As the fossil fuel divestment movement has grown in recent years, an interesting thing has happened. The focus of the discussion has shifted from purely ethical ("I don't want to be financing climate change") to financial ("If the world gets serious about tackling climate change, my coal investments will be worthless.") This talk of a so-called carbon bubble has given many people — myself included — a new sense of urgency about figuring out exactly where our money is and is not invested. But where to start?

Investing can be a tricky and intimidating subject at the best of times, and in a diverse, global economy, it can be extremely hard to understand what it is that any one business you are invested in really does. Add to that the fact that the divestment movement is made up of a broad and diverse group with different perspectives on divestment (some investors only want to divest from coal — others from all fossil fuel interests), and it's tempting to give up before you even get started.

A new web tool called Fossil Free Funds aims to simplify all that.

Created by shareholder advocacy nonprofit As You Sow, using Morningstar fund holding data, the site was built in collaboration with leaders in the divestment movement including Fossil Free Indexes, Carbon Tracker Initiative, BrightScope, and HIP investor. Free to use, this new web tool reveals any fossil fuel holdings in 1,500 of the most-held mutual funds covering five major fund families including Fidelity, Vanguard, and TIAA-CREF. Between them, the site's creators say, these fund families control record keeping at 75 percent of all employer-sponsored retirement plans.

The tool also provides tools for investors to personalize their criteria for the types of companies they want to screen for. Here's more from the group's press release:

"For investors wishing to more rigorously define "fossil free," screens for coal, fossil-fired utilities, and service companies like Halliburton are available. Funds clear of investments in a screen, earn a green badge with a maximum of five. Out of 1,500 funds with the highest plan count, only 12 diversified and SRI funds earned five badges, including Parnassus Endeavor (PARWX), Portfolio 21 Global Equity (PORTX), USA Mutuals Barrier (VICEX), Brown Advisory Sustainable Growth (BAWAX), PAX World Growth (PXGAX), Green Century Balanced (GCBLX), Gabelli SRI (SRIGX), and Shelton Green Alpha (NEXTX)."

This Web tool arrives at a time when the divestment movement appears to be picking up momentum. Activists announced last week that individuals and organizations representing $2.6 trillion in assets have already committed to the divest-invest movement, California just passed a bill to divest its largest pension funds from coal and activists in the U.K. are now targeting local government pension funds which they say have huge amounts invested in potentially risky fossil fuel assets.

Let's hope that Fossil Free Funds has the bandwidth to cope with some busy Internet traffic.