Comments on: Siberian seabed methane: first numbers http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/?utm_source=rss&utm_medium=rss&utm_campaign=siberian-seabed-methane-first-numbers Global warming and the future of New Zealand Wed, 23 May 2012 11:23:46 +0000 hourly 1 http://wordpress.org/?v= By: Mitchell http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11247 Mitchell Fri, 12 Mar 2010 18:52:32 +0000 http://hot-topic.co.nz/?p=4289#comment-11247 Gareth, Thank you for this post. Dr. Shakhova and Dr. Semiletov have indeed done the world good service in this work, and are a credit to the scientific community. I shall continue to follow this work closely as I have now for four years. Of course, I'm well aware there are those that will continue disputing the details of methane release in the Arctic. As you are well aware, a methane burst of 50Gt or greater from the ESS (e.g. per their EGU paper) would resolve the matter permanently. As always, thank you for your website. Gareth,
Thank you for this post.

Dr. Shakhova and Dr. Semiletov have indeed done the world
good service in this work, and are a credit to the scientific
community.

I shall continue to follow this work closely as I have now for
four years. Of course, I’m well aware there are those that will
continue disputing the details of methane release in the Arctic.
As you are well aware, a methane burst of 50Gt or greater from
the ESS (e.g. per their EGU paper) would resolve the matter permanently.

As always, thank you for your website.

]]> By: C3P0 http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11189 C3P0 Wed, 10 Mar 2010 19:46:31 +0000 http://hot-topic.co.nz/?p=4289#comment-11189 Oh, sorry, I am also slightly mistaken, its the difference between the average lifetime and the life time of the last (extra) emission. So if I put ten trout in a shark pool the average life time might be 2 minutes, but if I put an eleventh in the average lifetime may become 2 min 10 seconds, but the life time of the eleventh is two min and 30 seconds. AR4 calculates average life time is 8.7 years, but effective lifetime of a pulse emission is 12 years. Oh, sorry, I am also slightly mistaken, its the difference between the average lifetime and the life time of the last (extra) emission.

So if I put ten trout in a shark pool the average life time might be 2 minutes, but if I put an eleventh in the average lifetime may become 2 min 10 seconds, but the life time of the eleventh is two min and 30 seconds.

AR4 calculates average life time is 8.7 years, but effective lifetime of a pulse emission is 12 years.

]]> By: Rob Taylor http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11186 Rob Taylor Wed, 10 Mar 2010 08:47:34 +0000 http://hot-topic.co.nz/?p=4289#comment-11186 My reference for the methane lifetime was the "Encyclopedia of World Climatology" (Springer, 2005), p.394, "Greenhouse Effect and Greenhouse Gases" by A.J. Pitman. Pitman in turn references TAR from 2001, so your figure is later and better. My reference for the methane lifetime was the “Encyclopedia of World Climatology” (Springer, 2005), p.394, “Greenhouse Effect and Greenhouse Gases” by A.J. Pitman. Pitman in turn references TAR from 2001, so your figure is later and better.

]]> By: Gareth http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11133 Gareth Tue, 09 Mar 2010 00:09:55 +0000 http://hot-topic.co.nz/?p=4289#comment-11133 The post at the top of this thread, of course! All my links work fine, but DW's is wrong - he left an "f" off the end. Now fixed. The post at the top of this thread, of course!

All my links work fine, but DW’s is wrong – he left an “f” off the end. Now fixed.

]]> By: C3P0 http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11132 C3P0 Mon, 08 Mar 2010 23:54:46 +0000 http://hot-topic.co.nz/?p=4289#comment-11132 Which one? Links not working on yours and dappled 2nd Which one? Links not working on yours and dappled 2nd

]]> By: Gareth http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11129 Gareth Mon, 08 Mar 2010 22:45:12 +0000 http://hot-topic.co.nz/?p=4289#comment-11129 Did you even bother to read the post? Look at what Ed Dlugokencky says... Did you even bother to read the post? Look at what Ed Dlugokencky says…

]]> By: C3P0 http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11128 C3P0 Mon, 08 Mar 2010 21:43:11 +0000 http://hot-topic.co.nz/?p=4289#comment-11128 Your second link is broken. Dappled I’m not sure of your point. The historical increase is likely caused by anthropogenic emissions (I think we agree here?). We are discussing if arctic emissions are causing a new increase. Given that historical increases and recent variations have occurred I cannot conclude that the recent increase is due to arctic release without seeing a wider study looking at sources and sinks. Do you disagree? Your second link is broken.

Dappled I’m not sure of your point. The historical increase is likely caused by anthropogenic emissions (I think we agree here?). We are discussing if arctic emissions are causing a new increase. Given that historical increases and recent variations have occurred I cannot conclude that the recent increase is due to arctic release without seeing a wider study looking at sources and sinks.

Do you disagree?

]]> By: C3P0 http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11127 C3P0 Mon, 08 Mar 2010 21:38:36 +0000 http://hot-topic.co.nz/?p=4289#comment-11127 "Igor Semiletov has said that when he started working in the area in the 1990s, there wasn’t as much methane being emitted." Oh in that case don't worry about normal scientific caution “Igor Semiletov has said that when he started working in the area in the 1990s, there wasn’t as much methane being emitted.”

Oh in that case don’t worry about normal scientific caution

]]> By: Gareth http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11126 Gareth Mon, 08 Mar 2010 21:18:27 +0000 http://hot-topic.co.nz/?p=4289#comment-11126 That's three years of 7 ppb increases -- 21 ppb. The guys measuring the stuff thinks it's significant. It doesn't appear to be "normal" for the region. We don't have definitive data, but Shakhova's co-author, Igor Semiletov has said that when he started working in the area in the 1990s, there wasn't as much methane being emitted. That’s three years of 7 ppb increases — 21 ppb. The guys measuring the stuff thinks it’s significant.

It doesn’t appear to be “normal” for the region. We don’t have definitive data, but Shakhova’s co-author, Igor Semiletov has said that when he started working in the area in the 1990s, there wasn’t as much methane being emitted.

]]> By: Dappledwater http://hot-topic.co.nz/siberian-seabed-methane-first-numbers/#comment-11125 Dappledwater Mon, 08 Mar 2010 21:11:52 +0000 http://hot-topic.co.nz/?p=4289#comment-11125 "I don’t expect 7 out of 1750 to be significant when there is historical variation. But I haven’t done the test."- C3. "Historical variation" http://cdiac.ornl.gov/trends/atm_meth/graphics/eth_ld3ave.gif "Recent variation" http://agage.eas.gatech.edu/images/Data_figures/gcmd_month/ch4_monS5.pdf “I don’t expect 7 out of 1750 to be significant when there is historical variation. But I haven’t done the test.”- C3.

“Historical variation”

http://cdiac.ornl.gov/trends/atm_meth/graphics/eth_ld3ave.gif

“Recent variation”

http://agage.eas.gatech.edu/images/Data_figures/gcmd_month/ch4_monS5.pdf

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