Thread: Computer Simulations

Given that more people have been killed by earthquakes and tsunamis over the ages than by "global warming", why is it that "global warming" grabs more headlines?

Why is it so difficult to predict seismic events and so seemingly easy and definite to predict alleged warming trends?

Both these predictions must rely on computer simulation, using information from past, and given that past is greater for seismic data, thousands of years vs a few hundred for industrial society and alleged AGW, such simulations would be expected to be more accurate in former instance than latter.

depends on the time scale - i can confidently predict that there will be a major earthquake in California in the next century
however, it might be rather hard to say that, say, San Francisco will be hit by a for 8.4 earthquake next wednesday at 9.05am local time

likewise, predicting the localised effects of global warming for the coming years is more prone to variation than more generalised statements about statistical probability of certain events around the globe in the next century

Global warming has barely got going. So far, the world has experienced less than 1 C increase on average, and a sea level rise of only 2 to 3 mm per year. How much more we get in the future is problematic, and projections change all the time. There is a new projection which suggests a doubling of CO2 will lead to about a 2.4 C average rise, rather than the more extreme suggestions we have seen so far.
Climate sensitivity to carbon dioxide more limited than extreme projections, research shows

Originally Posted by skeptic

There is a new projection which suggests a doubling of CO2 will lead to about a 2.4 C average rise, rather than the more extreme suggestions we have seen so far.

The IPCC 2007 range was 2 to 4.5C, so this new estimate is within the IPCC range. I am only mentioning this lest your mention of extremes might be construed as referring to mainstream climate science consensus, which would be incorrect.

Given that more people have been killed by earthquakes and tsunamis over the ages than by "global warming", why is it that "global warming" grabs more headlines?

It's really hard to compare the direct effects of an earthquake or Tsunami to the indirect effects of climate change which precipitate droughts, massive storms, heat waves and warfare of displaced peoples etc. A UN study puts their estimate about about 150,000 a year so far, but its at best an educated guess because many killing events aren't analyzed in detail for attribution. Attribution is a description of if those killing event would have happened at all in a cooler&more humid world, or how much more intense they were as a result compared to a cooler world. Sometimes, those comparisons aren't graduated either. A levy that's over topped by a few inches and drowned a thousand, might not have happened at all if it wouldn't have rained as much for example.

Doubling is a useful benchmark for comparison but no longer a realistic maximum--as the rest of the world is dramatically increasing in industrial production and modern living, we'll be lucky to keep Co2 below triple the per-industrial levels.

Also Finger, temperature (and other variables) are not just modern and future climate simulation based, but also on our increasing knowledge of paleoclimate data which is helping figure out the sensitivities.

Originally Posted by Lynx_Fox

Given that more people have been killed by earthquakes and tsunamis over the ages than by "global warming", why is it that "global warming" grabs more headlines?

It's really hard to compare the direct effects of an earthquake or Tsunami to the indirect effects of climate change which precipitate droughts, massive storms, heat waves and warfare of displaced peoples etc. A UN study puts their estimate about about 150,000 a year so far, but its at best an educated guess because many killing events aren't analyzed in detail for attribution. Attribution is a description of if those killing event would have happened at all in a cooler&more humid world, or how much more intense they were as a result compared to a cooler world. Sometimes, those comparisons aren't graduated either. A levy that's over topped by a few inches and drowned a thousand, might not have happened at all if it wouldn't have rained as much for example.

Doubling is a useful benchmark for comparison but no longer a realistic maximum--as the rest of the world is dramatically increasing in industrial production and modern living, we'll be lucky to keep Co2 below triple the per-industrial levels.

Also Finger, temperature (and other variables) are not just modern and future climate simulation based, but also on our increasing knowledge of paleoclimate data which is helping figure out the sensitivities.

Is hard to compare actual dead bodies and destroyed buildings to things nebulous which may have other causes and probably in fact do? GET OUT! You know, in old days there was droughts, massive storms, heat waves, wars, and famines- even in the ancient Greece, no joke! What was causing them then, "climate change", weather, what? Good thing whatever it was is still not around or we would be REALLY screwed!

Paleoclimate data is all PREINDUSTRIAL so what relevance has it to AGWankers? Is NATURAL, baby, all organic, granola groovy, peace and love and put THAT in your bong and smoke it, esteemed moderator. And Prince thinks you mean "levee", not so? He struggles SO with your English, must take break now...

levee - definition of levee by the Free Online Dictionary, Thesaurus and Encyclopedia.

Do you wish to have a serious conversation....or don't you? If you don't we can fix that :-)

I've provide one example how you might conduct an attribution study. Take a current drought that effects food production. Run a set of models of nearly similar conditions except for it starts at some cooler level. By comparing soil moisture and what we know about the crop you can compare it to losses from average conditions as well as the amount of attribution, that is additional crop losses, in the warmer world. You than run this against food availability and resultant deaths. Similar studies have been done on not only droughts, but floods, heat waves etc.

Paleoclimate data is all PREINDUSTRIAL so what relevance has it to AGWankers?

