Climate Change / Global Warming

[Soralin]

Edit: oh right, I was going to say something about the carbon tax too. The argument that the carbon pricing system will affect our competitiveness might hold water if we weren't giving extremely generous subsidies to trade-exposed industries. And households, who aren't even paying for CO2 emissions. IMO, too much of the money is going back to the polluters, disincentivising any real investment in lowering their emissions, but I understand that there's a need for political compromise to get anything done.

I am under the impression that even without subsidies, coal will still be a much cheaper option then alternatives. Until we can find an energy source cheaper then coal, implementing a carbon tax is going to hurt standards of living/jobs.

Mmm, not really, or at least it depends on what you want your coal power plants to do. http://en.wikipedia.org/wiki/Cost_of_el ... _by_source It varies based on locations and estimates, but from the first one, from the US DoE, for new power plants starting in 2016, Advanced Nuclear would cost about $113.9/MW*h, putting it about 4% more expensive than Advanced Coal, at $109.4/MW*h. On the other hand it's about 20% more expensive than Conventional Coal, which is about $94.8/MW*h (not sure what the difference between conventional and advanced is, I'm guessing conventional is a lot dirtier). But on the other hand, if you want to do Carbon Sequestration, Advanced Coal with CCS is $136.2/MW*h, nearly 20% more expensive than Advanced Nuclear. Edit: Ah, didn't notice before, these numbers include what would be a 3% increase in capital costs for carbon costs. So, without that, Advanced Nuclear would be about 6% more than Advanced Coal, without sequestration.

I'm sure that these could vary over time as well, with increased coal costs, or mass production of nuclear plants, or so on. Also, nuclear is listed there as having an even better capacity factor than coal does. And note, that while there isn't a carbon tax yet, there is a nuclear tax, levied on all nuclear fuel, that goes to pay for dealing with the waste produced.

In short: gradually replacing all coal power is not necessarily a nightmare scenario in the long run. But they last for decades and decades, and replacing them before their time adds to the bill in the short run.

And yeah, this. Which is why it's important to switch over to replacing out power generation from coal to nuclear or other sources now, rather than later. Since if we can make the replacements gradually, over time as coal plants are decommissioned, and as new power plants need to be made to keep up with demand, it'll be only a small cost, since those new power plants needed to be built anyway. Which will certainly be much cheaper than trying to replace a whole bunch of stuff, all at once.

[Iceman]

- Global average temperature has risen over the last the century, and is still rising. This is a trickier claim than it looks. "Global average temperature" is not a directly measurable thing, it's a constructed aggregate with lots of potential pitfalls. And "rising" too is only a trend in a far more complicated time series. But over the last 20 to 30 years, we have learned enough to make this claim with high certainty anyway.

Global temperatures have risen. At any given time, they'll either be rising or falling. Again, a very big part of my objection...is we have no way of knowing if the current rise is unusual or not...and quite to the contrary, we've seen similar rises and drops just in the past 2000 years...suggesting that the current one is NOT unusual.

- Greenhouse gases exist, and are present in our atmosphere. That is, there are gases that are observed to cause heat trapping under laboratory conditions.

And they've always been present. Sometimes at higher levels, sometimes at lower ones. We do not know how the actual global ecosystem responds to rising levels...we do know there do exist mechanisms that are capable of reducing it.

- The presence of these gases has indeed a significant impact on the temperatures on the surface of the planet. This is a harder claim than the previous, since there is no direct counterfactual to compare it with in a laboratory. But any attempt to model temepratures on earth, from simple and rough to complicated, leads to far too low temperatures if they do not take greenhouse effects into account. And we have other planets and moons to verify such modelling attempts with. But simple models are not accurate enough to say something about the effects of changes in the greenhouse gas levels.

This again suffers from the similar issues. The Earth 'Reacts' to higher gas levels because of water and Life, in ways that Venus cannot. We cannot do a lab test that simulates or predicts the earth's capacity to react to higher levels. But we know historically it DOES react and absorb.

