Last week I looked at how water was becoming the new oil.

The world is running out water because of climate change population growth and urban to rural migration. We are seeing it the world over. In Australia, towns in Queensland are running out of water. In Taiwan, the water shortage has been declared a national security issue. In China, they're raising the price of water to stop people wasting it. Water shortages are also being reported in India.

In a recent report, consultants at McKinsey warn that most of the world will be facing acute water shortages by 2030.

The solutions to the problem, like more sophisticated irrigation systems and desalination plants, are neither cheap nor easy. That's particularly true in places like China where water conservation policies would affect industry and reduce GDP by several points.

Still, there are solutions. Fixing the water crisis will require governments around the world to work together. It's as critical a problem as climate change. And as with climate change, addressing the issue requires international co-operation. And given the problems we saw at Copenhagen, that will be a major challenge.