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Messages - AmbiValent

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Arctic sea ice / Re: The 2019 melting season
« on: August 25, 2019, 10:51:07 PM »
For the first time this year, starting to see some ice formation in the ESRL model: yellows and browns in the figure, on the Asian side to the N of where very strong bottom melt continues.
Strong melt right next to strong freeze looks odd - or rather more like ice movement instead of change. I expect a stronger contrast between whole regions in Start-to-Mid-September.

Arctic sea ice / Re: Are you hoping to witness a BOE?
« on: August 23, 2019, 06:25:20 PM »
A BOE is pretty irrelevant. It will be small beer compared to all the other stuff that happens as and when enough CO2 for a BOE to be possible accumulates. A BOE will simply be a symptom that we are living in a 2-3C world, it won't actually cause anything extra to happen in that world.

If we get there under BAU, I hope to live that long, but I also hope BAU dies in the next decade.
I fear that while a single BOE just barely fitting the requirement might not mean much "extra", but the less sea ice there is to melt, the more we will move from an Arctic that spends the summer around 0C to a warmer one - and some regions will make the transition earlier than the rest. Or rather, we have clearly left the start of the transition behind us and are slowly on the way to the other side.

Arctic sea ice / Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« on: August 09, 2019, 09:49:21 AM »

Why did CO2 go up during the interglacials over the last 800,000 years?

The release of stored CO2 can be both a cause and an effect of global warming.

As for the interglacials, they were started by the Milankovic cycles. Regularly, the changes in Earth's orbit and axial tilt lead to conditions in which high latitudes in the Northern Hermisphere - where there are continents that warm quicker than oceans - get a maximum amount of energy which starts a strong melting.

This melting then starts to set free stored CO2 (and also adds more water vapor to the atmosphere, which is also a greenhouse gas), which makes the melting stronger.

This melting lasts for thousands of years. During this time, the phase of optimal conditions in the Milankovich cycles has already ceased, and the process is no longer driven by them.

Eventually, the warming stops due to a new equilibrium. And since the conditions are no longer the optimal ones, a very slow cooling begins during which CO2 is stored away again. But this storing away takes a much longer time than setting it free. So after the melting at the start of the interglacial, we've had thousands of years of extremely slow cooling, and it was so slow that human civilisations developed their agriculture in this relative stability.

So the greenhouse effect of CO2 did not start the interglacial, but it kept it going long after optimal conditions has passed.

Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 07:52:43 PM »
So, agreed on the centrality of data.  But I think it is not just fine, but scientifically healthy to make well-reasoned, thoughtfully calibrated predictions.  And if some of those don't turn out to be 'true', that is the way it is with predictions and we are still actively learning ...
I agree, it's scientifically important to continuously test models and prediction to see which ones work best, and possibly which factors played a role in it. This doesn't mean the ones we have right now are bad, but that they can still be improved.

Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 05:35:08 PM »
Ummm... I have a question about the discussion of when we should pay attention to data or prediction. Shouldn't we pay prime attention to the present when considering new record bad conditions?

It seems to me that predictions are nice to have, but it's not like they're actual data, and it's also not like we could avert anything by knowing the prediction a few days in advance. And predictions that fail to manifest seem to harm credibility.

On the other hand, looking at data afterwards often comes with comments like "it was bad, but it's getting better now". Gee, usually a new record is followed by a reversal to the mean. But that doesn't mean everything is well, because it's a decreasing mean which means just the regular up and down WILL bring new records, we're just not sure exactly when.

So I think one should look at the present, and note the records. And every new record is more evidence that there can be no true recovery unless the causes for the crisis change.

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: January 29, 2019, 12:16:57 PM »
Is the data the two-day average? Then the one-day error data will affect both days' published values, but the 28k increase would be real, since it exchanged a day with error-less data with another such day. And tomorrow the error should be gone completely.

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