As we have long since acknowledged, this past decade has been a warm decade in the run of things. The prior two decades showed a warming trend while this present decade saw that trend fully developed and a flattening out at its high. The past two years has seen precipitous decline suggesting that the warm decade may be over. This could be a response to the accelerated warming of 2007 or the commencement of a decadal downtrend and my bet is presently on the latter.

In the meantime, according to these reported numbers, we have added one inch or so to ocean over that period. That is too big to be a mistake so it gives us a magnitude for global response to a rise in temperature. According to this it has mostly come from the Greenland sheet which fits observations. It seems a bit rich, but is obviously not.

And yes, if this were to continue at this present temperature range it is plausible to anticipate an inch of rise per decade until the Greenland sheet is eliminated. Of course, Mother Nature is already signaling the opposite.

It seems though that two cold winters notwithstanding that the sea ice retreat is as quick as the past two years, suggesting that it takes a bit more than a simple drop in average temperatures. We also understand a bit better, reports of access during the Viking era. Once the bulk of the sea ice is reduced, the lower level remains quite stable in the face of colder weather.

That suggests that a simple repeat of 2007 every decade or so will progressively reduce the ice pack. It also suggests that historic conditions were a direct and unusual result of the little ice age itself and are not to be considered the natural default. So unless the little ice age comes back we can expect Greenland to get back in the dairy business and the Northwest Passage will continue to open every summer.

I suggest that we are living through the restoration of normal climatic conditions that will be similar to the medieval optimum and this will last until perhaps something goes bang in Alaska.

As an aside, the language of this item is intemperate at best and the numbers and claimed facts are been exaggerated right across the board. However 3.1 mm per year over a decade is a believable number since it is easy to construct accurate enough tidal gauges and the like in enough places to be so assured.

Oceans Rising Faster Than UN Forecast, Scientists Say (Update2)

amorales2@bloomberg.net.

This list of headlines is a reminder of just how unpredictable weather can be. Our spring has on average been a bit late as compared to amazingly early just two years ago. I still think that what we are experiencing is a return to normalcy from a decade of somewhat warmer weather whose trend line finally reversed just as it all became very noticeable.

I do not think that the heat surplus in the Northern Hemisphere is completely eliminated and that there are still possibilities for the Arctic sea ice based on its unusual thinness. Thus if enough open water exists, enough energy can be absorbed to at least initially slow ice recovery for a while.

The question that is not answered satisfactory as yet is whether or not the gross heat content is increasing, neutral or in actual decline. It was increasing for at least thirty years ending with the winter of 2008 in a completely surprising downswing. When I say increasing, I mean not that it was accelerating but that there was a net gain each and every year that I think pretty well averaged out year after year. It was enough to destroy a lot of sea ice.

I now think that it has at least returned to neutral and could well continue into the negative and we will then see a slowly accelerating increase in the total sea ice again.

We already know that there is an apparent thirty to forty year hurricane cycle that also fits this apparent pattern. What we do not understand is the apparent conservatism in atmospheric heat content. We want to think that incoming matches outgoing in a very quick dance. This is telling us to be not so fast.

A one percent increase in the heat content of the equatorial ocean would be invisible and immeasurable but would nudge the atmosphere in the type of decadal cycles been observed. A modest increase in the heat content of the winds entering the Arctic would be unnoticeable in the lower latitudes, yet deliver a summer’s aggressive melting as we saw in 2007.

One other thing that is poorly understood by most. The Arctic gyre is small compared to the surrounding oceanic gyres that extend to the equator. However it seems consistent enough in the summer to deliver pretty uniform storm free weather. That is it warms up and stays pretty warm for a few brief months if cool might be considered warm. The point that I am making is that the big events are all else where in terms of shifting the climate around and a little surplus heat goes a long way in the Arctic.

So if we have cool spring, the Arctic is unlikely to be contributing much at all. More likely, a late warming for whatever reason is driving the lag in the climate and considering the shifts back and forth, I hate to make any suggestions.


Brrrrr. Too cold for ice cream! Parts of U.S. forecast to have a 'year without a summer'