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Solar Activity Not a Key Cause

slo1
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12/30/2013 9:14:50 AM
Posted: 2 years ago
http://www.sciencedaily.com...

The findings overturn a widely held scientific view that lengthy periods of warm and cold weather in the past might have been caused by periodic fluctuations in solar activity.

Research examining the causes of climate change in the northern hemisphere over the past 1000 years has shown that until the year 1800, the key driver of periodic changes in climate was volcanic eruptions. These tend to prevent sunlight reaching Earth, causing cool, drier weather. Since 1900, greenhouse gases have been the primary cause of climate change.


The findings show that periods of low sun activity should not be expected to have a large impact on temperatures on Earth, and are expected to improve scientists' understanding and help climate forecasting.
slo1
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12/30/2013 9:20:26 AM
Posted: 2 years ago
zooey momma!

I don't know that this puts the proverbial nail in the coffin as far as understanding the full effect of solar cycles on climate, but it may have made a decent assessment of a hierarchy of warming causes by intensity.

The aggregate data and studies such as this make the island that the pro industrial - CO2 ignorers stand on smaller and smaller.
Such
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12/30/2013 9:51:47 AM
Posted: 2 years ago
That's not entirely surprising to me... in retrospect, I think it should be pretty obvious that the delicate balance on which our climate depends regarding our relationship with the sun should make it obvious that something like solar activity wouldn't effect a gradual change over time, and would instead cause either an extreme change over a rather short period, or have no real effect at all.

I think this is a losing battle, though. Those that care enough to know about such things aren't the same people that are directly causing pollution issues, and those that are directly causing pollution issues are empowered and given incentive to act on that power by everyone else who neither cares about such things, nor has the power to change it directly.
slo1
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12/30/2013 11:07:43 AM
Posted: 2 years ago
At 12/30/2013 9:51:47 AM, Such wrote:
That's not entirely surprising to me... in retrospect, I think it should be pretty obvious that the delicate balance on which our climate depends regarding our relationship with the sun should make it obvious that something like solar activity wouldn't effect a gradual change over time, and would instead cause either an extreme change over a rather short period, or have no real effect at all.

I think this is a losing battle, though. Those that care enough to know about such things aren't the same people that are directly causing pollution issues, and those that are directly causing pollution issues are empowered and given incentive to act on that power by everyone else who neither cares about such things, nor has the power to change it directly.

You are right. If the overall populace cared they would purchase from companies publishing and reducing their co2 emissions. I guess that is why it is so important to get to the point of truly understanding humanity's impact on our living environment. An informed decision is better than one made in ignorance.
16kadams
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12/30/2013 11:10:02 AM
Posted: 2 years ago
Interesting.
https://www.youtube.com...
https://rekonomics.wordpress.com...
"A trend is a trend, but the question is, will it bend? Will it alter its course through some unforeseen force and come to a premature end?" -- Alec Cairncross
v3nesl
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12/30/2013 11:23:21 AM
Posted: 2 years ago
At 12/30/2013 9:14:50 AM, slo1 wrote:
http://www.sciencedaily.com...

The findings overturn a widely held scientific view that lengthy periods of warm and cold weather in the past might have been caused by periodic fluctuations in solar activity.

Research examining the causes of climate change in the northern hemisphere over the past 1000 years has shown that until the year 1800, the key driver of periodic changes in climate was volcanic eruptions. These tend to prevent sunlight reaching Earth, causing cool, drier weather. Since 1900, greenhouse gases have been the primary cause of climate change.


The findings show that periods of low sun activity should not be expected to have a large impact on temperatures on Earth, and are expected to improve scientists' understanding and help climate forecasting.

So how do they know what the sun activity was in the past? Sounds to me like they guessed. I expected to find that they correlated some measure of radiation (other than heat), but no, they correlated "models", which is another name for guesses.

I wouldn't get too excited about this, sounds to me like the kind of thing you do for a senior project, ya know?
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slo1
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12/30/2013 11:35:14 AM
Posted: 2 years ago
At 12/30/2013 11:23:21 AM, v3nesl wrote:
At 12/30/2013 9:14:50 AM, slo1 wrote:
http://www.sciencedaily.com...

