Visualizing the Shrinking Sea Ice | Hacker News Reader

Visualizing the Shrinking Sea Ice

theatlantic.com

82 pointsuptown33 comments

>The chart’s data comes from the National Snow and Ice Data Center, a collaboration between NOAA and the University of Colorado. This is the oldest data set for sea ice available—it goes back to 1978. (That’s a pretty long time, at least for satellites: Landsat, the longest continuously operated satellite-data program, only started six years earlier.)

The satellite era for Arctic ice did not start in 1979. It started in 1973. The 1990 IPCC report shows a graph of it:

http://www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_chapte...

[see page 30 of the .pdf (= page 224 of the IPCC report) Figure 7.20a]

It shows the ice grew ~1.5 million km before 1979, and has declined since then. So starting the record in 1979 (at a peak) is a bit of a cheat.

>Mapbox has also placed the sea-ice levels next to Earth’s mean atmospheric temperature.

Also be wary of talk of average atmospheric arctic temperature increases. They certainly have increased, but that obscures the whole picture. It's only in the summer that arctic air temperatures rise above freezing, and summer temperatures have not increased at all since 1958. See all years here:

http://ocean.dmi.dk/arctic/meant80n.uk.php

It's variations in winter, spring and autumn (when air temperatures are still well below freezing) that has raised the average temperature. In my view the ice is probably mainly melting from below from heat transported from the Atlantic. Less insulating ice allows water (~ +4c) to warm the colder air above it. It's not melting from above from increased air temperatures as the article seems to imply.

[18.55 Edited for idiocy]

Aaah the never ending debate about global warming. It's been proven to be a scam so many times and everyone has their favorites.

To me when NASA came and admit the rising temperatures on Earth do match up with rise of temperatures on most other planets of our system, including Mars, because the Sun has its rising/declining activity patters and some go into thousands of years, this was clear indication humans are like a drop of blood in a Pacific Ocean. AFAIK, there are not human-made factories on Mars.

End of discussion.

UN's IPCC assessment reports - the fifth published last year - may give you some perspective on science's view of climate change (which is the commonly used term).

is this a troll post copied and pasted from facebook?

Here is a chart of the cycles you are referring to, going back over 400,000 years. Look at the green one in the middle. You may have to look a little higher, all the way into the chart above it, in fact. Notice anything peculiar around the turn of the century?

[1] http://i.imgur.com/cHbKpLh.jpg

There's no evidence that Mars is exhibiting long term warming trends, and most bodies in the solar system are not warming. The sun is currently in a cooling cycle, and all evidence indicates that solar forcing has a much lower impact on rising temperatures than increased greenhouse gases.

Explained here:

http://www.skepticalscience.com/global-warming-other-planets...

It took me about 10 seconds of googling to find the answer explained easily for the layperson as to why you were wrong- and yet, you've never so much as taken that basic step, let alone examine any of the scientific literature on the topic, and you immediately jumped to the conclusion that the overwhelming majority of scientists who study climate and Earth sciences worldwide are wrong. There have been hundreds of papers written on the topic, all by experts who reach conclusions that disagree with you, and you examined none of that research. It is the sheer arrogance of the climate change denier that is so startling to me.

>indicates that solar forcing has a much lower impact on rising temperatures than increased greenhouse gases.

Could be. But I would argue that sites like SkS, which are fairly partisan in their views like to look only at TSI and ignore other solar factors.

The Sun effects us in many unexpected ways. See for example here: http://science.nasa.gov/science-news/science-at-nasa/2013/08...

And here:

http://iopscience.iop.org/article/10.1088/1748-9326/10/5/054...

The last link (looking at the UV part of the spectrum) could explain the warming of the Atlantic we have been experiencing, See this graph of the AMO (yes, not the same as the NOA outlined in the paper - but related) and NH temperatures:

http://www.woodfortrees.org/plot/esrl-amo/from:1960/mean:30/...

The AMO does seems to be "externally forced" I.e. not related to CO2, but probably/possibly some solar related mechanism.

http://www.nature.com/ncomms/2014/140225/ncomms4323/full/nco...

The whole thing is damn complicated. Different parts of the spectrum impact on different parts of atmospheric chemistry (e.g. ozone), and inter-relate with components like earth and solar magnetic fields, particles, GCRs, etc.

Science is never settled (as SkS would have us believe) it's still in progress.

>> This is a clear indication humans are like a drop of blood in a Pacific Ocean

It is hardly an indication of that. Large quantities of carbon were locked away millions of years ago and are now being released. Billions of tons of fossilized vegetation and algae going up in smoke is hardly a drop in the ocean.

Denial doesn't end anything. Every ice pack on earth has melted or is currently melting. That means the globe is warming. Now, we really have End of discussion.

> It's only in the summer that arctic air temperatures rise above freezing

Which "freezing" are you talking about? 0C (32F)? Because sea ice has a different freezing point.

> In my view the ice is probably mainly melting from below from heat transported from the Atlantic.

How does ocean acidification (possibly) factor in?

Also, the sea ice itself is much fresher than the ocean, so it's melting temperature is much closer to 0C than you might expect. And even the distinction between freezing seawater and freshwater at the surface is less then 2C, so it's not a huge difference.

I can't think of an obvious way that acidification factors in, unless there are important connections between sea ice and sensitive biological factors (I'm not aware of any, but I'll wait to be corrected).

> Also, the sea ice itself is much fresher than the ocean, so it's melting temperature is much closer to 0C than you might expect

It's not just about the sea ice melting, but also the sea ice forming. How does sea ice become "fresher" than the salt water that it formed from? How is that processing being affected?

