Archive for the ‘global warming’ Category

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A new round of Antarctic ice alarm

March 28, 2015

The alarm of a catastrophic meltdown of the Antarctic cycles up and down every year or two.  A journal article says the rate of melt is increasing, the popular press picks up on it and breathlessly warns about huge sea level rises sinking coastal cities around the world. We are told that x number of gigatonnes of ice per year are being dumped off the continent and wreaking their havoc on the world.   Then another study says “not so fast,” the mass losses aren’t that great after all.  Or, some crazy old skeptics ruin all the fun by recklessly bringing some logic to the discussion.

Today we have “Volume loss from Antarctic ice shelves is accelerating” (Paolo, et. al., Science, 2015).  The abstract warns us

“Overall, average ice-shelf volume change accelerated from negligible loss at 25 ± 64 km3 per year for 1994-2003 to rapid loss of 310 ± 74 km3 per year for 2003-2012.”

310 km3 per year (roughly the same as 310 gigatonnes per year) is pretty high compared to most other estimates. So you will probably see many references to this number because the bigger and scarier the more the press likes it.  But for the more sober minded, consider the following comparison of ice loss estimates from “Ice sheet mass balance and climate change” (Hanna, et. al., Nature, 2013)

Various estimates of ice mass change in the antarctic

Various estimates of ice mass change in the Antarctic

How does the recent Science paper compare?  If we place it on estimate plots from Hanna’s paper it would look like this..

Ice sheet mass balance and climate change - Hanna - Nature - 2013 v4

The Paolo Nature paper is an outlier.  But lets take them at their word.  They say that the Antarctic, on average, shed about 300 more Gigatonnes of ice per year during the 2003 to 2012 period than during the 1994 to 2003 period.  Where did all this ice go?  In to the oceans, of course.  That is why we have the great sea level rise scare.

So it follows that the sea level should have been rising faster during the 2003 to 2012 period than during the 1994 to 2003 year period.  How much faster?  Well, every gigatonne of water dumped into the oceans raises the sea level by about 2.78 microns. So 300 gigatonnes of extra water per year would raise the sea levels about an extra 840 microns a year, or about an extra 0.84 mm per year.  We are told that satellite data indicates that the global sea level is rising about 3 mm per year.  0.84 mm per year is a significant fraction of 3 mm per year, so such a rate increase should really stand out in the sea level rise data..

Well, here is some of that satellite sea level rise data…

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This discussion has been about ice that is moving from the land to the sea and raising the sea level.  But let’s take a quick moment to look at the sea ice that surrounds Antarctica.  While this ice does not contribute to changes in the sea level, it does say something about the conditions in that area.

seaice_anomaly_antarctic - Cryosphere Today 150328

Do you see a trend?  I see a trend.  And I know there are variety of “just-so stories” to explain away this trend, but I am unconvinced.

Conclusion

Between 1994 and 2003 the average sea level rise rate was 3.77 mm/yr, according to satellite data (University of Colorado).  If the Antarctic were depositing an average of about 300 more gigatonnes of water in the ocean per year in the following years (2003 to 2012), then the average sea level rise rage from 2003 to 2012 should have increased by about 0.84 m/yr, to 4.61 mm/yr.

Instead, the average sea level rise rate from 2003 to 2012 dropped to 2.66 mm/yr.

The claim of a huge rise in ice loss from the Antarctic over this period is quite implausible.

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Plain Speaking from John Coleman

October 22, 2014

John Coleman, co-founder of the Weather Channel, knows a thing or two about the climate.  He recently had plenty to say about global warming hysteria.  In an open letter to the UCLA Hammer Forum he said…

The ocean is not rising significantly. The polar ice is increasing, not melting away. Polar Bears are increasing in number. Heat waves have actually diminished, not increased. There is not an uptick in the number or strength of storms (in fact storms are diminishing). I have studied this topic seriously for years. It has become a political and environment agenda item, but the science is not valid.

Here’s John explaining the basics…

 

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Vermeer and Rahmstorf paper rejected

January 31, 2014

Vermeer and Rahmstorf had a paper rejected by the journal “Climate of the Past.” This news is 16 months old, but I just heard about it, and could find very few references about it on the web.

This paper, On the differences between two semi-empirical sea level models for the last two millennia,  promoted their earlier sea level rise models.  They couldn’t seem to get traction with this paper.

Here are some reviewers’ comments…

One of the major problems with this work is the decidedly biased analysis and presentation.

Highly biased analysis and presentation.

It currently takes significant effort to figure out which pairs of models and training data sets the authors use, and whether they have evaluated all the relevant combinations of the same.

No surprise here.  Rahmstorf has a history of alluding to all kinds of data sets and implying that he has taken them into consideration, but only presenting results for those that support his thesis.

And the final blow…

In the light of the two negative reviews and one comment which all require new analyses and point to fundamental flaws in the methodology of the current paper, I regret to inform you that my conclusion is to support rejection. I strongly dissuade the authors from submitting responses and a revised version.

Here is the paper…

Click for full PDF version

Here is the reviewers’ discussion that lead to the the rejection.

Of course, Vermeer and Rahmstorf do not give up that easily, and similar papers have been shopped around to other journals