The debate about climate change is over. Global warming, which several scientists warned us about many decades ago — and which most of us ignored — has already happened. The planet on which many of us were born has gone and won't be returning.

To avoid global catastrophe in the next couple of decades, we must courageously pull our proverbial heads out of the sand, face the challenge and act.

Harvard graduate Bill McKibben and co-founder and director of 350.org, states: "If we do everything we possibly can, we're not going to avert huge problems, but maybe — if we work absolutely all out — we might be able to stay on this side of complete civilization-scale chaos."

So what must we do to preserve the planet? Continuing on our current path is not an option. We have to stop the fossil-fuel companies from dumping carbon dioxide, without penalty, into the atmosphere. They will not do that without a fight.

Dan Apfel, executive director of the Responsible Endowments Coalition aptly declares of the fossil-fuel industry, "Its existence is fundamentally against our existence."

Money talks, and, to get the industry to listen we need to ask our large institutions to immediately freeze any new investments in coal, oil and gas. Then within five years, these universities, retirement funds (e.g. CalSTRS, CalPERS, SCERA), places of religion, cities and counties need to divest all funds from any fossil-fuel investments.

The intention is not to bankrupt the likes of Exxon but to economically and politically marginalize them. We have to take away their freedom to pollute without penalty and also diminish their power to dictate our national energy policy.

To those concerned about any financial risk in divesting, a recent report by Patrick Geddes, chief investment officer of Aperio Group, concludes that divestment from the top 200 fossil-fuel companies would increase theoretical return risk by a mere 0.003 percent. The risk of not divesting, however, is an uninhabitable planet.

Investing in fossil fuel is also becoming increasingly risky since, to avoid global catastrophe, a looming carbon bubble will have to pop. We cannot emit more than 565 gigatons of carbon dioxide into the atmosphere before 2050. At our current rate of an annual emission increase of 3percent, we will reach that limit in around 16 years — before royal baby George will have a chance to graduate from high school.

Where will you, your children and grandchildren be in 2030?

The fossil-fuel industry already has the capacity to emit 2,795 gigatons of carbon dioxide from its current reserves, which is five times the prescribed safety limit. These reserves are currently logged as saleable assets, and since 80 percent of these assets are unburnable if we are to maintain a livable planet, the fossil-fuel industry will have to keep them in the ground and write-off $20 trillion, collapsing its stock value.

Yet, Exxon still spends $100 million every day in search of even more hydrocarbons to burn, including in the now-melted Artic. Oh, the irony.

So let's heed the warnings of the climate scientists this time and take action. We can no longer wait for government to regulate emissions. Time is running out. We should band together and support the burgeoning fossil-fuel divestment movement.

After all, divestment from South African corporations successfully helped end apartheid. In Wen Stephenson's (The Nation) words: "What's more na?e? The belief that we can afford to go on burning coal without robbing our children of a livable future on this planet? Or believing in the possibility of a fearless and determined peoples' movement to change the course we're on?"

It's time to get to work.

<i>Jane Vosburg is a retired teacher and a resident of Santa Rosa.</i>