I think they use 1951-1980 for consistency. That's the base period they used when they started producing anomaly tables back in the 1980s. By continuing to use the same period for baseline it's easier to compare all of their work. If they switched to a 1981-2010 baseline they'd update all of their old anomaly tables to the new baseline. It wouldn't make any difference to the relative differences between two temperatures or the shape of the curve, just where the zero anomaly line gets drawn in the graph.
Yes, look at the Vostok data. The indicated temperatures 425K year ago remained above the current temperatures for over 25K years by the scale of the graph. Yes, there was a sharp peak toward the end of that period but that doesn't obviate the fact that the interglacial period was quite long. I'd be surprised if you could get any scientist who studies ice cores to agree that they have a resolution as fine as 20 years and 15 degrees (we are talking Celsius here aren't we?) is greater than the Earth average for the transition from a full glaciation to a full interglacial (the range on the Vostok graph is less than 11C). Now if you meant to write 1.5 degrees, that I can believe.
Milankovitch Cycles don't pause but they vary. MC components include eccentricity (see *), obliquity (cycle length ~41K years), axial precession(~26K), apsidal precession (25,771.5 to ~21,636) and orbital inclination (~100K). The harmony between those different cycle lengths is complex.
* It's interesting that the eccentricity has a rather complex set of variations. From Wikipedia:
The major component of these variations occurs on a period of 413,000 years (eccentricity variation of ±0.012). A number of other terms vary between components 95,000 and 125,000 years (with a beat period 400,000 years), and loosely combine into a 100,000-year cycle (variation of 0.03 to +0.02). The present eccentricity is 0.017 and decreasing.
So with the beat period of 400K years and the major component cycle of 413K years it wouldn't be surprising that effects of eccentricity are similar now to what they were 400K years ago. I take that as corroborating evidence that the extralong interglacial of 425K years ago and the present are related by similar MC conditions.
We've been measuring TSI by satellite continuously from the 1970s. The variation during that time is the range I gave in the previous post. Maybe there have been times in the past when solar radiation changed out of that range (not taking into account the Sun very slowly heating up as it ages) but I've never seen any scientific evidence for that.
Maybe it doesn't take much solar variance to affect the climate but we're in the midst of the lowest solar cycle in over a century (Cycle 24 which started in 2008) yet temperatures continue to rise. How long did you say that delay was?
The first thing you need to do when making the comparison you did is to find out if they used the same baseline. If they didn't then you need to shift one graph or the other in your comparison so they are using the same baseline. Otherwise your comparison is meaningless.
1951-1980 is just the period that NASA uses for their baseline. The reason it it 30 years long is that is the classical climatological period as defined by the World Meteorological Organization. It is not cherry picking. You could use any 30 year period for your baseline and it would be just as meaningful. All a different baseline would do is shift the graph up or down without changing the shape of the curve at all.
Cute little bit of mathturbation there. Yes, carbon dioxide is only 0.04% of the Earth's atmosphere but the rise in CO2 levels from about 280 ppm (where it was for the past ~8.000 years) to 400 ppm (where it is now) is entirely man-made. 3% isn't a lot but when you get an additional 3% every year it starts to add up.
Oh FFS! Two clicks (the link in the story then the link to the first hyperlink on that page) take you to this page that is the source data you were too damn lazy to seek out. It would take more work and probably reading several scientific papers to understand the methodology used to produce it but it's out there if you're not too lazy to look it up on your own. You can't get everything delivered to you on a silver platter (unless you're wealthy enough to pay someone to do it for you). Sometimes you have to work for it.
And the effects of anthropogenic global warming, possible collapse of our global civilization, major shifts in agricultural regions may result in the starvation of billions.
And that all the models to date have proven woefully poor and inadequate at their predictions. Showing that their understanding is far from complete.
Or maybe your understanding of what climate models do is too woefully poor and inadequate for you to judge how well they do.
Regarding the surfacestations.org cite in your subsequent post you should read this paper [PDF] that uses the surfacestations list of poorly sited weather stations to test the compensation for UHI effects in the temperature record. It found that the adjustments for poorly sited weather stations actually have a slight cooling bias compared to well sited weather stations.
