climate change intensified the amount of rainfall in recent hurricanes

[mistermack]

4 hours ago, Strange said:

I don't think the average sea temperature has increased by 1º, has it?

That's a point, but String Junky didn't specify what the 1 degree referred to. As the overall average temperature of the ocean is only 4 degrees C, a rise of 1 degree seemed an unlikely scenario. If the whole ocean DID warm by a whole degree, I would have thought that Greenland and Antarctica would be in floods of meltwater by then. To warm the entire ocean a whole degree would probably take thousands of years of high atmospheric temperatures. (that's a guess on my part ) 

This page claims that the oceans started warming 135 years ago, 70 years before CO2 levels showed any significant rise. That was about the time the little ice age ended, so it makes sense. They claim a 1.1 C rise in surface temps since then, but it takes an awful lot longer for the entire ocean to warm.    https://www.livescience.com/19414-oceans-warming-135-years.html   

[iNow]

3 minutes ago, mistermack said:

To warm the entire ocean a whole degree would probably take thousands of years of high atmospheric temperatures. (that's a guess on my part ) 

Thank goodness you clarified this. I would never have known otherwise...

3 minutes ago, mistermack said:

This page claims that the oceans started warming 135 years ago, 70 years before CO2 levels showed any significant rise.

Whoa, good catch. I need to refresh my math skills. I had know idea 1850 was only 70 years ago!

 

[mistermack]

Just now, iNow said:

Thank goodness you clarified this. I would never have known otherwise...

I did clarify it especially for you. 

3 minutes ago, iNow said:

Whoa, good catch. I need to refresh my math skills. I had know idea 1850 was only 70 years ago!

I know it's confusing, that was 1948. Have you tried using a calculator?

[beecee]

11 hours ago, druS said:

 

beecee, I'm not trying to be funny, I'd like your thoughts (from the reference paper) 'Hindcast' attribution method

Is there not a difference between a forecast and a hindcast? A difference between something that a simulation "projects" to something that it looks back on?

 

No probs.....While always being of the mind that "if" we are to err on this subject, we need to err on the side of caution. My views were greatly enforced when I was fortunate enough to watch a doco called "Chasing Ice" a few years ago. I believe that sums it up. A visually spectacular doco and irrefutably based on much observational evidence and the hindcast attribution method. 

I have mentioned it before but again worth repeating, if anyone has not seen it, then I suggest you change that and get a copy or watch on Netflix.  https://chasingice.com/

[Ken Fabian]

Quote

Half a degree in my lifetime can hardly be called change. Tiny fluctuation would be closer.

 

I live somewhere where half a degree is often the difference between frost and no frost on any given winter night - and perennial weeds that were kept in check by frosts can and are becoming rampant with warmer winters and fewer frosts. More labour, more cost for weed control.

Around here the fire danger season starts sooner and finishes later with that "insignificant" half a degree of global average warming - and, significantly, the non-fire danger season is noticeably shorter. Burning during the cool season to reduce fuel loads is an important part of reducing the intensity and risks of out of control bushfires later - the opportunities for doing so are fewer and the risks of them escaping containment are increasing. More labour, more equipment requirements, more vigilance. The impacts of "hardly change at all" are actually very real. When I consider the likelihood of several more degrees I am legitimately alarmed.

This relates to one of the questions I asked - "If where you live appears to benefit from global warming but other places suffer does that have any influence on your thinking?" 

9 hours ago, DirtyChai said:

And it's that continued irresponsible exaggeration of extreme and unrealistic figures that makes people describe "reasonable climate change proponents" as alarmists!

Not irresponsible - looking at worst case scenarios is an essential part of risk management - although my own mention of 3-6 degrees of warming was not even looking at the worst case. I was asked for a citation for further temperatures rises reaching those levels and I gave one, and it showed the potential for higher temperatures than what I suggested.

The 2000ppm CO2 levels probably is unrealistic - well, it is clearly labelled as an EXTREME scenario - but there are still influential people who do advocate maximising the use of fossil fuels, who want no limitations placed on their use, who want and expect all known reserves of fossil fuels to get used, which could indeed take it to that 2000ppm level - so scenarios for very high emissions continuing for the rest of this century are not impossibilities.  A total breakdown of international agreements and internal policies to reign in emissions is something actively being campaigned for and undermining confidence in climate science has been a key theme being used to do so. I sort of presume views like Mistermack's, if widely shared by policy makers, would raise the likelihood of that, making "unlikely" and "extreme" scenarios more likely.

