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Comment by refurb | Hacker News Reader

In terms of sea level changes, however, the study found the effects of melting are more drastically felt in regions farther from its source.

Would be nice if they had a theory why.

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Part of the reason is gravitational effects. When a large amount of ice melts, the Earth's gravity is shifted away from that region.

This gives you a sense of the absolutely huge amount of ice we're talking about. For example, if the West Antarctic Ice Shelf collapses we'll see about 10 metres of sea level rise, but mostly in the northern hemisphere. To underline just how much ice this is, this effect will slowly be counteracted as the ground below slowly rebounds (as it no longer has a huge amount of ice crushing it down from above).

Potentially related is the centrifugal effect - the Earth bulges at the equator slightly because of spin. Logically, melted ice would tend to cause water to "rise" more at the equators (further from the ice caps) than near the poles.

...and that would slow the rotation of the earth.

I'd love to see a calculation of how much ice would have to melt for us to add another leap second.

Or to back it up, how would timekeeping bodies deal with that?

Would we actually remove a second because there would technically be less "time" (measured in days, meaning axial revolutions of the Earth) per year?

It's been done. I can't find the reference, but apparently the extreme accuracy of atomic clocks has proven that the mass of water moving from the poles to the equator has slowed the earth's rotation as predicted.

There's a reference and some discussion at http://arstechnica.com/science/2016/04/the-leap-second-becau...

This makes me wonder. Could it affect seismic activity?

Indeed it can!

"rapid deglaciation promotes earthquakes ... rebound stress that is available to trigger earthquakes today is of the order of 1 MPa. This stress level is not large enough to rupture intact rocks but is large enough to reactivate pre-existing faults that are close to failure."

- https://en.wikipedia.org/wiki/Post-glacial_rebound#State_of_...

I wonder if this is related to the streak of big earthquakes happening currently in Italy.

There are several reasons, the main one being that glaciers and ice sheets exert a large gravitational pull.

http://harvardmagazine.com/2010/05/gravity-of-glacial-melt

http://m.nautil.us/issue/33/attraction/why-our-intuition-abo...

From the last article:

"Three things happen. One is that you’re dumping all of this melt water into the ocean. So the mass of the entire ocean would definitely be going up if ice sheets were melting—as they are today. The second thing that happens is that this gravitational attraction that the ice sheet exerts on the surrounding water diminishes. As a consequence, water migrates away from the ice sheet. The third thing is, as the ice sheet melts, the land underneath the ice sheet pops up; it rebounds."

Maybe I'm daft but one suggested itself to me: if you add more very cold water locally, that influences the temperature and pressure/density differentials with existing currents. It's presumably the effect on those currents that causes more water to build up elsewhere.

Gravimetry has been used to track ocean currents, and water temperature will presumably effect currents.

https://www.google.com/amp/s/www.washingtonpost.com/amphtml/...

Awesome.

Check out the north Atlantic cold spot. It has already contributed to making summers in Ireland even more miserable for the last 10 years.

I've missed the last 6 summers in Ireland but I hear you!

They do. Search for Jerry Mitrovica (Harvard geophysicist) on YT for explanations.

Whatever it is, you can be certain that the solution is massive taxation and central control by bureaucrats.

Try a revenue neutral carbon tax.

We're trying. The left opposes it because it doesn't make government bigger: https://www.washingtonpost.com/opinions/the-lefts-opposition...

I'm not ideologically in favor of smaller or bigger government. I want smarter government, and there's nothing smart about passing legislation that will reduce the state government's revenue by between $80 and $900 million a year without defining what services to cut.

Also, "bigger government" is a vague enough definition that it could easily apply to this initiative. It creates a new category of tax, and a new category of tax credit. It will probably reduce the government's revenue, but the legislature can and most likely will raise revenue in other places to plug the gaps rather than cutting necessary agencies.

The same people who want a smaller government are also usually in favor of a balanced budget amendment, which would force any proposal to cut taxes or raise spending to specify how it balances.

Meanwhile, the right can't even recognize it's a real issue.

What do you think the bigger barrier is?

It is worse when the people who know they should act choose not to.

By and large the left aren't choosing not too, they are unable to act because we need to drag the right along kicking and screaming.

If we don't bring the right along then they'll either block any action (America) or create a huge fear campaign and repeal the action (Australia).

In Australia we tried a scheme with very low economic impact (despite scaremongering to the contrary) carbon tax, which provably reduced emissions before its repeal.

http://www.smh.com.au/environment/climate-change/carbon-pric...

Our Environment Minister doesn't believe in Climate Change. I expect we'll utterly fail to do something like this again.

That reminds me, where's my $750 Mr Abbott/Turnbull?

Well, when you largely ignore a problem for 27 years, the solution tends to get expensive. The decades go by ...

https://youtu.be/4Jnu09xQ4lk

http://www.presidency.ucsb.edu/ws/?pid=45811

People have had 50 years to start solving the problem on their own.

So have all the world's governments. That's not a very strong argument.

Nothing will happen otherwise. We've already shown that.

Don't you think this is a bit too serious issues to waste energy on petty political divisions? Anyway, they only entities that can do something are governments. People are good at locally optimizing their own lives. Not so good at optimizing the good of the whole.

Where did the water for the ice come from? What is the optimal sea level for the governments to set? How do you calculate an energy output without knowing it's environment? Why do scientist, who are dependent on government funding, use words like 'suggest', 'surprised', or 'consensus'?

The truth is that none of us know what the actual dimensions of our solar system were 5,000 years ago, nor do we know the measurements in the next 1,000.

An object is never the same when nature is applied over time.

> What is the optimal sea level for the governments to set?

I don't think anyone is suggesting or has suggested such a policy. Rather, the recommendation is "avoid changing things, especially when the outcomes are probably negative and their magnitude highly unknown".

> who are dependent on government funding

Plenty of scientists who are funded by non-government grants agree that climate change is real.

Plenty of non-climate scientists have looked at the data and agree that climate change is real.

Plenty of non-scientists with training in a scientific discipline -- who have never received and will never receive a penny of grant money in their lives -- have looked at the data and agree that climate change is real.

This particular ad hom is tired and unfounded.

> Why do scientist, who are dependent on government funding, use words like 'suggest', 'surprised', or 'consensus'?

Suggest: because this is one study/measurement, and others should repeat the measurement and/or come to the same conclusions by other methods.

Surprised: Because they're surprised.

Consensus: When 90+% of trained experts agree on something, that's pretty much as close to a consensus as you can get in a large population.

> Where did the water for the ice come from?... How do you calculate an energy output without knowing it's environment?... The truth is that none of us know what the actual dimensions of our solar system were 5,000 years ago nor do we know the measurements in the next 1,000. An object is never the same when nature is applied over time.

We engineer systems and make scientific measurements and predictions with high accuracy every day without knowing the exact origin and trajectory of everything in the universe.

There is only one legitimate way to criticize climate science, and that is by producing contrary facts. Everything else is noise. There are a limited number of potential facts which could overturn AGW; similarly gravity is considered difficult to disprove. The kind of mental processes which would use speculation about the future to contradict empirical fact seem antithetical to any coherent worldview, let alone a scientific one.

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