climate change "skepticism"

[Grayman]

before this is exploited by do-gooder politicians, hollywood stars, and a certain girl from sweden who is yet to learn the 9x9 multiplication table, I want to see conclusive evidence that this was caused by CO2 emissions.

edit: k I looked at the daily max temperature in australia, not gonna deny it's been trending upward

View attachment 4969

edit2: jeez and the rainfall is going down pretty significantly
View attachment 4970

Source pleez. Junk argument and sources award! Are these local rainfall graphs that you are blaming on global temp and co2 changes?

https://www.climate.gov/news-features/featured-images/2017-state-climate-global-drought (Wow not much change in droughts globally
https://www.epa.gov/climate-indicators/climate-change-indicators-us-and-global-precipitation (Increase of precipitation!??!) Wat thu?

The droughts in Australia are due to regional changes and an increase of 1 - 2 deg average temperature does not cause fires. Most if not all if the problems are because of people cutting down trees (Large trees). Large trees keep the area below shaded and moist. Large trees actually deter fires because they deter small growth of plants, especially dry plants, below them and their canopy typically sits above the fire. Going back and replanting small trees does not fix the problem... until years later and they are bigger if they don't burn up before then...

I would argue that the only contribution CO2 has to the fires is that it contributes to the growth of more young plants and therefore produces more fire fuel. This is called "Global Greening"

Carbon Dioxide Fertilization Greening Earth, Study Finds - NASA

From a quarter to half of Earth’s vegetated lands has shown significant greening over the last 35 years largely due to rising levels of atmospheric carbon

www.nasa.gov

Oh but global changes can cause regional changes and therefore global warming is at fault for Australia?!?! Well science it baby! I don't see anything that actually can take us from point A to b to c to d that shows how global warming actually caused the regional changes you see in Australia. All I see is correlation, not causation. Regional changes always occur and may occur due to planetary alignments, ocean currents, sun, jet streams, and the changing tilt of the earth and possibly in small part geological changes in the crust. Who is to say that if the CO2 never increased Australia wouldn't be in the same situation they are in now?

 

[redbaron]

@Grayman are you trolling?

 

[redbaron]

Global trends in temperature increase mean that the regional things that affect climate and cause heatwaves for example, are exacerbated and more severe than they otherwise would be.

Moreover, climate change is not limited only to temperature changes as a result of greenhouse emissions. Deforestation (another issue we face in Australia) is a major factor and has been linked to decreased rainfall as well.

Increase in average temperatures, deforestation leading to reduced average rainfall, combined with localised weather systems. Increased severity and increased duration of heatwaves with less overall rain = exponentially worsening bushfire seasons.

Average temperatures have been increasing in Australia and globally for quite some time:

Annual climate statement 2020

Global Surface Temperature | NASA Global Climate Change

Vital Signs of the Planet: Global Climate Change and Global Warming. Current news and data streams about global warming and climate change from NASA.

climate.nasa.gov

Also it's not just that the temperature increases. Increased temperatures mean decreased humidity, especially in desert areas where rainfall is scarce and the drier climate results in deadlier fires. No scientist is claiming that there's more fires simply because the temperature is higher: it's the effects of a higher average temperature that create conditions for more extreme occurrences of bushfires.

 

[Ex-User (14663)]

@Grayman i don’t think I made any claims as to whether global warming causes those trends on a local level. That remains a hypothesis because I can easily find graphs like that for other place in eg Southeast Asia where there is no upward trend.

 

[Grayman]

Better to focus on local deforestation and charity groups instead of giving your money to someone in government abusing the term 'climate change' so that they can give your money away to special interests.

 

[Rebis]

Do none of you pay attention to Donald Trump?

Climate change is fake, get real ladies.

 

[Grayman]

Do none of you pay attention to Donald Trump?

Climate change is fake, get real ladies.

Actually he said Man Made Global Warming is a Chinese Hoax. Everyone knows the climate changes!!! Even the ladies!