If we don't end up with the extreme scenarios it will be in large part because of people taking the science on climate change seriously enough to seek and campaign for alternatives.

One of the other themes of anti climate action campaigning is blaming the messengers - ie climate scientists and climate action advocates.

Who is it labelling reasonable climate change proponents as alarmist? I suggest it is predominately people campaigning against strong climate action, as part of counter-messaging efforts to undermine overall confidence in all those expert studies and reports - who want the whole issue to be seen (falsely) as exaggeration.

Suggesting we should try and avoid worst case scenarios (which, within those reports, are scenarios, not exaggerations) isn't what gets climate change proponents seen as alarmists, it is constant and widely disseminated counter-messaging claiming they are alarmists that is promoting the idea that they are alarmists. In the absence of constant counter-messaging what was in those reports - which is by any measure, genuinely alarming - would be much more likely to be taken seriously and acted upon. Which would, of course, make the extreme scenarios less likely.

Organised opposition engaging in counter-messaging to prevent strong climate action has never been a reaction to irresponsible alarmist exaggeration, it is a response to the legitimately alarming mainstream expert advice. That opposition chose to do so for their own reasons - I think mostly responsibility avoidance although they may well have alarmed themselves with their own alarmist economic fears of going without fossil fuels.

Edited November 16, 2018 by Ken Fabian

[Moontanman]

On 11/14/2018 at 3:37 PM, beecee said:

https://phys.org/news/2018-11-climate-simulations-wetter-windier-hurricanes.html

Climate simulations project wetter, windier hurricanesNovember 14, 2018, Lawrence Berkeley National Laboratory

New supercomputer simulations by climate scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have shown that climate change intensified the amount of rainfall in recent hurricanes such as Katrina, Irma, and Maria by 5 to 10 percent. They further found that if those hurricanes were to occur in a future world that is warmer than present, those storms would have even more rainfall and stronger winds.

Read more at: https://phys.org/news/2018-11-climate-simulations-wetter-windier-hurricanes.html#jCp

the paper:

https://www.nature.com/articles/s41586-018-0673-2

Anthropogenic influences on major tropical cyclone events

Abstract

There is no consensus on whether climate change has yet affected the statistics of tropical cyclones, owing to their large natural variability and the limited period of consistent observations. In addition, projections of future tropical cyclone activity are uncertain, because they often rely on coarse-resolution climate models that parameterize convection and hence have difficulty in directly representing tropical cyclones. Here we used convection-permitting regional climate model simulations to investigate whether and how recent destructive tropical cyclones would change if these events had occurred in pre-industrial and in future climates. We found that, relative to pre-industrial conditions, climate change so far has enhanced the average and extreme rainfall of hurricanes Katrina, Irma and Maria, but did not change tropical cyclone wind-speed intensity. In addition, future anthropogenic warming would robustly increase the wind speed and rainfall of 11 of 13 intense tropical cyclones (of 15 events sampled globally). Additional regional climate model simulations suggest that convective parameterization introduces minimal uncertainty into the sign of projected changes in tropical cyclone intensity and rainfall, which allows us to have confidence in projections from global models with parameterized convection and resolution fine enough to include tropical cyclones.

 

You should have roade out Florence, 4 days of hurricane and an incredible amount of rain, 45 years of hurricane and this one was the rainiest and longest lasting by far of any I've seen... 

[StringJunky]

6 hours ago, mistermack said:

That's a point, but String Junky didn't specify what the 1 degree referred to. As the overall average temperature of the ocean is only 4 degrees C, a rise of 1 degree seemed an unlikely scenario. If the whole ocean DID warm by a whole degree, I would have thought that Greenland and Antarctica would be in floods of meltwater by then. To warm the entire ocean a whole degree would probably take thousands of years of high atmospheric temperatures. (that's a guess on my part ) 

This page claims that the oceans started warming 135 years ago, 70 years before CO2 levels showed any significant rise. That was about the time the little ice age ended, so it makes sense. They claim a 1.1 C rise in surface temps since then, but it takes an awful lot longer for the entire ocean to warm.    https://www.livescience.com/19414-oceans-warming-135-years.html   

Yeah, I think it was sea temperature rise.

