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Comment by jknoepfler | Hacker News Reader

So if I asked you to bet at 50/50 odds that next year would be colder on average than this year, you'd take the bet?

It seems people do take a variation of this bet quite often; they keep moving to and investing in coastal cities and regions.

Are you asking about the weather in one specific year? Weather is not climate.

Yes, weather is climate. But that isn't what OP said.

Climate is long term patterns. Weather is what is happening at a specific time. If the distinction wasn't made then someone could argue that a cold winter day disproves warming.

that is not relevant to the wager I proposed, which still stands.

I'm well aware of the distinction between weather and climate. I was asking if the climate change skeptic would take a bet that the global mean temperature (operationalized in some acceptable way) would decline in 2021 compared to 2020. If they believe that the earth is not, on average, getting hotter, then they should be indifferent to this bet (inter-year variation should be random around a fixed point).

I don't think any intellectually honest person is indifferent to this bet. Everyone believes there is a solid chance that the climate is actually getting warmer, and almost no one would wager serious money at even odds on a globally colder 2021.

If you wouldn't bet against the climate getting warmer, then I don't think you have any place calling yourself a "climate change skeptic"

In a similar vein, I invest in index funds because I'm not a market skeptic. The market (at the moment) tends to grow year over year. I put my money where my mouth is in the market, I'd do the same on global temperature, and I'd win (on average, if I bet year over year, unless something changes dramatically).

> If you wouldn't bet against the climate getting warmer, then I don't think you have any place calling yourself a "climate change skeptic"

The climate isn't getting warmer or colder just because next year's temperature does.

sure, but if I believe the climate is getting warmer or colder, I know where to place my bets. feel free to propose a better or more precisely defined bet.

That's not what climate is about. Also, it depends on location, in many places it was colder in 2019 than in 2018. If you're talking about some calculated "global" temperature, it doesn't exist in a valid form.

Are you claiming that it is not possible to find a trend in a mean temperature of a great many points across the globe, over a long period of time?

What makes such a measurement an "invalid form"?

It is not possible if there aren't valid temperature measurements available for all points throughout the measured period of time, so that many temperatures are "interpolated", estimated etc.

Except that we do have a massive number of recorded temperatures across a massive number of locations in the last 100 years. Climate models, some dating back to the 1970s, have correctly predicted global temperature changes in the 50 years since based on this data.

The measurements are real, and there is an established history of the models being generally correct (if not in specific details) by now. Climate study is not the new science you seem to think it is.

> Climate models, some dating back to the 1970s, have correctly predicted global temperature changes in the 50 years since based on this data.

Can you point me to one such model? One that actually predicted temperatures correctly back in the 1970s and not after various recent "adaptations" like "corrected" emission data?

> The measurements are real

Yes, measurements are real. Interpolations, resulting "global" temperatures and predictions aren't.

you can, in fact, compute a mean temperature for the globe. and you can, in fact, plot a trend line over that mean. and that mean is, in fact, meaningful.

On a crude first pass, I will accept any combination of the following datasets, assuming they are updated in 2020 and 2021:

HadCRUT4 (from UK Met Office Hadley Centre and the University of East Anglia’s Climatic Research Unit)

GISTEMP from the NASA GISS

MLOST from the NOAA

JMA from the Japan Meteorological Agency

I'm open to other datasets. I'm not choosy.

So, you would have lost the bet in 2016 and 2017. Did climate get colder?

no, a noisy measure around a globally increasing trend line went down.

I believe that the noisy measure goes up, on average, because it is (noisily) measuring a warming climate. I'll make that bet every year, and I will come out ahead...

using the trend line, you could set odds at which the betting on a colder 2021 would be the correct bet - but it isn't 50/50, which it would be if the process were random noise.

as a professional poker player I'm not surprised by this argument, but I am saddened.

edit: do you actually not understand the basics of statistical inference? this is like, middle-level high school math.

> * I'll make that bet every year, and I will come out ahead...*

Good luck with that, but you first asked about one year (next year), which is a different matter altogether.

> (edit: do you actually not understand the basics of statistical inference? this is like, middle-level high school math.

I completely understand your point and how you are trying to move the goalpost from an easily refutable argument to something more useful. Perhaps your "professional poker player" mind doesn't understand that recent increases/decreases in temperature averages affect next year's weather, whereas past poker games don't affect your current one.

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