Jeez NetNed, I can't believe anyone is still trying to use volcano emissions of CO2 as a factor. That they are only around 1% as compared to anthropogenic CO2 emissions is well known and has been for over a decade.
Nuclear power's biggest problem is that it's too expensive to compete financially with most other forms of power production. The only way to significantly ramp up the rate of building nuclear power plants is with massive government subsidies.
The 1951-1980 baseline is just the average temperature of those 30 years (the classical climate period as defined by the World Meteorological Organization). It includes all of those "wild swings" that you mention. It doesn't matter what you use as a baseline. The anomalies are just the temperature minus the baseline so the relative differences between temperatures is preserved. If you wanted to use the actual temperatures rather than anomalies you could show a graph that went from 55F to 61F (or 13C to 16C) but the curve of the graph wouldn't change.
The "stability" of the baseline period doesn't matter. Even during the baseline period when you plot the actual temperatures of individual years they are above or below the baseline unless they just happen by coincidence hit the baseline.
I'm not saying the models are necessarily incorrect. I'm just pointing out that they are, in fact, only predictions and models. The only way to judge their validity is to measure their ability to predict trends over time.
The only way to really measure the quality of a climate model is after the fact. Rerun the model with real world inputs such as the actual increase in greenhouse gases, the actual timing of ENSO, the actual timing of volcanic eruptions, the actual variation in TSI. When that is done the current climate models do quite well which gives us confidence in their quality.
Reasons that are not entirely understood, pointing to a an increase in CO2 that seems to correspond to a rise in temps is a nice reasoned assumption,...
And there is a nice causal link in CO2's absorption spectrum in the infrared. That is not an assumption.
How many near consecutive broken records does it take for weather extremes to no longer be called 'anomalies'?
You misunderstand the use of the term "anomaly". When climate scientists want to compare temperatures it's often more useful to look at how the temperatures vary from some baseline temperature rather than just looking at an absolute temperature. An example of why this is useful: Consider two temperature stations 20 miles apart. There is usually a correlation between temperatures so close together. But if one station is 1000 feet higher than the other it will normally show a cooler temperature than the lower station just because of the higher elevation. But if you look at anomalies for the two stations, their variance from the baseline for each station, they may be the same. So the temperature at the lower elevation station might be 75 degrees F compared to a baseline temperature of 70F and the temperature at the higher station may be 72F compared to a baseline temperature of 67F. Different temperatures but the same anomaly.
The Sun is by far the dominate factor in temps here on Earth.
Absolutely true, compared to the Sun other sources such as internal heat from the Earth and heat from combustion (human & natural) are mere rounding errors. But the next most dominant factor in the temperature of the Earth is the presence of greenhouse gases in the atmosphere. Without them the average temperature on the surface would be around 0 degrees F rather than around the 58F that it is.
And it's not stable (and none of the climate guys are modeling it, not their field). So, whither solar radiance?
What about solar radiance? I would say the Sun is quite stable. It has the 11/22 year cycle that causes less than 1% variation in average TSI which is between 1365.5 and 1366.5 W/m^2 at the top of the atmosphere. Even in the current "lowest since 1750 when accurate records start" cycle 24 TSI has remained well above 1365 W/m^2. Climate scientists are not ignoring solar radiance, they just realize the variation is small enough and regular enough they can mostly treat it as a constant for the sake of climate modeling. They may have to do some tweaking if the solar cycles remain low for a while but it won't make a big change to their results.
absent Mankind - are we facing a huge drop in temps, or a huge spike? If you look at the ice core data, we've been in a historical anomaly for the past 10k years, and we'd normally have returned to glaciers covering Europe by now. The 100k year glaciation cycles are thought to be solar cycles, but no one knows why the cycle was broken. Over we overdue for a sharp return to the norm? Or is the current ice age ending, and we're due for a warm Earth (no ice at the poles, or anywhere year-round)? It's the biggest question: is the warming effect of man's CO2 a bad thing, or a good thing, or a rounding error?
