Merged Global Warming Discussion II: Heated Conversation

[lenny]

The problem is not the paper but the journalist commenting the paper and writing about our future as if it should be the future in the paper.

i hate it when that happens.

thanks for coming back to this post. i will read the paper when i get home (currently in an airport headed there).

 

[lenny]

I had no idea you were actually disputing all of the proxies for past climate.

i had no idea i was doing that either. and on reflection, i don't think i did .

if we wanted to consider change in temperature over the last hundred years, and contrast that number with the distribution due to "natural variability is in the current stable range " then how many independent observations do we have from that distribution ... how well can we establish the (statistical) significance of the last hundred years? is N=10, or 100? or???

did you provide estimate N?

alternatively: what is the uncertainty (not the value itself, the uncertainty in the estimated value) in the annual global mean temperature in 2000? in 1900? in 1800? in 1600? in 800? and so on.

and how do those numbers constrain the accuracy with which we know the historical variation (the distribution of) 100 year changes in global mean temp? (which of course requires subtracting one uncertaint temperature from another.)


again: this post is not intended to cast doubt on recent warming, rather it comes from a deep desire not to oversell the observational basis for our claims regarding "natural variability".

i'll look a the paper you suggested. thanks.

 

[DC]

News from Svensmark, he got the evidence he was looking for. deems that cosmic rays can indeed create large anough particles to from clouds.

from all the stuff coming from the deniers and climatesceptics i always liked Svensmark idea. simply because far away supernova influence the cloud formationin our atmosphere.

http://arxiv.org/pdf/1202.5156.pdf
preprint.

very intersting research.
(no i don't think its a game changer, it may have some influence, but guess not too much, and its a very complicated not well understood influence anyway, damn coulds. )

 

[CapelDodger]

alternatively: what is the uncertainty (not the value itself, the uncertainty in the estimated value) in the annual global mean temperature in 2000? in 1900? in 1800? in 1600? in 800? and so on.

That would be the grey band on the good old Hockey Stick back to about 1000CE; before that it doesn't get much worse for a good few thousand years, as sediment and ice cores usually go back a fair way.

and how do those numbers constrain the accuracy with which we know the historical variation (the distribution of) 100 year changes in global mean temp? (which of course requires subtracting one uncertaint temperature from another.)

Bring the statistics to bear and I've no doubt it could be done. The only useful variation would be between one century average and the next (surface temperatures being notoriously ephemeral in comparison to ocean heat-content), which may throw up some historical limit to compare to the current rate of change.

Tactically, I'd steer away from this kind of tail-chasing, which is a common refuge of deniers. This is one case where anectodotal evidence can be legitimately persuasive .

 

[AlBell]

brrrrr!

http://www.telegraph.co.uk/earth/en...o-actually-were-cooling-claim-scientists.html

 

[Reality Check]

News from Svensmark, he got the evidence he was looking for. deems that cosmic rays can indeed create large anough particles to from clouds....

For a start that paper does not address the fundamental problem with his idea that global warming is caused by cosmic rays, i.e. What's the link between cosmic rays and climate change?

Hypothetically, an increasing solar magnetic field could deflect galactic cosmic rays, which hypothetically seed low-level clouds, thus decreasing the Earth's reflectivity and causing global warming. However, it turns out that none of these hypotheticals are occurring in reality, and if cosmic rays were able to influence global temperatures, they would be having a cooling effect.
...
In fact cosmic ray flux has lagged behind the global temperature change since approximately 1970 (Krivova 2003).

By itself, Response of Cloud Condensation Nuclei (> 50 nm) to changes in ion-nucleation (to be published in the November 2013 Physics Letters A), is an interesting paper with little connection to climate change. It is just possible that this would have a tiny effect on cloud coverage but there are better candidates for the major drivers of cloud coverage, e.g. the El_Niño–Southern_Oscillation (A Decade of the Moderate Resolution Imaging Spectroradiometer: Is a Solar–Cloud Link Detectable?)

 

[DC]

Is there any hope for the hardcore deniers?

in debate about AGW I often get the argument that while Humanity emitted record levels of CO2. there was no increase in SAT. this clearly shows that CO2 has very little if any effect on temperatures. some even claim this is empirical evidence falsifying the AGW theory.

