Global Warming

[kittygrrl]

Your thoughts. Fiction or Fact?

[Martina]

Hard to deny after this week. I heard on the radio today that most people in the U.S. think it's real, but that it's low on their list of priorities. That's why we haven't heard much about it during the election.

Sandy may have changed that. We'll see.

[Gráinne]

I am a geologist by major. My thoughts:

"Global warming" can either mean the natural warming of the planet or the hypothesis that man is destroying the atmosphere and warming the planet by our own actions.

Earth has always had climate change, either cooler or warmer, most obviously in the Ice Ages. The Mesozoic era, when the dinosaurs dominated, was actually warmer than we are now.

Skipping way ahead to the early Middle Ages, before 1300, they too were a warm period which was historically marked by the first few Crusades, and great journeys and a general leap forward for civilizations. But starting about 1300 and certainly by 1340, we entered what is called the "Little Ice Age". The LIA was much cooler and damper. The poor climate and failed crops left Europe's population a sitting duck for the Black Plague, smallpox, syphillis, and you name it.

As an aside, the ravages on society due to these epidemics led to great social change as feudalism collapsed and a new middle class emerged. The Roman Catholic church, though very powerful, found competition in the rise of Protestantism due in part to people's disillusionment with a church powerless against disease. The roots of later revolution in France, the Holy Roman Empire, and ultimately Russia were sewn by governments failing to respond to people in crisis. Obviously, all of these effects had other causes but the climate factor is interesting.

The LIA lasted until about 1850, and we've been warming ever since. Realize that the Industrial Revolution, which got going about the same time, only affected a small part of the planet as a whole-western Europe and northeast America. Even today, we actually have more wilderness land in America than we did 60 years ago. Car and industrial emissions are much more tightly regulated than in the 1950's and 60's.

So, in short, we are warming but it's my belief that man is not the great influence on it. Call me cynical, but it's worth looking into just what the "scientists" are saying, and following the (big) money involved. I'm all for recycling and using our resources responsibly, of course, but climate change in itself is natural and our main responsibility is not to build in hazardous areas (easier said than done).

[girl_dee]

Thank for that info!

i feel it's evolution. Like what guihong just posted, the world is evercharging.

i don't understand why people expect the Earth's climate to stop changing.

[kittygrrl]

Originally Posted by guihong

I am a geologist by major. My thoughts:

"Global warming" can either mean the natural warming of the planet or the hypothesis that man is destroying the atmosphere and warming the planet by our own actions.

Earth has always had climate change, either cooler or warmer, most obviously in the Ice Ages. The Mesozoic era, when the dinosaurs dominated, was actually warmer than we are now.

Skipping way ahead to the early Middle Ages, before 1300, they too were a warm period which was historically marked by the first few Crusades, and great journeys and a general leap forward for civilizations. But starting about 1300 and certainly by 1340, we entered what is called the "Little Ice Age". The LIA was much cooler and damper. The poor climate and failed crops left Europe's population a sitting duck for the Black Plague, smallpox, syphillis, and you name it.

As an aside, the ravages on society due to these epidemics led to great social change as feudalism collapsed and a new middle class emerged. The Roman Catholic church, though very powerful, found competition in the rise of Protestantism due in part to people's disillusionment with a church powerless against disease. The roots of later revolution in France, the Holy Roman Empire, and ultimately Russia were sewn by governments failing to respond to people in crisis. Obviously, all of these effects had other causes but the climate factor is interesting.

The LIA lasted until about 1850, and we've been warming ever since. Realize that the Industrial Revolution, which got going about the same time, only affected a small part of the planet as a whole-western Europe and northeast America. Even today, we actually have more wilderness land in America than we did 60 years ago. Car and industrial emissions are much more tightly regulated than in the 1950's and 60's.

So, in short, we are warming but it's my belief that man is not the great influence on it. Call me cynical, but it's worth looking into just what the "scientists" are saying, and following the (big) money involved. I'm all for recycling and using our resources responsibly, of course, but climate change in itself is natural and our main responsibility is not to build in hazardous areas (easier said than done).

I have to confess I am a little confused on this subject and read many conflicting ideas about if this new warming is more man made then just part of a cycle. I appreciate your expert opinion and leaning towards it being more of a natural cycle perhaps accelerated by our over use of fossil fuels. The only thing that bothers me is that some ice ages, including the little one seems to have been caused by a major volcano eruption?? Please correct me if I am wrong as I'm strictly going on my memory..btw, what a wonderful study!

