In Physics Today (Oct 2013), a nice summary: "The Arctic shifts to a new normal" by Martin O. Jeffries, James E. Overland, and Donald K. Perovich http://dx.doi.org/10.1063/PT.3.2147

@Allen, "if we quickly stop using fossil fuels we will back away from the tipping point and things will return to say 1950 regimes." When we stop the emission tomorrow, the current trends in sea level rise and temperature change are going to continue for probably a couple of decades, just to respond to the current 400ppm CO2 level (and I am not mentioning the temp rise due to the change in aerosols when we stop emitting them). The CO2 concentration was around 310 in 1950; it is my understanding that it will take very long (>100s of years?) for nature to get us back there.

The IJIS graph hasn't been updated the last 2 days. Hopefully tomorrow they catch up.

"Growth systems with significant delays in their feedback loops are virtually guaranteed to collapse." Help me understand this better - how can it be determined whether the feedback loops are slow; compared to what?

2.2 m km2 sept avg Larry, great initiative; The whole arctic seems to me to be unstable, transitioning to a new state, so and such it seems possible that we get a new minimum this year. I find it difficult to estimate the rate of re-freeze; it tends to be high in recent years. @Erimaassa - could you check the math? My calculations show 26% - not 0.026%

My thoughts went to Jim's "impossible hamster" when I read the message from our CEO that we "only experienced single digit revenue growth in Q1 - these are challenges we must overcome".

Andy, so it is you we hear playing the piano? That shows many talents!

Lodger, Thanks for explaining the Daisyworld. I was completely lost when I stumbled on that term.

Talking about ENSO, reminds of what happened last year: “This is one of the most challenging outlooks we’ve produced in recent years because El Niño decided not to show up as expected,” said CPC deputy director Michael Halpert I wonder if they have an explanation for this?

I read this recently: As 21st century technology strains to become ever faster, cleaner and cheaper, an invention from more than 200 years ago keeps holding it back. It's why electric cars aren't clogging the roads and why Boeing's new ultra-efficient 787 Dreamliners aren't flying high. We need to leapfrog the engineering of making of batteries

Espen wrote (Feb 11): Lots of crushed sea ice North of Nares Strait (Kennedy / North West Greeenland), it seems to develop hour by hour: http://ocean.dmi.dk/arctic/kennedy.php ... and it seems to me to be still developing. Is this a normal process this time of year?

Very nice Andy! Thanks for sharing.

Yesterday I watched on NASA TV “Science Uncut: Arctic on the Edge?". I took away from it that things are changing in the arctic, and that we can expect a seasonal ice free arctic in the summer around 2100. To me, that all seems pretty far away, considering the changes in the arctic we saw in the last couple of years. Is there a disconnect between scientists and reality, or did I misunderstand the message?

@Bob "micro-solar systems installed at a rate of over 1,000 per day." And the world population growth is about 200,000 per day. That makes it a really big effort.

Buddy - "another year or two of record setting melting on Greenland" ... I doubt something that is happening far from home that is not felt directly will trigger a change; only an empty supermarket at home, or a major river running dry close to home or anything else that is widely felt can cause a change in behavior - and only after the fact. There is no better driver in promoting fuel efficient cars then an increased price of fuel - warning of higher fuel prices just doesn't do the trick.

@Paddy, Crandles This is caused by the way these numbers are calculated. In one of the other threads out here is an in depth explanation. It is basically caused by the 15% threshold - if a grid cell has >15% of ice, the cell is considered to be 100% of ice. If that block is for 6 days (>15% of the month) filled with >15% of ice, then for the month, it counts as 100% ice. Suppose that block of ice floats from grid cell to grid cell, that single block of ice can make 5 grid cells count as 100% ice for the monthly figure. The daily figure would show 1 grid cell of 100% of ice during each day of the month. Bas.

Protege - thanks for explaining that sentence "September ice volume was about 800 km3 less than the prior minimum on September 10 2011 though this difference is within the estimated uncertainty of PIOMAS." I have always been in doubt about what "this difference" would refer to. Could you suggest a better way to put it?

As for the El Nino - La Nina cycle, is it expected this cycle to stay stable (and unchanged from the past) with all the changes we are seeing right now?

Talking about some of the consequences - one that I never thought of at least: http://en-maktoob.news.yahoo.com/fish-shrink-global-warming-leaves-them-gasping-oxygen-170000778--sector.html

Neven, thank you for maintaining this wonderful site. It really inspires. As for the dot you added for 2012; it seems it points at 2015; shouldn't it be moved further to the left?