[Moontanman]

21 hours ago, mistermack said:

I'm not sure what is the point behind your mentioning it. The problem is historical, it's being dealt with, and it's a consequence of growth of a city, and paving over of land. Anyway, climate change isn't done either, is it? Half a degree in my lifetime can hardly be called change. Tiny fluctuation would be closer.

 A half degree is world wide average, it contributes to wild swings from the norm, like the insurance commercial says, several 500 year floods in a decade...   

[coffeesippin]

On 11/15/2018 at 4:47 AM, mistermack said:

Meanwhile, here in the UK, we've had a nice spring, lovely sunny summer, and the autumn is nice too. So it's not all bad news. No water shortages, no floods. 

Thanks, climate change. 

Put it a few extra cords of wood for winter though.

On 11/16/2018 at 2:23 PM, beecee said:

No probs.....While always being of the mind that "if" we are to err on this subject, we need to err on the side of caution. My views were greatly enforced when I was fortunate enough to watch a doco called "Chasing Ice" a few years ago. I believe that sums it up. A visually spectacular doco and irrefutably based on much observational evidence and the hindcast attribution method. 

I have mentioned it before but again worth repeating, if anyone has not seen it, then I suggest you change that and get a copy or watch on Netflix.  https://chasingice.com/

My forecast lands in the water, usually, but my hindcast usually hooks the trees behind me.

[beecee]

3 hours ago, coffeesippin said:

Put it a few extra cords of wood for winter though.

My forecast lands in the water, usually, but my hindcast usually hooks the trees behind me.

I suggest you watch the video I linked to. And again, if there is any erorr/s in climate change, we are obliged to err on the side of caution...Our children, and their children demands it.

[druS]

16 minutes ago, beecee said:

I suggest you watch the video I linked to. And again, if there is any erorr/s in climate change, we are obliged to err on the side of caution...Our children, and their children demands it.

Yes agree beecee. But we confuse a question of science (strengths or otherwise of hindcasting and the accuracy of the reporting) with a matter of ethics or philosophy (cautionary principal) and policy (what we should do about it).

My query here is about the system of hindcasting and the accuracy of reporting the results as a projection.

Edited November 18, 2018 by druS

[beecee]

1 minute ago, druS said:

1 minute ago, druS said:

My query here is about the system of hindcasting and the accuracy of reporting the results as a projection.

 

I urge everyone to watch the "Chasing Ice" documentary.

[iNow]

^seconded

[druS]

5 hours ago, iNow said:

^seconded

 

Perhaps you can offer a better reference then.  What we have from beecee is a detour to a site that invokes me to get excited but does not offer me the film that apparently I need to watch to answer my question. I have seen many scenarios here on this forum where that would meet with moderators making comment.

I am happy watch it. Open minded. But the URL sends me to a place that is openly seeking support for advocacy and does not offer viewing of the film.

And with or without this possibly eye opening film, my question is very basic.

IS a hindcast accurately reported as a projection?

[iNow]

 

[Ken Fabian]

14 hours ago, druS said:

IS a hindcast accurately reported as a projection?

Interesting question. I think it is mostly about choice of words and I can't see it as a big problem - but is running climate models from the conditions current 100 years ago to see how well they "project/predict" climate changes only up to where we have real world data to compare to really prediction? Well, it does get called hindcasting to distinguish it from models that start with near-present known conditions to see what future conditions might be.

Hindcasting is done to verify how well the models work given various inputs, such as including the known rise in things like GHG concentrations, solar input and occurrences of volcanic eruptions over the period. Or alternatively without the rising GHG to see how climate might have changed without them.

Is it a prediction (or projection) if it only projects from further in the past up to when real world data runs out? I don't think calling it that is completely unreasonable, but it probably deserves clarification.

_____________________________________

There are a lot of misunderstandings about climate model projections/predictions and, like claims of reasonable climate concerns being labelled alarmist, a lot of the claims about modelling getting it wrong originate in the counter-messaging by those opposed to climate action. The "pause/hiatus" controversy for example arose from mistaking - often on purpose and ignoring expert objections - the average of many model runs giving an 0.x degrees per year of warming as predicting that every year will be 0.x degrees warmer than the one before. Which is like saying because models of seasonal temperature changes based on Earth's axial tilt say that on average each Spring day will be warmer than the day before - and therefore, because we just had a string of cooler than that average days, the models are wrong and Summer won't be warmer than Spring. And then suggest it could be the start of a new ice age.

