Comments

1. #1 NewEnglandBob

   August 4, 2009

   Rut-Roh, global warming could cause melting then we are in deep, watery trouble.

2. #2 Greg Laden

   August 4, 2009

   A total meltdown of the glacial ice would increase the amount of water in the oceans by about 2 percent. (But there are complications)

3. #3 Nathan Myers

   August 4, 2009

   Of course nobody has even a faint idea what the cloud cover will do at the higher temperatures and C02 levels. We might end up in a global ice age after all, despite all. The global thermonuclear war likely to occur once the ice age starts might fend it off, or accelerate it. The survivors won’t even know if it did, either way.

4. #4 Nathan Myers

   August 4, 2009

   Incidentally, I’m astonished at the precision. Do we really know the oceans’ volume to ten significant figures? I’m almost equally impressed at knowing swamps’ volume to five figures. Who knows what’s under there?

5. #5 jimspice

   August 5, 2009

   So if you juiced every living thing on earth, you would have a cube 10.4 K on a side? But there would be no one left to measure it?

6. #6 Greg Laden

   August 5, 2009

   Nathan: As far as swamps and groundwater go, there is, of course a whole science dedicated to that and although it is harder to measure, I’m sure we essentially “know it” even if we (well, actually, you) don’t know how other people measure it!

   As to the precision, there is no particular reason why we don’t have the precision indicated here, but I’ve not assessed that or made adjustments in these numbers. But do remember that significant digits is a buggaboo (sp?) If the measurements were made in cubic miles, the precision would go up with the same signficant digits. If the measurements were made in cubic centimeters the precision would go down. This is cubic kilometers. Cubic kilometers seemed like the right unit to use, but they are kind of small for planetary geology, so I would take the precision on the fresh water values with a grain of salt.

   But only a grain, or it will become salt water.

   If you go to the USGS source, there will be a reference to the source, where the method of estimating is probably given.

7. #7 Nathan Myers

   August 5, 2009

   If people wouldn’t strip off error bars, they wouldn’t have to keep answering questions like this.

8. #8 Mark P

   August 5, 2009

   Well, two percent isn’t much, but, unfortunately, the place it will be most obvious is in shallow water and lowlands. Where we like to live.

9. #9 jj

   August 5, 2009

   Well, two percent isn’t much, but, unfortunately, the place it will be most obvious is in shallow water and lowlands

   Glacial Ice melt is NOT major concern regarding sea level rise due to global warming. It’s the expansion of sea water volume at higher temps. Or at leased that’s what I’ve heard via lectures.

10. #10 Nathan Myers

    August 6, 2009

    Greg: Measurement precision doesn’t change when you change units, it just moves the decimal point around.

11. #11 greg laden

    August 6, 2009

    Nathan: Well, that’s what I meant. If you look at those numbers, one has no a priori reason to question precision, but given what is being measured, seeing apparently significant digits as they are, one might suspect. But if we change to smaller units, and retained the same actual precision, you would see a lot of zeros on the right side and the perception that they are over-precise would vanish, yet the numbers are exactly the same (just different units).