Archive for the ‘climate change’ Category

h1

Barack Obama: Glaciologist

September 6, 2015

The avid outdoors-man and eminent scientist, Barack Obama, has been trekking through Alaska lately.  He is lamenting the demise of the great glaciers of the North.  He is surely grieving over the harm that man is inflicting on the planet by spewing his toxic CO2.  The Washington Post reports

Standing near the foot of the Exit Glacier, which has receded 1.25 miles since 1815 and 187 feet last year alone, Obama said “this is as good of a signpost of what we’re dealing with it comes to climate change as just about anything.”

The man certainly has a way with words – a true poet.

I guess we are supposed to be alarmed because 187 feet per year is a lot faster than 1.25 miles per 200 years.  After all, 1.25 miles in 200 years averages out to only 33 feet per year.  The message we are supposed to get is that the Exit Glacier is receding about 6 times faster now than its average over the last 200 years.  This, of course, is due to the CO2 that vile humans use to poison the atmosphere and it means endless and escalating disaster unless we socialize the economy of the world.

But what does the National Park service say about the retreat rate of Exit Glacier? The following table of retreat distances and rates comes from the National Park Service’s “The Retreat of Exit Glacier.” Annotation in red was added by me.

Exit glacier retreat annotatedSo, this data confirms Obama’s assertion that the Exit Glacier has retreated 1.25 miles in the last 200 years.  But it also makes it quite clear that it was retreating as fast, or faster, 100 years ago.

If CO2 is the culprit today, what was the culprit 100 years ago?  The following graph shows the amount of anthropogenic CO2 in the atmosphere as a function of time going back to 1750.  The data comes from Oak Ridge National Laboratory.  I made the plot and added the annotation. It’s kind of hard to explain why the retreat rate was so much greater in the past when there was less than 10% of the anthropogenic atmospheric CO2 than there is today.  Perhaps Professor Obama will elucidate.

anthro atmos carbonMy wife and I were up in Alaska a few years ago, and we also visited some some of those receding glaciers.  At Glacier Bay National Park, which is several hundred miles southeast of Exit Glacier, I happened to pick up a park pamphlet that had the following series of illustrations showing the glacier extents in the park going back to 1680.

glacier bay extents v3The first thing that jumps out at you is the rapid ice advance between 1680 and 1750 and the subsequent retreat between 1750 and 1880.  The pamphlet said

“The Little Ice Age came and went quickly by geologic measures.  By 1750 the glacier reached its maximum, jutting into Icy Strait.  But when Capt. George Vancouver sailed here 45 years later, the glacier had melted back five miles into Glacier Bay – which it had gouged out.”

As an aside, a co-worker once told me that the Little Ice Age was not a global phenomenon, but rather, local to Europe.  He cited the Union of Concerned Scientists as the source of this insight.  But there it is, in Alaska!

It is hard to argue with the Union of Concerned Scientists because they’re, well, scientists.  Not just anybody can be a Concerned Scientist.  You have to send a check first.  My wife used to send a check years ago, but it was from our joint account so I figure I was only half a Concerned Scientist then.  Now I guess I am just a wholly unconcerned scientist.

IMG_1546 v2Anyway, Obama was getting excited about 1.25 miles of glacier recession since 1815, and a whopping 187 feet in the last year.  That pamphlet that I mentioned also had a large map of the Glacier Bay area marking the location of the various glaciers back to 1760. It’s easy to string the locations together and calculate the recession rate of these glaciers.  The image at the left  shows the map as I marked it out for Grand Pacific Glacier. (Click to enlarge.)

I have plotted the distance as a function of time for three glacier routes using this crude method.   As you can see below, these glaciers have receded at a much faster rate than Exit Glacier.  But Exit Glacier and the Glacier Bay National Park glaciers have one thing common:  they all retreated at their maximum rate back when anthropogenic atmospheric CO2 levels were very low compared to today.

Glacier retreatLet’s take a closer look at the Grand Pacific Glacier.  John J. Clague and S. G. Evans (J. of Glaciology)  used various data sources to plot the retreat of the Grand Pacific Glacier.  I have converted their data to miles and overlaid it with my coarser data from the map. The Clague data and the map data agree nicely, but the Clague data fills in some of the gaps.  The most interesting point is that like Exit Glacier, the retreat rate for the Grand Pacific Glacier was greatest around the last part of the 19th century. In fact, the Clague data may indicate that the Grand Pacific Glacier was slightly progressing, not retreating, during most of the 20th century.

Grand Pacific Glacier retreatIt is pretty clear that the Grand Pacific Glacier was retreating fastest around 1860.  Where is that on the anthropogenic atmospheric CO2 timeline?  The graph below shows that the anthropogenic atmospheric CO2 level was only about 2% of today’s level when the Grand Pacific Glacier was retreating at its fastest by far!

CO2 and Grand PacificHow is that possible???????  I thought it was high CO2 levels that caused the glaciers to recede.

h1

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…

This slideshow requires JavaScript.

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.

h1

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…