Because, it can provide a sensitivity range based on the climate fluctuation during the period which we than further used to approximate sensitivity into the future. By doing so it be compared to other types of simulations confirm or deny their outputs. Thus far comparisons have been in the ballpark within a factor of two or so. (we've been in that same ballpark for nearly 60 years).

Originally Posted by marnixR

depends on the time scale - i can confidently predict that there will be a major earthquake in California in the next century
however, it might be rather hard to say that, say, San Francisco will be hit by a for 8.4 earthquake next wednesday at 9.05am local time

Good analogy. Similarly, it is far easier to make climate predictions for decades or centuries ahead than weather forecasts for even a few days ahead.

Originally Posted by Strange

Originally Posted by marnixR

depends on the time scale - i can confidently predict that there will be a major earthquake in California in the next century
however, it might be rather hard to say that, say, San Francisco will be hit by a for 8.4 earthquake next wednesday at 9.05am local time

Good analogy. Similarly, it is far easier to make climate predictions for decades or centuries ahead than weather forecasts for even a few days ahead.

Is easy to make predictions of any timescale. What is difficult is making ACCURATE predictions or forecasts:

21st century global cooling trend debunks United Nations computer climate models -- Earth Changes -- Sott.net

So we cannot with certainty predict either earthquakes or climate. Thus computer models at this stage of the art (not science) want considerable improvement. Such is the position of Prince.

Go read this thread which includes an actual study of temperature by people who actually study such things. Or you can provide a credible study that perhaps your article didn't bother to reference. Given that its facts about temperature trend over the past ten years....I kinda doubt it there is an actual study. But give it a shot.

global temperature change with ENSO, solar cycles and volcanic eruptions removed?

Originally Posted by Lynx_Fox

Do you wish to have a serious conversation....or don't you? If you don't we can fix that :-)

I've provide one example how you might conduct an attribution study. Take a current drought that effects food production. Run a set of models of nearly similar conditions except for it starts at some cooler level. By comparing soil moisture and what we know about the crop you can compare it to losses from average conditions as well as the amount of attribution, that is additional crop losses, in the warmer world. You than run this against food availability and resultant deaths. Similar studies have been done on not only droughts, but floods, heat waves etc.

Paleoclimate data is all PREINDUSTRIAL so what relevance has it to AGWankers?

Because, it can provide a sensitivity range based on the climate fluctuation during the period which we than further used to approximate sensitivity into the future. By doing so it be compared to other types of simulations confirm or deny their outputs. Thus far comparisons have been in the ballpark within a factor of two or so. (we've been in that same ballpark for nearly 60 years).

Rubbish. As you yourself have stated elsewhere, multiple factors affect climate, and has Prince has stated repeatedly, climate variation is a trivial contributor to mortality today as compared to other causes, and to mortality from the same source in the past. Data show that as CO2 level rises, so far the picture is getting better, not worse. If this changes in future, will increase of CO2 from human activity be responsible?

No.

Paleoclimate did not affect and was not affected by modern industrial civilization. What is so hard about this obvious fact for you to acknowledge?

Is easy to make predictions of any timescale. What is difficult is making ACCURATE predictions or forecasts:

21st century trend? I don't care if it's said to be cooling or warming, the 21st century is not quite 11 years old. (And it already has the hottest decade ever recorded.) If you want to know about climate trends , the latest research tells us that the absolute minimum period required is 17 years. Separating signal and noise in atmospheric temperature changes: The importance of timescale The 30 year standard for climate averaging still looks pretty good for determing trends.

The most accurate projection that I admire, mainly because it was done with computing power that a modern phone now uses, was the 1988 set of projections from Jim Hansen. He got one thing a bit wrong and another spectacularly right. (The right one was really a bit of serendipity. He had to put in a major volcanic eruption - because we expected one in the relevant period. He just happened to use the exact time that Pinatubo did its thing.)

The one thing he got wrong was to use a climate sensitivity of 4.2 for doubling. If he'd used what we now take as the standard, he'd have been right on the money. A tour de force. See Skeptical Science's debunking of the myth that he got it wrong. Hansen's 1988 prediction was wrong

Originally Posted by Lynx_Fox

Go read this thread which includes an actual study of temperature by people who actually study such things. Or you can provide a credible study that perhaps your article didn't bother to reference. Given that its facts about temperature trend over the past ten years....I kinda doubt it there is an actual study. But give it a shot.

global temperature change with ENSO, solar cycles and volcanic eruptions removed?

Prince has seen this thread and commented on it. For some reason, comment is no longer present. Computer guys have a saying, "garbage in, garbage out". Ultimately computer models, no matter how accurate, must have adequate data in order to produce useful product. If program is skewed this compounds error, but DOES tend to produce results preferred by skewers. Whether results conform to reality is of secondary importance, or none at all, so long as desired outcome is assured.