The findings overturn a widely held scientific view that lengthy periods of warm and cold weather in the past might have been caused by periodic fluctuations in solar activity.

Research examining the causes of climate change in the northern hemisphere over the past 1000 years has shown that until the year 1800, the key driver of periodic changes in climate was volcanic eruptions. These tend to prevent sunlight reaching Earth, causing cool, drier weather. Since 1900, greenhouse gases have been the primary cause of climate change.


The findings show that periods of low sun activity should not be expected to have a large impact on temperatures on Earth, and are expected to improve scientists' understanding and help climate forecasting.

So how do they know what the sun activity was in the past? Sounds to me like they guessed. I expected to find that they correlated some measure of radiation (other than heat), but no, they correlated "models", which is another name for guesses.

I wouldn't get too excited about this, sounds to me like the kind of thing you do for a senior project, ya know?

Of course there is no direct method to measure past history. Most of it is pieced together by the quantity of cosmogenic isotopes in ice core samples which are correlated to time by the depth.

I agree that one should not get too excited. It think it was well know that volcanic eruptions which put particulates in the air would have a greater effect on climate, especially because it blocks the sun high in the atmosphere, on the other hand climate skeptics can't use the sun as the magic bullet that proves it has a greater role in climate change than elevated CO2 concentrations in the atmosphere.
16kadams
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12/30/2013 11:50:55 AM
Posted: 2 years ago
So I am looking at the study and found a few issues.

(1) They are using the conventional climate models. These models assume that TSI has little affect on the climate, when this is actually a debated issue in the literature. Further, these models do not account for amplification feedbacks from solar activity. A paper published in Climate of the Past, in 2011 by Varma et al. finds that the sun controls (rather correlates with) ocean patterns which are known to affect regional and global climate. The authors conclude that the sun (likely) drives these cycles, which means the solar variations are amplified by oceanic currents. When they include this, they can account for temperatures over the last 3,000 years. Further, cosmic rays are another hypothesis. Research by Svensmark and Shaviv prove this. Whether or not you agree with it (even I am a bit skeptical of the cosmic ray theory), there are many amplification ideas which this paper didn't even try to account for.

(2) Look at their solar data in the study. They change their data source from Steinhibler et al to Wang et al around the beginning of the 19th century. If they had kept the same data source they would have found stronger solar effects in the 20th century. Steinhibler and Beer 2013 predict a strong cooling if the solar patterns continue on the current path -- therefore I suspect had they stayed consistent with their former source, their conclusions would have been different.

(3) The study did not look into solar activity accumulated over time. Studies which do this claim that this single phenomena explains 95% of the climate change over the last 400 years or so. The study was also able to account for the 1950-1970 slight cooling and 1973-2005 fast warming using solar data. (see Dan Pagburn, over at hockeyschtick).

Now, another study exactly like the one cited found opposite conclusions. A study published in Earth and Planetary Science Letters found that solar activity explains climate change over the last 200,000 years.

Further, how the study claims volcanoes cause large temperature changes over time (short term they are vital) I do not know. For example, the Little Ice Age, to my knowledge, wasn't a period of large volcanic activity but was the most recent large dip in temperatures. Further, since the study claims the sun does not affect our climate, how would the study explain hot house and ice age periods of our climate?

Further, the study uses tree rings as one of its main sources of temperature data. As we know, mikes nature trick replaces tree rings with more accurate thermometer data around 1970, the divergence problem. However, as tree rings cannot produce modern temperature, why assume they are accurate in the past? Indeed, the study changes their solar data which makes the sun look less potent in the modern era AND use, at least some of the time, flawed temperature proxies.

Further, the study said GHG caused temperature changes since 1900. However, only 0.1 degree C from 1900 - 1940 can be explained by human created GHG (this is citing the fellow from skeptical science, the Dana guy if I recall. I think he wrote this while responding to the CATO paper). However, about 0.4 degrees C of warming occurred over that period. And around 1900, very little of the CO2 in the atmosphere was human induced, and the levels were fairly low. Therefore, the study doesn't really support other research on the topic.

Again, it is impossible for volcanoes to explain the Little Ice Age, whereas Perry and Hsu 2000 in PNAS find that the sun correlates extremely well with these LIA and other similar periods of time, as well as noting that humans flourished when the sun was at an all time high. To quote them, "The contribution of solar-output variations to climate change may be significant". Note they said this AFTER they said the modern warming being caused solely by CO2 is unlikely.