The interglacial period of around 425,000 years ago appears to have been longer than normal so I'm not sure I'd say we're overdue for a new glacial period yet. The cycle of glaciations appears to be largely driven by variations in orbital and rotational parameters of Earth collectively known as Milankovitch Cycles. They cause more variation in TSI at Earth's orbit than internal solar variations and they also cause changes in the distribution of TSI on the Earth. The current interglacial reached a peak temperature during the Holocene Climatic Optimum around 6,000-8,000 years ago and has been slowly cooling ever since. That is until recently when the increase in greenhouse gases in the atmosphere has caused a sharp spike in temperature. Climate scientists have calculated it's impossible for a new glacial cycle to start as long as CO2 remains above 240-250 ppm. The slow cooling of the Holocene would have eventually caused CO2 to drop as the oceans cooled and other factors absorbed CO2 but we've interrupted that cycle.
Whether it's a good or bad thing for Earth doesn't matter. It's the effects on our global civilization that matter to us. A little warming was probably warranted to halt the slow slide to the next glaciation but we've overshot what is necessary for that. Will our current civilization be resilient enough to withstand the changes that are coming? I guess we'll find out.
Hmm... science itself just is. That other stuff you mention just applies to people who are not very literate scientifically. Of course that applies to a majority of people.
I'm curious, what is it you think is the big question in the "It's the Sun" debate that they're ignoring?
That's why it's nearly impossible to have a rational discussion about either topic. Fortunately, for evolution there is the talk.origins FAQ, where all the arguments against evolution are taken seriously and debunked carefully without calling anyone an idiot. For global warming there's no such resource - mostly because no one is actually interested in the topic, other than as a tribal identifier.
I'd have to say that the arguments page from Skeptical Science does a pretty good job of debunking arguments against anthropogenic global warming.
Slashdot Mirror
I think they use 1951-1980 for consistency. That's the base period they used when they started producing anomaly tables back in the 1980s. By continuing to use the same period for baseline it's easier to compare all of their work. If they switched to a 1981-2010 baseline they'd update all of their old anomaly tables to the new baseline. It wouldn't make any difference to the relative differences between two temperatures or the shape of the curve, just where the zero anomaly line gets drawn in the graph.
Yes, look at the Vostok data. The indicated temperatures 425K year ago remained above the current temperatures for over 25K years by the scale of the graph. Yes, there was a sharp peak toward the end of that period but that doesn't obviate the fact that the interglacial period was quite long. I'd be surprised if you could get any scientist who studies ice cores to agree that they have a resolution as fine as 20 years and 15 degrees (we are talking Celsius here aren't we?) is greater than the Earth average for the transition from a full glaciation to a full interglacial (the range on the Vostok graph is less than 11C). Now if you meant to write 1.5 degrees, that I can believe.
Milankovitch Cycles don't pause but they vary. MC components include eccentricity (see *), obliquity (cycle length ~41K years), axial precession(~26K), apsidal precession (25,771.5 to ~21,636) and orbital inclination (~100K). The harmony between those different cycle lengths is complex.
* It's interesting that the eccentricity has a rather complex set of variations. From Wikipedia:
The major component of these variations occurs on a period of 413,000 years (eccentricity variation of ±0.012). A number of other terms vary between components 95,000 and 125,000 years (with a beat period 400,000 years), and loosely combine into a 100,000-year cycle (variation of 0.03 to +0.02). The present eccentricity is 0.017 and decreasing.
So with the beat period of 400K years and the major component cycle of 413K years it wouldn't be surprising that effects of eccentricity are similar now to what they were 400K years ago. I take that as corroborating evidence that the extralong interglacial of 425K years ago and the present are related by similar MC conditions.
We've been measuring TSI by satellite continuously from the 1970s. The variation during that time is the range I gave in the previous post. Maybe there have been times in the past when solar radiation changed out of that range (not taking into account the Sun very slowly heating up as it ages) but I've never seen any scientific evidence for that.
Maybe it doesn't take much solar variance to affect the climate but we're in the midst of the lowest solar cycle in over a century (Cycle 24 which started in 2008) yet temperatures continue to rise. How long did you say that delay was?
The first thing you need to do when making the comparison you did is to find out if they used the same baseline. If they didn't then you need to shift one graph or the other in your comparison so they are using the same baseline. Otherwise your comparison is meaningless.
