Category Archives: sea ice

Agreement polar ice sheets are melting

Many climate scientists felt the conclusions on effects of global warming in the 2007 IPCC review were too conservative. One reason was the estimation of likely melting of ice sheets and its effects.

Problem was that there was insufficient knowledge to draw definite conclusions. And the measurements of changes in ice sheets just wasn’t accurate enough.

That’s now changed and a large number of experts agree global warming has caused loss of ice from these ice sheets. And this has contributed to measured increases in sea level.

Richard A. Kerr reports in Science (see Experts Agree Global Warming Is Melting the World Rapidly):

“Forty-seven glaciologists have arrived at a community consensus over all the data on what the past century’s warming has done to the great ice sheets: a current annual loss of 344 billion tons of glacial ice, accounting for 20% of current sea level rise. Greenland’s share—about 263 billion tons—is roughly what most researchers expected, but Antarctica’s represents the first agreement on a rate that had ranged from a far larger loss to an actual gain. The new analysis, published on page 1183 of this week’s issue of Science, also makes it clear that losses from Greenland and West Antarctica have been accelerating, showing that some ice sheets are disconcertingly sensitive to warming.”

He’s referring to the major paper by Andrew Shepperd and others, A Reconciled Estimate of Ice-Sheet Mass Balance.

Over recent years climate change deniers/contrarians/sceptics have cherry picked data to counter any suggestion that the earth’s large ice sheets are melting. They have pointed to increased amounts of ice in Eastern Antarctica to balance reports of massive losses of ice in the Arctic. (Have a look at this animation to see how such data can be cherry picked). Similarly they have tried to hide concern of the loss of land ice by stressing reports of local increases in sea ice.

But the paper by Shepperd et al. combined data from satellite altimetry, interferometry, and gravimetry measurements. This provides more reliable estimates of changes in the ice sheets, and gives some detail of these changes. This figure from the paper gives an idea of the detail of their findings. It shows that all the major regions of the polar ice sheets except one (East Antarctica) have lost mass since 1992. The authors also estimate that mass loss from the polar ice sheets has contributed roughly 20 percent of the total global sea level rise during that period (at a rate of 0.59 ± 0.20 millimeter year−1 ).

Figure S1 from Shepperd et al.: Cumulative ice mass change of West Antarctica ((WAIS) East Antarctica (EAIS), Greenland (GrIS), and the Antarctic Peninsula (APIS).

And to underline the fact that denier claims of amounts of ice increasing in Antarctica are false, NASA recently displayed this figure showing data from Antarctica from their satellite measurements

Monthly changes in Antarctic ice mass, in gigatones, as measured by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites from 2003 to 2011. Image credit: NASA-JPL/Caltech; NASA GSFC; CU-Boulder; Technical University of Munich; Technical University of Denmark; Delft University of Technology, Aerospace Engineering, Netherlands; Durham University, UK; Leeds University, UK

Could those climate change deniers/contrarians/sceptics please stop hiding behind claims that gains by Antarctic ice sheets balance losses from ice sheets in Greenland and the Arctic.

They don’t.

See also:
Science: Major Regions of Polar Ice Have Been Shrinking Since 1992
Polar Ice Sheets Losing Mass, Several Methods Show
New Study Shows Global Warming Is Rapidly Melting Ice at Both Poles
Human-Caused Climate Change Signal Emerges from the Noise
Study: Polar ice sheets in Antarctica, Greenland melting 3 times faster than in ’90s
Ice Sheet Loss at Both Poles Increasing, Study Finds
Projections of sea level rise are vast underestimates
“Hard” “Authoritative” Evidence Of Climate Change Begins To Overwhelm Even Fox

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Christmas gift ideas: One for the kids

Books are ideal Christmas presents. And as I am spending some time dealing with family business I thought reposting some of my past book reviews over the next few days could be useful am repeating some of my past book reviews.

I should have reviewed more books for children. But here’s a good one – about an important scientific topic.


