This post was authored by Lisa Renstrom, a Trustee of Bonwood Social Investment.

Imagine an economy fueled daily by the sun’s energy.  Jobs are opening up in sustainable companies that previously struggled to survive in a fossil fuel dependent world.  Imagine that this robust, creative economy is no longer undermined by the political power of the fossil fuel industry, that energy markets are driven by consumers rather than by political manipulation and industry leverage.

Progressive philanthropy can help turn this vision into reality.  Doing so will require divesting  from fossil fuels and investing in preferred alternatives: in infrastructure and local efficiencies; in clean energy and technology; and in sustainable agriculture and consumer products.

This vision has compelled me to purge my personal and philanthropic assets of the fossil fuel industry.  It was not “simple.”  The deep-rooted conservative, Nebraskan father figure financier often surfaced arguing, “Divestment isn’t practical.  How will you maintain your asset allocation, how will you replace that return on investment?”

Moral reasons are my core impetus for divesting.  Fortunately, though, any doubts raised by that stern-voiced specter in the black suit are quelled by financial data.  In fact, financial literature and testimony show divestment to be a prudent and risk adverse decision.

Fossil fuel stocks, whose valuations are linked to their reserves, are over-valued.  Conservative estimates point to a “carbon bubble” many times larger than the recent $2 trillion housing bust.  When investors realize that up to 80% of current fossil fuel reserves cannot be used, the carbon bubble will pop, with profound economic consequences.

Such warnings are coming from a growing body of financial analysis, including Carbon Tracker, the London School of Economics, Lord Nicholas Stern, The Grantham Institute, HSBC, Standard & Poor’s the University of Oxford, and the Economist. The existence of a global carbon bubble and the reality of stranded fossil assets are fast becoming mainstream wisdom.

So here’s my invitation: join me and significant portfolios like the Wallace Global Fund (WGF) in a Divest-Invest Foundation Initiative.  Two years ago, WGF committed to full divestment of its portfolio from the fossil fuel industry by 2014.  In partnership with other foundations — including newer ones that never invested in fossil fuels — we can create a community of practice.  Together we can use philanthropy’s resources, power, reputation and credibility to support a broader Divest–Invest movement and other campaigns.  Now is the time for philanthropy to direct its power toward creative investments scaled to meet the challenges of the global climate crisis.

Whether you decide to divest just your personal assets or those of a foundation, I commend you.  If you could start with a 5% carve out for reinvestment, I urge to begin.

Divesting from fossil fuels and investing in new energy solutions emanates from the courage to help steer humanity away from fossil fuel dependence. It asserts our say in our future. It demands that we support solutions rather than sinking further into a destructive spiral.  We will need to support expansive, aggressive movements in order to effectively stem climate change.  But our many small steps today can get us where we need to be tomorrow.

 Lisa Renstrom is a Trustee of Bonwood Social Investment.  She is a member and former president of Rachel’s Network and of the Sierra Club.  She serves on the Board of Directors of Interfaith Power and Light, the Green Science Policy Institute, ecoAmerica, and Rachel’s Action Network.  She is an alumna of the Harvard Business School Owner/President Management Program and holds a Master’s degree in Public Policy from the Kennedy School of Government.