Les dinosaures à Kyoto (2)

Suite du message Les dinosaures à Kyoto :

Ma réflexion s'articule autour de deux points :

> le climat est très complexe à modéliser et on peut faire dire, le pire étant quand c'est inconscient, ce qu'on veut à un modèle qu'on a du mal à recaler (je le sais, j'en ai fait), même pour des choses plus simples que le climat.

Par exemple, on me dit : la montée des eaux va amplifier l'évaporation, peut-être, mais est ce que ça ne va pas augmenter la capacité d'absorption du Co2 de l'océan et l'albedo global ? Je n'en sais fichtre rien.

Je suis conscient que les modèles nous prédisent des catastrophes mais voilà : je ne les crois pas fiables.

Si un astronome me disait qu'une comète va percuter la terre dans vingt ans, je serais tenté de le croire, car on maîtrise relativement bien les trajectoires des corps célestes, on a découvert des planètes avant de les voir en analysant les aberrations de trajectoires d'autres planètes. Où et quand la climatologie a-t-elle prouvé un tel degré de connaissance ?

On n'est pas capable de donner une météo fiable à15 jours et on serait capable de prévoir le climat dans 100 ans ? Alors que des deux problèmes, le deuxième est peut-être le plus complexe et qu'il ne mobilise pas autant de moyens que le premier ?

> or, les décisions prises suite à ces modèles et ces projections sont extrêmement couteuses, cet argent ne serait il pas mieux utilisé ailleurs (lutte contre le SIDA, éducation, etc.)

Je disais que, dans un cas aussi incertain, il vaut mieux réagir qu'anticiper, ou, si vous préférez, anticiper plus tardivement plutôt que de prendre des décisions hatives.

J'avais oublié un point, c'est : "Messieurs les savants, continuez à travailler et à raffiner notre savoir, perfectionnez vos modèles."

Je me suis souvenu (mieux vaut tard que jamais) que sur ce sujet j'avais déjà publié un article :

La relative absence d'importance d'empêcher le réchauffement global (B. Lomborg)

Enfin, dans la pile de Herald Tribune en retard, j'ai trouvé cet article sur le fait que les dirigeants chrétiens évangéliques tournent écolos. Il ne pouvait mieux tomber puisqu'il recoupe exactement mon propos (oui, oui, je sais encore un argument d'autorité) :

(Vous trouverez au lien suivant l'article de RH Nelson sur environnementalisme et théologie cité par J. Tierney : ENVIRONMENTAL RELIGION: A THEOLOGICAL CRITIQUE)

And on the Eighth Day, God Went Green By JOHN TIERNEY (NYT)

816 wordsPublished: February 11, 2006

And on the eighth day, God said, Let there be a thermostat for the heavens and the earth, and God saw that it was good. And God said, Let no man adjust it more than 2 degrees Fahrenheit, or 1 degree Celsius, until the end of time.

Now that evangelical Christians have joined the battle against global warming, we may as well acknowledge that America has one truly national religion: environmentalism.

Its tenets, already taken for granted in the blue states, were embraced this week by the Christian leaders who formed the Evangelical Climate Initiative. They haven't yet rewritten Genesis, but their advertising campaign warns of ''millions of deaths'' from biblical scourges -- floods, droughts, pestilence -- unless humans make a ''sacred commitment'' to stop global warming.

It may look odd for evangelicals to be taking up Hollywood's most fashionable cause, but the alliance makes perfect sense. Environmentalism has always fundamentally been a religion -- ''Calvinism minus God,'' in the words of Robert Nelson, a professor of environmental policy at the University of Maryland. He calls the global warming debate the latest example of environmentalist creationism.

The Puritans and other Calvinists believed that God was revealed not just in Scripture but also in the ''Book of Nature.'' To them, the wilderness was an unchanged record of God's handiwork at ''the Creation,'' offering a glimpse of the world before man's pride and sinfulness alienated him from nature and caused him to be expelled from Eden.

Environmentalists have had similar notions, starting with John Muir, who considered nature ''a mirror reflecting the Creator.'' Al Gore urged the ''moral courage'' to secure ''our place within creation.'' When Bruce Babbitt was secretary of the interior, he called plants and animals ''a direct reflector of divinity,'' and he warned Americans not to ''recklessly destroy the patterns of creation.''

There is one large problem with this version of creationism. The world we see was not created in a week, and it has looked a lot different in the past.

The forests that seemed divine to the Puritans and to Muir and Babbitt were not present at the Creation. They were merely the latest adaptation to changing climatic conditions and competition with other species, including humans -- Indians had been managing the forests by cutting trees and setting fires. There is no such thing as a ''natural'' forest in America, Nelson writes, unless you reject creationism and define nature as ''the Darwinian vision of unremitting struggle for survival.''

Darwin's Book of Nature isn't as morally satisfying as Calvin's, at least not for those who enjoy berating Americans for their sinful desires to cut down trees and burn fossil fuels. But it does make for a clearer way to think about global warming. Instead of assuming that humans will be punished for tinkering with God's handiwork, you can consider the best strategy for our species' survival.

That means rejecting the assumption that we must immediately start atoning for our excesses. Solutions like the Kyoto treaty amount to expensive hair shirts that appeal to penitents but not necessarily to economists. Even economists who support the Kyoto treaty acknowledge that it will make only a small difference far in the future while imposing serious costs today.

And those costs seem too high to other economists, like the four Nobel laureates and their colleagues who met in Copenhagen in 2004 to study proposals to help the world's poor. The Copenhagen Consensus, as they called it, was that programs to slow global warming are one of the worst investments -- far less worthwhile than programs to immediately combat disease and improve drinking water and sanitation.

Saving lives now makes more sense than spending large sums to avert biblical punishments that may never come. Scientists agree that the planet seems to be warming, but their models are so crude that they're unsure about how much it will heat up or how much damage will be done. There's a chance the warming could be mild enough to produce net benefits.

For now, the best strategy is to refine the forecasts and look for the cheapest and least painful ways to counteract global warming, including heretical ideas like geo-engineering schemes to cool the planet by blocking sunlight. It's hard today to imagine how that would be done -- or how environmentalists would ever allow something so ''unnatural.'' But maybe they could be convinced that we're just resetting God's thermostat back to the eighth day of Creation.