future. We've made some progress on CO2 as the economic  position of coal and renewables has changed, taking CO2 off the worst case path. However non-CO2 pollutants, aerosols (decreasing too fast), methane and N2O, are all on worst case paths and total net forcing is increasing at about the same rate as RCP85. The only good news is that the rapid increase in forcing is temporary, there are only so many aerosols to be eliminated.

So where does that leave us? In a rapidly changing climate unfortunately. The masking effect of aerosols has fooled us and helped put us on a path that maximizes climate shock. We masked GHG warming for a long time while we slowly added GHG to the atmosphere. Now we are unmasking at a relatively rapid rate, without serious emission control. A dangerous policy combination. We are headed toward our climate future at an accelerating rate, while at the same time not preparing for the consequences. Buckle up.

https://www.theclimatebrink.com/p/exploring-the-drivers-of-modern-global

[Typhoon Tip]

3 hours ago, chubbs said:

An interesting question. Stepping back don't think that Team Mann or Hanson are that far apart. They are still on Team Climate Science. Saw a chart recently, but can't recall where, so can't post, that showed that Hanson's yellow cone overlay the CMIP6 projections, i.e., acceleration is expected due to an increase in forcing. However, think that the Mann/IPCC team is losing unfortunately. As I will explain below.

Hanson is right that aerosols are key for untangling our recent climate history. The chart below taken from a recent Climate Brink blog (link below) illustrates this. Aerosols have been masking the effects of CO2 and other GHG. There have been 3 broad GHG and aerosol forcing regimes (dates rough): 1) Pre-1970 where aerosols increased at roughly the same pace as GHG and masked almost all GHG warming, 2) 1970-2014 where aerosol emissions stabilized due to increasing clean air regulation allowing a steady rise in net man-made forcing (GHG+aerosols) as GHG continued to increase and 3) The last decade or so with decreasing aerosols which unmasked GHG in the atmosphere causing the rate of forcing to increase. We are now getting the effect of new GHG as they are emitted, plus the old GHG that had been masked. Temperatures have tracked forcing (warming rates and dates rough): 1) Before 1970 - stable, 2) 1970-2014: steady 0.18 increase, 3) Post 2014: 0.25+ per decade. 

Of course the regimes didn't change as suddenly and other factors have played a role as described in the Hanson paper: sun, volcanoes, shipping rules, etc. Hanson is also right that an increasing aerosol effect implies higher climate sensitivity when using recently observed temperatures to estimate climate sensitivity.  However, there are other ways of estimating climate sensitivity, i.e, Hanson is underestimating the uncertainty in ECS. I don't see enough evidence that climate sensitivity is at the high end. What has happened though is the low end has been lost, ECS is not under 3, recent science and the acceleration in temperatures make that clear. My personal range is 3-4C per CO2 doubling.

More important than climate sensitivity, it is clear that policy and emissions aren't following any IPCC scenario; and, with the election of Trump aren't likely to in the near future. We've made some progress on CO2 as the economic  position of coal and renewables has changed, taking CO2 off the worst case path. However non-CO2 pollutants, aerosols (decreasing too fast), methane and N2O, are all on worst case paths and total net forcing is increasing at about the same rate as RCP85. The only good news is that the rapid increase in forcing is temporary, there are only so many aerosols to be eliminated.

So where does that leave us? In a rapidly changing climate unfortunately. The masking effect of aerosols has fooled us and helped put us on a path that maximizes climate shock. We masked GHG warming for a long time while we slowly added GHG to the atmosphere. Now we are unmasking at a relatively rapid rate, without serious emission control. A dangerous policy combination. We are headed toward our climate future at an accelerating rate, while at the same time not preparing for the consequences. Buckle up.

https://www.theclimatebrink.com/p/exploring-the-drivers-of-modern-global

 

If Hansen is right that aerosols are a kind of 'silver bullet' physical cause for the surge in global heat performance in 2023 ( ...continuing 2024  etc..), that's a very bad look for the ambit of the field/science.