I am not saying the study you cited is wrong. It is extremely interesting (the parts I have read), and looks to have insights to the current warming debate. Studies like this one are vital to the debate. However, to say solar variations are not one of the key causes to climate change over that period is preposterous.
https://www.youtube.com...
https://rekonomics.wordpress.com...
"A trend is a trend, but the question is, will it bend? Will it alter its course through some unforeseen force and come to a premature end?" -- Alec Cairncross
16kadams
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12/30/2013 11:52:11 AM
Posted: 2 years ago
You can get the study here: http://www.nature.com...
https://www.youtube.com...
https://rekonomics.wordpress.com...
"A trend is a trend, but the question is, will it bend? Will it alter its course through some unforeseen force and come to a premature end?" -- Alec Cairncross
16kadams
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12/30/2013 11:55:19 AM
Posted: 2 years ago
At 12/30/2013 11:50:55 AM, 16kadams wrote:
So I am looking at the study and found a few issues.

(1) They are using the conventional climate models. These models assume that TSI has little affect on the climate, when this is actually a debated issue in the literature. Further, these models do not account for amplification feedbacks from solar activity. A paper published in Climate of the Past, in 2011 by Varma et al. finds that the sun controls (rather correlates with) ocean patterns which are known to affect regional and global climate. The authors conclude that the sun (likely) drives these cycles, which means the solar variations are amplified by oceanic currents. When they include this, they can account for temperatures over the last 3,000 years. Further, cosmic rays are another hypothesis. Research by Svensmark and Shaviv prove this. Whether or not you agree with it (even I am a bit skeptical of the cosmic ray theory), there are many amplification ideas which this paper didn't even try to account for.

(2) Look at their solar data in the study. They change their data source from Steinhibler et al to Wang et al around the beginning of the 19th century. If they had kept the same data source they would have found stronger solar effects in the 20th century. Steinhibler and Beer 2013 predict a strong cooling if the solar patterns continue on the current path -- therefore I suspect had they stayed consistent with their former source, their conclusions would have been different.

(3) The study did not look into solar activity accumulated over time. Studies which do this claim that this single phenomena explains 95% of the climate change over the last 400 years or so. The study was also able to account for the 1950-1970 slight cooling and 1973-2005 fast warming using solar data. (see Dan Pagburn, over at hockeyschtick).

Now, another study exactly like the one cited found opposite conclusions. A study published in Earth and Planetary Science Letters found that solar activity explains climate change over the last 200,000 years.

Further, how the study claims volcanoes cause large temperature changes over time (short term they are vital) I do not know. For example, the Little Ice Age, to my knowledge, wasn't a period of large volcanic activity but was the most recent large dip in temperatures. Further, since the study claims the sun does not affect our climate, how would the study explain hot house and ice age periods of our climate?

Further, the study uses tree rings as one of its main sources of temperature data. As we know, mikes nature trick replaces tree rings with more accurate thermometer data around 1970, the divergence problem. However, as tree rings cannot produce modern temperature, why assume they are accurate in the past? Indeed, the study changes their solar data which makes the sun look less potent in the modern era AND use, at least some of the time, flawed temperature proxies.

Further, the study said GHG caused temperature changes since 1900. However, only 0.1 degree C from 1900 - 1940 can be explained by human created GHG (this is citing the fellow from skeptical science, the Dana guy if I recall. I think he wrote this while responding to the CATO paper). However, about 0.4 degrees C of warming occurred over that period. And around 1900, very little of the CO2 in the atmosphere was human induced, and the levels were fairly low. Therefore, the study doesn't really support other research on the topic.

Again, it is impossible for volcanoes to explain the Little Ice Age, whereas Perry and Hsu 2000 in PNAS find that the sun correlates extremely well with these LIA and other similar periods of time, as well as noting that humans flourished when the sun was at an all time high. To quote them, "The contribution of solar-output variations to climate change may be significant". Note they said this AFTER they said the modern warming being caused solely by CO2 is unlikely.

I am not saying the study you cited is wrong. It is extremely interesting (the parts I have read), and looks to have insights to the current warming debate. Studies like this one are vital to the debate. However, to say solar variations are not one of the key causes to climate change over that period is preposterous.