 

[Ex-User (14663)]

Problem with climate change is that it’s one thing to measure changes in temperature (which itself is an extremely intricate process and historical data needs to be inferred indirectly using tree rings and whatnot) , and another to assert cause and effect in the weather system. Eg the notorious Mann-Bradley-Hughes papers that started the whole thing back in 90s looked at whether the supposed temp increase was due to solar activity or co2. In my professional opinion as a statistician their analysis was pretty garbage, but either way they concluded with marginal statistical significance that it was co2 and not solar. And the rest is history - history of hysteria, political agendas, and agitprops

 

[Rebis]

Problem with climate change is that it’s one thing to measure changes in temperature (which itself is an extremely intricate process and historical data needs to be inferred indirectly using tree rings and whatnot) , and another to assert cause and effect in the weather system. Eg the notorious Mann-Bradley-Hughes papers that started the whole thing back in 90s looked at whether the supposed temp increase was due to solar activity or co2. In my professional opinion as a statistician their analysis was pretty garbage, but either way they concluded with marginal statistical significance that it was co2 and not solar. And the rest is history - history of hysteria, political agendas, and agitprops

Is it the 1998 papers? I'll have a read for breakfast.

 

[Hadoblado]

I'm finding it kinda hard posting here because it feels like everyone is responding to absent or unstated positions.

I guess the general sentiment I want to express is that while fact is not dictated by scientific consensus (truth is not a democracy), opinions deviating from those of the majority of experts should be well substantiated and address the reasoning of those experts. So when Serac says he's looked through a paper and in his expert opinion they did a shit job, I kinda want to know what his issue with their analysis is.

I've been a fly on the wall for a lot of these kinds of discussions, and they almost inevitably turn into shouting matches or two separate circle jerks had in parallel (the accepters and the deniers).

While I don't think shouting matches are productive, I think the alternative is often more sinister. Either climate change is happening or it is not, one of the parties is misinformed and spreading misinformation. If we never discuss it or address what each other are saying, we're knowingly giving equal audience to misinformation.

 

[Daddy]

They can measure the CO2 levels in the oceans, as well as the atmosphere, and they do see increasing CO2 concentrations to go with increasing global temperatures.

They also know that CO2 absorbs more radiation from the sun. So CO2 is "at least" a contribution to changing temperatures, if not the major player.

However, other possibilities like volcanic activity, solar flares, and varying orbits with the sun aren't enough to account for the increased radiation absorption. But given that rising CO2 is due to rapid deforestation (less plant life to absorb carbon), rapid burning of fossil fuels, and that CO2 has been known to destroy plant life in the oceans by increasing the acidity of the ocean, it remains the most plausible hypothesis as the major player.

Now I`m on a tablet on my couch and don't want to be linking sources, but there's also a scientist that thinks previous temp changes on the Earth might have been due to volcanic activity burning massive amounts of plant life (or oil, because that's what it is).
Now that may not be true, but climate change skeptics love to claim increasing global temperatures are normal throughout history, but they themselves do not know what caused the temp changes to begin with to legitimately argue what's "normal". So it's a little ironic, the skeptics. They are against the science, but also pretend they are being scientific by being anti-science about it.

 

[Ex-User (14663)]

@Rebis yes it's the ones from 98 and 99, linked below

http://www.meteo.psu.edu/holocene/public_html/shared/articles/mbh98.pdf

http://www.meteo.psu.edu/holocene/public_html/shared/research/ONLINE-PREPRINTS/Millennium/mbh99.pdf

 

[peoplesuck]

What if releasing poison into our air were a bad idea, and we didnt need an expert to tell us that?
TBH, I think its silly the way we treat our environment, but if everyone else doesnt give a fuck, I dont need to feel bad about loving rotary engines.
its a win in every way, other than the loss of life and death of the planet.

 

[Ex-User (14663)]

Now I`m on a tablet on my couch and don't want to be linking sources, but there's also a scientist that thinks previous temp changes on the Earth might have been due to volcanic activity burning massive amounts of plant life (or oil, because that's what it is).
Now that may not be true, but climate change skeptics love to claim increasing global temperatures are normal throughout history, but they themselves do not know what caused the temp changes to begin with to legitimately argue what's "normal". So it's a little ironic, the skeptics. They are against the science, but also pretend they are being scientific by being anti-science about it.

why does one need to determine the exact model for temperature change in order to argue against a specific variable determining the temperature? That doesn't make logical sense.

