6 ms·

Just a reminder: When floating ice melts in water the level of the water does not rise. https://www.youtube.com/watch?v=aOCqHRpQh88 https://www.youtube.com/watc

Just a reminder: When floating ice melts in water the level of the water does not rise. https://www.youtube.com/watch?v=aOCqHRpQh88 https://www.youtube.com/watch?v=aOCqHRpQh88

Florin_Andrei 9y ago
It's not real. It's real but it's not caused by us. It's caused by us but the water does not rise. The water does rise but that's actually good. etc.
- mirimir 9y ago
  Well, one could bet in futures markets that coastal cities will flood, and so on.
  - tdfx 9y ago
    Is there actually a viable way to currently do this?
    - deleted 9y ago
      [deleted]
    - cloudwalking 9y ago
      Buy land at 50 ft. elevation? I only half kid.
      - taneq 9y ago
        I checked the elevation last time I bought a house. I'm not even kidding. 63' above sea level, worst comes to worst I'll have a beachfront property to sell when I want to buy my houseboat.
        cloudwalking 9y ago
        Yes I did as well. One of my requirements in shopping for a house was >50 feet above sea level. It won't matter in the short run but it definitely will matter in the long run. Unfortunately if the sea rises 20 feet, I will still have a house but my whole area will be a lot less lucrative...
- blank_2 9y ago
  Well it could be real depending on whose definition we're going by. I remember a teacher in school giving us pictures of skyscrapers buried in water. Is that realistic? As for the cause, there is bound to be disagreement when you try to reduce it down to a single factor. If the waters aren't muddied enough by these oversimplifications, along come the thought police to tell us that racism is to blame. It's not hard to see why people think this discourse is a cover for something else.
  - Oletros 9y ago
    > If the waters aren't muddied enough by these oversimplifications, I didn't knew that papers were oversimplified, because you're talking about science, not the media, isn't?
- blank_2 9y ago
  We believe in freedom of expression, but let's censor/threaten whoever disagrees with us, because their opinions are harmful. We believe in gaining a consensus, but you'd better believe what we say or else.
  - mirimir 9y ago
    Based on what hasn't happened in recent decades, I'd say that climate-change deniers have won. So it goes.
    - blank_2 9y ago
      If they have won, they have only won because the game has been given to them. It's clear to see that a lot of their arguments are just reactionary, as Florin_Andrei pointed out.
  - yongjik 9y ago
    Mouseover text of https://xkcd.com/1357/ https://xkcd.com/1357/ : > I can't remember where I heard this, but someone once said that defending a position by citing free speech is sort of the ultimate concession; you're saying that the most compelling thing you can say for your position is that it's not literally illegal to express.
    - blank_2 9y ago
      I think you're missing the point. I am not defending a position. I was merely pointing out the irony in trying to force a consensus. Also, there is a difference between thinking that people speaking freely is good for a society's health, and trying to win a legal/ego battle. If people can't handle a relatively neutral discussion about such things, then they might as well say so up front. I can understand if people have run out of patience, but it's far from being one-sided.
mirimir 9y ago
True. But it does tell you that the ice is melting. Which indicates heat input.
endorphone 9y ago
Melting is a proxy for warmer waters. Water becomes less dense (e.g. expands) as it warms above 0C (a little bit less for salt water). When you have a volume the size of the oceans, a small increase is a big surface volume change.
- nimchimpsky 9y ago
  Eh ? Sea level rises are due to land based ice melting.
- discoursism 9y ago
  Edit: this paragraph is full of lies. -- There are a lot of things to be worried about with global warming, but I have never heard the density of ocean water listed among them. Water at 24 C is 0.002 less dense than water at 14 C. Since 10 C swings in global temperatures would long have caused catastrophes in other domains, I don't think we'll be much bothered by this small of a change in ocean density. Please enlighten me if I am incorrect. Edit: thanks, all. I stand corrected.
  - teraflop 9y ago
    A 0.002 relative change in density is actually quite a lot, if you consider that the oceans are 12,000 feet deep on average.
  - flukus 9y ago
    If I'm correct (not a hydrologist) 0.002 decrease in density translates to a 2M (~6 feet) sea level rise per KM of ocean. Some quick googling suggest that the average ocean depth is close to 4KM. So even small changes can have noticeable effect, particular when it's combined with other changes.
    - yters 9y ago
      I'd be interested to hear more on this. Is this warming uniform throughout the entire depth? Does the change in density impact the ocean uniformly or mostly on the top layer where the pressure is less?
InclinedPlane 9y ago
Just a reminder: the climate is a dynamic system with many feedback loops, one of the most prominent feedback systems is albedo (amount of light reflected or absorbed). Snow/ice cover (on land or sea) reflects sunlight, cooling the Earth. Bare ground or water absorbs sunlight, warming the Earth. Melting of arctic sea ice is a positive feedback loop that will increase warming and can lead to a progression toward a different climate equilibrium (a warmer one) that could be hard to break out of even if CO2 levels come down.
- kbutler 9y ago
  How much sunlight does the Arctic get? I've seen discussion that the heat lost from the relatively warm ocean water when not covered by ice exceeds the additional heat absorbed by low albedo, suggesting that lack of ice cover is actually a net negative feedback. I have no personal calculations as to the magnitude of either effect, but I am skeptical of positive feedback loops, as they are inherently unstable. Note that we get significant ice loss every summer, followed by rapid gains in ice, which seems to cast doubt on the significance of any positive feedback.
  - teraflop 9y ago
    Of course the sea ice normally returns every winter. Even at a modest 50 degrees of latitude, the insolation in summer is 6 times higher than in winter [1], so over short timescales, seasonal effects are so huge that they obscure the effects of any positive or negative feedback loops. That doesn't mean those loops don't exist and can't be significant over larger timescales. [1]: http://www.applet-magic.com/insolation.htm http://www.applet-magic.com/insolation.htm
    - kbutler 9y ago
      Right, so you have high insolation for some number of days. This provides heat at a rate of 300-500 W/m2 at peak, but that peak drops off, so the average insolation over the course of the year is low in polar areas. This is a positive feedback of open water (albedo ~.1 vs ice ~.6) and is limited by the duration of high insolation over open water. The maximum insolation is at the summer solstice (June) when there has been a smaller decline in arctic ice area (10%? http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ http://nsidc.org/arcticseaicenews/charctic-interactive-sea-i...) By the date of low ice extent in September, the sun is getting pretty low for polar areas (low angle, low duration, low insolation - see the equinox data in your link: http://www.applet-magic.com/insolation.htm http://www.applet-magic.com/insolation.htm) Open water loses heat much more rapidly than ice-covered water, with the rate dependent on temperature, wind speed, etc. One study found open water heat flux was about 250 W/m2 vs 75 for ice pack in March/April (http://onlinelibrary.wiley.com/doi/10.1029/94JC02485/abstract http://onlinelibrary.wiley.com/doi/10.1029/94JC02485/abstrac...). I didn't find references to give averages or graphs over a year. However long the ocean remains open, it radiates excess heat at an increased rate vs ice pack - a negative feedback of open water, limited by the area and duration of open water.
yters 9y ago
He's not wrong. Why the down votes?
- adrr 9y ago
  He isn't right. https://oceanservice.noaa.gov/facts/sealevelclimate.html https://oceanservice.noaa.gov/facts/sealevelclimate.html
  - yters 9y ago
    Stick a piece of ice in a cup of water, mark the water level before and after the melt, and tell me what happens.
    - Oletros 9y ago
      Thermal expansion effect in cup of water is a little smaller than the thermal expansion effect in the oceans
      - yters 9y ago
        Thermal expansion is a separate issue. Ice melt in and of itself does nothing to raise water level.
  - downvote_me 9y ago
    The commend says 'floating ice' the link you point at says 'ice on land'. The commender is 100% right but apparently the HN crowd has a lot of people that just love to downvote (which is why downvoting should be banned).
    - Oletros 9y ago
      The link the op points says: "First, as the oceans warm due to an increasing global temperature, seawater expands—taking up more space in the ocean basin and causing a rise in water level."

Just a reminder: When floating ice melts in water the level of the water does not rise. https://www.youtube.com/watch?v=aOCqHRpQh88 https://www.youtube.com/watch?v=aOCqHRpQh88

Florin_Andrei 9y ago

It's not real. It's real but it's not caused by us. It's caused by us but the water does not rise. The water does rise but that's actually good. etc.

mirimir 9y ago
Well, one could bet in futures markets that coastal cities will flood, and so on.
- tdfx 9y ago
  Is there actually a viable way to currently do this?
  - deleted 9y ago
    [deleted]
  - cloudwalking 9y ago
    Buy land at 50 ft. elevation? I only half kid.
    - taneq 9y ago
      I checked the elevation last time I bought a house. I'm not even kidding. 63' above sea level, worst comes to worst I'll have a beachfront property to sell when I want to buy my houseboat.
      - cloudwalking 9y ago
        Yes I did as well. One of my requirements in shopping for a house was >50 feet above sea level. It won't matter in the short run but it definitely will matter in the long run. Unfortunately if the sea rises 20 feet, I will still have a house but my whole area will be a lot less lucrative...
blank_2 9y ago
Well it could be real depending on whose definition we're going by. I remember a teacher in school giving us pictures of skyscrapers buried in water. Is that realistic? As for the cause, there is bound to be disagreement when you try to reduce it down to a single factor. If the waters aren't muddied enough by these oversimplifications, along come the thought police to tell us that racism is to blame. It's not hard to see why people think this discourse is a cover for something else.
- Oletros 9y ago
  > If the waters aren't muddied enough by these oversimplifications, I didn't knew that papers were oversimplified, because you're talking about science, not the media, isn't?
blank_2 9y ago
We believe in freedom of expression, but let's censor/threaten whoever disagrees with us, because their opinions are harmful. We believe in gaining a consensus, but you'd better believe what we say or else.
- mirimir 9y ago
  Based on what hasn't happened in recent decades, I'd say that climate-change deniers have won. So it goes.
  - blank_2 9y ago
    If they have won, they have only won because the game has been given to them. It's clear to see that a lot of their arguments are just reactionary, as Florin_Andrei pointed out.
- yongjik 9y ago
  Mouseover text of https://xkcd.com/1357/ https://xkcd.com/1357/ : > I can't remember where I heard this, but someone once said that defending a position by citing free speech is sort of the ultimate concession; you're saying that the most compelling thing you can say for your position is that it's not literally illegal to express.
  - blank_2 9y ago
    I think you're missing the point. I am not defending a position. I was merely pointing out the irony in trying to force a consensus. Also, there is a difference between thinking that people speaking freely is good for a society's health, and trying to win a legal/ego battle. If people can't handle a relatively neutral discussion about such things, then they might as well say so up front. I can understand if people have run out of patience, but it's far from being one-sided.

mirimir 9y ago

True. But it does tell you that the ice is melting. Which indicates heat input.

endorphone 9y ago

Melting is a proxy for warmer waters. Water becomes less dense (e.g. expands) as it warms above 0C (a little bit less for salt water). When you have a volume the size of the oceans, a small increase is a big surface volume change.

nimchimpsky 9y ago
Eh ? Sea level rises are due to land based ice melting.
discoursism 9y ago
Edit: this paragraph is full of lies. -- There are a lot of things to be worried about with global warming, but I have never heard the density of ocean water listed among them. Water at 24 C is 0.002 less dense than water at 14 C. Since 10 C swings in global temperatures would long have caused catastrophes in other domains, I don't think we'll be much bothered by this small of a change in ocean density. Please enlighten me if I am incorrect. Edit: thanks, all. I stand corrected.
- teraflop 9y ago
  A 0.002 relative change in density is actually quite a lot, if you consider that the oceans are 12,000 feet deep on average.
- flukus 9y ago
  If I'm correct (not a hydrologist) 0.002 decrease in density translates to a 2M (~6 feet) sea level rise per KM of ocean. Some quick googling suggest that the average ocean depth is close to 4KM. So even small changes can have noticeable effect, particular when it's combined with other changes.
  - yters 9y ago
    I'd be interested to hear more on this. Is this warming uniform throughout the entire depth? Does the change in density impact the ocean uniformly or mostly on the top layer where the pressure is less?