1951-1980 is just the period that NASA uses for their baseline. The reason it it 30 years long is that is the classical climatological period as defined by the World Meteorological Organization. It is not cherry picking. You could use any 30 year period for your baseline and it would be just as meaningful. All a different baseline would do is shift the graph up or down without changing the shape of the curve at all.
The data used for this particular story is here.
Cute little bit of mathturbation there. Yes, carbon dioxide is only 0.04% of the Earth's atmosphere but the rise in CO2 levels from about 280 ppm (where it was for the past ~8.000 years) to 400 ppm (where it is now) is entirely man-made. 3% isn't a lot but when you get an additional 3% every year it starts to add up.
Oh FFS! Two clicks (the link in the story then the link to the first hyperlink on that page) take you to this page that is the source data you were too damn lazy to seek out. It would take more work and probably reading several scientific papers to understand the methodology used to produce it but it's out there if you're not too lazy to look it up on your own. You can't get everything delivered to you on a silver platter (unless you're wealthy enough to pay someone to do it for you). Sometimes you have to work for it.
And the effects of anthropogenic global warming, possible collapse of our global civilization, major shifts in agricultural regions may result in the starvation of billions.
I'd really like to see you justify that statement with some serious cites of scientific papers.
(But didn't we go over this a couple of threads back and you kept throwing things at me that weren't global in scope? So nevermind.)
And that all the models to date have proven woefully poor and inadequate at their predictions. Showing that their understanding is far from complete.
Or maybe your understanding of what climate models do is too woefully poor and inadequate for you to judge how well they do.
Regarding the surfacestations.org cite in your subsequent post you should read this paper [PDF] that uses the surfacestations list of poorly sited weather stations to test the compensation for UHI effects in the temperature record. It found that the adjustments for poorly sited weather stations actually have a slight cooling bias compared to well sited weather stations.
Jeez NetNed, I can't believe anyone is still trying to use volcano emissions of CO2 as a factor. That they are only around 1% as compared to anthropogenic CO2 emissions is well known and has been for over a decade.
You misinterpreted what you read. The baseline for the anomalies is 1951 to 1980 but the temperature record goes back to 1880, 136 years.
January 2016 had a higher anomaly than 136 previous years of January's and had a higher anomaly than any of 1632 months from 1880 to 2015.
Nuclear power's biggest problem is that it's too expensive to compete financially with most other forms of power production. The only way to significantly ramp up the rate of building nuclear power plants is with massive government subsidies.
The 1951-1980 baseline is just the average temperature of those 30 years (the classical climate period as defined by the World Meteorological Organization). It includes all of those "wild swings" that you mention. It doesn't matter what you use as a baseline. The anomalies are just the temperature minus the baseline so the relative differences between temperatures is preserved. If you wanted to use the actual temperatures rather than anomalies you could show a graph that went from 55F to 61F (or 13C to 16C) but the curve of the graph wouldn't change.
The "stability" of the baseline period doesn't matter. Even during the baseline period when you plot the actual temperatures of individual years they are above or below the baseline unless they just happen by coincidence hit the baseline.
30 years is the World Meteorological Organization standard for climatology. So using 30 years is a standard practice.
I'm not saying the models are necessarily incorrect. I'm just pointing out that they are, in fact, only predictions and models. The only way to judge their validity is to measure their ability to predict trends over time.
The only way to really measure the quality of a climate model is after the fact. Rerun the model with real world inputs such as the actual increase in greenhouse gases, the actual timing of ENSO, the actual timing of volcanic eruptions, the actual variation in TSI. When that is done the current climate models do quite well which gives us confidence in their quality.
Reasons that are not entirely understood, pointing to a an increase in CO2 that seems to correspond to a rise in temps is a nice reasoned assumption, ...
And there is a nice causal link in CO2's absorption spectrum in the infrared. That is not an assumption.
How many near consecutive broken records does it take for weather extremes to no longer be called 'anomalies'?