[Glenn]

Originally Posted by kittygrrl

The only thing that bothers me is that some ice ages, including the little one seems to have been caused by a major volcano eruption?? Please correct me if I am wrong as I'm strictly going on my memory..btw, what a wonderful study!

Vostok Ice Core Data, Antartica- Well, yes there could be another ice age coming again soon considering the last ice age was only 10,000 years ago, and the Earth is 4 billion years old. Back in the day, Folks use to sacrifice a virgin to volcano to stop it from erupting. Method must work since some of us are still living here and prospering. I suggest we throw Mitt Romney into a volcano tomorrow. It will appease the gods of fear-mongering, and the gods of bull-shi*t, and I'm sure we'll be just fine

[kittygrrl]

Originally Posted by Glenn

Vostok Ice Core Data, Antartica- Well, yes there could be another ice age coming again soon considering the last ice age was only 10,000 years ago, and the Earth is 4 billion years old. Back in the day, Folks use to sacrifice a virgin to volcano to stop it from erupting. Method must work since some of us are still living here and prospering. I suggest we throw Mitt Romney into a volcano tomorrow. It will appease the gods of fear-mongering, and the gods of bull-shi*t, and I'm sure we'll be just fine

i think the volcano would spit him right back out too full of ....!

[aishah]

i don't know enough about global warming to know. i've found the info on this thread really interesting because most people i know accept global warming and human involvement in it as fact, so it was really cool to hear a different perspective. it definitely made me stop and think.

i do think corporations are doing a lot of fucked up shit to the environment. i don't know if that's causing global warming, but it's causing enough other problems to scare me.

i'm curious for folks who know more about this than i do - what do you think about the theory that we're going through a great extinction that's driven partly by human actions? i heard this (and the idea that we might have another huge volcanic eruption sometime soon) only recently.

[kittygrrl]

Permafrost in Alaska is thawing..it contains mega amounts of carbon which can form into methane..not good

[Rockinonahigh]

I honestly beleave the earth has gone thrue many cyckes of cooling then warming in varying degrees and will contenue to do so.I'm not a scientis but I do read lots of earth/ cutural history and it says thay had happen a lot of times,onething for shure we best be mindful of how our ancestors got thrue the weather changes so we will be able to do the same by inproveing on the how and why they did as well as they did.the satistics of survival of the fitist will be inproved on but useing th technology we have at hand.

[kittygrrl]

Originally Posted by Rockinonahigh

I honestly beleave the earth has gone thrue many cyckes of cooling then warming in varying degrees and will contenue to do so.I'm not a scientis but I do read lots of earth/ cutural history and it says thay had happen a lot of times,onething for shure we best be mindful of how our ancestors got thrue the weather changes so we will be able to do the same by inproveing on the how and why they did as well as they did.the satistics of survival of the fitist will be inproved on but useing th technology we have at hand.

Do you rilly think we would do better? I don't believe they would, many would die only a very few could manage that enviroment. I'm not sure what the temperature would be but that brings all kinds of interesting questions (ie what would you burn for fuel?) Many would starve, society would disappear, disease would run rampant, people would do desperate things..

[dreadgeek]

Originally Posted by kittygrrl

Your thoughts. Fiction or Fact?

At present, I think it would be prudent to accept, at least provisionally, that climate change is happening and that there is good reason to believe that humans are contributing to this. I base this, in part, because one of the rules of the game in science is that you make predictions and if your prediction is born out by observation, you are justified in presuming you are on the right track.

To take just one example, current models (which are imperfect but still have their utility) predicted that we would start losing the Arctic ice cap sometime around 2015. We are pretty much on track for that to happen (we could have no summer ice cap in the Arctic next year or perhaps 2014). To me that looks like a prediction that is being confirmed in real-time. Yes, the planet has been both warmer than it is now and colder than it is now. Yes, our species survived both relatively warmer climates and relatively colder climates. This should not make us quite so complacent, however. The last real ice age almost wiped the species out. We are genetically 'small' which means that for our huge numbers, there should be more genetic diversity than there actually is. This means that our species went through a population bottleneck fairly recently (less than 100000 years ago).