Why?  because one knew that was coming.  After all the science spanning the last three decades, from posit to super computing and back, no one or source that I can recall put out a prediction that said, "Warning:  in February of 2023 a geological event of planetary scale will occur"   

And it's that arithmetic that bothers me. That one factor, aerosols and consequence, was missed.   So since the Industrial Revolution ( and at some discrete scale it likely could be scienced that man's control over fire is when it all really began ... ) yeah... we have an idea of chemistry changes in the atmosphere, more importantly, that which is contributed from Human activities ... but in so far as "HOW" exactly that will manifest consequences? 

If we're missing one factor::big consequence scenarios, the likes of which can move the needle so fast at the scale of an entire planet, that doesn't sense like any predictions for the rest of this century and beyond are very credible, then.  When we have to factor in a compendium of secondary ... tertiary feed-back harmonic consequences, it really sinks one's hopes. 

It almost senses like we are witnessing a relativistic, slow moving climate explosion already. From a human's vantage and perception of events in time there's no p-wave or shock to signal the detonation has occurred.  But, relative to geological scales it's moving along at "explosion" rates. 

Yet again .. I come back to my core tenet in why the sense of urgency lags.  It is because the factual nature of climate change's objectiveness is challenged to appeal to any of the five senses, of the individual, at any given moment.  This is intuitively going to be a disadvantage when then integrating that experience in shaping the motivations at group scales.  People respond to what is inimical via at least one of the corporeal senses, first. They don't motivate based upon mere advice - particularly when the scope of the advice is so vast.  "If it's so big, why can't I see it?"   There's also a ginormous intellectual capacity gap in humanity, one where those privy to the perils of climate change and in a willingness - because of the imperative it all implies - to accept the objective reality, are the minority. To the ballast of population, it is largely untenable beyond hearing someone else's advice.  That's a scary proposition for a species boasting north of 8 billion farters.  

For everyone else.. humanity stands on the railroad track of destiny, and the iron beneath their feet whirs with the vibration of what's to come, yet they are too busy arguing over the color shoes they are wearing while in the engagement to really even notice.

[TheClimateChanger]

3 hours ago, chubbs said:

An interesting question. Stepping back don't think that Team Mann or Hanson are that far apart. They are still on Team Climate Science. Saw a chart recently, but can't recall where, so can't post, that showed that Hanson's yellow cone overlay the CMIP6 projections, i.e., acceleration is expected due to an increase in forcing. However, think that the Mann/IPCC team is losing unfortunately. As I will explain below.

Hanson is right that aerosols are key for untangling our recent climate history. The chart below taken from a recent Climate Brink blog (link below) illustrates this. Aerosols have been masking the effects of CO2 and other GHG. There have been 3 broad GHG and aerosol forcing regimes (dates rough): 1) Pre-1970 where aerosols increased at roughly the same pace as GHG and masked almost all GHG warming, 2) 1970-2014 where aerosol emissions stabilized due to increasing clean air regulation allowing a steady rise in net man-made forcing (GHG+aerosols) as GHG continued to increase and 3) The last decade or so with decreasing aerosols which unmasked GHG in the atmosphere causing the rate of forcing to increase. We are now getting the effect of new GHG as they are emitted, plus the old GHG that had been masked. Temperatures have tracked forcing (warming rates and dates rough): 1) Before 1970 - stable, 2) 1970-2014: steady 0.18 increase, 3) Post 2014: 0.25+ per decade. 

Of course the regimes didn't change as suddenly and other factors have played a role as described in the Hanson paper: sun, volcanoes, shipping rules, etc. Hanson is also right that an increasing aerosol effect implies higher climate sensitivity when using recently observed temperatures to estimate climate sensitivity.  However, there are other ways of estimating climate sensitivity, i.e, Hanson is underestimating the uncertainty in ECS. I don't see enough evidence that climate sensitivity is at the high end. What has happened though is the low end has been lost, ECS is not under 3, recent science and the acceleration in temperatures make that clear. My personal range is 3-4C per CO2 doubling.

