The Question Is: How Much Acceleration Is Involved In SLR - 7?

Fig. 12015 Lowest Year Early-On

This year has seen early low Arctic Sea Ice levels (Fig. 1).

It is at a point where the trend line is showing that, without an acceleration in the 2015 current melt rate, the 2012 level will (at least temporarily) take first place again.

And it looks like that could happen in a few days.

That is, if 2015 stays on its current trajectory, this year's melt rate will result in a drop below the 2012 rate, which is the current historical record low year for Arctic Sea Ice cover.

In Fig. 2 the current trend is shown by the light blue line, then is projected out (red line) to where it is going without any acceleration.

In Fig. 3 the required acceleration is shown as a red line curving below the 2012 melt rate at this time of year back then.

So, it remains to be seen whether the 2015 melt rate will increase to stay in the lead.

In this series I have tried to make the point that the rate of acceleration varies all the time, like traffic at an intersection with congestion.

Some times the traffic moves slower, sometimes it accelerates, but the unknown is when each will happen.

Fig. 3 Acceleration Needed to beat 2012

Once it happens it is easier to calculate how long it will take to finally get through the jam.

In the present scenario, the 2015 melt will have to imitate the 2012 pattern.

That would require an acceleration at this time, as the 2012 season did at this time (Fig. 3).

All that can be said is that it is not clear which way things will go in June because there are some cooler trends and some warmer trends, each of which could play the deciding role in causing acceleration or causing a slow down in the melt.

Let's review the impact of acceleration in terms of the Hansen 5, 7, and 10 year  doubling (acceleration), and the Dredd Blog sea level rise (SLR) 3 yr. doubling model (The Evolution of Models - 10).

And for grins, the 2 yr. doubling (The Question Is: How Much Acceleration Is Involved In SLR - 5?).

Acceleration per NOAA

The effect that 2, 3, 5, 7, and 10 year doubling has is that it determines when SLR reaches the 1 m / 3 ft. level:

10 yr = 2067
7 yr = 2055
5 yr = 2045
3 yr = 2035
2 yr = 2031

(The Question Is: How Much Acceleration Is Involved In SLR - 5?).  We focus most on 1 m / 3ft. because it is a point where many locations that are tidal will experience serious problems, especially with coastal infrastructure and ports (The 1% May Face The Wrath of Sea Level Rise First).

So, what does sea ice have to do with it?

The Arctic will warm faster (acceleration) when the ice cover melts and the darker ocean begins to absorb sunlight in contrast to the ice reflecting sunlight.

And that is why we watch the sea ice cover melt rate to see if 2015 will take the lead from 2012 as the year closest to the year when there is no ice cover on the Arctic Ocean.

The previous post in this series is here.