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Comment by sunir | Hacker News Reader

True, why trust anything. It is not as if there is some systematic way to over time iteratively improve a rational model that is testable and verifiable through a competitive process.

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How would you propose testing or verifying a non-falsifiable model? Each sample of future data we have tends to show our models to be simply broken except in the most broad sense of a longterm gradual increase in temperatures. For instance from 2001 and 2010 the warming slowed to 0.11C per decade. [1] For the 17 years before then was 0.17C. There was not a single model that predicted this and, in spite of a number of after the fact hypotheses for that apparent decline, there is still no decisive answer. Does this not kind of bother you?

We might argue that well since they're getting the overall picture right, that they must be fundamentally correct, even if they don't perform so well on the micro scale. But I'm not sure this is a reasonable argument. In particular, the past 400k years of Earth [2] show a very regular waxing and waning of temperatures, with the scale increasing upwards of 10C from the frequently extremely rapid transition from the mins to the maxes. Not only is about now when you would expect to be entering a warming era, but we've yet to even hit the highs of temperatures the planet reached in relatively recent geologic history, though before humans even existed. This is no way suggesting that humans are not contributing to the current phase of climate change, yet at the same time is it really particularly insightful to propose that temperatures will continue to do as they've done for hundreds of thousands of years?

As usual I'm sure people will just downvote this, but I genuinely have no clue why. It's as if its taboo to ask, what I think, are completely reasonable questions. At the same time it's completely kosher to freak out and suggest climate change could imminently end the very species of humankind, which is not a remotely realistic outcome even in the most catastrophic and near 0 probability level outcomes.

[1] - https://www.scientificamerican.com/article/did-global-warmin...

[2] - https://upload.wikimedia.org/wikipedia/commons/f/f8/Ice_Age_...

It’s a reasonable question. The work is learning how to get a reasonable answer.

Whether or not the world has been warmer in the past is entirely and completely irrelevant. The only thing that matters is that we are provably massively accelerating the current warming, causing changes to weather, water and food systems we rely on for our survival. If we don't make equally massive sacrifices to fix this, we will lose our food, water, and land. This isn't the time for middlebrow devils-advocate games, it is the time for action.

Why do you think we'll lose our food, water, and land? Let's start with a couple of important maps. This [1] is a map of where US farmland is. This [2] is where US water resources are. So of course we need to consider these things in terms of climate change. I quite like the simulator the NOAA has set up here [3]. It lets you increase or decrease water levels and dynamically see the effect. Perhaps the most surprising thing though is this [4]. That's an article that illustrates what the world would look like if somehow literally all ice in the world melted, some 216 feet of sea level rise. And indeed the world would be quite reshaped, but the surprising thing is by how little. Suffice to say you wouldn't need to start building an ark. And as an relevant aside, sea levels have already risen more than 400 feet since the the most recent interglacial warming period started some ~20,000 years ago. [5] Somehow, life went on.

To be clear I 100% agree with you on changes, but not losses. And I am in no way playing devil's advocate. I think the things I've asked, and said, are reasonable. They're completely authentic in any case, and I am 100% open to changing my view. If anything I've said is inaccurate in any way, or any question technically unreasonable - please do share. Apologies on the excessive amounts of links here, but I find this is a topic where disinformation is excessive and so I think it's important to cite most facts.

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[1] - https://www.nrcs.usda.gov/Internet/FSE_MEDIA/nrcs143_010966....

[2] - https://water.usgs.gov/ogw/gwrp/activities/images/StudyLocat...

[3] - https://coast.noaa.gov/slr/

[4] - https://www.nationalgeographic.com/magazine/2013/09/rising-s...

[5] - https://www.giss.nasa.gov/research/briefs/gornitz_09/

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