Even 50-year-old climate models correctly predicted global warming • Hacker News Board

Re: Even 50-year-old climate models correctly predicted global warming

#151

Post by exclusiv » Thu, Dec 05, 2019, 1:40 AM UTC

onhn wrote: post #41

minikites wrote: post #2

People who don't believe in anthropogenic climate change at this point are no better than people who believe the Earth is flat.

Not sure about ordering people like this, but to your underlying point: I would say that the evidence for Earth not being flat is directly and immediately observable in everyday life. Climate change evidence on the other hand, one has to either put in some effort in the form of research/reading, or, place trust in an authority or peers.

Totally agree. And you can still believe man is a contributor (though not the primary cause) and that the climate change doomsday that is pushed is completely oversold. The parent's comparison is not accurate at all.

Re: Even 50-year-old climate models correctly predicted global warming

#152

Post by gameswithgo » Thu, Dec 05, 2019, 1:41 AM UTC

starpilot wrote: post #59

ekianjo wrote: post #48

Where is the story hère though? So they looked retroactively and found some models in the past that fitted with current observations even though they had no clue that China would become such a powerful force in terms of CO2 emissions? If you run random models and wait long enough you will always be able to find at least one model that predicted the current observations. That does NOT mean the models were right, it me…

Yeah, this could be survivorship bias: https://motls.blogspot.com/2017/03/selection-of-climate-mode... As someone who's written basic fluid dynamics codes, I'm blown away by the complexity of climate models. The errors I ran into in debugging my relatively straightforward codes were incredibly subtle. Like pressures, velocities still "looking right" but still being wrong, due to numerical viscosity and other artifact…

total heat content of the planet is way way simpler than fluid dynamics

Re: Even 50-year-old climate models correctly predicted global warming

#153

Post by pstuart » Thu, Dec 05, 2019, 1:42 AM UTC

bitlax wrote: post #88

pstuart wrote: post #64

Earlier quoted context omitted.

Lead by example and institute policies that strongly support taking aggressive action. This won't happen while Trump is in office, unfortunately.

Well I'll take that bet. Climate activists have advocated that precisely the opposite should happen: that they should maintain or even increase their growth since they are developing economies.

You're betting that Trump is going to push policies that address climate change? The same individual who says that climate change is a hoax? Who praises clean coal and says that wind turbines cause cancer?

Re: Even 50-year-old climate models correctly predicted global warming

#154

Post by scottlocklin » Thu, Dec 05, 2019, 1:45 AM UTC

bduerst wrote: post #113

bitlax wrote: post #53

Earlier quoted context omitted.

How do we convince China and India to lessen their CO2 production in any meaningful way?

China is the largest green energy producer in the world, doubling the output of the U.S.

Chyeah sure bro. Ever actually been there?

https://www.google.com/search?q=china+smog&source=lnms&tbm=i...

Re: Even 50-year-old climate models correctly predicted global warming

#155

Post by KirinDave » Thu, Dec 05, 2019, 1:45 AM UTC

huffmsa wrote: post #149

KirinDave wrote: post #92

Earlier quoted context omitted.

[flagged]

1. Pretty sure suggesting murder suicide is against the rules. 2. The warm areas of are planet aren't recently poor. There's a very narrow habitable band of temperatures in which human society has thrived. The extreme energy needed to develop those areas is contributing more to the degradation of the environment than benefit to the species it is providing. It's not sustainable. It's going to kill us all. Not everyone…

1. I'm pretty sure I was suggesting not having kids. It's a bit terrifying that you went here.

2. This doesnt change the calculus of what you're proposing at all. And it's not energy that is the missing resource; that's available in quantity. It's resources and water.

Sitting here saying, "Well the people I'm proposing the death of are historically poor and therefore their hardship inevitable" isn't a rebuttal, it's a rationalization.

Re: Even 50-year-old climate models correctly predicted global warming

#156

Post by huffmsa » Thu, Dec 05, 2019, 1:46 AM UTC

lukifer wrote: post #135

huffmsa wrote: post #87

Earlier quoted context omitted.

I'm mostly concerned about the scale were looking at. A 50-100 year uptick is nothing on the timescales that the planet operates on. Even 20k years is miniscule.

