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Watsisname
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General global warming / climate chage discussion

08 Feb 2017 02:35

More than all of the warming is due to anthropogenic causes.  This is because without the anthropogenic greenhouse forcing, Earth would have cooled, not warmed.
 
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Gnargenox
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General global warming / climate chage discussion

08 Feb 2017 02:53

I've heard quite the contrary .
https://judithcurry.com/2015/05/06/quan ... heric-co2/
This is a bit heady with statistics and charts but I respect your opinion and ability to decipher all of this.

Final outcome: Projected contributions of natural and anthropogenic emissions to the long-term global accumulation of CO2 in the atmosphere.
projections.jpg
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General global warming / climate chage discussion

08 Feb 2017 03:40

Watsisname wrote:
Source of the post More than all of the warming is due to anthropogenic causes.  This is because without the anthropogenic greenhouse forcing, Earth would have cooled, not warmed.

This is extremely difficult to verify.
This more than 100% of the observed warming due to humans causes some confusion.  That is, "is most of the observed warming caused by humans?" and "are human factors more important than natural for climate change?" two very different questions.
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Watsisname
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General global warming / climate chage discussion

08 Feb 2017 04:48

Gnargenox:

Sure.  The analysis is an attempt to characterize changes in carbon sources and sinks over time, by which to determine how much of the CO2 in the atmosphere is attributed to humans or by nature, and how these concentrations change over time and in the future. 

Sounds reasonable enough, and the graphics are nice.  Unfortunately, the methodology is based on assuming that the concentration and isotopic ratios in the Arctic are representative of the dynamics of sources and sinks everywhere, and that is a really poor modelling assumption. There are a lot of important carbon sources and sinks around the planet which depend on conditions differently, and it simply is not possible to understand carbon cycling by looking at one region in isolation. To think about it, simply consider how land use change will affect the modelling assumptions.  Land use change is one of many important spatially and temporally dependent changes in carbon cycling.

A further cause for concern is that the results of this analysis strongly contradict what we know from paleoclimate evidence, where we've seen how carbon cycling changed, as well as how it affected the temperature.  (Think of the PETM).

At any rate, I'm not particularly interested in spending a lot of time reviewing a blog as a substitute for academic research into a scientific matter.  If the source is associated with a well cited journal article, coupled with a review of other literature in the field, then that would be another thing.  That is how a scientific community builds a strong base of knowledge and with confidence behind it.  The study of carbon cycling and its implications to climate change is an entire field of research in itself, and it is well reviewed through the IPCC.  We're not likely to arrive at a good understanding of it by looking at a blog article or even a single paper.

-------------------------

So, back to the question at hand.  How do we know how much of the warming is attributable to anthropogenic causes?  (This is for Midtskogen, too). 

The way we look at this is to examine the balance of energy into and out of the Earth system (essentially, applying the laws of thermodynamics and radiation).  Things which affect change in that balance are called "radiative forcings", meaning they act to change the effective flux of radiation from the Earth's surface to space.  It turns out that the greenhouse forcing has been the most significant of these forcings, and more so through the 21st century under high emission scenarios.


You said you haven't seen much technical discussion of this subject, which is really surprising to me because studies relevant to it appear regularly on it in scientific journals, for example the Journal of Geophysical Research: Atmospheres.  Or as described earlier, a good synthesis of all knowledge in climate science lies in the IPCC reports and summaries, which are free to view.

Let's look at a figure from Chapter 10 of WGI:

Image
 
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Gnargenox
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General global warming / climate chage discussion

08 Feb 2017 12:52

I completely understand your desire not to get bogged down in the view points of a single paper or study of a single area as a source of carbon. I appreciate your graphic as well, yet I don't understand the reasoning of placing natural causes in blue and both natural and man made causes in red, when most people are interested in man made contributions solely. I also wonder how we managed to warm up the northern Pacific Ocean the most out of all areas shown.

