This is the week of critical meetings to find answers on what to do about global warming. In New York, the United Nations will be looking at tighter emission mandates and the Bush administration will be looking at voluntary pledges, although one has to wonder whether non-binding goals are that effective.

But as Jeffrey Ball says in The Wall Street Journal, the fundamental issue is coming up with a scheme that will provide incentives for the developing world to cut emissions. It's all very well for the developed nations to talk about emissions reductions but in places like China, India and other parts of Asia, it's a different story altogether.

Another issue is whether there can be incentives for companies to go green.

Rupert Murdoch's News Corporation, for example, which takes in Fox News, the New York Post and soon The Wall Street Journal, has pledged to be carbon neutral by 2010. "Their footprint is 641,150 tons of carbon. That's the equivalent of taking 130,000 cars off the road," greenpeace research director Kert Davies told ABC News.

Other companies getting in on this include Virgin, Dupont, BP and NBC Universal.

Environmentalists say that even if the companies are doing it for less than altruistic reasons, like public relations and marketing, it still has a positive impact.

But does it? All these schemes have one big weakness: there is no accurate way to measure either the emissions or the carbon that is ostensibly being saved elsewhere. Tree-planting is one solution, but how many forests can you grow. Also, there is no single standard out there to appraise the quality of the claims for carbon neutrality and the quality of the marketed offsets. Businesses, for example, can calculate their direct operational emissions from electricity, gas and transport use. However, many fail to do an audit calculating emissions from other sources such as paper, waste generated and outsourced activities.

And they seem to ignore the carbon emissions coming from the outsourced operations, including the call centers in places like Bangalore.

All this means is that there are no simple solutions to one of the big issues confronting the world today.