When environmentalists ring alarm bells about climate change, endangered species, oceans at risk or other unsustainable trends, we're routinely pegged as pessimists, alarmists, or catastrophists.
Just last week, the authors of a NASA-funded report were called "doomsayers" because they said that widening income inequality and environmental degradation could lead to the collapse of modern societies, unless we do something to address these issues.
That last point is critical. Their warning, like all warnings about unsustainable trends, was issued because they believe that if we recognize a risk to our quality of life, we'll do something about it.
It's the belief that we'll respond to risks that inspires people like me to speak out about environmental concerns. We sound the alarm to educate the public and encourage change. Far from being pessimistic, we speak out because we're optimistic. We believe that change is not only needed, but that it is possible.
We know change doesn't come easily. We can see, for example, that a global pact to cut emissions continues to be elusive. But we have faith that, in time, we will solve this problem. And in the meantime, from the growth in renewable energy, to the advances in electric cars, to the mainstreaming of environmentalism, there are many concrete reasons to be optimistic.
In the face of adversity, we remain optimistic because we know that change is nearly always resisted by those invested in the status quo, and progress is hard fought. But history tells us that things do change, and mostly for the better.
If we look to the civil rights movement or the gay rights movement, for example, we can see that the history of progress is one where change is resisted, but eventually a tipping point is reached and a new normal is established. So it has been for practically every social movement to date. And so it is for environmentalism today.
The pessimists are the ones who don't believe that we can change. And the really pessimistic ones believe that we'll fail to change, even when we all agree that we're courting disaster.
Such pessimism was exhibited by Exxon Mobil, in their recent bet against action on climate change.
Here's a little background: The world's leaders, including Canada, have committed to limit global warming to 2 degrees Celsius, which is the upper limit that scientists tell us is safe. And for that to happen, some two thirds of the world's reserves of oil, gas, and coal cannot be burned. All of this means that fossil fuel companies like Exxon may be overvalued, since all of them hold large amounts of "unburnable carbon" in their reserves, and oil that cannot be burned isn't worth very much.
In response to pressure from investors, Exxon Mobil agreed to look at whether any of their reserves would be impacted by actions to cut emissions, and to assess their exposure to what has become known as the "carbon bubble." What did the company find?
While Exxon Mobil admitted that climate change is a serious problem, the company's opinion is that governments are "highly unlikely" to adopt policies that cut emissions by any significant measure any time soon and the "low carbon scenario" is practically impossible. In short, Exxon believes that we'll continue to guzzle oil even though that will lead to a future in which extreme weather events, flooding, droughts, extreme heat waves, and food insecurity, among other things, will pose a direct threat to the lives and livelihoods of people across the world.
Yes, Exxon believes that even though our best scientists are telling us that this is what lies in store unless we cut our emissions, we will fail to act. Strangely, one reporter called this an "overly rosy view." I call it pessimistic. It's downright cynical.
As for me, I'll continue to be optimistic. My kids demand it of me. While I know that change is always hard fought, I also know that change is possible.
As Margaret Mead wisely said, ""Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it's the only thing that ever has."
ALSO ON HUFFPOST: