h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

My wife has listened to this audio course on "Energy and Climate: Science for Citizens in the Age of Global Warming", by a professor of physics:

http://www.teach12.com/ttc/assets/coursedescriptions/154.asp

The link has a pretty detailed description of the contents, FWIW. My wife recalls that the final lecture concludes that there is no perfect answer, but as the link above concludes, "There is potential for considerable energy savings both by individuals and industry."

It is my belief, based on mostly popular "knowledge" and analogy to simpler thermodynamic systems, that we are indeed in an age of global warming. Due to the scale in both time and mass of the dynamics of the atmosphere, it seems to me doubtful that anything we do now can prevent the effects of this warming from being felt. What we can do is perhaps lessen the time until the trend reverses, or at least stops (the ever-popular aircraft carrier steering analogy). On the other hand, I live in southeastern Colorado, on the eastern slope of the Rockies, at about 7000 feet. We're too far from any ocean and too high to ever get much rain or snow. I'm hoping that the melting of the ice cap and the marginal change in atmospheric temperature combine to put enough water in the air mass to reach us here. Too bad for the low lying coasts but it could be good for some of us.

The ozone holes are caused by polar vortexes, which the vortexes
happen naturally because of the rotation of the earth.

I don't claim to be an expert but I have been studying global climate change in university and know a couple of things.

1. it's not all our fault. The Milankovitch Cycle relates to how the earth orbits the sun. A combination of three things affect our distance to the sun
a: obilquity(axial tilt) periodicity 42000 years
b:procession of the equinoxes(wobble) 21000 yrs and
c:eccentricity of orbit(whether it's circular or eliptical)96000 yrs

The Milankovitch cycle runs for 100,000 50,000 and 10,000 yrs. We are currently in a 10,000 yr cycle and guess what... we're at the end of it. Which means that we're getting further away from the sun(slowly but surely) and getting colder.

But, I hear you argue, I thought this was global WARMING aren't we getting hotter? Indeed we are. In the last 140yrs the average temperature for the northern hemispere has gone from around -0.5*C to over 0.5*C. For a thousand years before that the temperature has always been between -0.5*C and 0*C. So what has caused this sudden increase? Well that brings me to the second thing I know.

2: Alot of it is our fault. Carbon dioxide levels have risen UNBELIEVABLY fast. In the pre-industrial world the level of CO2 in the atmosphere was 270ppm(parts per million). In 1998 the level was 370ppm increasing at a rate of almost 3ppm A YEAR. Some scientists say that when the level passes 400ppm we will have passed a threshold from which there will be no turning back, the CO2 will be in the atmosphere to stay.

And I think ww all know at this stage what CO2 does. Traps the suns heat which warms up the earth which melts all the ice which reduces the salinity of the oceans which disrupts the north atlantic drift which then won't bring the nice warm air up to us which means we're all going to die... just kidding, humans survived the last ice age (and the mini ice age in the mid 1800s) and we'll survive the next easily enough... time to get out the woollies.

Interesting. Could you elaborate on that 400ppm threshold for CO2, I've not heard that before and am interested to see why some think it will be there to stay?

erm... i'll have to check it out again but i will get back to you. while you're waiting you might like to check out this site

http://yosemite.epa.gov/oar/globalwarming.nsf/content/index.html

We have a curious tendency in debates like this to deal in extremes as though partial disasters don't count. If it is all right because "we" survived previous Ice Ages, does that mean, phew, it's all right so long as point zero zero one percent of "us" survive the next?

On the other extreme we equally happily plump for Cold War thinking. The nuclear capability of the superpowers was described in terms of "mutually assured destruction" -- and a lot of people's reaction to that was to take Tom Lehrer seriously and think, oh, well, if we all go together then that's OK too.

What are we talking about? Should we really do nothing in the face of a coming discomfort that will all make the wars, pestilences, famines and disasters that the world now experiences seem like the light entertainments of a golden age?

And it's not as though we don't know what direction to move. And it's not as though we are being asked to forego our health or vigour.

I don't think there is alot we can do recumbentman. the damage has already been done. even if we stopped burning ALL fossil fuels today the effects of global warming would still be felt tomorrow (and the day after). and speaking of "the day after tomorrow" that was obviously just hollywood nonsense, the enviroment is a gradual thing and there's no logical reason why 'we' all couldn't survive.

Oh -- sorry, I must have panicked there.

So what's the likely scenario? The coastlines change, we all retire peacefully and equitably to the hills . . . well, maybe a little jostling and squabbling . . . mass migration is a wee bit traumatic, no?

From everything I’ve read, if the models are right and global warming results in the next ice age, it’s going to take a 1000 or more years. I’m not sure that mass migrations are going to be necessary. I suspect that the we may not even realize that we’re migrating.

As for the coast lines changing, we don’t need global warming for that. Hurricanes, tsunamis, earthquakes, mud slides and other natural and man made disasters are changing the coast lines everyday.

I’ve been at a beach one year and had to walk a couple hundred yards to get to the water. The next year I’ve had to walk a hundred feet. The erosion happens that quickly after a storm. So what do we do. We go out to see and dredge up huge amounts of sand to extend the beach so we have some where to tan in the warm weather. Of course the next beach north rapidly erodes and the process starts all over again the next year.

As for should we do nothing? I think the question may be better posed by asking, what can we do that won’t back fire on us. I agree that we need to start conserving fossil fuels now and look for reasonable alternatives. The flip side is, we can’t be reactionary and rush to action without considering the consequences of our actions.

(Tries to picture the world rushing to action to conserve something without considering the consequences of our actions)

Can't work up a convincing picture of that somehow.

Well, if you believe Aubrey de Grey's contention (http://news.bbc.co.uk/1/hi/uk/4003063.stm) that we'll soon be able to extend human life spans to 1000 years, this whole discussion of a coming ice age becomes a little more personal.

Regardless of whether we're contributing to global warming or not, I still think we should cut down on the use of fossil fuels because: 1) they're messy; 2) we're running out of them; and 3) wastefulness is usually more costly than conserving.

quizzical
(stocking up on sun screen and warm woolies...)