And you good sir continue to ignore the relative magnitude of effects, despite it being explained multiple times, often with actual studies showing the comparative values. Right now, as best science can tell there's nothing going on in nature to explain the late 20th century warming, yet we have a hypothesis now more than a half century old that not only explains the average lower atmospheric warming....it also explains where the warming is happening (high latitude) as well as the huge smoking gun of stratospheric cooling. It is now the dominant forcing and probably will be for the next century unless nature throws a huge and unpredictable event (e.g. large comet impact, super volcano etc).

Originally Posted by adelady

Is easy to make predictions of any timescale. What is difficult is making ACCURATE predictions or forecasts:

21st century trend? I don't care if it's said to be cooling or warming, the 21st century is not quite 11 years old. (And it already has the hottest decade ever recorded.) If you want to know about climate trends , the latest research tells us that the absolute minimum period required is 17 years. Separating signal and noise in atmospheric temperature changes: The importance of timescale The 30 year standard for climate averaging still looks pretty good for determing trends.

The most accurate projection that I admire, mainly because it was done with computing power that a modern phone now uses, was the 1988 set of projections from Jim Hansen. He got one thing a bit wrong and another spectacularly right. (The right one was really a bit of serendipity. He had to put in a major volcanic eruption - because we expected one in the relevant period. He just happened to use the exact time that Pinatubo did its thing.)

The one thing he got wrong was to use a climate sensitivity of 4.2 for doubling. If he'd used what we now take as the standard, he'd have been right on the money. A tour de force. See Skeptical Science's debunking of the myth that he got it wrong. Hansen's 1988 prediction was wrong

"Hottest decade ever recorded"? Dear lady, can you refer Prince to source?

Ultimately computer models, no matter how accurate, must have adequate data in order to produce useful product. If program is skewed this compounds error, but DOES tend to produce results preferred by skewers. Whether results conform to reality is of secondary importance, or none at all, so long as desired outcome is assured.

I don't know whether it's just the way you express it, but data is not the basis for climate modelling. Data for initial conditions is vital for weather forecasting models, but not at all for climate models. Physics is the basis. Radiative transfer equations and a whole lot of mathematisation turning circulation features (Hadley cells etc) into useful inputs.

Or did I misread your comment.

Originally Posted by Lynx_Fox

And you good sir continue to ignore the relative magnitude of effects, despite it being explained multiple times, often with actual studies showing the comparative values. Right now, as best science can tell there's nothing going on in nature to explain the late 20th century warming, yet we have a hypothesis now more than a half century old that not only explains the average lower atmospheric warming....it also explains where the warming is happening (high latitude) as well as the huge smoking gun of stratospheric cooling. It is now the dominant forcing and probably will be for the next century unless nature throws a huge and unpredictable event (e.g. large comet impact, super volcano etc).

Oh, yeah. Nature will kill millions as it has for all of recorded human history and prehistory, you can take that much to the bank. Why AGW cultists only get upset over HYPOTHETICAL prospect of human activity doing same sort of thing is beyond understanding of Prince. Late 20th century warming? What about the recent "hottest decade ever recorded"? Relative magnitude of effects? Okay, which is bigger, Sun or terrestrial atmosphere?

Magnitude of this atmosphere compared to effects of human activity on said atmosphere?

Said atmosphere and relation of same to climate, poorly understood. Ergo, models suck, GIGO. Q.E.D.

Carbon dioxide forcing alone insufficient to explain Palaeocene-Eocene Thermal Maximum warming : Abstract : Nature Geoscience

Originally Posted by adelady

Ultimately computer models, no matter how accurate, must have adequate data in order to produce useful product. If program is skewed this compounds error, but DOES tend to produce results preferred by skewers. Whether results conform to reality is of secondary importance, or none at all, so long as desired outcome is assured.

I don't know whether it's just the way you express it, but data is not the basis for climate modelling. Data for initial conditions is vital for weather forecasting models, but not at all for climate models. Physics is the basis. Radiative transfer equations and a whole lot of mathematisation turning circulation features (Hadley cells etc) into useful inputs.

Or did I misread your comment.

Of course, if desired outcome is preordained, actual measurements are irrelevant. Thank you for clarification, dear lady, and good night to all. Prince goes now to the mattress to cool off overheated brain, smoke and the DEADLY DREADED CO2 must be issuing from the royal ears soon!

Originally Posted by The Finger Prince

"Hottest decade ever recorded"? Dear lady, can you refer Prince to source?

Pretty much all of them as we already discussed last week.
Several Satellites
Land temperatures
Ocean Temperatures
Most of these are compiled including the raw data in this article.
Global temperature evolution 1979

Hottest decade?

The 13 warmest years have all occurred in the 15 years since 1997. See 2011: World

And this is worth a look. The Big Picture Just because I really, really like the animated displays.

Originally Posted by adelady

Hottest decade?

The 13 warmest years have all occurred in the 15 years since 1997. See 2011: World

And this is worth a look. The Big Picture Just because I really, really like the animated displays.

And this despite having the deepest solar minimum for nearly a century in between. Prince, your ignorance is very obvious.