I can understand that this is confusing as it is counterintuitive.
and I explain to them how other factors can overwhelm the CO2 forcing and this is what most probably is happening currently. yet they keep saying the same.

so I started using a new argument to counter it. I hoped it makes clear to them how their argumentation is flawed.
I point to the time period 1940-1940. TSI rose to its highest levels in the past 400 years. (TSI increased 1-1.5W/m² between maunder minimum and 1960)
yet global temperature fell globally, not only flat, no global cooling, despite TSI rising to its highest levels.

then I say, does that show that the SUN has very little if any effect on the climate?

then they get all angry and tell me how dumb I am, and how other factors like PDO can overcome that solar forcing......

then I ask so and the currently negative PDO, sinking TSI cannot explain the cancelling out of the CO2 forcing?

but they assure me no, that is not possible.....

are those people lost cases? they just really don't want to understand.

or is my logic flawed? I think not.

 

[lomiller]

i had no idea i was doing that either. and on reflection, i don't think i did .

See the chain below

I don’t find that to be a particularly good point. We have quite a good understanding of what the natural variability is in the current stable range

do you mean "understanding" or do you mean "evidence" ?

by "good numbers" i meant empirical evidence.

There are a number of papers looking at how the earth’s temperature has changed over the last 10 000 years. This is actually something that is looked into quite intensely a number of different ways. Your post certainly made it seem like you didn’t think any of this evidence exists.

did you provide estimate N?

Each paper will have its own range. There is no 1 single estimate for me to provide.

alternatively: what is the uncertainty (not the value itself, the uncertainty in the estimated value) in the annual global mean temperature in 2000? in 1900? in 1800? in 1600? in 800? and so on.

The uncertainly is higher as you go back in time, however it’s not so high that strong statements can’t be made.

and how do those numbers constrain the accuracy with which we know the historical variation (the distribution of) 100 year changes in global mean temp?

You have this backwards. Other than large volcanic eruptions, which show up clearly in the paleo climate record there is NO evidence for rapid changes. The error margins mean there is some possibility of a rapid change that is revered quickly, but constrain how large and persistent such a change could possibly be.

The fact that the data doesn’t rule out such a isn’t a sound argument for assuming one occurred, especially when we already know we can identify this type of rapid change when it occurs due to volcanic eruption.

At this point it’s also worth pointing out that you seem to be falling for the obfuscation about natural variability often presented in denier blogs. A volcanic eruption is part of the natural variation in climate. It’s not however, an unforced change. Likewise the steady decline in global temperature from ~8000 years ago to ~100 years ago is probably mostly natural but again it’s not unforced. This type of natural variation not only fits with current understanding of the earth’s climate, it’s explainable only with the same theory and models that predict extreme rates of warming resulting from greenhouse gasses.

This differs from internal variability, which can be estimated by models and confirmed by examining the data. Internal variability is essentially random and its influence drops out of the data within a couple decades so model effectiveness can be evaluated using weather station data.

 

[acesuv]

Global Warming is disputable

More of the guy which is featured in my last thread. This time, his opinions on global warming.

Screenshot of the Facebook post: i.imgur.com/cnRontA.png

Article which is linked in the post: www [DOT] telegraph [DOT] co [DOT] uk/earth/environment/climatechange/10294082/Global-warming-No-actually-were-cooling-claim-scientists.html

 

[uke2se]

More of the guy which is featured in my last thread. This time, his opinions on global warming.

Screenshot of the Facebook post: i.imgur.com/cnRontA.png

Article which is linked in the post: www [DOT] telegraph [DOT] co [DOT] uk/earth/environment/climatechange/10294082/Global-warming-No-actually-were-cooling-claim-scientists.html

We have a thread for global warming denial. We also invite people's own opinions.

Also, science isn't usually done in the media.

And finally, no, global warming isn't disputable.

 

[DC]

Global Warming is disputable

not really, not rationally

 

[nimzov]

"Global Warming is disputable"

===

The data says otherwise.

 

[Reality Check]

More of the guy which is featured in my last thread. This time, his opinions on global warming.

Why do you think that we would be interested in the personal opinion of some random guy on Facebook, acesuv?
This is the science section of the forum. We know what the science states about global warming, e.g. the global surface temperature of the Earth has been measured to have an increasing trend over the last century or more. So global warming is a fact and not disputable.

