A new building code.

Rising sea levels will now be a factor in determining council approval of building plans.

Many people think this will only affect beach front land, and will therefore only apply to the rich people who can afford to live with the beach at their door - and marvellous water views.

The implications will be much wider, and eventually this will determine the value of land and existing homes across a huge swathe of Australian cities, towns and villages.

If we have a rise in sea levels the outflow of rivers and creeks will change. During flood rains that coincide with high tide water will not be able to drain away, hence land that did not previously flood will be inundated.

Council flood maps will illustrate this danger - and it will occur a long way inland from river entrances and the coast.

It signals a change in land values that will affect many people. Not only will some vacant land decrease in value because councils will no longer allow development, but existing homes will be shunned by mortgage lenders because of the risk factor.

There is also the prospect of such existing homes being excluded from flood insurance by the insurance industry.

The full implications have not yet been fully appreciated by many people, but for those considering either a land purchase or buying an existing home it would be a good idea to think long and hard about it's height above sea level, something that is difficult to determine at a casual glance.

Such a determination is likely to become a new industry. Just as property appraisal now involves many searches, in future height elevation above sea level is likely to be the determining factor in loan approvals.