- Concentrations of several greenhouse gases are rising, in particular CO2. We can accurately measure their concentration in several ways, such as direct air samples or by observations of the optic properties of a column of the the atmosphere. This is a complicated technical issue, but pretty uncontroversial in its execution.

We're definitely putting CO2 up there, A lot of scientists point out that the current levels should be a lot higher, given how much we're putting up there...something must be starting to react and absorb it.

- The increase in greenhouse gases is caused by human activities. That's what our (imperfect) understanding of their spread and accumulation predicts, but it is also verified by isotopic measurements. The ratio of carbon-12 to carbon-13 in the atmosphere changes the way you would expect, if carbon levels are increasing as the result of fossil fuel burning.

And again, despite that, something's happening...automatic compensation seems to be occurring.

- The observed increases in concentration, combined with the laboratory properties, are more than enough to explain the observed temperature rise in a naive simple model without much feedback mechanisms. This is called "forcing" and is the input for more realistic models.

In a static world with no feedback or realism, CO2 rising would increase temperatures...not as much as they say however, since there are points in the past with higher Greenhouse gas levels but colder temperatures. There are other mitigating variables we are unaware of and cannot mimic.

The capstone of the evidence, which is perhaps more controversial, would be our detailed understaning and modelling of the relevant feedback mechanisms. The big weaknesses here are mostly forward-looking, in predicting which mechanisms will be relavant in the future, beyond the observed and studied range of parameters. But I'd say it is indeed reasonable to have doubts about the accuracy of our current understanding, even backwards-looking to already observed phenomena. This understanding is not as 'hard' as all the stuff above, even if it is the best we have. It is about combining imperfectly understood phenomena in complicated relations, which does have lots of room for error.

This is very much the area where the dispute truly does occur. Most scientific objection lies right here...in the 'your model does not have predictive ability' or 'your model is basically wrong' area. We don't know what the Earth's reaction is to this stuff. We're just assuming the worst case scenario.

Still, that doesn't somehow make all the other stuff "just assuming". If you want to doubt the causal link between human activity to the observed tmeperature increases, you have to assume both that
A. Our detailed understanding of feedback mechanisms is completely wrong, in such a way that the (observed!) increased forcing from greenhouse effects is nearly fully counteracted by those feedback mechanisms,
and B. There are also other, as yet unobserved and unknown mechanisms that do produce the observed temperature increase, but that escape from those feedback mechanisms that negate the effects from greenhouse gases.

A is definitely the case, we do not in anyway understand the chain of causality in the ecosystem in any way.
B is certainly true to a part...there are definitely other mechanisms we have no clue about (or in many cases that we DO know about, but are left out of models because it's less 'scary' if you include them)

I'd say that either A or B separately would be a plausible doubt. But both at the same time is asking a lot. At the very least, people would have to describe the alternative mechanisms, and show their active presence at the same level of detail that the greenhouse gas mechanism has been observed. And yes, people have studied sunspots.

Again, you want to compare a static thing to a system we know absorbs that thing...but without giving it time to do so. That's the big recency biased and irrational problem here...people have this mentality that these changes are immediate, perceptible and irreversible. There's simply no foundation for that in anything truly scientific.
There's some science stuff that others disagree with that say that like, in 100,000 years this could be an issue.

There is no immediacy here...there is no danger, there is no problem.

Natural economic forces are going to lead to us reduces CO2 emissions...literally thousands of years prior to it hitting any point where it'd be a problem for temperature.

There is no big deadline we have to stop doing something by. There is a complete and utter scare tactic.

The reality is we don't know if this is occurring...it's probably NOT occurring at all...and even if it was, we've got tons of time to 'fix it' even though its not even frigging harmful in the first place because we just arbitrarily picked a temperature and decided we like it.

