Reply to: August 2014 Warmest on record, globally

[SpontaneousOrder]

That's not quite accurate; 'model', as in 'climate model' usually implies a complex piece of software run on a supercomputer many times. The 'model' used by Hansen consists of the following:

1. Take the estimated contribution to SLR from ice sheet disintegration - about 1mm/yr, giving 1cm for the decade 2005-2015
2. Observe that this has doubled over the last decade.
3. Assume it carries on doubling each decade

This gives a rise of approx 5m this century. So there were no 'various model runs', it was more a fag-packet illustration of a geometric progression. As Hansen noted,



Ice sheet breakup is problematic and hard to model, to the extent that the 2007 IPCC report simply included it as a linear term in their SLR estimates:



Hansen is at the other end of the spectrum, assuming the breakup will be dynamic, and non-linear, and he lays out his reasons in the references to the above paper. At no point however, did he state that 5m was his most likely number.

So you agree with me then? (apart from I should have said 'projections' (i.e. Richard Alley's) instead of 'models' - which has nothing to do with the point anyway)

[pjclarke]

It was an outlier among all of the results run from various models; That doesn't mean that Hansen necessarily thought it unlikely - only that a single result of several predicted consequences of that magnitude.

Hanson actually went on to justify that particular result as being plausible based on the data from the IPCC, due to non-linear ice sheet melting.

I.e. Hanson didn't say "Hey, i found this outlier result which seems unlikely". He said "Hey - you know this outlier result? Well i reckon it's not as spurious as you might assume".

That's not quite accurate; 'model', as in 'climate model' usually implies a complex piece of software run on a supercomputer many times. The 'model' used by Hansen consists of the following:

1. Take the estimated contribution to SLR from ice sheet disintegration - about 1mm/yr, giving 1cm for the decade 2005-2015
2. Observe that this has doubled over the last decade.
3. Assume it carries on doubling each decade

This gives a rise of approx 5m this century. So there were no 'various model runs', it was more a fag-packet illustration of a geometric progression. As Hansen noted,

Of course I cannot prove that my choice of a ten-year doubling time for nonlinear response is accurate, but I am confident that it provides a far better estimate than a linear response for the ice sheet component of sea level rise under BAU forcing.

Ice sheet breakup is problematic and hard to model, to the extent that the 2007 IPCC report simply included it as a linear term in their SLR estimates:

Dynamical processes related to ice flow not included in current models but suggested by recent observations could increase the vulnerability of the ice sheets to warming, increasing future sea level rise. Understanding of these processes is limited and there is no consensus on their magnitude.

Hansen is at the other end of the spectrum, assuming the breakup will be dynamic, and non-linear, and he lays out his reasons in the references to the above paper. At no point however, did he state that 5m was his most likely number.

[SpontaneousOrder]

And of course contextualised with the statement:



I'm not sure why you guys are getting so hung up with an outlier from a single scientist, but it is certainly there, and PJ certainly quotes it with a contextualising statement.

More worrying I think, are attempts to take this outlier and cast is as a prediction. That would be quite wrong, wouldn't it?

It was an outlier among all of the results run from various models; That doesn't mean that Hansen necessarily thought it unlikely - only that a single result of several predicted consequences of that magnitude.

Hanson actually went on to justify that particular result as being plausible based on the data from the IPCC, due to non-linear ice sheet melting.

I.e. Hanson didn't say "Hey, i found this outlier result which seems unlikely". He said "Hey - you know this outlier result? Well i reckon it's not as spurious as you might assume".

[EternalOptimist]

And of course contextualised with the statement:



I'm not sure why you guys are getting so hung up with an outlier from a single scientist, but it is certainly there, and PJ certainly quotes it with a contextualising statement.

More worrying I think, are attempts to take this outlier and cast is as a prediction. That would be quite wrong, wouldn't it?

thats because you have a short memory.

we were discussing catastophism, and I was congratulating pj on his distancing himself from these alarmist claims. Something that all right minded people should do imho.

[Old Greg]

sorry
thats my lingo. when i said noone, I meant me. thats the way we talk around here

i am not responsible for any extremists out there, even if they do oppose the global warming scam.

Enough of your nonsense. You are a crook and a charlatan.

[Old Greg]

Possibly the link i referred to earlier: http://forums.contractoruk.com/gener...ml#post1752654


Quoted a bit including this:



So it's 'plausible'.

And of course contextualised with the statement:

Hansen described his projection as an outlier, and highly non-linear, most of the rise occurring long after 25 years.

I'm not sure why you guys are getting so hung up with an outlier from a single scientist, but it is certainly there, and PJ certainly quotes it with a contextualising statement.

More worrying I think, are attempts to take this outlier and cast is as a prediction. That would be quite wrong, wouldn't it?

