What's their motivation?

Feb. 25 (Bloomberg) -- Duke Energy Corp. and investors such as BlackRock Inc., the biggest publicly traded asset manager in the U.S., today backed President Barack Obama’s push for a “market-based cap” on greenhouse gas emissions.

Emissions trading « SmallCapWorld

Last Friday, I spoke with Neil Eckert, CEO of London-based Climate Exchange plc (LSE: CLE, OTC Pink Sheets: CXCHY; http://climateexchangeplc.com), which is not only the pioneer in emissions trading and other clean-tech issues such as water extraction rights trading, but is, practically speaking, the only global exchange with a meaningful stake in this fast-growing area.

...In a recent report, major institutional holders included Invesco Asset Management (29.85%), Harbert Management (17.42%), BlackRock (8.37%), Fortis, Moore Capital, and others. Lehman Brothers had a stake that was apparently sold off on the open market and is now history. Insiders including directors own 20.55%.