My larger concern, aside from parochial concerns about the long-term prospects for our species survival, is that there we are well on our way to being the cause of the sixth largest extinction event the planet has ever seen. That puts us in the company of large asteroid strikes and super-volcano eruptions. Large, complex species can't adapt on a dime and we are not giving species enough time to adapt to the change in climate. The follow-on effects could be pretty drastic. Lose a predator species and suddenly their prey could have a population explosion which could cause further problems as they either expand into human inhabited areas.

Am I certain that humans are causing climate change? No, however none of the current alternative explanations, at least none that I've read, are able to account for the rapidity of the change. It's not enough to be able to say "maybe it is a solar cycle" one must be able to explain why the solar cycle explanation is superior to the view that humans are the prime cause and the alternative should also be able to explain any anomalies that the current model cannot. I don't believe that the solar cycle model can explain the Greenland ice sheet loss.

cheers
Aj

[dreadgeek]

Originally Posted by guihong

I am a geologist by major. My thoughts:

"Global warming" can either mean the natural warming of the planet or the hypothesis that man is destroying the atmosphere and warming the planet by our own actions.

Earth has always had climate change, either cooler or warmer, most obviously in the Ice Ages. The Mesozoic era, when the dinosaurs dominated, was actually warmer than we are now.

The only problem I have with this is that yes, the Mesozoic was warmer but the species that were alive then but are no longer alive now were adapted to *that* climate. When the climate changed drastically and rapidly, most likely due to an asteroid strike, whole phyla were wiped out because they didn't have time to adapt. As you are aware, a change in climate happening over, say, 200K, 300K, 500K, years is one thing (that's a lot of generations for some animals) is one thing. That same change happening over a period of 100 or 200 or 300 years is not a lot of time at all. Sure, that's a lot of *mouse* generations but it's only 15 generations--at most--for, say, elephants or whales or, for that matter, us.

My concern isn't with the rise in temperature in absolute terms--provided we don't see serious spikes outside of the normal range that shouldn't be a problem. Rather, my concern is with the combination of the rapidity of change and the degree of change. Six or seven degrees C within a century is a big shift and one that I'm not sure how many species that live in temperate or arctic climes could handle that sort of shift long term.

I know that species extinction happens. I know that *mass* species extinction happens. But once we become aware that *we* are causing mass extinctions, I think both prudence and ethics dictate that we at least consider doing something to ameliorate the situation. We can't stop big rocks from hitting the planet (well, maybe we could) but we can stop ourselves from heating the planet so much that we get into a really bad feedback loop and then, a few thousand years from now, some intelligent species, following a faint radio broadcast that could *only* have come from an intelligent species, parks its ship in low-earth orbit and finds that Sol has two very hot, rocky planets with runaway greenhouse effects instead of the one it currently has.

Cheers
Aj

[dreadgeek]

Originally Posted by Rockinonahigh

I honestly beleave the earth has gone thrue many cyckes of cooling then warming in varying degrees and will contenue to do so.I'm not a scientis but I do read lots of earth/ cutural history and it says thay had happen a lot of times,onething for shure we best be mindful of how our ancestors got thrue the weather changes so we will be able to do the same by inproveing on the how and why they did as well as they did.the satistics of survival of the fitist will be inproved on but useing th technology we have at hand.

We have some advantages they didn't have and they have some advantages we didn't have. We have better technology and so more of us could likely survive a harsher ice age than our paleolithic ancestors did. That said, our die-off would likely be *much* larger simply because we are so much more numerous. Keep in mind, though, that given the small genetic diversity of our species (I know we don't look like we are genetically relatively homogeneous but we are) we've had one very close brush with extinction. The current understanding is that all 7 billion of us are the descendants of, perhaps, no more than 10000 breeding pairs living ~75-100000 years ago. Yes, we bounced back and did so quite magnificently but as I said earlier, there's a lot of genetic diversity we lost during that time.

As far as how we might adapt as a species is anyone's guess. We are still evolving as a species but we've changed the rules of the game so much that it's just this side of impossible for us to know what kinds of traits are being selected for.

Cheers
Aj

[Ginger]

Originally Posted by dreadgeek

We have some advantages they didn't have and they have some advantages we didn't have. We have better technology and so more of us could likely survive a harsher ice age than our paleolithic ancestors did.

Only those with access to that technology would survive. And they are outnumbered by a majority growing both proportionately and in quantity.