Edit: I wrote this fairly fast. The study cited primarily focuses on the past 1000 years, not 200,000. I was thinking about many things, so expect a few errors.
But that was the biggest one.

Also the study has a few interesting references which I plan to read. Since you, Slo, are an intelligent person interested in the issue I am posting these here for you too.

Eddy, J. A. Maunder minimum. Science 192, 1189"1202 (1976).

Swingedouw, D. et al. Natural forcing of climate during the last millennium: Fingerprint of solar variability. Clim. Dynam. 36, 1349"1364 (2011).

Van Hateren, J. H. A fractal climate response function can simulate global average temperature trends of the modern era and the past millennium. Clim. Dynam. 40, 2651"2670 (2012).

Gray, L. J. et al. Solar influences on climate. Rev. Geophys. 48, RG4001 (2010).
https://www.youtube.com...
https://rekonomics.wordpress.com...
"A trend is a trend, but the question is, will it bend? Will it alter its course through some unforeseen force and come to a premature end?" -- Alec Cairncross
RoyLatham
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12/30/2013 12:48:08 PM
Posted: 2 years ago
I only read the article abstract, $32 to read the whole thing is a bit too much. The authors acknowledge that the sun was responsible for the Medieval Warm Period and the Little Ice Age, the two main events in climate before the present warming. But looking at their graph of past temperatures, the MWP and the Little Ice Age barely exist. That's the bogus "hockey stick" temperature reconstruction that is tuned to discount anything but CO2.

Their conclusion is circular: if you use a temperature reconstruction that's designed to discount everything but CO2, you conclude that only CO2 affects climate. Volcanic activity produces sharp spikes in climate that last a few years, and the anomalies are so large they cannot be ignored. But there have been few volcanic events large enough to put stuff into the upper atmosphere where it has a significant effect.

I think 16K makes good points. Climate is far more complex that the author's models acknowledge. The CO2-dominated models did not predict the fact of no increase in global warming for the past 15 years. It seems that long term cycles of ocean currents dominated, and it would take many thousands of years to change the cycles.
16kadams
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12/30/2013 12:50:14 PM
Posted: 2 years ago
At 12/30/2013 12:48:08 PM, RoyLatham wrote:
I only read the article abstract, $32 to read the whole thing is a bit too much. The authors acknowledge that the sun was responsible for the Medieval Warm Period and the Little Ice Age, the two main events in climate before the present warming. But looking at their graph of past temperatures, the MWP and the Little Ice Age barely exist. That's the bogus "hockey stick" temperature reconstruction that is tuned to discount anything but CO2.

nonono. They say the sun hasn't affected climate over the last 1000 years. Rather they say other studies do find a relationship.


Their conclusion is circular: if you use a temperature reconstruction that's designed to discount everything but CO2, you conclude that only CO2 affects climate. Volcanic activity produces sharp spikes in climate that last a few years, and the anomalies are so large they cannot be ignored. But there have been few volcanic events large enough to put stuff into the upper atmosphere where it has a significant effect.

I think 16K makes good points. Climate is far more complex that the author's models acknowledge. The CO2-dominated models did not predict the fact of no increase in global warming for the past 15 years. It seems that long term cycles of ocean currents dominated, and it would take many thousands of years to change the cycles.

Yay
https://www.youtube.com...
https://rekonomics.wordpress.com...
"A trend is a trend, but the question is, will it bend? Will it alter its course through some unforeseen force and come to a premature end?" -- Alec Cairncross
RoyLatham
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12/30/2013 1:01:27 PM
Posted: 2 years ago
At 12/30/2013 12:50:14 PM, 16kadams wrote:
nonono. They say the sun hasn't affected climate over the last 1000 years. Rather they say other studies do find a relationship.