More important than climate sensitivity, it is clear that policy and emissions aren't following any IPCC scenario; and, with the election of Trump aren't likely to in the near future. We've made some progress on CO2 as the economic  position of coal and renewables has changed, taking CO2 off the worst case path. However non-CO2 pollutants, aerosols (decreasing too fast), methane and N2O, are all on worst case paths and total net forcing is increasing at about the same rate as RCP85. The only good news is that the rapid increase in forcing is temporary, there are only so many aerosols to be eliminated.

So where does that leave us? In a rapidly changing climate unfortunately. The masking effect of aerosols has fooled us and helped put us on a path that maximizes climate shock. We masked GHG warming for a long time while we slowly added GHG to the atmosphere. Now we are unmasking at a relatively rapid rate, without serious emission control. A dangerous policy combination. We are headed toward our climate future at an accelerating rate, while at the same time not preparing for the consequences. Buckle up.

https://www.theclimatebrink.com/p/exploring-the-drivers-of-modern-global

I think we also need to consider the possibility that our estimates for aerosol forcing are incorrect relative to preindustrial, before claiming instead that our estimate of climate sensitivity to carbon dioxide is incorrect. It seems like it was a very smoky, dusty time. Is it not possible that the globally averaged sky is now clearer than it was in the preindustrial times, and that aerosols have shifted from a cooling effect to a warming effect? If this is possible, then, it would not just be unmasking greenhouse warming but also directly contributing (that is, causing) warming relative to preindustrial in recent decades. The question to consider - are human changes in fire suppression and land management perhaps now outweighing human pollution in recent decades? With also a possibility that natural changes set on by warming are contributing... for instance, Sahara dust is predicted to decrease in response to warming. Has that already commenced relative to preindustrial?

[chubbs]

37 minutes ago, Typhoon Tip said:

If Hansen is right that aerosols are a kind of 'silver bullet' physical cause for the surge in global heat performance in 2023 ( ...continuing 2024  etc..), that's a very bad look for the ambit of the field/science.

Why?  because one knew that was coming.  After all the science spanning the last three decades, from posit to super computing and back, no one or source that I can recall put out a prediction that said, "Warning:  in February of 2023 a geological event of planetary scale will occur"   

And it's that arithmetic that bothers me. That one factor, aerosols and consequence, was missed.   So since the Industrial Revolution ( and at some discrete scale it likely could be scienced that man's control over fire is when it all really began ... ) yeah... we have an idea of chemistry changes in the atmosphere, more importantly, that which is contributed from Human activities ... but in so far as "HOW" exactly that will manifest consequences? 

If we're missing one factor::big consequence scenarios, the likes of which can move the needle so fast at the scale of an entire planet, that doesn't sense like any predictions for the rest of this century and beyond are very credible, then.  When we have to factor in a compendium of secondary ... tertiary feed-back harmonic consequences, it really sinks one's hopes. 

It almost senses like we are witnessing a relativistic, slow moving climate explosion already. From a human's vantage and perception of events in time there's no p-wave or shock to signal the detonation has occurred.  But, relative to geological scales it's moving along at "explosion" rates. 

Yet again .. I come back to my core tenet in why the sense of urgency lags, it's that the factual nature of climate change's objectiveness is not appealing to the five sense of the individual, at any given moment.  This is intuitively going to be a disadvantage when integrating that experience at the group scales.  People respond to what is inimical via at least one of the corporeal senses, first. They don't motivate based upon mere advice - particularly when the scope of the advice is so vast.  "If it's so big, why can't I see it?"   There's also a ginormous intellectual capacity gap in humanity, one were the those privy to the perils of climate change, and a willingness - because of the imperative of it - to accept the objective reality, do not present the ballast of population.  That's a scary proposition for a species boasting north of 8 billion farters.  