That said, our die-off would likely be *much* larger simply because we are so much more numerous.

Keep in mind, though, that given the small genetic diversity of our species (I know we don't look like we are genetically relatively homogeneous but we are) we've had one very close brush with extinction.

I'm sorry, I'm not getting the connection (why it's "Given" that (despite or because of?), our small generic diversity we've had one close brush with extinction. Can you explain again, please?

The current understanding is that all 7 billion of us are the descendants of, perhaps, no more than 10000 breeding pairs living ~75-100000 years ago. Yes, we bounced back and did so quite magnificently but as I said earlier, there's a lot of genetic diversity we lost during that time.

As far as how we might adapt as a species is anyone's guess. We are still evolving as a species but we've changed the rules of the game so much that it's just this side of impossible for us to know what kinds of traits are being selected for.

I wonder if we're selecting for traits enabling people to have more resistant to environmental toxins.

Cheers
Aj

Interesting.

[Toughy]

At the end of Bill Clinton's last term global climate change was accepted by the overwhelming majority of scientists in and out of the field across the world........so was evolution.

It's only in the US there is this denial of climate change and evolution. Frankly I don't give a shit...........what I can see with my own eyes is the ice caps melting, the glacier packs on all the moutains/volcanoes melting rapidly (look at pics of Mt Rainer....it's scarey).....and the pollution being churned out in India and China at alarming rates........there is a problem....a big one.

Let's not be more stupid and let's do everything we can to eliminate the human contribution to the problem.....in ALL countries particularly the newly industrialized countries..........

stop basing everything on oil as the provider of energy....we are way smarter than that

[dreadgeek]

Originally Posted by IslandScout

Interesting.

I'm sorry, I'm not getting the connection (why it's "Given" that (despite or because of?), our small generic diversity we've had one close brush with extinction. Can you explain again, please?[/quote]

Certainly. It's not that we had a brush with extinction *because* of our lack of genetic diversity. The small amount of genetic diversity among our species is an *effect* of that brush with extinction not the cause. A few of different things point toward this being the case. The first--and the one which, more or less, gives birth to the other two is that both the mitochondrial DNA variation (I'll refer to this as mtDNA from here on out) and the Y-chromosome variation is less than what we would expect given our numbers. All seven billion of us carry one of seven mtDNA variations. The roughly 49% of humans who care a Y-chromosome are all in some 15 groups. Again, this is smaller than one would expect. For example, chimpanzees have much more genetic diversity and worldwide they don't make up even 1% of human numbers but any two given chimps that are not closely related will share far fewer genes than any two non-related humans will.

This kind of anomaly cries out for explanation. Since mutations in all species accumulate at fairly predictable rates once you can work backward and start to see where those genes started and how they radiated out amongst existing human populations. What that work has shown is that every human being alive is related to a fairly small population, of ~10000 breeding pairs, that lived in sub-Saharan Africa in the range of 75 to 100K years ago.

The easiest way to think about this is the relationship between you and distant cousins. Somewhere out there are people whom you are distantly related to that you have no idea that you share genes with them. If, however, we sequenced your DNA and their DNA and, assuming we were lucky, had access to all the intermediary DNA we could work backward to where your shared genes come from. In much the same way, although obviously over a much longer time period, with a far larger sample and with lots of gaps in that sample, we can work back where various genes found in populations had their origins.

I won't bore you with the mathematics of it but there are certain things that just follow from certain observations. For example, since mtDNA is passed down, pretty much unchanged, from the mother it means that there must have been a mitochondrial Eve (in other words some woman or women who carried the copies of the mtDNA that all humans have). Even though evolution tends to homogenize a population because it favors those genes that work better in their environment, there's a *lot* of genetic diversity that is just missing in our species and the only real explanation for it--given that we know the mutation rate in the species--is that a lot of the diversity was wiped out and then bounced back.

As far as how we might adapt as a species is anyone's guess. We are still evolving as a species but we've changed the rules of the game so much that it's just this side of impossible for us to know what kinds of traits are being selected for.

I wonder if we're selecting for traits enabling people to have more resistant to environmental toxins.