Each individual model run actually show similar year to year variability that the real world does - ups and downs, pauses and accelerations, within the range of expected variability; that they do so is indicative of how well they work, not how badly. They just don't have those ups and downs in the same place each time. Which is why temperature trends look at averages over enough time that the expected variability doesn't mask underlying longer term changes.

That variability from year to year averages out to a very wobbly line if the period averaged over is too short, such as with "The Pause" which showed less warming than the 0.x degrees per year - and large parts of that variability can be attributed to known climate processes. The largest would be ENSO - el Nino Southern Oscillation - which causes year to year temperature changes much larger than the underlying warming trend - take a ten year period and if there are more la Nina years than el Nino then global average temperatures will be lower, despite an underlying warming trend. The other way about and they will be higher and it could look like warming has speeded up - it takes about 20 years or more for averaging for them to see past the global average temperature swings ENSO induces. Climate scientists most often use 30 years to be sure and routinely point out that looking at shorter periods can be very misleading.

Of all measures of global warming I think this one most directly shows actual gain of heat by Earth's climate system - and whilst it has year to year variability a much shorter period for averaging is needed to see past it. Ocean Heat Content shows no sign of an early 21st century Pause in warming (and is not explainable as ".. a consequence of growth of a city, and paving over of land.")  -

Edited November 18, 2018 by Ken Fabian

[druS]

Thanks Ken. I will find time to dig into your response. Really appreciate you putting the time in to provide it.

[hypervalent_iodine]

!

Moderator Note

I have removed several posts from this thread. If anyone wishes to discuss the minutia of climate change beyond the scope of the article beecee linked, please open a new thread. 

 

[mistermack]

If you got hold of a big computer, one of the biggest, and wrote a super program to forecast the lottery results, and then put all the previous lottery results into it, and tweaked and tweaked until the model correctly forecast all of the previous lottery numbers retrospectively, your chances of forecasting the NEXT result correctly would still be nearly nil. I wouldn't even spend a pound on a ticket. 

Start a gigantic bank account, and make all of the climate scientists put their pension money in it. When they come to retire, pay out on how successfully they predicted what the climate would be like on retirement day. You might see some more realistic efforts, if their own money depended on it.

[Ken Fabian]

10 hours ago, mistermack said:

If you got hold of a big computer, one of the biggest, and wrote a super program to forecast the lottery results, and then put all the previous lottery results into it, and tweaked and tweaked until the model correctly forecast all of the previous lottery numbers retrospectively, your chances of forecasting the NEXT result correctly would still be nearly nil. I wouldn't even spend a pound on a ticket. 

Start a gigantic bank account, and make all of the climate scientists put their pension money in it. When they come to retire, pay out on how successfully they predicted what the climate would be like on retirement day. You might see some more realistic efforts, if their own money depended on it.

Yet people who actually study climate and work on these problems do believe the nature and likely extent of climate consequences of human emissions can be predicted.  That you don't understand how that can be done (and doubt that it can) does not mean that they do not know how that can be done. Perfect prediction? No,  but the broad sweep of changes and their consequences can be well predicted.

The fundamental connection between greenhouse gas concentrations and global climate is well understood.

The US National Academy of Sciences and The Royal Society -

Quote

There are well-understood physical mechanisms by which changes in the amounts of greenhouse gases cause climate changes.

and

Quote

Further climate change is inevitable; if emissions of greenhouse gases continue unabated, future changes will substantially exceed those that have occurred so far. There remains a range of estimates of the magnitude and regional expression of future change, but increases in the extremes of climate that can adversely affect natural ecosystems and human activities and infrastructure are expected.

I expect people holding positions of trust and responsibility to take the expert advice seriously - that for such people to ignore or reject it, because they don't understand it, can't understand it or don't want to understand it is negligence.