Book Review: Evolution: How We and All Living Things Came to Be by Daniel Loxton

Reading level: Young Adult
Price: US$12.89, NZ$40.99
Hardcover: 56 pages
Publisher: Kids Can Press, Ltd. (February 1, 2010)
ISBN-10: 1554534305
ISBN-13: 978-1554534302

Today, February 12, is Darwin Day. The anniversary of Charles Darwin’s birth 201 years ago. So I have decided to review a new book on evolution.

It’s a short book, but an important one. Important because it’s for kids – it’s aimed at children of ages 8 – 13. It’s about an important area of science, evolutionary science. I think kids will learn from this book, and they will enjoy the experience.

“Evolution” is beautifully illustrated and clearly written. Important evolutionary ideas are well explained in brief sections, often illustrated with examples and metaphors as well as pictures. Daniel Loxton is the editor of Junior Skeptic and regularly writes and illustrates for children so he is the ideal author for such a book.

I like the way that many of these sections use questions as chapter headings. “What about us?”, “Survival of the fittest?”, “If evolution really happens, where are the transitional fossil?”, “How could evolution produce something as complicated as my eyes?” are a few examples. The sorts of questions kids will commonly hear. Loxton devotes the second part of his book to such questions, ones commonly raised by creationist critics of evolution. This is good technique for capturing the reader’s attention and encouraging them to read further.

Loxton uses many examples and metaphors, as well as pictures, to illustrate ideas. His illustration of mutations acting over time with the metaphor of the children’s’ game “telephone” is done in both words and pictures.

My main criticism is that he didn’t use a metaphor to illustrate the important idea of “deep time.” A simple description of rock layers and differentiation of fossils is inadequate – even for an adult. One needs to compare the immensity of time with something pictorial, like the distance between people, houses, cities, countries, planets, and so on. An illustration of the process of fossilisation could also have helped.

However, kids of this age are continuously learning. They are always confronting ideas and words needing further explanation. So I think it is great that this book includes a short glossary (which does include a description of fossilisation) and index. This helps encourage the young reader to explore further – especially when they come across unfamiliar words.

The religion question

Several reviewers have expressed reservations about Loxton’s short answer to the question “What about religion?” Perhaps it would have been better to leave this out – but on the other hand it is a common question which kids will have to confront. Loxton’s inadequate reply was unavoidable, given the unwritten social rule that religion has a special role in our society. That we are not allowed to criticise religion. Any properly adequate reply would have lead to people being “offended” and campaigns to exclude the book for schools.

So perhaps the best advice is that he gave – kids should discuss this with family and friends. I think there are many things in this book which will raise further questions in the reader’s minds. Maybe it’s religion, the way fossils are formed, how life began, the age of the earth or universe. If this leads to discussions with family, friends and teachers – great. It’s all part of education.

So, I can highly recommend this book. It will be a great gift for the target age group – but even some of us older “kids” could probably learn from this short clearly written and beautifully illustrated book.

That’s my opinion. Now I must pass it on to my 9 year-old granddaughter and get her reaction.

See also:
Evolution: How we and al living things came to be – available from Fishpond.co.nz.
forgoodreason Interview with Loxton about the book
Skeptics’ Guide to the Universe Interviews Daniel loxton
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That hacking scandal

The current phone hacking scandal in the UK brings back some memories. It’s taken several years for those hacking crimes to reach public consciousness and create a storm of disgust. I wonder how long it will be before we get to find out who was behind the “climategate” hacking scandal? It was obviously well organised and had  a big political effect, despite the tameness of the emails released.

But I bet the true story behind that hacking will be interesting.

Thanks to Treehugger for the timely reminder (see Cold Case: Who Hacked Climatic Research Unit Emails Back In 2009?)

I also have to thank treehugger for bringing this handy infographic to my attention. It’s from ReuseThisBag.com and compares the scientific consensus and the sceptics arguments over global warming. Click on the image for a larger version.

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