We may be. It's hard to know. There's different levels of selection as well. For instance, purely by happenstance we likely *are* being selected for disease resistance because living in cities exposes you to far more pathogens than living in a low-density hunter-gathering-fishing village. The problem is that sometimes, we select for things that have no adaptive function *other* than that in a certain population certain traits may become 'fashionable'. For instance, if red-hair is considered to a mark of beauty within a population then, on average, more red-haired children will be born. Several hundred generations down the road, there's a a lot of red-haired people around. No one remembers *why* red-hair was considered popular 500 years ago, maybe it lasts in some folk story but it has no adaptive significance. It's another level of selection called sexual selection and it can have very profound but weird consequences. A couple of examples within our own species may be breast size in women (it isn't adaptive in the sense that women with larger breasts have more or healthier babies) or facial hair in men (which seems like an advertisement of virility). It may be that these are the kinds of traits that become 'fashionable' at some point in a species' evolutionary history and then become locked in. Both breast size and facial hair are perfect kinds of 'signals' for sexual selection because they are useless (and therefore costly) and hard to fake. The textbook example of this kind of selection is the tail of peacocks. They're big, expensive to build (in the sense of the calories that go into building that can't be used for building, say, better flight muscles) and make it very difficult for peacocks to fly. However, peahens prefer peacocks with large, brightly colored, garish plumage. It would be better for the peacocks to grow smaller tails that were still larger than their neighbors but then, that would mean that it would behoove a neighbor to have a slightly larger tail than that. Does it help the male survive? No. It does, however, help him spread more genes around because males with the best plumage have the best mating opportunities.

Because of medicine, with the exception of some disease resistance, I don't know that we are going to be selecting for physical traits as much as we are for mental traits. But it's hard to predict future evolution because nature is far more clever than we are and she knows what she likes.

Cheers
Aj

[dreadgeek]

Originally Posted by IslandScout

Interesting.

We have some advantages they didn't have and they have some advantages we didn't have. We have better technology and so more of us could likely survive a harsher ice age than our paleolithic ancestors did.

Only those with access to that technology would survive. And they are outnumbered by a majority growing both proportionately and in quantity.

Wanted to say one other thing about this. I wasn't really talking about *high* technology. I'm talking about technologies that are more recent than the HGF toolkit but are on the other side of the iPhone/computers/exotic materials science/etc. technologies. I'm talking about simple things like steel tools (something we've been making for 4000 years), bronze (which we've been doing the best part of 6000), writing, literacy, agriculture (which is a technology whether we realize it or not), printing, gunpowder, steam power, long-distance sailing technology, scientific method, etc. All of those predate the 20th century by a very comfortable, multi-thousand year margin and *none* of them were available to humans 50000 years ago. So the fact that we could work steel and bronze, preserve what we learn through writing things down, and the rest of the suite of tools humans had *fully* up and running before anyone even thought about the Industrial Revolution, would mean that we were far ahead of our long-forgotten ancestors.

We tend to underestimate the power of literacy, writing and scientific method, in particular, because they are so ubiquitous and they work so well that they've just become part of the infrastructure of life. Yet these are all very powerful technologies. We wouldn't have to, just to take three examples, reinvent agriculture, steel or bronze working because we've written down how to do those things. It means we can preserve knowledge across generations in a very durable form. Those are the kinds of technologies I was speaking of and should have been more specific about them.

Cheers
Aj

[dreadgeek]

So I'm curious, particularly to those who may not believe that climate change is happening, what would it take to convince you? Is there some observation or piece of evidence that you would find compelling? If so, what would that piece of evidence look like?

Cheers
Aj

[Sachita]

Originally Posted by dreadgeek

So I'm curious, particularly to those who may not believe that climate change is happening, what would it take to convince you? Is there some observation or piece of evidence that you would find compelling? If so, what would that piece of evidence look like?

Cheers
Aj

I'm kinda like Toughy on this one. I hear so much crap and could drive myself fucking nuts with it all. I know what I see and even with that I just can't get too wrapped up in it. its not that I don't care, I do and I am as proactive as they come.

I think that almost any of theories could happen. I believe that earth changes are part of evolution and will happen regardless. I believe humans have accelerated the process. Then again some religious crazy group might find a way to end life as we know it.

I use to make myself crazy with it all trying to prepare for the worse case. Now I am reasonable prepared, have food storage, solar panels, seeds, guns, ammo and the ability to survive without electric, money or supermarkets. But if some idiot nukes us I probably won't survive radiation or the countless other things that could happen.

Today I live in the now as much as possible. I just don't get wrapped up in it.