 

[Ex-User (14663)]

btw when I was talking about the garbageness of the MBH-papers, it can be pretty easily illustrated by figure 7 in the 98 paper: there you have the 4 timeseries in question: northern-hemisphere temperature, solar flares, CO2, and volcanic dust.

what they did was applying a 200-year window rolling correlation (have no idea why they picked exactly 200 years) and concluded: hey, CO2 has the highest correlation at this point in time.

looking at those timeseries it should be obvious that you can arrive at any conclusion you want based on what methodology you use and what length of rolling window you use for the correlation. For example you had a period of 100 years between 1800 and 1900 where temperatures trended downward while CO2 was trending upward.

at the very least, a more correct way to analyze those time-series would be to use some multivariate autoregression model like VAR, which is routinely used to infer (granger) causality in multivariate timeseries. Instead they opted for a home-made correlation technique where they paired up the explanatory variables against temperature one at a time – something which probably even freshman-students in statistics can tell you is a foolish way to do multivariate inference.

but even then, the only thing you have is a very low-resolution set of timeseries where ultimately the only thing you can say is: we have a bunch of potential explanatory variables – Co2, solar activity, volcanic dust, and probably an infinitude of other variables – which have trended upward while temperatures have also trended upward, so we can pick any one of these to "explain" the rise in temperature, while in fact based on statistical evidence we have no clue what causes what.

 

[Hadoblado]

Thanks

I guess I'm a little skeptical of reducing the evidence for climate change down to the methodology of one study from 20+ years ago. That article has been cited 1500+ times, and I doubt you're the first person to question their methods.

Regarding 200 years:
"A window width of 200 yr was chosen to ensure that any given window contains enough samples to provide good signal-to-noise ratios in correlation estimates. Nonetheless, all of the important conclusions drawn below are robust to choosing other reasonable (for example, 100- year) window widths."

Is your issue with which years they picked or how long the window is? Isn't 1800-1900 when the correlation becomes evident or am I misreading that?

Is there a reason they need to pick a window instead of providing a correlation for the entire recorded period?

What are the grey bars they talk about in the description? I can't see any.

 

[Ex-User (14663)]

I was wrong about one thing, actually. They didn't look at correlations between temp and the others one at a time, they applied multivariate regression. Which makes it slightly more reasonable, but still a very hackey way to do the analysis

I guess I'm a little skeptical of reducing the evidence for climate change down to the methodology of one study from 20+ years ago. That article has been cited 1500+ times, and I doubt you're the first person to question their methods.

true

Regarding 200 years:
"A window width of 200 yr was chosen to ensure that any given window contains enough samples to provide good signal-to-noise ratios in correlation estimates. Nonetheless, all of the important conclusions drawn below are robust to choosing other reasonable (for example, 100- year) window widths."

Is your issue with which years they picked or how long the window is? Isn't 1800-1900 when the correlation becomes evident or am I misreading that?

this 200-year window thing shows the problem with that whole regression approach they chose, because it means the whole analysis hinges on that parameter. And once the analysis hinges on a parameter, the whole analysis becomes meaningless because the results will vary based on what number they choose. Here they even said "we picked 200 because it gives a good signal-to-noise ratio". Question would be: how on earth do you know that in advance. I would say they probaly didn't know it in advance and tried different numbers until they reached a result that looked interesting. That's basically statistical fraud.

Is there a reason they need to pick a window instead of providing a correlation for the entire recorded period?

based on eye-balling those graphs I would say it's quite likely that if you used the full period then CO2 wouldn't come out as the most significant factor, it would probably be solar irradiance.

What are the grey bars they talk about in the description? I can't see any.

not sure, I think that graph has been messed up when it was scanned.

 

[Hadoblado]

Hmmm...

Do you think the inclusion of more years would alter the main point though?

What the window they present shows is that CO2 was not as good of a predictor of NH temperature as solar irradiance, until around 1840 where it increasingly improved in predictive validity, overtaking solar irradiance around 1880, and then continuing to improve in that correlation strength up to what looks like a strong correlation.