I don't spend much time reading IPCC reports, as I've noticed many times their results seem implausible and are sometimes completely disingenuous, remaining unchecked for many years before they are corrected. For example, the Himalayan glaciers are supposed to completely disappear by the year 2035, as they stated in a 2007 article, but that was not redacted until 2 years later. Credibility is also shaken when emails discussing withholding data is revealed, much like the recent claim by Dr. Bates that NOAA has done the same. That is not to say they are full of rubbish, just that everything needs to be taken with a grain of salt. They need to be more scrupulous in their claims if they are to be the ultimate source of scientific information and their decrees to be used to formulate global economic policy. Too many times they have had to change their predictions, and many times observational data was seen to be less influential than first claimed. It alllmmoossttt seems biased.

A well referenced blog discussing such:
https://wattsupwiththat.com/2014/01/01/ ... nal-draft/

I tend to follow NASA data more often than NOAA data reports
http://www.nasa.gov/sites/default/files ... iefing.pdf

The NIPCC tends to contradict everything the IPCC says, from whether or not CO2 is beneficial or harmful to agriculture to what sources flooding and storms will come from. Again I tend to lean away from government funded panels that influence economic policy and prefer non-governmental panels to provide other view points.
NIPCC homepage: http://climatechangereconsidered.org/


I think this forum is a great place to discuss climate change as well as changes though out the solar system. Here are some recent links about places other than Earth that are undergoing rapid change from what we have seen. Admitidly the window of time we have been making observations is minuscule.

●Venus Winds: http://www.esa.int/Our_Activities/Space ... ing_faster
●Venus Rotation: http://www.esa.int/Our_Activities/Space ... fting_gear
●Mars Warming: http://news.nationalgeographic.com/news ... rming.html
●Jupiter Stripe: http://science.nasa.gov/science-news/sc ... oststripe/
●Red Jr: http://science.nasa.gov/science-news/sc ... mar_redjr/
●Jupiter Radio Emission: http://www.science20.com/news_articles/ ... iter-93369
●Saturn Superstorm: http://science.nasa.gov/science-news/sc ... turnstorm/
●Uranus Auroras: http://news.nationalgeographic.com/news ... ce-hubble/
●Uranus Storms: http://arxiv.org/pdf/1501.01309v1.pdf

I ran across 3 dozen other links about Solar influences on Earth's climate but since there are so many I'll leave that for everyone to research themselves.
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Watsisname
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General global warming / climate chage discussion

08 Feb 2017 16:50

Gnargenox wrote:
Source of the post I completely understand your desire not to get bogged down in the view points of a single paper or study of a single area as a source of carbon.

I'm not sure if you do.  It's essentially the same thing as not desiring to spend my time analyzing proposals of the "electric universe" posted on popular websites.  Sure, the argumentation sounds reasonable to a layperson, but it's wrong, and it takes time and effort to explain why. If I had to analyze all the ideas proposed outside of academic circles for correctness, it would be a full time job and I would have to charge money for it. :)  What I am happy to do is take a quick look and see if it appears credible or if there are significant misconceptions involved, and if it passes a first look I'll pursue it deeper.

That's not to say everything posted in a blog article even among skeptical circles is going to be wrong (sometimes they do hit on very important things and even help the climate science community that way), but if that is your primary source of information then you risk a greater abundance of misleading information.

The most important lesson here is that for the typical interested reader, a good skill to have is how to determine the reliability of information on the internet or other sources.  Anyone can make a nice analysis from a convincing-sounding string of arguments and post it on the internet.  What separates an academic journal article from that is that the flow of logic is continuously supported through in line references to other work in that field -- essentially, a review of previous knowledge by other people before them, and statements of how all this work ties together. 
 
What are good source of information for climate science?  Same as any other field of science:  Journals, dissertations, literature reviews.  You can be happy to look at blog articles, and I often do, too.  But understand what you're getting into and that these should supplement your knowledge by serving as a comparison with other sources, instead of being your primary source for information.

Does that make sense?

Gnargenox wrote:
Source of the post I appreciate your graphic as well, yet I don't understand the reasoning of placing natural causes in blue and both natural and man made causes in red, when most people are interested in man made contributions solely.

The difference of the two curves and their comparison to the observations reveals something about the attribution of global warming to human causes. The temperature evolution that we observe is consistent with natural + anthropogenic forcings, and is not consistent with natural forcings alone.  In other words: anthropogenic forcings are necessary and sufficient to explain the warming that we observe, because without them, the temperature would remain essentially flat over this interval.