You misunderstand the use of the term "anomaly". When climate scientists want to compare temperatures it's often more useful to look at how the temperatures vary from some baseline temperature rather than just looking at an absolute temperature. An example of why this is useful: Consider two temperature stations 20 miles apart. There is usually a correlation between temperatures so close together. But if one station is 1000 feet higher than the other it will normally show a cooler temperature than the lower station just because of the higher elevation. But if you look at anomalies for the two stations, their variance from the baseline for each station, they may be the same. So the temperature at the lower elevation station might be 75 degrees F compared to a baseline temperature of 70F and the temperature at the higher station may be 72F compared to a baseline temperature of 67F. Different temperatures but the same anomaly.
The Sun is by far the dominate factor in temps here on Earth.
Absolutely true, compared to the Sun other sources such as internal heat from the Earth and heat from combustion (human & natural) are mere rounding errors. But the next most dominant factor in the temperature of the Earth is the presence of greenhouse gases in the atmosphere. Without them the average temperature on the surface would be around 0 degrees F rather than around the 58F that it is.
And it's not stable (and none of the climate guys are modeling it, not their field). So, whither solar radiance?
What about solar radiance? I would say the Sun is quite stable. It has the 11/22 year cycle that causes less than 1% variation in average TSI which is between 1365.5 and 1366.5 W/m^2 at the top of the atmosphere. Even in the current "lowest since 1750 when accurate records start" cycle 24 TSI has remained well above 1365 W/m^2. Climate scientists are not ignoring solar radiance, they just realize the variation is small enough and regular enough they can mostly treat it as a constant for the sake of climate modeling. They may have to do some tweaking if the solar cycles remain low for a while but it won't make a big change to their results.
absent Mankind - are we facing a huge drop in temps, or a huge spike? If you look at the ice core data, we've been in a historical anomaly for the past 10k years, and we'd normally have returned to glaciers covering Europe by now. The 100k year glaciation cycles are thought to be solar cycles, but no one knows why the cycle was broken. Over we overdue for a sharp return to the norm? Or is the current ice age ending, and we're due for a warm Earth (no ice at the poles, or anywhere year-round)? It's the biggest question: is the warming effect of man's CO2 a bad thing, or a good thing, or a rounding error?
The interglacial period of around 425,000 years ago appears to have been longer than normal so I'm not sure I'd say we're overdue for a new glacial period yet. The cycle of glaciations appears to be largely driven by variations in orbital and rotational parameters of Earth collectively known as Milankovitch Cycles. They cause more variation in TSI at Earth's orbit than internal solar variations and they also cause changes in the distribution of TSI on the Earth. The current interglacial reached a peak temperature during the Holocene Climatic Optimum around 6,000-8,000 years ago and has been slowly cooling ever since. That is until recently when the increase in greenhouse gases in the atmosphere has caused a sharp spike in temperature. Climate scientists have calculated it's impossible for a new glacial cycle to start as long as CO2 remains above 240-250 ppm. The slow cooling of the Holocene would have eventually caused CO2 to drop as the oceans cooled and other factors absorbed CO2 but we've interrupted that cycle.
Whether it's a good or bad thing for Earth doesn't matter. It's the effects on our global civilization that matter to us. A little warming was probably warranted to halt the slow slide to the next glaciation but we've overshot what is necessary for that. Will our current civilization be resilient enough to withstand the changes that are coming? I guess we'll find out.
Hmm... science itself just is. That other stuff you mention just applies to people who are not very literate scientifically. Of course that applies to a majority of people.
I'm curious, what is it you think is the big question in the "It's the Sun" debate that they're ignoring?
Don't worry, I was just trolling you.
That's why it's nearly impossible to have a rational discussion about either topic. Fortunately, for evolution there is the talk.origins FAQ, where all the arguments against evolution are taken seriously and debunked carefully without calling anyone an idiot. For global warming there's no such resource - mostly because no one is actually interested in the topic, other than as a tribal identifier.
I'd have to say that the arguments page from Skeptical Science does a pretty good job of debunking arguments against anthropogenic global warming.
Wow! I never thought I'd see roman_mir paraphrase Karl Marx who wrote "Religion is the opiate of the masses".
If you think models are so critical to the science you're probably right.
The science doesn't depend on models. It depends on the radiative properties of carbon dioxide and other greenhouse gases.