There is a great deal of doubt as to what will happen next - but let's be clear about what we mean by that: the low end, most optimistic forecast is a 2C rise; Scientists agree that level of rise is now unavoidable due to past missed targets. The high end, pessimistic forecast is 8C+. 2 degrees is already enough to be mighty expensive economically, globally.

This as an example like I tend to mean...people seriously believe this sort of nonsense, and they'll tell you it's gonna happen in like '30 years man!' The Earth's temperature hasn't changed by 8 degrees in the past 30 Million years, let alone the next 30. People are being told this nonsense to SCARE THEM.
There's being told water levels could 'Rise 200 feet!' ...do a quick volume calculation on the Earth and you'll see how they got that number...they took 100% of the ice on Earth, ignored displacement (because much is already underwater), then added that volume to the current sphere of Earth and the radius rose 200 feet. Nevermind that temperatures would have to increase about 30 degrees for that to occur.
That's the type of propaganda you're dealing with from the 'Green' side.

If someone told the truth...'this might begin to be an issue in 800 to 1400 years, lets keep an eye on it' no one would care.

[gmalivuk]

If someone told the truth...'this might begin to be an issue in 800 to 1400 years, lets keep an eye on it' no one would care.

That's also not the truth. This is a thing that is happening now.

[Iceman]

If someone told the truth...'this might begin to be an issue in 800 to 1400 years, lets keep an eye on it' no one would care.

That's also not the truth. This is a thing that is happening now.

Ya...no it isn't....

[Charlie!]

If someone told the truth...'this might begin to be an issue in 800 to 1400 years, lets keep an eye on it' no one would care.

That's also not the truth. This is a thing that is happening now.

Ya...no it isn't....

Would you say the same thing if a doctor, and then maybe a whole hospital full of doctors, told you you had lupus? What expertise do you have in the field, to just make flat assertions?

[Iceman]

I'd say it if they saw me using a cell phone, then yelled out "Gee Willikers YOU HAVE CANCER NOW!" and threw my Blackberry out the window.

It's a common sense thing, you can always find some scientist willing to over-react to something, especially when it is very popular to do so.

Remember when bird flu and swine flu killed you and everyone you love?....neither do I...but I do remember a scientist on CNN telling me it was about to.

Besides...It's never Lupus.

[elasto]

I'm genuinely puzzled as to why you are so confident that the vast majority of scientists are wrong. Where is your evidence that these tens of thousands of researchers are mistaken? Remember that in science the fame and the glory is always in overturning the status quo, so there is always huge incentive for each new batch of climate scientists to come up with an alternate theory or a previously unknown feedback mechanism. No one has succeeded, and that should give you pause for thought.

None the less, you aren't posting any actual evidence, just repeating 'but how can we possibly know it's all too complicated!' and, at this point, it's either blind faith or trolling, and neither can be seriously debated with. This is 'serious business' after all.

[Vash]

I'd say it if they saw me using a cell phone, then yelled out "Gee Willikers YOU HAVE CANCER NOW!" and threw my Blackberry out the window.

It's a common sense thing, you can always find some scientist willing to over-react to something, especially when it is very popular to do so.

Remember when bird flu and swine flu killed you and everyone you love?....neither do I...but I do remember a scientist on CNN telling me it was about to.

Besides...It's never Lupus.

I forget the precise statistic, but the survey of research data actually says that 67% of climatology studies on global warming support it. 33% mention limitations of the research methods. There is no legitimate opposition, and I have not heard of any legitimate researcher claiming that the claims were overinflated much (we're talking maybe 100 years for catastrophic temperature increase instead of 50 years. You can assume those figures are imprecise. I haven't read up on this in 2 years). If you don't lean toward thinking the research supports man-made global-warming, you are a victim of propaganda.

[elasto]

Btw, I can't let this post pass without commenting on it:

It's a common sense thing, you can always find some scientist willing to over-react to something, especially when it is very popular to do so.

Remember when bird flu and swine flu killed you and everyone you love?....neither do I...but I do remember a scientist on CNN telling me it was about to.