For everyone else.. humanity stands on the railroad track of destiny, and the iron beneath their feet whirs with the vibration of what's to come, yet they are too busy arguing over the color shoes they are wearing while in the engagement to really even notice.

You make good points but I have a few bones to pick. I don't think silver bullet is the right word. Its never just one thing in weather/climate. Aerosols help explain the acceleration in temperatures in the past 15 years, but other factors had to align to produce a spike in 2023. I would not put much of the blame on science either. They have been ringing the climate alarm bell for a while and have long recognized aerosols as a key uncertainty. The lack of concern/urgency has caused aerosol science to be underfunded. Agree that climate's complexity make it difficult to deal with; but, also think our own human nature is important. We have certain attributes that get in the way of facing climate and certain other problems: short-term focus, self interest, greed, resistance to change,  confirmation bias, denial, etc.

[TheClimateChanger]

8 minutes ago, TheClimateChanger said:

I think we also need to consider the possibility that our estimates for aerosol forcing are incorrect relative to preindustrial, before claiming instead that our estimate of climate sensitivity to carbon dioxide is incorrect. It seems like it was a very smoky, dusty time. Is it not possible that the globally averaged sky is now clearer than it was in the preindustrial times, and that aerosols have shifted from a cooling effect to a warming effect? If this is possible, then, it would not just be unmasking greenhouse warming but also directly contributing (that is, causing) warming relative to preindustrial in recent decades. The question to consider - are human changes in fire suppression and land management perhaps now outweighing human pollution in recent decades? With also a possibility that natural changes set on by warming are contributing... for instance, Sahara dust is predicted to decrease in response to warming. Has that already commenced relative to preindustrial?

Note that millions of acres of rangeland would burn each and every year. Late summer until the start of winter were clearly very hazy, smoky periods in the past. Even if this was mostly a seasonal phenomenon, it may be possible that aerosols emitted in this time frame have a greater climate impact than aerosols emitted at other times during the calendar year. Perhaps leading to autumn cooling and an earlier start to winter (more ice and snow). So our modeling simply looking at total emissions of aerosols might also be overlooking the fact that not all emissions are equal, and that emissions during the summer and fall are much more impactful on the global climate.

[chubbs]

2 minutes ago, TheClimateChanger said:

Note that millions of acres of rangeland would burn each and every year. Late summer until the start of winter were clearly very hazy, smoky periods in the past. Even if this was mostly a seasonal phenomenon, it may be possible that aerosols emitted in this time frame have a greater climate impact than aerosols emitted at other times during the calendar year. Perhaps leading to autumn cooling and an earlier start to winter (more ice and snow). So our modeling simply looking at total emissions of aerosols might also be overlooking the fact that not all emissions are equal, and that emissions during the summer and fall are much more impactful on the global climate.

Scientists have been looking at preindustrial climate impacts for a while. Burning, land-use change, and agriculture released GHG and aerosols and changed albedo. Not sure what the latest science says, but post-industrial impacts are much larger.   Below is a 2021 write-up I googled up.

https://www.globalpolicyjournal.com/blog/24/02/2021/ruddiman-hypothesis-debated-theory-progresses-along-interdisciplinary-lines

 

[Typhoon Tip]

1 hour ago, chubbs said:

You make good points but I have a few bones to pick. I don't think silver bullet is the right word. Its never just one thing in weather/climate. Aerosols help explain the acceleration in temperatures in the past 15 years, but other factors had to align to produce a spike in 2023. I would not put much of the blame on science either. They have been ringing the climate alarm bell for a while and have long recognized aerosols as a key uncertainty. The lack of concern/urgency has caused aerosol science to be underfunded. Agree that climate's complexity make it difficult to deal with; but, also think our own human nature is important. We have certain attributes that get in the way of facing climate and certain other problems: short-term focus, self interest, greed, resistance to change,  confirmation bias, denial, etc.

