Q: Could global warming really slow down the Gulf Stream and cool Europe, or maybe even start a new ice age?
Unfortunately I'm not finding the actual Marketplace piece he was listening to, but the story linked above is the same one: global warming, even 1-2 degrees, could (a similar BBC article said "would") melt the Greenland icecap, diluting the salinity of the waters of the northern Atlantic and slowing or changing the course of the major source of Europe's relatively warm climate (as compared to other places at the same latitude). The results could devastate, among other things, the vineyards of France, and presumably change the range of the rain in Spain.
Well, darn it.
All right. I was trained as a geologist, many a year ago. It didn't take long to learn the fundamental lesson that the Earth is not a hunk of rock that can be held in stasis. Climate change is the norm; the fact that someone is around and able to watch it happen is the most significant difference between this time and, say, the Wisconsinan glaciation of some 20,000 years ago (when, surely, there were people around, but their interest was personal and far from academic). All the agitation of all the "concerned" groups in the United States and elsewhere will not halt the process.
Finally, "concerned" groups appear to have realized that "ordinary" people are on to this fact, and they've changed the nomenclature: no longer is the big bugaboo "The Coming Ice Age" (because many people reasonably believe that we're in an interglacial period anyway, and there will be another ice age no matter what we do) or "Global Warming" (because, first, the evidence is less than compelling in spots, and second, eternally, climate change is the norm) but "Abrupt Climate Change." Abrupt climate change, human-caused, to which the marvelous feedback loop of Mother Gaia will be unable to respond, and disaster will follow.
No, sorry. Disaster will not follow. The Earth, Mother Gaia if you will, has survived and thrived through absolutely no free oxygen but lots and lots of volcanogenic carbon dioxide, through abundant free oxygen (one of the more corrosive gases around, witness rust and tarnished silver), through meteor strikes, through the drift and smash of continental plates into and away from one another such that, at one point, the average summer temperatures in the center of the massive supercontinent known as Pangaea were perhaps twenty degrees hotter than the American interior desert today, through ice ages that buried Great Britain under a mile of glacier (it's still rebounding - measurably), through two-day catastrophic floods draining 3000-square-mile, 2000-foot-deep lakes that carved drainage systems amazing to shutterbugs today, and above all through that terrible scourge life in every available niche. She is as vital now as she was when the biggest land critter was a centipede.
Don't get me wrong: when the polar ice caps melt - again - Manhattan, if it still exists, will be Atlantis, and Orange County will bloom like the rose. I'm not saying that human life will not be affected. But let's frame this debate appropriately: it's not the Earth that's in danger. It's Western civilization's current condition, and only that. Stop Climate Change - as well try to stop an earthquake. The Sahara Desert used to be a garden; can we delude ourselves that its hardscrabble residents today would not welcome more rainfall? Niagara and Angel Falls are ephemeral; the Great Salt Lake is ephemeral; the Nile is ephemeral; the Himalayas are ephemeral. We may not be as ephemeral as all that, we may be able to cheat the fate of most other species through careful application of our intelligence to the problem of our survival under constantly changing conditions, but so far our entire timerange as a genus, not even a species, is only a fifth of that of the apatosaurus. (Ask your kids.)
It's hard for me to get too worked up about "Abrupt Climate Change!"; as hurricanes, tornadoes, earthquakes, forest fires, floods continue to wipe our little creations off the map no matter what disaster preparedness and resource management we bring to bear, I wonder just how much effect we humans actually have on the robust and stunningly adaptive system we call the Earth. A major component of my belief in God comes from the presence of our massive oceans - the majority of our home planet, filled with a substance almost unmatched as a heat sink, and with unicellular life that kindly photosynthesizes for our benefit no matter how much forestland we convert to agriculture. It's as if God provided us with "baby gates" to keep us from killing ourselves until such time as we learn to do dangerous things safely.
As such, I hesitate to support, much less encourage, any precipitate action on our part to monkey with the system. Efforts at forest management in this country led to a tangle of underbrush that burned faster, hotter, and more destructively than any natural fire, when it finally and inevitably burned. Efforts to contain the Mississippi in straight concrete banks did nothing noteworthy to stop her cycle of flooding. Efforts to move wild animals too often lead to human tragedy, the animals' failure to thrive in their new environment, or the proliferation of other species just as undesirable - think of rabbits in Australia, or, in the plant kingdom, the nightmare of kudzu in the American South.
I don't claim that we can do no wrong. We have the ability to create persistent toxins; we have been and presumably are being an agent of extinction (but remember that extinction is first and foremost a natural process - many creatures and environmental conditions have brought about extinctions); there is some evidence that it's possible for us to trigger earthquakes under some specific circumstances. What I do advocate is caution, especially of our tendency to hubris. We are only human. We are not the protectors of Mother Earth but just one set of her tenants - arguably the most creative, but not even close to knowledgeable or prescient enough to "save" her from herself.