I seriously hope that the extent of your research on these topics is more than just soundbites on network news.

No serious scientist would ever say "bird flu and swine flu are going to kill you and everyone you love". The probability that an animal flu virus will first infect a human and then develop the ability to transmit from person to person is very low, but if it does so, the probability that it will then spread across the entire world is very high. Then, this new flu may have low mortality or high mortality, it's impossible to know for sure.

To attempt to mitigate against extremely low probability, extremely high damage events is wise even if the event does not come to pass. Blame the media for hyping up the risk if you wish, but don't criticise the science (which is invariably very precise in terms of risks and outcomes) or governments (who have a duty to put in measures to mitigate potential disasters - whether that's demanding buildings be earthquake-proofed in earthquake zones (even if no earthquake then occurs for 100 years) or buildings have fire exits (even if no building then catches on fire) or build up vaccination banks (even if no virus manages to develop the ability to transmit person to person)).

Climate change is slightly different, though, in that we can already see the effects of it in terms of ice caps melting and seas becoming more acidic etc. And, yes, the earth itself will almost certainly survive just fine, as will life. Ok, so a lot of species might die off but in a few million years there might be more species then than now. It's only humans who will find it all terribly expensive and inconvenient. Climate change is ultimately an economic argument, not a green one: Prevention not being at all cheap, but still a lot cheaper than cure.

[gmalivuk]

If someone told the truth...'this might begin to be an issue in 800 to 1400 years, lets keep an eye on it' no one would care.

That's also not the truth. This is a thing that is happening now.

Ya...no it isn't....

Wait, so now you're going so far as to deny the world is warming up at all?

[Iceman]

If someone told the truth...'this might begin to be an issue in 800 to 1400 years, lets keep an eye on it' no one would care.

That's also not the truth. This is a thing that is happening now.

Ya...no it isn't....

Wait, so now you're going so far as to deny the world is warming up at all?

It is...At any given time, it will be either warming..or cooling. Certainly couldn't find any evidence of it ever being stable for any period of time. No cause for alarm.

[Vash]

It is...At any given time, it will be either warming..or cooling. Certainly couldn't find any evidence of it ever being stable for any period of time. No cause for alarm.

Yeah, it's more about the extremity, and the cause. Edit: Why don't you cite some of the studies stating the limitations? We might learn something interesting about the data then. I don't think this propaganda is very useful.

[Iceman]

Exactly...which is both undetermined and not that extreme.

[Vash]

Exactly...which is both undetermined and not that extreme.

My edit came too late. Anyway, I'm not going to discuss this with you (especially not in a Serious Business) thread if you have nothing meaningful to say. Cite or leave. Why stick to this fallacious tangent?

[Zamfir]

Iceman, can you give an impression of the level of evidence you would like to see to be convinced that human activities are (or are not) causing changes to the climate? Clearly the current level of evidence doesn't convince you. But your comments here almost sound as if no level of evidence would have convinced you anyway.

You can always say, "it's too complicated, there could be a myriad of mechanisms we do not know yet". What would scientists have to do to convince you that their understanding of the relevant mechanisms is enough to draw conclusions like "human activity is (or is not) the main cause of rising temperatures"?

[elasto]

Exactly...which is both undetermined and not that extreme.

I'm still not getting why you believe it's not going to be very extreme. Can you give any reason beyond blind hope and a general distrust for science and scientists for that? Cos I can quote thousands of papers that say the chance of it being extreme is worryingly high.

Honestly, you're coming across like someone staying put in a city when the government has ordered an evacuation due to a hurricane being on the way, on the grounds that 'Pah. Weather forecasters are always predicting rain and then it's sunny and vice-versa. They can't know the hurricane wont veer off left or right or just burn itself out.' Technically you're right, it's just a hell of a risk you're taking, and others can quite justifiably view that decision as pretty foolish.

