02/11/2009 05:12 am ET Updated May 25, 2011

The skeptic who came in from the cold

I have in the past, and will again in the future, launch deservedly vicious tirades against the stupid and ignorant, paid and unpaid, energy company denialist stooges in the International Anti Global Warming Conspiracy. But I realize that in addition to these braying idiots there are still a few genuine skeptics, people who really have tried to keep up to date with evidence as it floods in, and who remain puzzled by aspects of it, or believe that some findings are contradictory, or who think that the accuracy of some measurements might be questioned. Such approaches are in the best traditions of science, and lead to further advances in theories, further refinements of analysis or measurement.

Perhaps the most common element of the world view of such skeptics is the proposition that climate has changed in the past, and that therefore the current changes are neither special nor, generally, of concern. Such people might also believe that if the current warming is just the latest bump in the roller coaster ride of world climates over hundreds of millions of years, then we can do little if anything to prevent it, but should act to adapt to the new conditions. This genuine set of beliefs has been cynically used by the denialists, but just because it can be misused, doesn't mean that skeptics shouldn't look at the world through such a prism.

But because of the misuse, "the climate has changed before" gets lumped in with "global warming on Mars" or "urban heat effects" or "more ice in Antarctica" as just another part of the random word generator nonsense that makes climate change denialism the UFO affirmation of the 21st century. But I have gradually realized that this is wrong and self-defeating. By responding impatiently ("Yes, the climate has changed before. So?") to skeptics and denialists alike we keep pushing together these reluctant and odd bedfellows.

Trouble is, I think, we haven't done a good job of explaining what we mean when we say the climate is changing as a result of global warming as a result of increasing CO2 levels. We don't mean "the climate hasn't changed before and now it is". Nor do we mean "all of the changes in climate we see now are the result of global warming". Nor do we mean "the only thing that influences climate is changing CO2 level". But these seem to be the messages that the skeptics are hearing, and, rightly, disputing. And having, in their mind, disputed those perceived messages, they then think there must be something wrong with the science that has formulated them, and so they poke away questioning stuff that doesn't, in fact, need questioning.

So let's clear the air (so to speak, ho ho). "Climate changes" is, yes indeed, a tautology on this old and complex blue dot on the outskirts of a galaxy. Ever since the planet stabilized enough to have a molten core inside and land (moving continents) and air and water outside, together with a variable and elliptical orbit around a variable star, etcetera etcetera, the average temperature and moisture regimes it has experienced have seen great swings and roundabouts, and the species human beings (and the ancestors of human beings) share this garden of eden with have appeared and disappeared like so many candles in the wind.

There have been times when the climate was very much harsher than today, and (with or without the help of rocky visitors from outer space) great raft loads, enough to fill Noah's Ark many times over, of species have been lost forever. Continents have moved through the latitudes, ocean currents have changed direction, large bodies of water have oscillated in temperature, mountains have risen, forests have been cleared. And human beings, since we evolved from the primeval ooze, have shivered through centuries of blizzards; tried to deal with drought through changes in agriculture; have seen glaciers wipe out villages; have walked across dry land bridges between land masses and been cut off when seas rose again; have painted pictures of creatures they shared the land with, now long gone; have developed clever engineering solutions to move water, or hold back sand dunes, or reclaim land from the sea, or make houses livable when baby it's cold outside or when there is a tropical heatwave. So, no secrets there, the only certain thing about the climate of the Earth is its uncertainty. If you plot a graph of average temperature of the Earth it bounces around like a ball in an arcade game - up to the top, back down to the bottom, whoops, up it goes again, and down. A jagged line looking for all the world like the trace of vibrations from an earthquake. A climatic earthquake.

But wait, there's more.

We have known for a long time that carbon dioxide can act as an accessory after the fact of climate change. Can (working in tandem with water vapor and even, Sarah Palin help us, methane), rather in the way that the rich get richer and the poor get poorer, make times of high temperatures even higher. Nothing magic, not the work of Harry Potter or Al Gore, just fundamental physics and, for good measure, ice on the cake, the measurement of past carbon dioxide levels. Wouldn't matter greatly, just another of those curiosities of this magnificently complex real estate designed for a billion or so people, except for one very inconvenient fact. Part of the ebb and flow of animals like dinosaurs and the trees they ate while waiting to provide transport for biblical humans is that they finished up being reduced to their carbon components which were then captured and stored safely underground. All of those once vibrant ancient communities, lush in biodiversity, vibrant in evolutionary potential, reduced to wet or dry black stuff forming some of the layers in the great layer cake of earth's geological history. Safely buried until a particular species of wise ape discovered you could burn the damn stuff and do all kinds of neat things like providing heat and light and running Hummers. Oh, and adding carbon dioxide to the air - invisible, odorless, tasteless, disappearing into the sunset, gone and forgotten. And more. And more.

And as it rises so it begins, inexorably, to push up that bouncing ball of changing climate. That choppy sea (to mix metaphors well beyond well beyond the capacity of anyone to control by pouring oil on troubled waters) with its millions of years of ups and downs is gradually forming into a wave as the ups become uppier. A big wave, threatening to engulf humanity and dinosaur descendants alike. Not just climate change, which continues on largely oblivious to the way it is being supercharged, but the mother of all climate changes, ready to unleash shock and awe, a weapon of mass destruction, on climate scientists and denialists alike.

So if you are a skeptic, paddling around in the shallows, watching the little waves bounce up and down and saying, to your children, "see, the sea is always changing, always has, up and down", then watch out for the tsunami just in sight on the horizon, doesn't look much in the distance, but it is moving fast. And when it arrives you will hear the voice of Crocodile Dundee booming out "Call that climate change? THIS is climate change."

So if you have been a skeptic on the grounds that climate has always changed, nothing to see here, move right along folks, then it is time you came in from the cold. We weren't talking about climate change, we were talking about CLIMATE CHANGE. And we need you on this side of the barricades, welcome any time, free pass, no questions asked, but please make it quick. Things are going to get a lot worse before (if) they get better.

And the vicious tirades against the stupid and ignorant, paid and unpaid, energy company denialist stooges can still be found on the Watermelon Blog - no free pass for them.