I think this is basically the case for anthropogenic climate change. CO2 wasn't the main driver of climate change, until it reached a saturation where it was. Now the climate will continue to get worse as we increase CO2 levels.

 

[Ex-User (14663)]

I see now there exist much more sophisticated methods for analyzing this stuff. In particular computer simulations that simulate the whole climate system with its various forcings (obviously including heat-trapping gases like CO2). That sort of stuff I can get behind.

https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter9-1.pdf

in other words: I'm a believer now

 

[Grayman]

I see now there exist much more sophisticated methods for analyzing this stuff. In particular computer simulations that simulate the whole climate system with its various forcings (obviously including heat-trapping gases like CO2). That sort of stuff I can get behind.

View attachment 5127

https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter9-1.pdf

in other words: I'm a believer now

A believer in what exactly? Climate change is a over inflated term that can mean many things. You didn't believe CO2 contributed to any warming? Or you now believe that contribution is more significant than you originally thought?

 

[Ex-User (14663)]

A believer in what exactly? Climate change is a over inflated term that can mean many things. You didn't believe CO2 contributed to any warming? Or you now believe that contribution is more significant than you originally thought?

not sure why you are so interested in the exact state of my brain but I would say I went from having mixed (or largely unsolidified rather) views on the scientific evidence to having the opinion that the scientific evidence corroborates the presence of anthropogenic forcings

btw that doesn't change the fact that I believe most people who march under climate-change banners are a bunch of sheep, but I guess they are sheep that (for now) are getting indoctrinated in the right things

 

[Daddy]

Now I`m on a tablet on my couch and don't want to be linking sources, but there's also a scientist that thinks previous temp changes on the Earth might have been due to volcanic activity burning massive amounts of plant life (or oil, because that's what it is).
Now that may not be true, but climate change skeptics love to claim increasing global temperatures are normal throughout history, but they themselves do not know what caused the temp changes to begin with to legitimately argue what's "normal". So it's a little ironic, the skeptics. They are against the science, but also pretend they are being scientific by being anti-science about it.

why does one need to determine the exact model for temperature change in order to argue against a specific variable determining the temperature? That doesn't make logical sense.

My point was, real science has to take account all the evidence they can and form the most plausible conclusion based on that evidence.

But any conclusion is always up for debate based on "new" evidence or a "better" interpretation of that evidence.

Problem I have with climate skeptics saying temperatures have always fluctuated is that they aren't interpretating anything because they don't present a theory for that change, nor do they even bring forth new evidence. They are simply deniers of the evidence and conclusions.
And I don't expect this to make sense to "you" at this point, but I'm still going to say it.

 

[Grayman]

My point was, real science has to take account all the evidence they can and form the most plausible conclusion based on that evidence.

But any conclusion is always up for debate based on "new" evidence or a "better" interpretation of that evidence.

Problem I have with climate skeptics saying temperatures have always fluctuated is that they aren't interpretating anything because they don't present a theory for that change, nor do they even bring forth new evidence. They are simply deniers of the evidence and conclusions.
And I don't expect this to make sense to "you" at this point, but I'm still going to say it.

Deniers and skeptics are two separate things. A skeptic doesn't deny the the core theories of AGW.

 

[Ex-User (14663)]

Problem I have with climate skeptics saying temperatures have always fluctuated is that they aren't interpretating anything because they don't present a theory for that change, nor do they even bring forth new evidence. They are simply deniers of the evidence and conclusions.
And I don't expect this to make sense to "you" at this point, but I'm still going to say it.

if one does this analysis with a null hypothesis of, say, "CO2 doesn't explain the variation in temperature the last 200 years", then contrary to what you're saying here, if one doesn't reject the null hypothesis then one would be perfectly correct in rejecting the claim that CO2 causes global warming while not having any model for variation in temperature whatsoever. That's how basic statistical inference works. Whether or not that is how most climate-change skeptics derive their beliefs is of course another question.

should I assume any of this will make sense to you? This is uncertain.