Why was most of the warming in the northern Pacific?  Short answer is that it has to do with the transfer of heat between the ocean and atmosphere, which involves the ocean circulations and ENSO.  The Pacific -- particularly with the deep ocean water -- is a very large reservoir for heat, and so whether the ocean puts out warmer or cooler water than usual matters a lot for the transfer of heat to or from the atmosphere.

Gnargenox wrote:
Source of the post I don't spend much time reading IPCC reports, as I've noticed many times their results seem implausible and are sometimes completely disingenuous, remaining unchecked for many years before they are corrected.

The IPCC does not perform research!

What the IPCC does is present a synthesis of all available literature in climate science.  Since climate science is an ongoing field of research, you can expect that knowledge to be updated. So if you say you don't spend time reading those reports because you think the results are questionable or whatever, then you're saying you have issues with climate science itself.

Gnargenox wrote:
Source of the post I ran across 3 dozen other links about Solar influences on Earth's climate but since there are so many I'll leave that for everyone to research themselves.

This idea goes back decades. :)  The Sun does influence the Earth's climate, but the current warming is not due to the Sun.  You can demonstrate this fairly easily (I'll walk you through the math if you're interested), by considering the change in flux at Earth due to solar variability -- it is too small to explain the changes that we observe, and the direction of the changes don't correlate anyway.  In general, the solar variability is small on short timescales (thankfully for us), and while it is big on very long timescales, the rock weathering cycle beats it on those timescales.

It became popular to look at how the Sun might affect climate by modifying clouds, and there is a connection there, but again, it's not what explains the current warming, or even climate changes in general throughout Earth history.  People have also looked at sunspots, cosmic rays, interstellar dust, frequency of ship pirating...

but the one thing that that does fit observations, has a clear basis in physics, and successfully connects to our understanding of change throughout Earth history, is the concentration of greenhouse gases in the atmosphere.
 
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Gnargenox
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General global warming / climate chage discussion

08 Feb 2017 18:41

lol, short and concise, I love it! and the photo too!
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midtskogen
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General global warming / climate chage discussion

09 Feb 2017 05:41

Gnargenox wrote:
Source of the post I don't spend much time reading IPCC reports, as I've noticed many times their results seem implausible and are sometimes completely disingenuous, remaining unchecked for many years before they are corrected. For example, the Himalayan glaciers are supposed to completely disappear by the year 2035, as they stated in a 2007 article, but that was not redacted until 2 years later.

The glacier claim came from WWF, who cited someone, who cited an informal speculation.  The claim should never have made it into the report, since it had not gone through any proper review.  This can happen when a report is written by many persons.  Also keep in mind that these reports are the result of committee work, which usually means that people tend to focus on smaller parts of the text, have agendas, reach consensus through "I'll vote for your paragraph if you vote for mine", etc.  The whole of the report will receive less focus than it should.
Besides, science needs decades to mature.  A couple of years is nothing.  Of all scientific papers published last year, expect very few still to be cited in 30 years.  Most scientific papers are quite forgettable. Unfortunately, when it comes to climate science, scientific papers are politicised before the ink dries.  Of course, in the case of alarming findings, one cannot always wait until the scientific hypotheses and theories mature.  If somebody publishes a paper predicting a 10 km asteroid impact Earth in 10 years, the wait will be too late if the paper's prediction is correct.  But shouting that the science is settled, therefore we must prepare for the asteroid, is likely not going to be helpful.

Watsisname wrote:
Source of the post That's not to say everything posted in a blog article even among skeptical circles is going to be wrong (sometimes they do hit on very important things and even help the climate science community that way), but if that is your primary source of information then you risk a greater abundance of misleading information.

It should be noted that some of these blogs are written by qualified people, like Judith Curry, Roger Pielke, Roy Spencer, and in the other lair a number of scientists are writing for realclimate.org.
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09 Feb 2017 12:31

Thanks midtskogen, I understand the nature and necessity of peer reviews and that the IPCC is only a mouthpiece, not a research group themselves. I also understand the process of science and how it can indeed be politicized way too soon. Knowledge is something that grows, through the process Watsisname mentioned and I know it can be difficult to maintain with so many poor sources trying to spin things the way they see fit.

I am not actually even questioning the statements thrown about by the media before its time, as I say I take it all with a grain of salt. Its the people that don't understand that, that are crying "the sky is falling" and the ones saying the public doesn't need to know all the facts, the public would be bogged down in the weeds with too much info. Then you have the media claiming climate deniers won't listen and therefore the debate should just be laid to rest. Well, the misunderstanding is no one knows or can or wants to say, how much of the change is anthropogenic. That number actually is buried in the weeds, purposefully it seems, in order to confuse the ignorant public, for some unknown agenda. The "its really complicated" answer just frustrates me and others, to the point that I am adamant public policy not change until we have the data we need or want that supposedly justifies taxing the air I exhale. Basically if we can not say to what degree humans are responsible how can we ever hope to say mankind can fix it properly and fairly without being alarmist?
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General global warming / climate chage discussion

09 Feb 2017 14:37

midtskogen wrote:
Source of the post The glacier claim came from WWF, who cited someone, who cited an informal speculation.  The claim should never have made it into the report, since it had not gone through any proper review. 

Yeah, unfortunately these things happen.  Sometimes sloppy studies make it through peer review, or are referenced before being reviewed at all.  We like to think peer review is a gold standard for separating the credible from the fluff, but it is not a perfect system.

Another issue is that media attention any particular study receives is poorly correlated to how important that study actually is to the field. A good example was a study which used mathematical fits for arctic sea ice decline and concluded that we could expect ice-free summers in just a few years.  It was an enormous outlier of a prediction, and the scientific community thought it was implausible based on the more sophisticated modelling work. But it nevertheless received a huge amount of press for being more dramatic.

It's things like these which I think confuse popular perception of what the confidence and uncertainties in these subjects are -- not just in climate science but in a lot of fields.  Another good example is the paper which announced lower confidence in accelerating expansion by supernovae data, which caused all kinds of public confusion about our understanding of dark energy and confidence thereof.  (PBS Spacetime did a great review of that.)
With all these difficulties in the interface of science and the public, it can be difficult for the curious person to figure out what constitutes reliable information and how to digest it.  The best answer I can give is to look at as wide a range of sources as you can and check how those sources compare with each other.  For the scientist, it means comparing sources with the academic literature -- is it published in journals, are those articles well cited, and are they consistent with a variety of other studies?  There is a metacognition involved with reading a paper as well -- what is the motivation and methodology, how thorough is their literature review, how do they determine and report the uncertainties, does each step logically follow, and so forth.

Gnargenox wrote:
Source of the post Well, the misunderstanding is no one knows or can or wants to say, how much of the change is anthropogenic. That number actually is buried in the weeds, purposefully it seems, in order to confuse the ignorant public, for some unknown agenda.


It's a dark magic that is held closely secret. :)

Come one now, you've just been shown how much of the change is due to anthropogenic versus natural causes, and how that answer is obtained.  Characterize the balance of energy into and out of the Earth system, what things affect that balance, and how their magnitudes have changed.  Run models with and without the anthropogenic forcings and see how well each compares with observations.  Summaries or details of this work are freely available for any curious person.
 
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11 Feb 2017 04:57

Much media attention focuses on the more extreme impacts of global warming.

This study is interesting for doing the opposite -- looking at how warming (in terms of radiative forcing) affects the frequency of mild weather. ("Mild" in a meteorological sense, as of course different people have different ideas of what is comfortable weather).  The result helps to visualize the non-uniformity of the impacts of climate change, and in particular the variation with latitude and season.

I think there is a certain weakness to the paper in the sense that the extent of increase or decrease in mild days depends a lot on the definition for mild temperature thresholds.  Even so, the results are consistent with what other studies have found in regard to change in the number of heating vs. cooling days, dew point temperatures, arability of land, and so forth.  It is also consistent with observations of how these factors actually have changed in recent decades, meaning that what we expect to happen on the regional scale due to global warming is indeed happening.

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