Part of the problem is that we only get one shot at this: By the time we find out whether you or the thousands of scientists are right it will be too late to do anything but geoengineering, which is potentially far more risky than simply shifting to a lower carbon economy.

The other issue is of which is worse: If the scientists are wrong, well, we've wasted a fraction of a percent of GDP in investing in clean energies that none-the-less carry their own benefits, such as being renewable and providing local jobs. If you are wrong it will cost way more than a fraction of a percent of GDP dealing with all the extra hurricanes, floodings, famines, wars and all the rest of it.

It's like the weigh-up governments make in deciding to order flu vaccinations: If the flu never mutates to transmit person to person or mutates into something totally harmless, well, the government has wasted a few million on vaccinations that never get used. If it does mutate to something highly dangerous, though, then tens or hundreds of thousands of extra lives could be lost if the government fails to stockpile (avian flu in its current form kills half the people it infects, for example, it just hasn't yet managed to mutate to spread person to person). It's an economic no-brainer, really, which is why all Western governments follow the best scientific advice on such matters. And, more often than not, the stockpiles do end up getting used - even with the recent high-profile animal flu pandemics failing to materialise.

[Charlie!]

It's a common sense thing

Common sense doesn't apply well to complex systems. If you're not familiar with cars, it's not just "common sense" if your spark plugs need to have their gaps adjusted - it's a specialized piece of knowledge, and you seem to be unfamiliar with climate science.

As for it just being "some" climate scientists, if by "some" you mean "over 90%," then sure. And yes, I agree, the news is a terrible filter - they even let global warming deniers on there

[Iceman]

Iceman, can you give an impression of the level of evidence you would like to see to be convinced that human activities are (or are not) causing changes to the climate? Clearly the current level of evidence doesn't convince you. But your comments here almost sound as if no level of evidence would have convinced you anyway.

You can always say, "it's too complicated, there could be a myriad of mechanisms we do not know yet". What would scientists have to do to convince you that their understanding of the relevant mechanisms is enough to draw conclusions like "human activity is (or is not) the main cause of rising temperatures"?

I would like to see a predictive model that is capable of estimating the Rate of Greenhouse gas emission AND Absorption, that includes some of these other factors external to the gas as well.

If we could see 100 year increments, over a reasonable period of time...say 100,000 most recent years, and this was the First time we ever saw a 0.8 degree change in 100 years, That'd be at least something, 1000 sample periods. But just in the past 2000 years, it seems like we've had 0.4, 0.6, 0.7 degree changes occur up and down, So it leads me to believe that the change we see as 'alarming' may be reasonably common.

Honestly, you're coming across like someone staying put in a city when the government has ordered an evacuation due to a hurricane being on the way, on the grounds that 'Pah. Weather forecasters are always predicting rain and then it's sunny and vice-versa. They can't know the hurricane wont veer off left or right or just burn itself out.' Technically you're right, it's just a hell of a risk you're taking, and others can quite justifiably view that decision as pretty foolish.

I like this example actually, because it applies very well to Halifax, where I used to live.

Because it's on the coastline, it is very much in the line that hurricanes eventually travel. Several times a year, there will be a Hurricane warning and you'll see on a the news a lot of Hurricanes around Florida making their way up.
Every single time, we'll be told there is a high liklihood that the hurricane will make it north and hit the coastline by us. It actually did it once in the 25 years I lived there, and a couple decent Tropical Storms.
When they said it, you had to keep a little eye on the Radar pics and what they were saying, and you could usually tell how much they were over-reacting by and if you needed to do anything.
The time it did actually hit, Hurricane Juan...it was pretty obvious it was really going to happen this time, so you took the precautions.

