Most of us, oddly enough, don't relish being told that if we don't change our ways, our planet is going to be wracked simultaneously with floods and droughts, potentially resulting in famine and millions of displaced people.
Most people's reaction seems to be to metaphorically pull a large, fluffy duvet over their heads and hide, or alternatively, to pour scorn on anyone suggesting such a doomsday scenario.
All of which probably means that Al Gore is a very brave man. He has been criss-crossing America, and indeed, other parts of the world, with a slideshow that has a very simple message: global warming is a reality.
Glaciers are melting, and so are polar ice-caps. In a very short time, perhaps mere decades, because of our profligate burning of fossil fuels, we could render this green and blue planet barren and inhospitable to human life. After viewing one of these slide-shows, a film producer suggested that Gore could reach far more people by making a movie. The result is An Inconvenient Truth, shown by the Green Party in a special preview last week in advance of its official release in Ireland. Gore might be considered doubly brave for embracing this mission, because in the US, he has a reputation for telling porkies in order to make himself look good. Bush supporters gleefully inquire how you can believe anything from a man who claimed to have invented the internet.
Of course, Gore never claimed to have invented it. Those who really had a seminal role in its invention came to his defence, saying that Gore had sponsored crucial legislation and thus was right to claim some credit.
Gore's critics claim that An Inconvenient Truth is filled with junk science and exaggerations. Even to these unscientific eyes, An Inconvenient Truth does have some over-simplifications. It is very much made for an American audience, where there is even more resistance to the reality of global warming than there is in Ireland. Notoriously, despite being one of the world's major polluters, the US failed to sign up to the Kyoto agreement aimed at reducing greenhouse gases.
Mind you, we don't exactly have the high moral ground in Ireland, because while we signed up, we used our favourite béal bocht tactic to get a derogation from the standards demanded of others.
Yet here in Ireland we do not have the same level of nay-sayers that Gore has to contend with in the US, people who seem to suspect that he is some kind of closet communist determined to wreck the economy. Gore retorts that listening to environmentalist concerns could actually be good for the economy.
Cars manufactured in the US cannot compete on the global stage because they are so fuel-inefficient and their emission levels are so high.
Even China's standards for cars are far in advance of the US.
Gore, commonly perceived as having the dynamism and personality of a plank, is a revelation in this film.
If he had managed to show the American people this relaxed, self-deprecating version of himself, there might have been none of that bother with hanging chads. He consistently emphasises hope.
He reiterates that we already know the answers to the problem of global warming. We simply lack the political will to implement the solutions.
Over and over, he presents global warming not only as the great moral issue of our time, but as an opportunity, as a potential issue that could unify the globe as people act together to solve the most serious dilemma the world has ever faced.
Yet he is also guilty of over-simplification, and of underplaying the massive scale of change that is needed on an individual, family, corporate and institutional level. Unless there is a persuasive coalition of political, economic, social and spiritual forces, we will continue to flounder.
We are light years away from the visionary leadership needed to mobilise popular support. Even in the most benign scenario, which is not as apocalyptic as Gore's vision, we are still facing massive loss of species and irreversible damage.
Political leadership alone will not be enough, if the manufacturing, financial and agricultural sectors do not begin to accept responsibility for the long-term good of this fragile planet.
From a social point of view, our whole suburban and commuter-based lifestyle is based on vast consumption of fossil fuels. One unexpected benefit of attempting to tackle the problem may be the strengthening of local communities, as the concept of living and working within a confined area becomes a necessity.
On a spiritual level, the churches and faiths have a valuable role to play. In this regard, with the notable exception of individuals like Fr Sean McDonagh, the Catholic Church has not given anywhere near enough leadership.
The Protestant World Council of Churches has been promoting environmental awareness since the 1990s. The Catholic Church needs to rediscover a neglected tradition of stewardship.
Global warming could be described as the ultimate pro-life issue. Unlike the popular media, which regularly casts doubt on the reality of global warming, or suggests that it is simply a natural phenomenon, the mainstream scientific community accepts that it is happening, and that it is being accelerated by the wilful wastefulness of the developed world.
The only scientific dispute is about the degree of seriousness of the consequences.
Gore does repeat one urban legend in the film to illustrate our failure to take action. He claims that a frog will leap out of boiling water, but will passively sit in water that is slowly heating up, until it is boiled to death. In reality, a frog thrown into hot water will probably die, and a frog in slowly heating water will struggle to escape.
It is a small point, and one that might easily be changed. Gore could retain his analogy, including a very cute graphic where an over-heated frog is rescued and set down on a sun-lounger on a lily pad. All he needs to point out is that despite the urban legend, frogs do not sit and stew, but human beings currently appear content to boil slowly as our atmosphere heats up.
It might neatly serve to illustrate that the average human who prefers to disregard the threat of global warming could fairly be assessed to be less intelligent than the average frog.