InclinedPlane 9y ago

Just a reminder: the climate is a dynamic system with many feedback loops, one of the most prominent feedback systems is albedo (amount of light reflected or absorbed). Snow/ice cover (on land or sea) reflects sunlight, cooling the Earth. Bare ground or water absorbs sunlight, warming the Earth. Melting of arctic sea ice is a positive feedback loop that will increase warming and can lead to a progression toward a different climate equilibrium (a warmer one) that could be hard to break out of even if CO2 levels come down.

kbutler 9y ago
How much sunlight does the Arctic get? I've seen discussion that the heat lost from the relatively warm ocean water when not covered by ice exceeds the additional heat absorbed by low albedo, suggesting that lack of ice cover is actually a net negative feedback. I have no personal calculations as to the magnitude of either effect, but I am skeptical of positive feedback loops, as they are inherently unstable. Note that we get significant ice loss every summer, followed by rapid gains in ice, which seems to cast doubt on the significance of any positive feedback.
- teraflop 9y ago
  Of course the sea ice normally returns every winter. Even at a modest 50 degrees of latitude, the insolation in summer is 6 times higher than in winter [1], so over short timescales, seasonal effects are so huge that they obscure the effects of any positive or negative feedback loops. That doesn't mean those loops don't exist and can't be significant over larger timescales. [1]: http://www.applet-magic.com/insolation.htm http://www.applet-magic.com/insolation.htm
  - kbutler 9y ago
    Right, so you have high insolation for some number of days. This provides heat at a rate of 300-500 W/m2 at peak, but that peak drops off, so the average insolation over the course of the year is low in polar areas. This is a positive feedback of open water (albedo ~.1 vs ice ~.6) and is limited by the duration of high insolation over open water. The maximum insolation is at the summer solstice (June) when there has been a smaller decline in arctic ice area (10%? http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ http://nsidc.org/arcticseaicenews/charctic-interactive-sea-i...) By the date of low ice extent in September, the sun is getting pretty low for polar areas (low angle, low duration, low insolation - see the equinox data in your link: http://www.applet-magic.com/insolation.htm http://www.applet-magic.com/insolation.htm) Open water loses heat much more rapidly than ice-covered water, with the rate dependent on temperature, wind speed, etc. One study found open water heat flux was about 250 W/m2 vs 75 for ice pack in March/April (http://onlinelibrary.wiley.com/doi/10.1029/94JC02485/abstract http://onlinelibrary.wiley.com/doi/10.1029/94JC02485/abstrac...). I didn't find references to give averages or graphs over a year. However long the ocean remains open, it radiates excess heat at an increased rate vs ice pack - a negative feedback of open water, limited by the area and duration of open water.

yters 9y ago

He's not wrong. Why the down votes?

adrr 9y ago
He isn't right. https://oceanservice.noaa.gov/facts/sealevelclimate.html https://oceanservice.noaa.gov/facts/sealevelclimate.html
- yters 9y ago
  Stick a piece of ice in a cup of water, mark the water level before and after the melt, and tell me what happens.
  - Oletros 9y ago
    Thermal expansion effect in cup of water is a little smaller than the thermal expansion effect in the oceans
    - yters 9y ago
      Thermal expansion is a separate issue. Ice melt in and of itself does nothing to raise water level.
- downvote_me 9y ago
  The commend says 'floating ice' the link you point at says 'ice on land'. The commender is 100% right but apparently the HN crowd has a lot of people that just love to downvote (which is why downvoting should be banned).
  - Oletros 9y ago
    The link the op points says: "First, as the oceans warm due to an increasing global temperature, seawater expands—taking up more space in the ocean basin and causing a rise in water level."