Mistermack, you are free to believe what you like unless you hold such positions of responsibility. But that individual human "right" does not extend to those who do have fiduciary duties of care. The scale and long duration of the problem and the extent of influence of those who seek to avoid addressing it can work to effectively indemnify them - hard corruption bypassing legal requirement in exchange for bribes, or soft corruption influencing regulators to make it not-illegal and exempt them - but the essential legal principles for people being accountable are well established within common law legal systems.

Edited November 20, 2018 by Ken Fabian

[CharonY]

10 hours ago, mistermack said:

If you got hold of a big computer, one of the biggest, and wrote a super program to forecast the lottery results, and then put all the previous lottery results into it, and tweaked and tweaked until the model correctly forecast all of the previous lottery numbers retrospectively, your chances of forecasting the NEXT result correctly would still be nearly nil. I wouldn't even spend a pound on a ticket. 

Start a gigantic bank account, and make all of the climate scientists put their pension money in it. When they come to retire, pay out on how successfully they predicted what the climate would be like on retirement day. You might see some more realistic efforts, if their own money depended on it.

Also, this is a blatant case where there is simply a gross misunderstanding what these models are and what they do. In the case of lottery the model is quite clear. A given ball has the same likelihood getting picked (well, 1/n-i for each pick) thus the model will allow us to test deviations from it. It does not predict the the next ball. That, in theory, could only be achieved if one could accurately model the mechanical movements in a system, in which each state is dependent on the previous one. Thus, beyond a few movements a mechanical simulation trying to predict which ball is going to end up is going to be difficult to near impossible.

The same thing is true for weather, for example. Depending on how chaotic your system is in a given geographic area, the ability to somehow predict the weather beyond a few days at most is very, very low. However, climate takes aggregate information over long time frames. I.e. in your example you are basically conflating weather forecast with climate change models. You are essentially stating that because we are unable to predict the precise temperature on July the 23rd in 2041 at 11 AM we cannot assess general patterns. Yet even without models we have little issue in predicting that winters are generally going to be colder than summers. Why, because we look at much rougher patterns. Individual days may vary, but the trend is clear. 

[StringJunky]

4 minutes ago, CharonY said:

Also, this is a blatant case where there is simply a gross misunderstanding what these models are and what they do. In the case of lottery the model is quite clear. A given ball has the same likelihood getting picked (well, 1/n-i for each pick) thus the model will allow us to test deviations from it. It does not predict the the next ball. That, in theory, could only be achieved if one could accurately model the mechanical movements in a system, in which each state is dependent on the previous one. Thus, beyond a few movements a mechanical simulation trying to predict which ball is going to end up is going to be difficult to near impossible.

The same thing is true for weather, for example. Depending on how chaotic your system is in a given geographic area, the ability to somehow predict the weather beyond a few days at most is very, very low. However, climate takes aggregate information over long time frames. I.e. in your example you are basically conflating weather forecast with climate change models. You are essentially stating that because we are unable to predict the precise temperature on July the 23rd in 2041 at 11 AM we cannot assess general patterns. Yet even without models we have little issue in predicting that winters are generally going to be colder than summers. Why, because we look at much rougher patterns. Individual days may vary, but the trend is clear. 

'Trend' is the operative word, and that seems to be what MM is not grasping.

Edited November 20, 2018 by StringJunky

[iNow]

To reinforce Charons excellent point, think of waves coming on shore at the beach and splashing against a wall.

We cannot with perfect accuracy predict where on a wall each individual wave will land, but we can very accurately predict the average landing point over 10 years.

Weather versus climate is the obvious comparison.

[CharonY]

1 minute ago, StringJunky said:

Trend' is the operative word, and that seems to be what MM is not grasping.

Indeed. In fact models could be used to test whether a lottery system deviates from the assumed equivalency between draws, and depending on the type of study this is what some have been doing. E.g. assuming that the the anthropogenic influence of CO2 was not there, what would be the expected temperature trend?

[StringJunky]

6 minutes ago, CharonY said:

Indeed. In fact models could be used to test whether a lottery system deviates from the assumed equivalency between draws, and depending on the type of study this is what some have been doing. E.g. assuming that the the anthropogenic influence of CO2 was not there, what would be the expected temperature trend?

In the same way, you can know if a lottery system is fixed by looking at the output over a long period against a similar one that isn't. The unadulterated model can be done mathematically.

Edited November 20, 2018 by StringJunky