[Island Chris]

I just spent 20 hours in the air on 3 flights, and then went straight to 2 workshops before the meeting after like 1 hours sleep (Auckland New Zealand). I gave a talk, but one of the others included that with 400 ppm CO2, the current level, sea level will rise 22 m. It will stabilize at +22 m and stay there unless CO2 goes above 700 ppm. They did not give a time frame, but recent papers said the fastest rate of sea level rise related to collapse of marine-based Antarctic ice sheets will occur in 200 years. That is not the whole 22 m, and that is rate: one could project that most of that marine based ice (+ Greenland) could be gone in 500 years.

This is ironic because the house we had built on the island is between 20 and 21 m elevation.

Chris

[Island Chris]

This is the SCAR meeting, which is Antarctic climate science. I did not post on what I did June 2-August 8: I worked with an excellent undergrad intern, and we together interpreted that Central Trough in Ross Sea is a >50 km-wide by 400 km-long pre-30 million year erosional trough. I is U-shaped. So, we interpret it as evidence for the earliest West Antarctic Ice sheet. The unconformity cuts down into what we interpret as faulted sedimentary rocks deposited during a rifting (extension) event that was over about 55 million years ago. The unconformity post dates the rifting, so its last erosion was after 55 Ma, and before 30 Ma. The first West Antarctic Ice was ~33.7 million years ago: recent work suggests the volume of the whole Antarctic Ice Sheet then was a bit larger than it is now.

Our glacial trough hypothesis was wildly controversial and 4 co-authors suggested we tone it down (we toned it down) and 1 asked to not be co-author.

I want to publish this: could be my highest impact paper. But could be the undergrad intern as first author; she will be famous and I will be "and others".

Chris

[Island Chris]

I should get the freak off the computer. I could have taken a boat out to a dormant volcanic island in Auckland Harbor, and hiked up to the crater. Fabulous weather, but it is winter, and the sun is low to the north at noon. And, west is to the left of the sun instead of the right. And, you have to be really careful as a pedestrian when you step off the sidewalk, as they all drive on the wrong side.

Chris

[Island Chris]

Below is my email to a neighbor at 22 m elevation, and to IW and HD
(island wife and heartland daughter):

I heard 3 excellent Keynote talks in a row yesterday; they were filmed and may be on-line (I'll ask). We may have 1000 years. Indeed, 22 meters is a real number. The say 17 m of sea level rise form marine-based Antarctic ice. Plus 5 m from Greenland. I thought Greenland was 6 or more meters. Tim Naish showed a graph that Antarctica can do 1 m of sea level rise per century. But then he discussed a meltwater pulse at 14 1/2 ka. I think Milene is working on this meltwater pulse for her coral ideas offshore Haiti. It was about 4 m rise per century. But, there were northern hemisphere ice sheets to melt then. Tim speculated that maybe 2 or 3 m of that could have come from Antarctica, but that was a Max; I'd guess (speculate) less.

The question is whether Greenland will melt much faster than 1000 years. I would speculate "yes".

***I'll add here for earthwaves that 1000 years may be at current 400 ppm CO2: if it goes 2x or 3x higher, + methane, one could assume some bets are off.

Chris

[Island Chris]

Went to Rangitoto island, the youngest volcano in the Auckland NZ field. Last eruption finished 600 years ago. There are footprints in the ash at the next island, so was witnessed from close. Meeting is over, so I walked from near downtown to Eden Hill. Check out the parks in Auckland on Google earth: if they are a hill, and round, they have a crater and are volcanoes. A quake beneath or near, say, LA would not be good, and aftershocks would become part of life for weeks and months. But imagine a volcano erupting for 100-200 years in a city! Not as violent and deadly as Naples Italy, but would get old pretty quickly.

Chris

[Jim W.]

Interesting that means the beach I grew up on on Puget Sound will be flooded possible in the next 20 years or there abouts. Right now nomal max hightide is measured at 13.5 ft above mean sea level which is the hight of the parking lot. The king tide we had last winter was 15.5 ft.. Oh well I guess certain things never last, at least my 15 yearold has gotten to have the run of the beach I grew up on. This also means that the SeaTac airport will be on an island eventually. This sealevel rise will have a magor impact on the shipping industry world wide to say the least!

[Island Chris]

Hi Jim,

In 20 years there may not be very big sea impacts of sea level rise except in some very low, flat places. It is only 3 mm/yr global now, or a bit more than an inch per decade, so 2" in 20 years. Not going to have a huge impact in a place with such large tide range. And, I checked the tide gauge record for Newport, Rhode Island (next island over) and there is no acceleration of rise yet. So, for now, local effects can outweigh global effects. Hey, one big quake with uplift rather than subsidence would cause a local (relative) sea level drop!

What is unclear is how fast the acceleration of sea level rise will be. Will it every get to 30 mm/year? When? 10 mm/yr?

Chris

[Jim W.]

When I was a little kid 60+ years ago, the mean hightide was at 13ft at the Normandy Park Cove Beach west of the Seattle Tacoma airport. It is now at 13ft 6in as I stated in the earlier post. So that is an inch rise in ten years average. Ten years ago it was about a little less than 2 inches below what it is now, I was the Beach Security Guard at that time. I will admit that the 2 bigger earthquakes in 65,72 and other shakings in the area may have had a local effect on the height of the ground at the beach over the years.

[Island Chris]

Hi Jim, while half of that 6" is global rise (maybe 2/3), at locked subduction zones some areas warp up and some warp down while locked, and then the motion reverses during the quake itself. Can be up to several meters in a quake (1964 Alaska) in areas where there is no long term vertical motion. If 2 m in 400 years, is 5 mm/yr, higher than even the current global rise. But, Seattle is inland from the likely locked part of fault, so subduction related vertical motions should be slower. The answer to ground vertical motion is likely known.

Chris

[Jim W.]

Thank you for your reply .