Comment by AuLaVache | Hacker News Reader

Comment by AuLaVache | Hacker News Reader

>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]

> 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.

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.

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