No dispute. And yet, I don't see any other instances of the a near-45-degree angle spike over the last 20k years (with the obvious caveat that our data on the past is imperfect). Like I said, not a smoking gun; just a clue that it's worth digging into. And from a Bayesian perspective, one must ask: what are the odds that that rising temperature would happen to correlate with CO2, for entirely unrelated reasons? https…

By no means do I want to hand wave it, I'm just personally not convinced of the presented outcomes.

I know that alarmism is the best way to get attention, but its also the best way for me to think you're a zealot who should be ignored.

Re: Even 50-year-old climate models correctly predicted global warming

#157

Post by jml7c5 » Thu, Dec 05, 2019, 1:47 AM UTC

ekianjo wrote: post #48

Where is the story hère though? So they looked retroactively and found some models in the past that fitted with current observations even though they had no clue that China would become such a powerful force in terms of CO2 emissions? If you run random models and wait long enough you will always be able to find at least one model that predicted the current observations. That does NOT mean the models were right, it me…

According to: http://www.realclimate.org/index.php/archives/2019/12/how-go...

>We gathered all the climate models published between 1970 and the mid-2000s that gave projections of both future warming and future concentrations of CO2 and other climate forcings – from Manabe (1970) and Mitchell (1970) through to CMIP3 in IPCC 2007.

If you're a cynic or suspicious: "projections of future warming" means they intentionally excluded studies that projected cooling.

Otherwise: it could have been written as "projections of future temperature", but they came across no studies that projected cooling.

This really makes me wish for open access journals, as most of the questions in this thread could be answered if it was possible for anyone to look at the paper.

Re: Even 50-year-old climate models correctly predicted global warming

#158

Post by DennisP » Thu, Dec 05, 2019, 1:49 AM UTC

ekianjo wrote: post #48

Where is the story hère though? So they looked retroactively and found some models in the past that fitted with current observations even though they had no clue that China would become such a powerful force in terms of CO2 emissions? If you run random models and wait long enough you will always be able to find at least one model that predicted the current observations. That does NOT mean the models were right, it me…

Whether or not China emitted lots of CO2 doesn't matter here. The old studies didn't predict how much CO2 the world would emit. They predicted how much the planet would warm, for various amounts of CO2 emissions. It turned out they were correct about that.

Among the models this study looked at was Hansen's. That's the NASA scientist who testified about global warming to Congress in 1988. It'd be quite a coincidence if there were lots of models with a wide variety of predictions, and the one model that was presented to Congress just happened by chance to be one of the few that got it right.

But if you can actually show that there were in fact a bunch of models by scientists of similar stature, which made really different predictions and were left out of this study, then that would be interesting.

Re: Even 50-year-old climate models correctly predicted global warming

#159

Post by thaumasiotes » Thu, Dec 05, 2019, 1:50 AM UTC

skosch wrote: post #130

throwyweather wrote: post #109

Earlier quoted context omitted.

Correctness of numerical codes is a huge and under-appreciated concern in climate models. There have been some attempts to apply software correctness techniques to climate models. For example, https://people.engr.ncsu.edu/jwb/papers/altuntas-correctness... Much more work in this direction is needed.

... but if you think, "hey, so the models could be wrong, how reassuring", think again. It's just as likely that reality is worse than predicted.

> It's just as likely that reality is worse than predicted.

This cannot possibly be correct; it's the same reasoning as the argument "Either the sun will rise tomorrow or it won't. These two possibilities exhaust the entire space. Therefore, the odds of the sun rising tomorrow are 50%, one in two." The premises are completely correct -- and unrelated to the conclusion.

Re: Even 50-year-old climate models correctly predicted global warming

#160

Post by henrifdrake » Thu, Dec 05, 2019, 1:51 AM UTC

jml7c5 wrote: post #157

ekianjo wrote: post #48

Where is the story hère though? So they looked retroactively and found some models in the past that fitted with current observations even though they had no clue that China would become such a powerful force in terms of CO2 emissions? If you run random models and wait long enough you will always be able to find at least one model that predicted the current observations. That does NOT mean the models were right, it me…

According to: http://www.realclimate.org/index.php/archives/2019/12/how-go... >We gathered all the climate models published between 1970 and the mid-2000s that gave projections of both future warming and future concentrations of CO2 and other climate forcings – from Manabe (1970) and Mitchell (1970) through to CMIP3 in IPCC 2007. If you're a cynic or suspicious: "projections of future warming" means they intentionall…

We didn't find any quantitative and peer-reviewed projections of cooling, or we would have included them. If you know of any, please let me know and I'll publish an update to the paper.