It was a response to your sentence:

"Hanson is right that aerosols are key for untangling our recent climate history." 

Beyond which ... I was just being very general in that missive.  You may notice that I didn't cite any other source or study, data or conclusions therein?  that's a red flag for rhetoric vs meaty value.   LOL  Silver bullet may sound strong, but that's just semantic word choice for affect.  Key. Main factor...  whatever -

But, I do believe there is real value/veracity in the idea that there is a range in a kind of consequence spectrum that is quite unknown, more importantly, that planetary ( PLANET ) wide huge movement is a warning that such unknowns have an intrinsic risk

[TheClimateChanger]

35 minutes ago, chubbs said:

Scientists have been looking at preindustrial climate impacts for a while. Burning, land-use change, and agriculture released GHG and aerosols and changed albedo. Not sure what the latest science says, but post-industrial impacts are much larger.   Below is a 2021 write-up I googled up.

https://www.globalpolicyjournal.com/blog/24/02/2021/ruddiman-hypothesis-debated-theory-progresses-along-interdisciplinary-lines

 

I was thinking more on the lines of this study: Reassessment of pre-industrial fire emissions strongly affects anthropogenic aerosol forcing | Nature Communications

Abstract

Uncertainty in pre-industrial natural aerosol emissions is a major component of the overall uncertainty in the radiative forcing of climate. Improved characterisation of natural emissions and their radiative effects can therefore increase the accuracy of global climate model projections. Here we show that revised assumptions about pre-industrial fire activity result in significantly increased aerosol concentrations in the pre-industrial atmosphere. Revised global model simulations predict a 35% reduction in the calculated global mean cloud albedo forcing over the Industrial Era (1750–2000 CE) compared to estimates using emissions data from the Sixth Coupled Model Intercomparison Project. An estimated upper limit to pre-industrial fire emissions results in a much greater (91%) reduction in forcing. When compared to 26 other uncertain parameters or inputs in our model, pre-industrial fire emissions are by far the single largest source of uncertainty in pre-industrial aerosol concentrations, and hence in our understanding of the magnitude of the historical radiative forcing due to anthropogenic aerosol emissions.

[TheClimateChanger]

37 minutes ago, chubbs said:

Scientists have been looking at preindustrial climate impacts for a while. Burning, land-use change, and agriculture released GHG and aerosols and changed albedo. Not sure what the latest science says, but post-industrial impacts are much larger.   Below is a 2021 write-up I googled up.

https://www.globalpolicyjournal.com/blog/24/02/2021/ruddiman-hypothesis-debated-theory-progresses-along-interdisciplinary-lines

 

But on your point, Sam Carana of Arctic News had previously made a good point that total warming may actually already be on the order of 2.3C if we include these preindustrial climate impacts. The total warming is dependent on the choice of baseline, but it should be evident that humanity has been altering the climate for a considerable amount of time prior to the Industrial Revolution. Obviously, the magnitude of such changes pale in comparison to those of the most recent 100 or 150 years; however, they are still very notable compared to natural variations.

Arctic News: pre-industrial

 

[TheClimateChanger]

On 2/5/2025 at 2:51 PM, TheClimateChanger said:

As a follow-up, this is why I have grown increasingly skeptical of natural variation. 

(1) The Medieval Warm Period, Little Ice Age and Roman Warm Periods were made up between the 1950s & 1970s. Prior to this time, the overwhelming view was that there had been little significant variation during the historical time (i.e., since roughly 1-2k years before Christ). Of particular note, the scientists living during the so-called Little Ice Age did not believe they were living in a little ice age. In fact, considering the same evidence offered in support of these variations, they did NOT find any compelling reason to conclude a significant change in climate had occurred.  More importantly, and this is a big point, the modern GLOBAL reconstructions appear to be largely consistent with the prior view. There appears to be little evidence to support the contention that any of these periods were significant deviations from a general long-term cooling trend.

