
Greenland's melting ice raised global sea level by 2.2mm in two months - perfunctory
https://www.theguardian.com/science/2020/mar/19/greenland-ice-melt-sea-level-rise-climate-crisis
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atonalfreerider
Has anyone considered the albeit short term emissions impact of grounding
flights due to COVID-19? Airlines have in some cases experienced over 70%
reduction in volume in the past weeks[0].

Not to mention, so many companies have been forced to adopt remote working
practices and social life has been forced into a sedentary routine. I wonder
what the inertial impact of this pandemic will be on emissions over the coming
years.

[0] [https://www.economist.com/business/2020/03/15/coronavirus-
is...](https://www.economist.com/business/2020/03/15/coronavirus-is-grounding-
the-worlds-airlines)

~~~
jupp0r
Air travel makes up for 2.5% of global carbon emissions. Not really worth
micro optimizing a lot in those 2.5% if you asked me. At least not if you can
focus efforts in energy production and cars instead.

~~~
rb666
Ya think?

"Unless market constraints are put in place, growth in aviation emissions will
result in the sector's emissions amounting to all or nearly all of the annual
global CO 2 emissions budget by mid-century, if climate change is to be held
to a temperature increase of 2 °C or less."

(from:
[https://www.wikiwand.com/en/Environmental_impact_of_aviation](https://www.wikiwand.com/en/Environmental_impact_of_aviation))

~~~
jupp0r
The article you quote validates my point by assuming other emissions can be
decreased to a minimum. If all emissions we have to worry about in 2050 was
air travel, that would be spectacularly good news!

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ekianjo
I can't find 2.2 mm mentioned anywhere in the study they refer to. Where is
that number coming from?

[https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020...](https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GL087291)

~~~
brlewis
I can't find it either. I only see gigatonnes. Even with a naive calculation
that assumes no ice reclaimed elsewhere, I get 1.8mm.
[https://docs.google.com/spreadsheets/d/1zC2c30kIkbx39v0gyY1P...](https://docs.google.com/spreadsheets/d/1zC2c30kIkbx39v0gyY1PrPJEFJW4LBMkYxW_RbdcKYc/edit#gid=0)

~~~
Arnt
Why is that naïve?

~~~
brlewis
Because in the opposite hemisphere, water is turning to snow and ice.

~~~
bregma
The ocean freezing anywhere is irrelevant: the mass of water in the ocean
stays the same regardless of its phase.

The problem discussed here is the Greenlad ice cap melting, which we can
assume increases the mass of water in the ocean.

The nature of ice caps in both Greenland and Antarctica is that they are in
deserts that go for years with zero precipitation. Ice accumulates steadily
through what we can think of as layers of frost every morning over centuries
until it covers entire continents kilometers deep. On the other hand, surface
melt due to increased seasonal insolation usually doesn't result in much
runoff: these are not glaciers that slowly flow out to sea, either.

~~~
brlewis
Just to make sure the context is clear, my main question is why the article
headline says this particular melt caused a 2.2mm global rise in sea level.
The melting described in the article would only account for a 1.8mm rise, in
isolation. If anything happening in Antarctica had an effect, it would lower
that number even further, making it more different from the headline. Does the
2.2mm number include other melting that the article and cited paper don't
mention?

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mysterydip
I was curious on the math for all this.

Surface area of earth = 510,064,472 km2

70 percent water = 357,045,130 km2

2.2mm = 0.0000022 km

volume = 785.499 km3

GIS area 1,710,000 km2

div vol by area = 459.3 mm

melting 1kg of ice from 0C = 333.55kJ

density of ice = 919kg/m3

785,499,000,000 m3 x 333.55 = 262,003,191,450,000 kJ

1J/s = 1w

2 months = 5,184,000s

= 50,540,739 kJ/s

= 50.540 GJ/s

= 181,944 GWh

making it the 24th largest electricity producer in the world (if it were all
electricity).

That's pretty incredible!

~~~
misja111
I got inspired by your calculation to fact check the article's claim of the
2.2mm see level rise. They apparently base this on the reported melting of 600
Billion tons of ice as stated in the article.

600 Billion (metric?) ton = 600000 Billion kg (or liter water) = 600 km3

This doesn't quite add up. I wonder where they got the 2.2 mm from ..

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PaulRobinson
Just been checking [http://grid.iamkate.com](http://grid.iamkate.com) and in
the UK as a country it seems to me that we're about 7% down on power usage
week on week as a result of people WFH.

The reduction in fossil fuels, the fact people are not necessarily able to get
their favourite foods (and there was already a backdrop of a rise in plant-
based diets in the UK anyway), the lack of commuting and travel, it all adds
up to me thinking our emissions are going to be much, much lower this year, at
least in the UK.

I'll be fascinated to see how much of that sticks, and whether we start to see
any reversals on data like this.

Doubtful, but if habits change in the next six months for good, well, it's a
silver lining. We can dream.

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gridlockd
Can somebody explain to me what the big problem of sea levels rising is.

Sure, at that rate, or even at that 100 times that rate, at some point in the
not-so-close future the coastline will move inward significantly. Beach
properties will become diving attractions.

I don't think I care. Tell my why I should care.

