What have Mexico City, Bill Clinton and JP Morgan got in common?

As this IHT.com article reveals, big banks, cities, and ex-politicians are getting together to make serious committments to tackling climate change.

New York, Chicago, Houston, Toronto, Mexico City, London, Berlin, Delhi, Karachi, Tokyo, Seoul, São Paulo, Bangkok and Melbourne are all teaming up with Citibank, UBS, Deutsche Bank, ABN Amro and JP Morgan to get carbon friendlier.

Sounds interesting. So what are they actually doing? Well, saving money - and carbon.

According to the IHT: "...participating banks would provide up to $1 billion each in loans that cities or private landlords would use to upgrade energy-hungry heating, cooling and lighting systems in older buildings."

The money, and interest, will be repaid using the savings made when energy consumption is reduced. This could be with reductions of around 20-50%, maybe more.

Bill Clinton's foundation acted as facilitator, bringing the cities and the banks together.

The plan is to start by energy auditing older city buildings. The financial structure is being designed by both the banks, a specialist financial services company called Hannon Armstrong, and the Clinton Climate Initiative.

And of course, some industry vendors will benefit hugely. According to the IHT some four big energy services players will undertake the upgrades. IHT.com says they will "guarantee a particular level of energy and monetary savings for particular projects under the plan."

Neat huh? When a problem is this big, its only collaborations like this that will tackle it.

While many big companies are getting excited by the money they can make with trading energy efficiency carbon credits on places like the Chicago Climate Exchange, its good to remember that much of the low carbon work to be done will require innovative thinking like this.

Some commentators are getting excited by the notion of motivating (particularly US) business on raw profits alone from a lower carbon world. And no doubt the US, as it always does, will grab the opportunities with both hands and drive innovation.

But increasingly companies, like these banks above, are going to have to get more and more into the messier business of partnerships, collaboration and trade-offs. While this will be good for tackling climate change, its also likely to offer large companies some valuable lessons in the broader corporate citizenship agenda that awaits them this century.

For any of you purely old school "business case or die" advocates out there, the IHT finishes off its piece rather nicely too:

"I've been involved in a couple billion dollars worth of projects in the last several years," said Bob Dixon, senior vice president of Siemens Building Technologies. "They've all paid for themselves in energy savings."