So basically, ya, if people panic about things All the time, for no good reason...but each time a team of experts is totally on board with panicking. You do tend to tune that out over time, or at least look into it for yourself. You can also go look into what some real scientists say, as opposed to the government or TV scientists.
People have a tendency to over-react...they actually enjoy over-reacting.
They over-react to environmental stuff, technology threats, cancer scares, diseases, weather, space phenomenon etc... they just like it. And every time it happens, tons of scientists and experts are right on board.
It doesn't really concern me at all if '90%' of scientists believe it...because at any given point, on the cutting edge of research 90% of people are probably total wrong. I also find a tendency for the pro-Global warming people to be climatologists, biologists, Earth Science people...and the bulk of the dissenters are Physicists, Astronomers and Mathematicians.

There's also very clearly a social punishment to denying the existence of this very trendy and popular thing.

It's the type of thing you're only denying for the sake of truth...it doesn't really Matter, because it really shouldn't change our course of action at all. All the things we plan to do should probably still be done...just for different reasons.
We should still move away from Fossil Fuels, we should still pollute less, or waste less stuff...because those are independently good ideas by themselves. I don't need a Boogey Man to enforce them...those ideas make economic and logical sense on their own.

When you add the Boogey man, you start to add illogical ideas though...like Ethanol, or Subsidized Mass Wind Farming etc... which can be harmful. Or you get weird things done in the name of the environment which directly harm lower class citizens, like Cash for Clunkers or something.

I think you should always stay rational, and always know why you're doing something. I don't believe in irrational fear as a motivator, regardless of who is using it for what purpose, even if they're using it for something ultimately good.
So when you combine the fear with the need to just shout down anyone who disagrees, you can create some problems.

And yes, I agree, the news is a terrible filter - they even let global warming deniers on there

Things like this, while just a little joke, are very true. 'Global Warming Deniers' are something that people simply want silenced, not something they want to consider at all. And the term 'denier' is intentionally used to draw comparison to the other type of 'denier' that no one likes.

[Charlie!]

And yes, I agree, the news is a terrible filter - they even let global warming deniers on there

Things like this, while just a little joke, are very true. 'Global Warming Deniers' are something that people simply want silenced, not something they want to consider at all. And the term 'denier' is intentionally used to draw comparison to the other type of 'denier' that no one likes.

I have considered it. Every climate scientist has already considered it. Although they have a right to say what they want, they shouldn't get free airtime from organizations that are supposed to filter this junk out along with the quack medicine salesmen and the "swine flu will kill us all!" lady.

Claiming that the other side wants you "silenced," when that other side contains the vast majority of the experts, is very strongly correlated with being wrong. Flat earthers. 9/11 truthers. Creationists. You've fallen into a trap that lots of people fall into, and you should start digging yourself out sometime. I'm not expecting you to do it right now, but within a few years would be good.

[Vash]

I would like to see a predictive model that is capable of estimating the Rate of Greenhouse gas emission AND Absorption, that includes some of these other factors external to the gas as well.

If we could see 100 year increments, over a reasonable period of time...say 100,000 most recent years, and this was the First time we ever saw a 0.8 degree change in 100 years, That'd be at least something, 1000 sample periods. But just in the past 2000 years, it seems like we've had 0.4, 0.6, 0.7 degree changes occur up and down, So it leads me to believe that the change we see as 'alarming' may be reasonably common.

I'll have to read more, but I was under the impression that that was already the case, and that this was a greater divergence than normal (as far as I can tell from the many charts I have seen).

I like this example actually, ... it was really going to happen this time, so you took the precautions.

The Weather Channel has plenty of reason to play up hurricanes. It's not at all analogous to climate scientists.

So basically, ya, if people panic about things All the time, for no good reason...but each time a team of experts is totally on board with panicking. You do tend to tune that out over time, or at least look into it for yourself. You can also go look into what some real scientists say, as opposed to the government or TV scientists.

Oh? And where do your sources come from?

People have a tendency to over-react...they actually enjoy over-reacting.
They over-react to environmental stuff, technology threats, cancer scares, diseases, weather, space phenomenon etc... they just like it. And every time it happens, tons of scientists and experts are right on board.