Even that newspaper article from The Telegraph is basically reporting rumors - the personal opinion of a couple of scientists not backed up by citations to the scientific literature. Note the journalistic and other errors in it

• Thinking that weather is climate, e.g. mentioning a "cold Arctic summer".
  Climate is weather on time scales of multiple decades (30 years is the internationally recognized standard, studies show that you have to get to ~17 years before natural variability and cycles becomes climate trends).
• Going on about the next unpublished IPCC report rather than the existing science.
• Not making their sources back up claims with evidence, e.g. "“uncertainty is getting bigger” within the academic community" by how much? Reported in what papers using what surveys of the academic community?
• Not recognizing the cherry picking in:
  "Long-term cycles in ocean temperature, she said, suggest the world may be approaching a period similar to that from 1965 to 1975, when there was a clear cooling trend".
  The simple fact is that you can find just about any trend in the ocean temperatures by picking a decade to get that trend.

 

[lenny]

And finally, no, global warming isn't disputable.

all science is disputable, no? thats sorta the point

its just that disputing the warming over the last 100 years does not get very far, in terms of the evidence, before it is rejected.

even this Telegraph article ends with the sentence:

"Other experts agree that natural cycles cannot explain all of the recorded warming."

 

[temporalillusion]

Skeptical Science Graphics used with permission.

 

[uke2se]

all science is disputable, no? thats sorta the point

its just that disputing the warming over the last 100 years does not get very far, in terms of the evidence, before it is rejected.

even this Telegraph article ends with the sentence:

"Other experts agree that natural cycles cannot explain all of the recorded warming."

I'd argue that global warming is a fact, not science. Explaining the observation of global warming is science.

 

[Varanid]

I'd argue that global warming is a fact, not science. Explaining the observation of global warming is science.

Sure, but it is a fact that isn't readily determined -- it requires significant research. This isn't a fact like the sky is blue, or water is wet. The research used to determine the fact isn't beyond scrutiny.

I am not an AGW denialist, just playing devils advocate for science's sake. There are numerous lines of evidence that support the observation, but one could argue against the accuracy or rigor of the research. He or she would be wrong, but he or she could make a valid argument along those lines.

 

[aleCcowaN]

all science is disputable, no? thats sorta the point

Exactly. Global warming is disputable, debatable, arguable, etcetera.

Anyway, I suspect "disputable" is used in the OP as the exact opposite of "indisputable" in a sense of being disavowable, what so far it's not.

 

[ehcks]

Sure, but it is a fact that isn't readily determined -- it requires significant research. This isn't a fact like the sky is blue, or water is wet. The research used to determine the fact isn't beyond scrutiny.

I am not an AGW denialist, just playing devils advocate for science's sake. There are numerous lines of evidence that support the observation, but one could argue against the accuracy or rigor of the research. He or she would be wrong, but he or she could make a valid argument along those lines.

I'm not sure how significant the research is to check some thermometers over a few decades and compare the temperatures in different places over time. It's been plainly obvious that the average global temperature has been going up for a while.

Now getting data on the last ten thousand years for comparison, that was significant research. Also kinda scary.
http://cdn.zmescience.com/wp-content/uploads/2013/03/10000-year-graph.jpg

 

[Reality Check]

Even that newspaper article from The Telegraph is basically reporting rumors ...

However that Telegraph article is a truncated version of a Mail on Sunday article by David Rose - a well known climate warming denier who has written several scientifically incorrect articles on the subject. Phil Plait has an article debunking it: No, the World Isn't Cooling

When I heard that the Mail on Sunday ran a climate change article over the weekend, I knew it would be bad. But when I clicked the link and saw it was written by David Rose, I braced myself for the worst.
...
The article in the Mail bears this out. In it, Rose makes a lot of jaw-dropping statements. To pick three, he says the world is cooling, Arctic sea ice increased 60 percent over last year at this time, and the International Panel on Climate Change is under so much attack they had to hold a "crisis" meeting.
These claims are at best misleading. The first and third are just wrong, and the second hugely cherry-picked. I’ll debunk these briefly here, but I’ll note you can get the grim details at the Guardian in a great article by Dana Nuccitelli and John Abraham and at Discover magazine. Hot Whopper has a dissection as well.