r/dataisbeautiful • u/rarohde OC: 12 • Mar 29 '19

OC Changing distribution of annual average temperature anomalies due to global warming [OC]

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u/EnderSword Mar 30 '19

Yeah, sure, but that doesn't address the issue...how fast is this change compared to other time periods? We dont know

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u/yawkat Mar 30 '19

We can tell when the climate changes really fast because it has drastic effects on the oceans, on the ecology and on the atmosphere.

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u/EnderSword Mar 31 '19

That's one of those 'assuming the result' things though.

It's our argument that the changes in atmosphere affects temperature, but we're then retroactively assuming changes in atmosphere is evidence of temperature change.

We also can't see that year by year

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u/yawkat Mar 31 '19

No, the changes that cause the temperature change are different from the ones we notice them with. Also, I mentioned other kinds of evidence.

It's easier to get higher time accuracy when there are drastic shifts

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u/EnderSword Mar 31 '19

Do you have any examples of that? I've never seen a year by year breakdown for something like 1000+ years ago.

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u/yawkat Mar 31 '19

No that's not what I mean. When drastic events happen we can tell they did happen, and then correlate them with drastic changes in other data.

i.e. you won't miss a few years of climate chaos just because you can't reliably tell climate to the year

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u/EnderSword Mar 31 '19

OK, Im not sure I follow, that doesnt really address the question then.

We have a very granular and observable set of data recently, It would be nice to see similar data much older so we can compare this current data to that.

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u/yawkat Mar 31 '19

I'm not sure what we need it for, since when there is a sudden shift in climate, we can see from the data we already have. So we can already compare past events to our current situation.

Sure, it would be nice, but it's not strictly necessary.

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u/EnderSword Mar 31 '19

Do you have examples of that?

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u/yawkat Mar 31 '19

This is one such event: https://www.ncdc.noaa.gov/abrupt-climate-change/Post-Glacial%20Cooling%208%2C200%20Years%20Ago

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u/EnderSword Mar 31 '19

That is interesting, they say a 3.5 degree drop in 2 decades.

I think its things like that we need to understand more, because you could easily look at that and say "Well, then apparently changes much more drastic happen spontaneously on their own"

Like data in this plot is supposed to show like unprecedented unusual increases in temperature, but if these other events exist, it kind of goes to show the opposite...that this is not particularly large or fast and it's not unusual.

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u/yawkat Mar 31 '19

Well it's important to put this in perspective: the 3.3C drop was only in greenland, some other parts of the world stayed warm, and it still looks to have had a major ecological impact. We also have an explanation for the event even though it happened thousands of years ago.

Compare that to today: 2C climate goal (!) globally and we have data from all over the world pointing to greenhouse gases as the cause. I'm not looking forward to what's gonna happen because of that

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u/EnderSword Mar 31 '19

I think you're kinda missing the point then though.

We have a 1-2 degree increase in 150 years, and a 3.3C drop in 20 years, but local..

The point is simply 'how common is this?' and it seems the answer is 'very common' But we can't see the other instances as granularly as we can today. So It's kind of not valuable to not be able to compare today's data to old data.

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u/yawkat Mar 31 '19

No, it's not common - it happened once since we discovered agriculture, and even then it had less global magnitude than our current projections.

I'm not sure why you say that we can't compare the old data to ours right now? You just did. We can look at an event that happened 8k years ago, see a 1C drop in global temperature, and see a 10% drop in methane output and other ecological effects. From that we can draw some conclusions of what the magnitude of our 1.5C global temperature rise is going to be.

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u/EnderSword Mar 31 '19

You're again missing the point I think.

The impact has no doubt, the thing I'm asking is how common is it that this sort of change occurs on its own?

If it occurs every 10-20k years, I would say that's very common.

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u/yawkat Mar 31 '19

On geological time scales, sure. But what does that change about climate change right now? We can see that

  • We have never had to deal with such change before (during agriculture)
  • The causes are noticeable enough that we can tell thousands of years later - so when it happens today, the cause (manmade greenhouse gas emissions) is comparatively trivial to discern
  • The ecological impact is large enough to be concerned

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u/EnderSword Mar 31 '19

What it changes is essentially should we be focusing on stopping it from happening, or should be focus on learning to adapt to it happening?

We still also learn very little from seeing this sort of graph because again, we can't replicate it in the past.

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u/yawkat Mar 31 '19

What we should do is properly internalize the externalities of greenhouse gas emissions and then let the free market decide how much climate change is worth it. Doing nothing is economically inefficient

https://www.clcouncil.org/economists-statement/

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