> ... is less then 2C, so it's not a huge difference.

That's really context dependent.

> can't think of an obvious way that acidification factors in

When you dissolve substances in a solution, it changes the melting/freezing points. This is how salt works to de-ice roads during the winter. The ocean is becoming more acidic because the concentrations of other substances in it are increasing. This can affect the freezing point required to form sea ice (or for existing sea ice to melt).

I'm not sure how, or to what extent, which is why I posed it more as food for thought.

Thanks for the 1990 ipcc link. The graph (page 7) of northern and southern hemisphere sea ice extent anomalies is interesting - they appear to have moved in rough opposition in most of the period from the early 1970s to 1990, as they are today.

If you want to see this in video, I recommend the documentary "Chasing Ice". It's available on Netflix.

agreed, it's a super documentary

At the same time (well, within a couple of years) antarctic sea ice is at record high levels

https://www.washingtonpost.com/blogs/capital-weather-gang/wp...

...which, as the article notes, is not necessarily good news: the southern ocean is warming.

What I got out of it is what I usually see with my attempts at being objective; we know this is happening, we don't fully understand why, and we don't fully know the pros and cons. There are guesses and theories, many of which I'm sympathetic to, that too many people are willing to move forward without being cautious.

The house is burning down, and we should be cautious?!

Yes. A horribly mismanaged attempt at putting out a house fire can cause unnecessary problems for the rest of the neighborhood.

But this is a house we can't actually leave. That changes the equation completely.

No it doesn't. Regardless of your particular situation, if you mismanage the solution, then chances are you are only making the problem worse.

Yes, the house is burning down! We have a whole lot of gasoline on hand. We can dump it all onto the burning fire to try and put it out.

Possible outcomes:

1) We manage to dump enough gasoline on it to starve it of oxygen quickly enough and the fire is burnt out. We clean up all the gasoline. The day is saved.

2) The gasoline catches on fire and the whole neighborhood burns down from our attempt to fix it.

3) We manage to dump enough gasoline on it to starve it of oxygen quickly enough and the fire is burnt out. The gasoline left behind isn't cleaned up well enough and it catches on fire a day later causing a bigger fire.

Or we choose to do nothing:

1) The house burns down. The fire does not spread. We build a new house.

2) The house burns down and the fire spreads, burning down the whole neighbourhood.

Or maybe we watch the fire for awhile and find a better way to put it out. The climate isn't as simple as this analogy. This isn't a black and white issue where we can dump our whole economy down the drain and everything is guaranteed to be rosy.

I dunno, billions of people seem perfectly willing to "move forward" with burning fossil fuels even when we don't fully understand its pros and cons. (I also use a gas heater and conventional vehicles, so I guess I'm one of them.)

Or does it not count as "moving forward" when we've been doing it for decades and there's a multi-billion-dollar industry that's interested in keeping the current direction?

Yep, I agree, and look how well the desire to move forward immediately with fossil fuels turned out. Thanks for providing an example of what I'm saying. It's not an evil aspect of the human race, it's just that we are extremely short sighted by our nature.

As for the corporations, of course they want to keep the current direction. It's how they make money. Regardless of the direction we choose in how to handle the situation, if we decide us doing something is warranted, I guarantee those same corporations will figure out a way to make money from it. The bad things you see them doing today against change will turn into bad things they'll do when they embrace change. My concern is that in our efforts to do something quickly we cause more harm than what we proposed to prevent or fix. In that vain, some of the accusations that I'm hearing about the diesel scandal in the EU is of a similar thought.

"article." The author got his Bachelors of Arts in Music.

If you put together the volume of extra sea ice gained around Antarctica, and the volume of land ice melted there, guess what? There is net melting of ice!

Grabbing one factoid out of context does not change the overall trend.

Not this shit again. Sea ice in the antarctic is relatively thin because it's seasonal, although somewhat thicker than previously imagined. You also have to bear in mind that Antartica is an actual continent with a huge land mass underneath it, whereas if/when all the ice in the arctic melts, then that's it, there will just be seawater and you won't be able to visit the North Pole. The weather systems are totally different, there are no mountains in the Arctic for example.

Frankly I'm coming to think that the best hope for the future is if the Arctic ice melts comletely every child in the English-speaking world gets pissed about Santa not having anywhere to live.

https://nsidc.org/cryosphere/seaice/characteristics/differen...

http://www.livescience.com/48880-antarctica-sea-ice-thicknes... << which somewhat supports your perspective; I'm making an effort to be even-handed and include as much relevant info as possible.

Maybe Northern Sea Route will become viable after all.

Why since 2005, are things the wrong way around? Increases in temperature match with increases in ice levels??!!

e.g. 2005 to 2007 saw a 0.09 decrease in temperature above norm, and a 1.16million km2 decrease in ice?

Then as the temperature increased, the ice did too, up to 2010, then temp and ice decline to 2012.

Since 2012 temp has been rising again and so has the ice.

And you wonder why there's skeptics out there?!

You can clearly see the overall trends of heat rising and ice decreasing, but graphs like this shouldn't be thrown out to the masses without reasonable explanation of the anomalies of the last 10 years.

Wow, The period of 2009 to 2012 was not kind for the ice at all. What caused such a large decrease?

Natural variation?

One contributor is an increase in the amount of heat flowing from the North Atlantic into the Arctic ocean. Another factor is that the volume of old, thick ice has been declining as well, so the ice present in 2015 is younger than what was present in 2000. This ice is less likely to persist through the summer melt season.

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