Jupiter's spots may be disappearing, as a result of climate change.

There's a serious issue underlying your joke, Rand. Part of the problem with the "global warming" debate is that one side tends to insist that the problem is dire, but caused entirely by humans -- hence entirely fixable by humans -- and the other side tends to insist the problem doesn't exist at all, or is some mild change such as have gone on since time immemorial and which pose no serious problem.

Unfortunately somewhat lost is the possibility that climate change is (a) real and serious, but (b) not anthropogenic. What then? I'd say serious climate change -- caused, say, by a modest fluctuation in the Sun's output -- could pose a threat to civilization worse than NEOs.

This story, and related stories of changes on Mars, suggest perhaps that there is an interesting and very "practical" reason for studying other planets up close, and for extended periods of time: it might give us important clues about the general nature of climate variation, and greater insight into how the Sun's output varies.

I look at it this way: The hottest the Earth has been in the last half a million years was 3 degrees C warmer than now. Each of those events was a spike in temperature followed by a gradual cooling. We are now seeing a spike - a couple millenia later we will see the decline.

People live in Death Valley - and we are not going to get anywhere near that temperature on most of the Earth. Worst case, we will do just fine. Best case, we shouldn't even bother doing anything. Logical conclusion, do the stuff that is relatively painless - like we are doing...

"Unfortunately somewhat lost is the possibility that climate change is (a) real and serious, but (b) not anthropogenic. What then?"

We build dykes around major capital cities, and put up with a few hundred thousand south pacific refugees each year for the next century. No big deal really.

The cost of a few flood barriers should be more than offset by the economic gains created by lowering the shipping distance between asia and europe by 4000km and the opening of siberia to farmland.

Anyone have any good links on the subject of climate change on Mars? I'd like them for a friend to read.

Some 10,000 to 12,000 years ago, the last major ice age ended. We're talking about global warming on a massive scale. Yet through it all, primitive men and women found a way to survive. Are we less able to adapt to change than they were?

I have no problem accepting that the climate is warming. The climate is constantly changing, so why not now? I'm unconvinced that humans are causing the warming but it's possible that we may be contributing to it in some way. The key to our survival through the ages is applying intelligence to adapt to change. If we can't do that, then we don't deserve to survive as a species.

Cecil, you can google it easily enough. Here's a few without axes to grind:

Sun's role in global warming may be underestimated.

Warming trends on Mars

Chris, major capital cities already have plenty of dykes. You meant dikes, I think.

But the major difficulties with climate change are not flooding of cities. They are more likely to be major shifts in the ecology, e.g. where you can grow wheat and where it's desert, where conifer forests can thrive and where it's going to be grassland, where fish can spawn, where tuna can feed, where there's gentle rainfall all year -- and where you get your water mostly in great howling monsoons.

Major shifts in the physical location of the various ecological niches would be quite disruptive to the world economy. Imagine what would happen if the American Midwest became as arid as the Sonoran Desert of the American Southwest and Mexico, and instead Saskatchewan and Alberta became the great "breadbasket" locations. Massive population shifts, that's what, and maybe more than the social structure of the US or Canada could easily stand.

A more alarming possibility is that shifts in habitable zones would happen so fast (i.e. over a century instead of a millenium) that animal and plant species could not adapt fast enough, and might go extinct. Conifer forests can migrate north only so fast, for example. If where they can grow moves north too fast, they'll just die. And it's not within human power to transplant millions of square miles of forest.

We already know the Earth has experienced profound climate changes. The Ice Ages are one example, and "Snowball Earth" (you can google it) is a far more drastic possibility. Life has survived those (albeit in the latter case only as single-celled organisms), and it would be very surprising if life could not survive anything in store for it in the next few millenia.

But it's far from clear that human civilization -- the world as we know it -- is as robust. We freak about the drastic consequences to our society of a 50% rise in the price of gasoline, fergawdsake. How are we going to cope with, say, the end of agriculture in the United States and the migration of 200 million Americans to Canada? Or England becoming as glaciated as Greenland is, if the Gulf Stream stops? Not especially well, perhaps. Particularly badly if we have little warning and do no prior planning.

So, if these things are coming, it would be good to know as early as possible. That's my point. I suspect if we got away from the question of "who's to blame?" we might be able to answer the question of "what, exactly, is happening?" a little better.

Climate change on Jupiter?

I didn't even know the Jovians had SUVs.

I've always liked Dennis Millers take on Global Warming:

"There are a lot of vying statistics, but I think the crux of it is the temperature has gone up roughly 1.8 degrees over a hundred years. Am I the only one who finds that amazingly stable? Hey, I'm happy it's gone up. I'm always a little chilly anyway.

Then people ask me if I'm worried about the effects of global warming on my kids. Well, obviously I love my kids and I want them to live to be a 100. So that's another 1.8. My kids’ kids? Three point six. I'll just tell them we moved to Phoenix."

"Major shifts in the physical location of the various ecological niches would be quite disruptive to the world economy."

Not really, any changes to climate patterns are going to occur over centuries.

If you look at how far land use patterns, agricultural mechanization, genetic engineering and transport technologies have advanced over even the last 25 years, changes from climate are going to be glacial (no pun intended) by comparison.

Oh, and yes, I meant dikes. I realised the error after I had posted.

Josh says: Then people ask me if I'm worried about the effects of global warming on my kids. Well, obviously I love my kids and I want them to live to be a 100. So that's another 1.8. My kids’ kids? Three point six. I'll just tell them we moved to Phoenix."

That'll work, but your numbers are off. Average mean temp in the US over that last hundred years didn't change. Worldwide, up .6 degrees. So, its even less of an increase than Miller mentioned.

Solar variation has been taken into account, what's bad is the radiative forcing from CO2.

"Solar variation has been taken into account, what's bad is the radiative forcing from CO2."

I think it's a little too early in the game to be making value judgements, mz. Yes, there is radiative forcing. What we don't know is the magnitude of the forcing, or whether in the grand scheme of things a 0.5C higher equilibrium has enough detrimental environmental impact to worry about.

We might be better off investing the several hundred trillion dollar cost of 'fixing' climate change on other pollution and global health issues like improving air and water quality, cleaning up heavy metal contamination, treating malaria and HIV in the developing world, and any number of other causes.

Not really, any changes to climate patterns are going to occur over centuries.

Jesus, don't be naive. Go look up the rate at which forests can migrate in km/year, and the projected rate at which they might have to migrate to keep up with changing climate zones. (And I emphasize 'might' because anyone who thinks we know enough to be sure of what those rates will be is naive, or a member of one of the cults on either side repeating dogma.)

You've mastered calculus, right? You're telling me the derivative must be small because the denominator is large. Hopefully the error in the logic jumps right out at you when it's phrased that way.