Comically, the so-called "Roman Warm Period" was previously theorized to be a "Roman Cold Period." This older line of belief stemmed from the observation that the height of global development was in northwest Europe and had shifted north with time from the Mediterranean. Thus, there was a belief that the Roman era was somewhat colder (or at least wetter) with a suppressed storm track that would have led to more favorable conditions for widespread agriculture. Conversely, in this theorized colder regime, the conditions in the north and west of Europe would have been colder and less suitable for agriculture, industry and civilizational development. Now, we're simply told by grifters that society always advances during periods of warmth, and warmth is good. I mean, really? While I don't have reason to doubt the current view, which of these two claims about the development of ancient Rome intuitively makes more sense?

(2) The Maunder Minimum, and the concept of grand solar minima, was made up in 1976. For hundreds of years, nobody suggested there was a multi-decadal period with little or no sunspots or solar activity. Scientists from the 1800s and early 1900s, who had previously looked at the same record, concluded that the records before about the middle of the 18th century were incomplete and had worked tirelessly to create an accurate reconstruction of solar activity that extended back to the invention of the telescope. Dr. Rupert Wolf's efforts were thrown by the wayside, in favor of this shocking claim of no sunspot activity. We now have approximately about 275 years of reliable sunspot records, and there has never been a grand solar minimum observed. My question to proponents of the grand solar minimum is - how much longer do we need to observe the sun without a grand solar minimum before we start to question whether there really is such a thing (or, at least, in the sense that the terminology is commonly used today).

Dr. Eddy, who described the Maunder Minimum, had deep ties to the U.S. military, and was not highly regarded by his peers at the time. His ties to the U.S. military certainly provide a compelling reason to create a new history of the sun/earth's climate. And, since the United States dominates this field, this is the only view you get to hear.

Here is a fairly recent Russian paper with a different conclusion:

The Maunder Minimum Is Not as Grand as It Seemed to Be, Zolotova and Ponyavin, 2015. Link: THE MAUNDER MINIMUM IS NOT AS GRAND AS IT SEEMED TO BE - IOPscience

(3) The supposed link between solar minima and cooling temperatures. The exact opposite was believed for hundreds of years. They even quantified the change in temperature during the solar cycle. So, it seems hard to believe that this would have been incorrect?  If you look it up, you might see the suggestion that this was because the scientists incorrectly believed that the dark spots resulted in less TSI. But this is incorrect, it was known that total solar irradiance was somewhat higher, which they considered to be a conundrum, which was resolved by the theory that, in essence, EEPs emitted from the sun could deplete stratospheric ozone, promote changes in cloudiness/storminess by acting as cloud condensation nuclei, and could impact atmospheric and oceanic circulations in ways that would promote arctic outbreaks into the middle latitudes. Today, all of these are now said to be linked to galactic cosmic rays which are said to occur with much greater frequency during solar minimum. If you look up old climate texts, you can actually see where it was previously theorized that something akin to a "grand solar maximum" could potentially lead to a new Ice Age. Make it make sense.

More on the so-called Roman Warm Period. This excerpt from William Henry Dyer's Ancient Rome (1864).

[TheClimateChanger]

1 minute ago, TheClimateChanger said:

More on the so-called Roman Warm Period. This excerpt from William Henry Dyer's Ancient Rome (1864).

Throughout the entire Roman Kingdom and the Republic there was the so-called Subatlantic period, in which the Greek and Etruscan city-states also developed.^[7] It was characterized by cool summers and mild, rainy winters.^[7]

At the same time there were a number of drastic winters, including the complete freezing of the Tiber in 398 BC, 396 BC, 271 BC and 177 BC.^[8] In subsequent centuries the reports of occasional harsh winters became associated with flooding rather than ice on the Tiber.^[8] Evidence for a cooler Mediterranean climate in 600 BC–100 BC comes from remains of ancient harbors at Naples and in the Adriatic which are located about one meter below current water level. Edward Gibbon, citing ancient sources, thought that the Rhine and the Danube were frequently frozen, facilitating the invasion of barbarian armies into the Empire "over a vast and solid bridge of ice".^[9] Suggesting colder climate, Gibbon also contended that during Caesar's time reindeer were commonly found in the forests of modern Poland and Germany, whereas in his time reindeer were not observed south of the Baltic.^[9]

