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Comment by oldandtired | Hacker News Reader

To make things real simple for those who can't use a search engine, try the following

earth surface area: 510072000 sq km

ocean surface area: 361132000 sq km

latent heat of melting (ice to water): 334 kJ/kg

From these you can calculate the amount (volume) of land based ice required for whatever ocean level rise you need and the amount of energy required to melt said ice.

Note that since only a portion of energy will enter ice, the total energy that would be needed to get the required energy transfer in the ice would be approximately 20 times required energy. This is based on studies done that indicate that it is about 5% of energy absorbed by the planetary system that transfers into the ice portion of the planet.

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  from sympy.physics.units import *
  import sympy
  pi = float(sympy.pi)

  earth_surface_area = 510072000 * kilometer**2

  ocean_surface_area = 361132000 * kilometer**2

  latent_heat_of_melting = 334 *(kilo*joule)/kilogram

  volume_for_1_meter_rise = (1*meter) * ocean_surface_area

  # https://en.wikipedia.org/wiki/Water_(data_page)
  density_of_water_at_0_deg_celsius = 0.9998395 * gram / centimeter**3

  mass_of_ice = density_of_water_at_0_deg_celsius * volume_for_1_meter_rise

  energy_for_melting = latent_heat_of_melting*mass_of_ice

  convert_to(energy_for_melting, joule) # 1.20598728796876e+23*joule

Is that a lot? Compare to the amount of energy received from the sun.

  # https://en.wikipedia.org/wiki/Sunlight#Total_solar_irradiance_(TSI)_and_spectral_solar_irradiance_(SSI)_upon_Earth
  solar_irradiance = 1.361 * (kilo*watt)/(meter**2)

  # https://en.wikipedia.org/wiki/Earth
  earth_radius = 6371 * kilometer

  earth_cross_section = pi * earth_radius**2

  total_solar_irradiance = solar_irradiance * earth_cross_section

  time_for_melting = energy_for_melting / total_solar_irradiance
  
  convert_to(time_for_melting, years) # 0.0220203816289806*tropical_year

What is your fudge factor for how much of that energy gets dumped into melting ice? 1000? 10000? Even then you get quite a few centimeters on the scale of decades or centuries.

Surface area? Don't you need volume to compute the thermal expansion of the ocean? And you also need the volume of land ice to compute how much might melt... if you want to convince people, you need to do more than just provide four statistics and walk away, you need to show how you use those to compute the level of expansion. Which you haven't done, and I'm 99% sure you can't with just those four numbers.

Surface area by height (1 to 10 metres) is volume. Of course, if one doesn't know that specific idea then one might be stuck. The volume of land ice can be assumed to be sufficient by the scenarios given. As far as ice expansion is concerned, not really relevant for a first approximation for the energy required as it is relatively small.

I mean you need to know the volume of all the water in the ocean. Because as the temperature rises the water expands, which leads to rising sea levels, in addition to the land ice melting.

To compute the total energy requirements, you don't really need to know the ocean volume, if you are willing to linearly approximate the thermal expansion. If you have less water, the same amount of energy will heat it up to a proportionally higher temperature and correspondingly expand it more, resulting in approximately the same sea level rise.

Obviously this breaks down if you want a more accurate figure, but in that case you also have to account for water shrinking with increasing temperature between 0 °C and 4 °C and so on.

In any case, melting a bunch of ice is a much more energy-efficient way of increasing the volume of liquid water than heating already molten water. The energy required for melting ice is roughly the same as that for heating the water to 80 °C, and 80 °C is not twice as voluminous as 0 °C water.

I find that when you're talking about technical things on the internet, it's best to assume the other person knows common knowledge and only doesn't know the idea you're trying to express. It's almost impossible that the GP didn't know V=A*h so pointing it out is more of an insult than anything useful.

Pray tell me: where in your calculations are you calculating the one variable that matters the most: "Mean Sea Level".

Shripadk, mean sea level is actually irrelevant as far as these calculation are concerned. Really irrelevant. The climate scientists throw around their 1 to 10 metre or more scenarios and so all we need concern ourselves with is the gross minimum volume of ice required to melt.

Since the planet is an oblate sphere with a non-uniform land distribution and we have a large moon orbiting the planet, any prediction of what we would expect to see as an ocean level rise will depend critically on where on the planet you are stationed as well as the effects of tides.

In addition, any rises of the magnitudes predicted will require more ice to be melted not less as there will be inundation effects that will, in effect, increase the amount of surface area attributed to the oceans.

Hence, all calculations are a minimum not a maximum. If you want to seriously model tidal and inundation effects, then the amount of energy will greater and hence more unexplained by these very climate scientists.

If they cannot give an explanation of the energy requirements for a minimum then they will most certainly be unable to explain for any situation requiring tidal and inundation effects to be accounted for.

So mean ocean level is irrelevant.

Again, we keep asking you for proof and citations and links to your sources, and you keep calling people liars and deflecting from answering the questions. Until you post links to sources that actually prove what you say, instead of reciting anecdotes about how some mean old scientist ignored you 15 years ago, there's no reason for anyone to take you seriously, and there's a lot of evidence explaining why you're treated like an anathema.

How is mean sea level irrelevant? Global warming directly affects the mean sea level. You don't need to go around measuring surface area/volume of ocean,ice and land and what not! All you need is to calculate the mean sea level and compare it with historical data.

And your theory on tidal effects of the moon falls flat because mean sea level takes all those factors into consideration! How? The name itself suggests that it's a "mean" over all variations in the sea levels due to tidal or inundation effects. Unless the gravitational pull of the moon dramatically increased or the moon got closer to the Earth your theory makes some sense. But the effects are pretty uniform. So mean sea level is the only meaningful statistic here. It's real and measurable. Everything else is bogus claims by climate change deniers!

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