The abstract of their article says: "Low solar activity has been linked to cooling during the Little Ice Age (ADR01;1450"1850; ref. 1) and there may have been solar forcing of regional warmth during the Medieval Climate Anomaly2, 3, 4, 5 (ADR01;950"1250; ref. 1)." They don't deny those studies, they conclude that because the MWP and Little Ice Age were such small climate events that solar forcing is trivial in the entire climate model. Had they used an accurate reconstruction of climate, they would have found a profound effect. That's quite different from acknowledging that the MWP and Little Ice Age were dramatic climate changes, but were caused by volcanoes.
16kadams
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12/30/2013 1:03:08 PM
Posted: 2 years ago
At 12/30/2013 1:01:27 PM, RoyLatham wrote:
At 12/30/2013 12:50:14 PM, 16kadams wrote:
nonono. They say the sun hasn't affected climate over the last 1000 years. Rather they say other studies do find a relationship.

The abstract of their article says: "Low solar activity has been linked to cooling during the Little Ice Age (ADR01;1450"1850; ref. 1) and there may have been solar forcing of regional warmth during the Medieval Climate Anomaly2, 3, 4, 5 (ADR01;950"1250; ref. 1)." They don't deny those studies, they conclude that because the MWP and Little Ice Age were such small climate events that solar forcing is trivial in the entire climate model. Had they used an accurate reconstruction of climate, they would have found a profound effect. That's quite different from acknowledging that the MWP and Little Ice Age were dramatic climate changes, but were caused by volcanoes.

"We instead conclude that solar forcing probably had a minor effect on Northern Hemisphere climate over the past 1,000 years, while, volcanic eruptions and changes in greenhouse gas concentrations seem to be the most important influence over this period."

However, yes, the fact the LIA and MWP are small is part of their argument.
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https://rekonomics.wordpress.com...
"A trend is a trend, but the question is, will it bend? Will it alter its course through some unforeseen force and come to a premature end?" -- Alec Cairncross
YYW
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12/30/2013 1:06:25 PM
Posted: 2 years ago
At 12/30/2013 12:48:08 PM, RoyLatham wrote:
I only read the article abstract, $32 to read the whole thing is a bit too much. The authors acknowledge that the sun was responsible for the Medieval Warm Period and the Little Ice Age, the two main events in climate before the present warming. But looking at their graph of past temperatures, the MWP and the Little Ice Age barely exist. That's the bogus "hockey stick" temperature reconstruction that is tuned to discount anything but CO2.

Their conclusion is circular: if you use a temperature reconstruction that's designed to discount everything but CO2, you conclude that only CO2 affects climate. Volcanic activity produces sharp spikes in climate that last a few years, and the anomalies are so large they cannot be ignored. But there have been few volcanic events large enough to put stuff into the upper atmosphere where it has a significant effect.

I think 16K makes good points. Climate is far more complex that the author's models acknowledge. The CO2-dominated models did not predict the fact of no increase in global warming for the past 15 years. It seems that long term cycles of ocean currents dominated, and it would take many thousands of years to change the cycles.

I agree.
RoyLatham
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12/30/2013 1:10:43 PM
Posted: 2 years ago
At 12/30/2013 1:03:08 PM, 16kadams wrote:

However, yes, the fact the LIA and MWP are small is part of their argument.

It's essential to their argument. If nothing ever happened before CO2, it's then easy to conclude that CO2 is responsible, save a few spikes from volcanoes.

Considering only a thousand years of climate history is cherry-picking to start with. Solar cycles are evident for millions of years. The "Holocene Optimum" about 5000 years ago, was warmer than the MWP. Trying to validate a climate model on only a thousand years of data is not a fruitful approach.
16kadams
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12/30/2013 1:11:52 PM
Posted: 2 years ago
At 12/30/2013 1:10:43 PM, RoyLatham wrote:
At 12/30/2013 1:03:08 PM, 16kadams wrote:

However, yes, the fact the LIA and MWP are small is part of their argument.

It's essential to their argument. If nothing ever happened before CO2, it's then easy to conclude that CO2 is responsible, save a few spikes from volcanoes.

Considering only a thousand years of climate history is cherry-picking to start with. Solar cycles are evident for millions of years. The "Holocene Optimum" about 5000 years ago, was warmer than the MWP. Trying to validate a climate model on only a thousand years of data is not a fruitful approach.

The response to STERN report said that if the MWP was warmer than today, co2 theory fails because models dont find it
https://www.youtube.com...
https://rekonomics.wordpress.com...
"A trend is a trend, but the question is, will it bend? Will it alter its course through some unforeseen force and come to a premature end?" -- Alec Cairncross