During the reign of Augustus the climate became warmer and the aridity in North Africa persisted.^[10] The biotopes of Heterogaster urticae, which in Roman times occurred farther north than in the 1950s, suggest that in the early Empire mean July temperatures were at least 1 °C above those of the mid-20th-century.^[3] Pliny the Younger wrote that wine and olives were cultivated in more northerly parts of Italy than in the previous centuries,^[4] as did Saserna in the last century BC (both father and son).^[8]

Climate of ancient Rome - Wikipedia

[TheClimateChanger]

Looking at the ancient reports, it would appear the Roman winter was harsher than our own and even appearing harsh to scientists living in the tail end of the so-called Little Ice Age.  It is reported that snow once settled to a depth of seven feet, and on another occasion, snow laid on the ground for fully 40 days in Rome. There are several recorded instances of the Tiber at Rome freezing solid. Now, it's true some of these predate the so-called Roman Warm Period; however, some of the reports overlap. Wikipedia cites 250BC-400AD as the timeframe for the warm period.

Curiously, it looks like this period was first characterized in 1995 and popularized in Nature in 1999. Wikipedia claims it was a "regional" phenomenon, but it's curious that just before this "regional" phenomenon, records from the same region are suggestive of a colder climate - at least during the winter.

The phrase "Roman Warm Period" first appears in a 1995 doctoral thesis.^[5] It was popularized by an article published in Nature in 1999.^[6]

More recent research, including a 2019 analysis based on a much larger dataset of climate proxies, has found that the putative period, along with other warmer or colder pre-industrial periods such as the "Little Ice Age" and "Medieval Warm Period," were regional phenomena, not globally-coherent episodes.^[7] That analysis uses the temperature record of the last 2,000 years dataset compiled by the PAGES 2k Consortium 2017.^[7]

Roman Warm Period - Wikipedia

[TheClimateChanger]

I do wonder if some of these observations of natural warm periods weren't influenced by the progression of the earth's axial tilt and seasonal precession. Looking back in history, the Holocene Climatic Optimum (c. 6kya) would have occurred during a time when the earth's axial tilt was very near its maximal value, which I think occurred around 10kya. Further, perihelion would have occurred during the summertime or early autumn in the Northern Hemisphere, as opposed to its occurrence during wintertime in recent centuries. These would have led to warming, but with a significant seasonal and Hemispheric variation. The Southern Hemisphere would not have warmed as much, although the albedo effects of the melting of snow and ice would likely cause net warming. Summers would be expected to be longer and hotter in the Northern Hemisphere, promoting ice and snow melt. However, winters could still have been surprisingly feisty even into the mid-latitudes as the earth would have been tilted further away from the sun and the distance of the earth to the sun would have been greater in that era.

During the early Roman period (c. 2.5kya), the axial tilt would have declined significantly but still have been greater than today. I believe perihelion would have occurred in or around November. So I wonder if it was simply a case of summers being comparable to modern times, but winters being much harsher? It seems to me the climate should naturally be cooling overall over the past several millenia, with perihelion being aligned so closely to the winter solstice and with the earth's axial tilt gradually decreasing over time.

[TheClimateChanger]

I do wonder if even some of these warmer Pleistocene interglacials might have had surprisingly feisty mid-latitude winters given what I'm learning about precession and Milankovitch cycles which have driven these period glaciations. I know I previously commented about someone who, obviously falsely, suggested DC might have had centuries of poor winters during the Medieval period, but even these interglacials might have presented with more pronounced seasonality than the modern climate. Many of the proxies (ice core, tree rings) would be picking up more heavily on the warmer summers. I think the PETM might be a better analog for future climate, as that seems to be a period of higher GHG concentration. GHG warming would differ in many ways from natural cyclical warming.

