Sunday, 11 November 2007
The world's amazing ....here and in Oz!
Just to prove that Geo Blog has really been in the Yorkshire Dales for the last few days.... here is the limestone pavement at the top of Malham Cove photographed yesterday. No matter how often I visit that spot, I am always amazed by what nature can produce in any landscape..............and so it was this evening when I got back to an Internet connection and could catch up with Mark's progress. I've only been away for three days and I find he's already on the Southern Ocean and heading east today, south of a collection of strange white blobs..... It absolutely looks as if someone has dropped something on the image. Closer scrutiny just makes the blobs into bigger blobs. Curiouser and curiouser! The last time that we saw white blobs like this was when Mark was passing through Iran - in the posting of 17th September simply called 'Big White Blob' . Then, as now, the explanation relates to salinity , an environmental problem which is particularly acute in this part of south west Australia. The 'lakes' in the image are the lakes of the Lake Grace system, shallow saline lakes which are the consequence of the clearing of the land around Lake Grace at the turn of the century which resulted in the whole area experiencing long term salinity problems as the water table rose to the surface bringing dissolved salts with it. There is a good explanation of the problem here on the Australian Government Department of the Environment and Water resources web site. And below, courtesy of Flickr, a couple of images to show what Lake Grace looks like.......
Further research reveals that salinity (sometimes referred to as the 'silent flood' ) in south west Australia is a direct consequence of intensive farming practices in a low rainfall area and that it may be one of the most serious environmental issues facing the area today. A few years ago ABC television broadcast a series of programmes outlining the threat posed by increasing salinity. And here is a map showing the parts of Australia where the threat of salinisation is greatest.
Some 2.5 million hectares of rural land are already affected by salinity, and there is the potential for this to increase to 15 million hectares. Much of this is Australia 's most productive agricultural land.