~~~
phaemon
Well, it seems folk weren't impressed with the technical aspects of your
question, but I'll give it a shot and ignore the moral aspect entirely.

What would happen at "100 times that rate"? That's about 10cm a month, or four
inches a month for Americans.

Firstly, the coast does not slope back at a constant angle from the sea, so
you can't just move uphill a few yards and think that everything will be fine.
Even if you could, try it now: try moving to an area that's, say, 20 yards
uphill from where you are. Today. Do you see the immediate problem?

But let's say you're already a fair height above sea level, so you've got a
few years, and you live in a coastal town. What is going to happen? Well,
after a few months, you're going to start having issues with high tides.
Sewers will flood, so you'll literally have a river of shite flowing in the
streets below. The piers down at the harbour will become dangerous at high
tide. Breakwaters will become ineffective. Warehouses will flood.

You've probably got a coastal road out of the town. With the higher tides,
you've got increased erosion, so after a particularly bad storm, there's a
major landslip, and you lose not only the road but the rail link out as well.
Goods can't get in or out of your town now.

The higher parts of the town are now islands, and you don't have a functional
slipway so it's difficult to even use boats. The shape of the coastline is now
in constant flux; it changes with every tide as mud and sand gets sloshed
around, which means that tides are completely unpredictable. Sometimes you get
a massive tide as more water is funnelled in, and other times it's barely
noticeable as mudbanks cut off whole areas of water.

Now, all this might even be manageable, if you have access to plenty of money
to rebuild, but who is going to rebuild when they'll have to do it all again
next year? And you're not going to get help from anywhere else, because this
is happening to _every_ coastal town all at once.

Of course, this is based on your extreme case of 10cm per month, so the real
question is "at what stage does this become unmanageable?". Is it 10cm per
year? 1cm per year over the course of a decade? Somewhere inbetween?

~~~
Fjolsvith
At the current rate of melt, how long is it until Greenland is out of ice and
we don't have to worry about it contributing 1.1mm of sea level rise a month?

~~~
phaemon
I dunno, a 1000 years or so? It doesn't seem worthwhile even roughly
calculating since it's rather obviously going to accelerate as it gets warmer.
It would be bizarre if it didn't!

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pupdogg
I'm not buying this. Someone please explain, in detail, how 2.2mm of sea level
can be measured precisely? What kind of tolerance are we talking about? 2.2mm
+/\- 5mm?

~~~
noiv
If you have volume and divide by surface area you'll get height.

~~~
pupdogg
How do you accurately (down to mm precision) determine volume of a moving
target?

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xaxsacsdaffbnk
Is it even solid science to measure sea levels over 2 months? How do you
measure "sea level"? It seems normal that ice melts as summer comes around. So
there would be fluctuations in sea level? How do they account for all the
possible variations to establish a sea level number?

~~~
yodsanklai
I suppose they measure the missing ice, and deduce the sea level.

~~~
bregma
They don't measure the missing ice either. They estimate it based on all kinds
of things (mostly models based on what they guess the answer should be). Some
of the actual measurements include the deviation in satellite orbit as it
passes over Greenland, from which they estimate the change in gravity, which
leads directly to an estimate of the change in mass. Since the rock is
unlikely to be changing on the time scale of a year or so, they assume it's a
change in ice mass. Given a typical annual precipitation of zero in central
Greenland, it's a safe bet that any change is mass is due to ice melt.

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TheSpiceIsLife
It’s hard to get excited about _2.2mm_.

I’m not saying it isn’t a problem, I’m just saying it’s not a scale humans are
likely to panic about.

If it were 2.2m in one month you can bet your left shoe we’d panic.

~~~
easytiger
The sea raises and lowers by up to 16000mm every day in parts in of Canada
during spring tides

~~~
_ph_
That would be over 600 meters, impressive :p. EDIT: the parent author
corrected his entry to still impressive 16 meters.

And of course tides/sea level is almost the same duality as weather/climate.

~~~
reimertz
> And of course tides/sea level is almost the same duality as weather/climate.

I tried to argue for the same point but lacked the word “duality” in my
corpus. Thank you, will use in the future!

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propogandist
Geologists studying glaciers have determined we're in an Interglacial Period,
where glaciers are contracting and it's also cyclical [1]

There's also natural wonders like the Great Blue Hole, a marine sinkhole off
the coast in Belize, which show this has been going on for some time. It was
"formed during several episodes of Quaternary Glaciation when sea levels were
much lower.. as the ocean began to rise again, the [124M] cave was flooded"
[2]

[1][https://en.m.wikipedia.org/wiki/Quaternary_glaciation](https://en.m.wikipedia.org/wiki/Quaternary_glaciation)
[2][https://en.m.wikipedia.org/wiki/Great_Blue_Hole#cite_note-
NA...](https://en.m.wikipedia.org/wiki/Great_Blue_Hole#cite_note-NASA-2)

