Tuesday, October 27, 2009



















Reference: Melting glacier uncovers island, cnet news, April 28 2007

A well circulated article about global warming compares Landsat phtotos taken on 8/11/1985 and 9/5/2002 and claims that carbon dioxide from fossil fuels is melting the icesheet over Greenland and exposing rocky peninsulas previously covered by ice (Melting glacier uncovers island, April 28, 2007). Please note that a significant amount of summer melt takes place between these dates. The comparison does not yield trend information from year to year because it is confounded by seasonal changes. To draw conclusions about long run trends in ice mass once would have to compare the ice on the same date for more than just two arbitrary years neither of which is recent.

Cha-am Jamal
Thailand

7 comments:

william said...

The first picture was taken in August 85, the second in September 02, the third in September 05. Twenty years of pictures showing a progressive diminuation of the ice coverage at the same time of year. I have no idea what proof you require but the first step is an open mind.

Jamal said...
This comment has been removed by the author.
Jamal said...

hello william. two points don't make a progression. besides, for comparison purposes the dates must be the same and you need a big enough sample size to flesh out the random variations. it's statistics 101. you have to do the data right or you'll get garbage in garbage out.

william said...

They aren't "two points" but two photos illustrating what ice loss is represented when scientists say that Greenland is losing 239 cubic kilometers of water (ice)a year. In the 1985 photo the islands are buried under ice. In the photo here the ice cover has gone. The pictures were both taken in late summer but 22 years apart.

Jamal said...

you need a bigger sample william - more than 2. and they have to be on the same date not 3 weeks apart during the melt season.

william said...

Please look at the ref pictures of the Athabaska glacier. Are you saying no conclusion may be drawn because A)the photos were not taken on the exact same date and B) there are only 2 points?
http://www.worldviewofglobalwarming.org/pages/glaciers.html

Jamal said...

thank you for the link, william. i will look at that and write again.
jamal