If concentrations of carbon dioxide approach PETM levels, can somebody explain why we wouldn't see PETM climatic conditions? Surely the configuration of the continents haven't changed that much over that time frame? And the sun's luminosity should have slightly increased relative to what it was during the early Eocene? Obviously, one difference is during the PETM, there was significantly less polar ice coverage prior to its onset. But over the coming millenia, one would expect this impact to lessen. Delayed, but not denied.

[TheClimateChanger]

1 hour ago, TheClimateChanger said:

I do wonder if even some of these warmer Pleistocene interglacials might have had surprisingly feisty mid-latitude winters given what I'm learning about precession and Milankovitch cycles which have driven these period glaciations. I know I previously commented about someone who, obviously falsely, suggested DC might have had centuries of poor winters during the Medieval period, but even these interglacials might have presented with more pronounced seasonality than the modern climate. Many of the proxies (ice core, tree rings) would be picking up more heavily on the warmer summers. I think the PETM might be a better analog for future climate, as that seems to be a period of higher GHG concentration. GHG warming would differ in many ways from natural cyclical warming.

If concentrations of carbon dioxide approach PETM levels, can somebody explain why we wouldn't see PETM climatic conditions? Surely the configuration of the continents haven't changed that much over that time frame? And the sun's luminosity should have slightly increased relative to what it was during the early Eocene? Obviously, one difference is during the PETM, there was significantly less polar ice coverage prior to its onset. But over the coming millenia, one would expect this impact to lessen. Delayed, but not denied.

One thing you have to wonder about is what is going on behind the scenes. I know a little while back, Elon Musk said he was more worried about CO2 becoming so high that it would be difficult to breathe. But this makes little sense. I was always under the impression that climate impacts would become catastrophic well before we reached those levels of CO2. You have to wonder if the U.S. government doesn't have contingency plans in place for solar radiation management. That comment would only seem to make sense if you believed we could engineer our way out of the temperature rise, but would not be able to withdraw enough carbon to prevent breathing impacts? Given Elon's ties to the U.S. government through SpaceX, you have to wonder if there isn't a plan in place to funnel taxpayer money to SpaceX in exchange for implementation of solar radiation management. In my opinion, we have already accidentally geoengineered our way to a Pliocene climate and seem well on our way to recreating the Eocene or Paleocene, maybe PETM in a bad case. As the U.S. government bureaucracy always has plans for just about every event, you have to assume they know full well how bad things really are. I mean they are blabbing on about a 2.5% chance of an asteroid hitting in 2032 and possibly needing to divert its course. Given how corrupt our government is (and I think people on both sides of the political aisle would agree with that statement), you have to wonder if there's really even an asteroid in danger of striking earth - or if it's not just another scheme to funnel taxpayer money to SpaceX to blow up a fake asteroid.

[chubbs]

Re the Mann vs Hanson discussion above, chart below (updated recently through 2024) shows how man-made forcing has increased in past decade or so leading to an increase in human induced warming. Link below has 2023 paper with details. Chart is for a 2024 update to the paper that is being prepared.

https://essd.copernicus.org/articles/15/2295/2023/

[TheClimateChanger]

15 hours ago, chubbs said:

Re the Mann vs Hanson discussion above, chart below (updated recently through 2024) shows how man-made forcing has increased in past decade or so leading to an increase in human induced warming. Link below has 2023 paper with details. Chart is for a 2024 update to the paper that is being prepared.

https://essd.copernicus.org/articles/15/2295/2023/

Just a perfect storm. Increased human-induced forcing, and it looks like whatever natural processes were in play for a few decades to keep the radiative forcing trend below the human-induced warming trend have reversed over the past several years [as both are now, more or less, on top of one another].