Jennifer Marohasy has a couple of posts on dryland salinity, including a link to an excellent survey of the recent debate by John Passioura (subscription required). Marohasy’s interpretation is (as always) that the problem has been grossly exaggerated. This kind of unvarying optimism (or the alternative position that environmental disaster is invariably impending) is a fine example of the ‘stopped clock‘ approach to punditry. If you make this kind of claim on every issue, you’re going to be right about half the time.

In the case of dryland salinity, it’s easy enough to find examples of both excess pessimism and excess optimism. Among the optimistic errors noted by Passioura are the assumption of the Western Australian government 20 to 25 years ago that the salinity problem was well in hand, and that there was no problem with large scale clearing. This was covered in a book by Beresford et al which I mentioned a couple of years ago. Another form of excess optimism is the belief that there are easy solutions. These include engineering solutions like the use of the Murray as a drain for saline water (seriously proposed in the not-so-distant past as Passioura notes) and, more recently, large-scale tree planting. As I observed in the post I’ve already mentioned, it’s turned out that in many cases, the area that has to be planted is so great and the time to fix the problem so long that, in a lot of cases, it appears not be economically feasible.

Another piece of bad news is that, whereas early studies focused almost exclusively on agriculture, dryland salinity can cause substantial economic losses through damage to roads, buildings and so on. On the other hand, remote sensing has suggested that the area affected by dryland salinity is less than first thought, and that trends are more variable. And the alarming estimate of 17 million hectares derived from the National Salinity Audit refers to the area that might (in the absence of policy change) have high water tables and therefore be at risk of dryland salinity, not the area that is likely to be actually affected.

If you want an easily accessible view of the problem (a little out of date now, but still very good), I recommend David Pannell’s 2001 AARES Presidential Address Dryland Salinity: Inevitable, Inequitable, Intractable? .

Update 8/2/06In response to a challenge to nominate an environmental issue where urgent action is needed, Jennifer Marohasy says

“In a recent blog post (a version of the same published as an article for The Land newspaper) I suggest something needs to be done about overgrazing in the Macquarie Marshes, This links back to the even more dramatic
Cattle Killing the Macquarie Marshes?.”

Despite the question mark, Marohasy is pretty confident the answer is “Yes’. Her evidence? “An aerial photo showing the line of demarcation between an overgrazed private property and ungrazed nature reserve. As she says, “the impact of grazing here is obvious and dramatic.”

But there are many, many similarly dramatic photos of environmental damage in the Murray-Darling. In these cases Marohasy rightly says that dramatic photos may be misleading and need to be backed up by scientific research (when the scientific research is produced she rejects it, but that’s by the way). [I will try to get some more info on this, and report what research has in fact been done].

How is that Marohasy is so quick, in this case, to label farmers as environmental vandals, and to call for urgent action, when she normally disputes conclusions based on decades of research?

A reading of the posts makes the answer pretty clear. The Macquarie Marsh graziers are in conflict with the irrigators she represents. Follow the money.