[EternalOptimist]

Anyway, EO, still interested in your views on:



So, EO, if I am the naive and ignorant one, how do you square:



With:



List of scientists opposing the mainstream scientific assessment of global warming - Wikipedia, the free encyclopedia

sorry
thats my lingo. when i said noone, I meant me. thats the way we talk around here

i am not responsible for any extremists out there, even if they do oppose the global warming scam.

[Old Greg]

Anyway, EO, still interested in your views on:

no offence taken. But you are displaying a fair amount of naivety and ignorance here.
no one has ever disputed that humans are affecting the climate, that the green house effect is real. Producing millions of journals that say the same is meaningless.

So, EO, if I am the naive and ignorant one, how do you square:

no one has ever disputed that humans are affecting the climate, that the green house effect is real.

With:

Scientists questioning the accuracy of IPCC climate projections
Scientists arguing that global warming is primarily caused by natural processes
Scientists arguing that the cause of global warming is unknown
Scientists arguing that global warming will have few negative consequences

List of scientists opposing the mainstream scientific assessment of global warming - Wikipedia, the free encyclopedia

[Old Greg]

dont you ? considering the 5m claim

i never heard of him denying it. I never heard of anyone denying he said it.
In fact I seem to recall he made a correction to the story, to get the 2028 (as opposed to 2018)

I think this is the correction of the 1998 interview:

Michaels also has the facts wrong about a 1988 interview of me by Bob Reiss, in which Reiss asked me to
speculate on changes that might happen in New York City in 40 years assuming CO2 doubled in amount. Michaels
has it as 20 years, not 40 years, with no mention of doubled CO2. Reiss verified this fact to me, but he later sent the
message: "I went back to my book and re-read the interview I had with you. I am embarrassed to say that although
the book text is correct, in remembering our original conversation, during a casual phone interview with a Salon
magazine reporter in 2001 I was off in years. What I asked you originally at your office window was for a prediction
of what Broadway would look like in 40 years, not 20. But when I spoke to the Salon reporter 10 years later -
probably because I'd been watching the predictions come true, I remembered it as a 20 year question." So give
Michaels a pass on this one -- assume that he reads Salon, but he did not check the original source, Reiss' book.

So an interview. To speculate. And this is how it was reported in the Salon:

The West Side Highway [which runs along the Hudson River] will be under water. And there will be tape across the windows across the street because of high winds.

Is this a scientific prediction of rising sea levels, or a storm surge, or just speculation in an interview in 1988. Who knows? But funnily enough, guess where this is:



Source

[SpontaneousOrder]

If this is the statement EO is referring to, it would be great if he could now point us to the point where PJ agreed with this.

Possibly the link i referred to earlier: http://forums.contractoruk.com/gener...ml#post1752654


Quoted a bit including this:

Hansen (2007) suggested that a 10-year doubling time was plausible, pointing out that such a doubling time from a base of 1 mm per year ice sheet contribution to sea level in the decade 2005-2015 would lead to a cumulative 5 m sea level rise by 2095.

So it's 'plausible'.

[EternalOptimist]

So do you believe that reflects Hansen's views or position?

dont you ? considering the 5m claim

i never heard of him denying it. I never heard of anyone denying he said it.
In fact I seem to recall he made a correction to the story, to get the 2028 (as opposed to 2018)

[Old Greg]

it was discussed in many places
try this one

So do you believe that reflects Hansen's views or position?

[EternalOptimist]

What would be really interesting, EO, just to show how you like to play things with a straight bat, is if you could advise as to where you got the West side underwater by 2028 story from.

it was discussed in many places
try this one

[Old Greg]

no offence taken. But you are displaying a fair amount of naivety and ignorance here.
no one has ever disputed that humans are affecting the climate, that the green house effect is real. Producing millions of journals that say the same is meaningless.

So, EO, if I am the naive and ignorant one, how do you square:

no one has ever disputed that humans are affecting the climate, that the green house effect is real.

With:

Scientists questioning the accuracy of IPCC climate projections
Scientists arguing that global warming is primarily caused by natural processes
Scientists arguing that the cause of global warming is unknown
Scientists arguing that global warming will have few negative consequences

List of scientists opposing the mainstream scientific assessment of global warming - Wikipedia, the free encyclopedia

[EternalOptimist]

Anyway, a bit off topic, but I found this interesting:

Scientific opinion on climate change - Wikipedia, the free encyclopedia



It's a good job we have so many people here who know better.

no offence taken. But you are displaying a fair amount of naivety and ignorance here.
no one has ever disputed that humans are affecting the climate, that the green house effect is real. Producing millions of journals that say the same is meaningless.

What the sceptics say is that the effect is so tiny its worth ignoring.

Most scientists would agree that if you peed into the ocean, sea levels would rise
anyone with common sense would say, so what ?