Yes, we know this. When the best models that exist (much better than guessing, even if you are massively dubious of them) predict catastrophe, it's a good reason to worry, though. You can use your argument against everything. You could say that nuclear weapons aren't dangerous because no one will ever launch them.

It doesn't really concern me at all if '90%' of scientists believe it...because at any given point, on the cutting edge of research 90% of people are probably total wrong. I also find a tendency for the pro-Global warming people to be climatologists, biologists, Earth Science people...and the bulk of the dissenters are Physicists, Astronomers and Mathematicians.

The statistic of climate scientists who believe it is 97% (again, imprecise because of memory). More telling is that all of the actual research supports it. There are limitations to the research, but that doesn't mean that what research there is has no value. There is no citation for biologists believing in global warming more than physicists, and it would make sense that scientists uninformed on the research could raise doubts. In fact, it would make sense for uninformed physicists to have more doubt than uninformed biologists, because physicists have a greater ability to think of contradictions to climate theories.

Of course, what would be most telling is an actual look at the research. From what I have seen, there is modeling based on all sorts of data. The link between CO2 is not solely based on long-term geological records (ice cores, etc.). There is Bayesian analysis of volcanic eruptions, for example.

There's also very clearly a social punishment to denying the existence of this very trendy and popular thing.

Yes, and I am not heaping on you that social punishment. I am pointing out that what you say has little basis.

We should still move away from Fossil Fuels, we should still pollute less, or waste less stuff...because those are independently good ideas by themselves. I don't need a Boogey Man to enforce them...those ideas make economic and logical sense on their own.

That is the central issue.

When you add the Boogey man, you start to add illogical ideas though...like Ethanol, or Subsidized Mass Wind Farming etc... which can be harmful. Or you get weird things done in the name of the environment which directly harm lower class citizens, like Cash for Clunkers or something.

I think those were dumb ideas that had nothing to do with global warming.

I think you should always stay rational, and always know why you're doing something. I don't believe in irrational fear as a motivator, regardless of who is using it for what purpose, even if they're using it for something ultimately good.

Yes, and it's less about fear, and more about trusting the experts over the guesses of anti-environmentalist political groups. Had this not been a political issue, there would have been no skepticism.

So when you combine the fear with the need to just shout down anyone who disagrees, you can create some problems.

This is itself a tactic to try to reduce disagreement. Disagreement is not shouting out.

[Iceman]

The Weather Channel has plenty of reason to play up hurricanes. It's not at all analogous to climate scientists.

You don't see the benefits of this to those scientists?

Oh? And where do your sources come from?

There's a nice list of a lot of the leading dissenters,

http://en.wikipedia.org/wiki/List_of_scientists_opposing_the_mainstream_scientific_assessment_of_global_warming

There really just is no evidence of this, its all anecdotal and guesswork, and a lot of real scientists have called it out as such. It's rather be with the smarter minority than a group-think majority on this one.

There is extreme benefit for pretending this crap is real, and no benefit to denying it.

People fully and openly admit their models are terrible and incomplete.

Can you honestly listen to a scientist say "It's going to rise 6 degrees in 50 years" and not laugh in their face for the level of ridiculous that is? The level of hyperbole involved in this is just insane. And there are So many scientists who are in the 'Global Warming exists' column who are like 'well...yeah...and in 10,000 years this may be a problem'
but You hear from the '20 Years your dog will literally burn to death in the park!' people, 'cause its more sensational.

I would like to see a predictive model that is capable of estimating the Rate of Greenhouse gas emission AND Absorption, that includes some of these other factors external to the gas as well.

If we could see 100 year increments, over a reasonable period of time...say 100,000 most recent years, and this was the First time we ever saw a 0.8 degree change in 100 years, That'd be at least something, 1000 sample periods. But just in the past 2000 years, it seems like we've had 0.4, 0.6, 0.7 degree changes occur up and down, So it leads me to believe that the change we see as 'alarming' may be reasonably common.

I'll have to read more, but I was under the impression that that was already the case, and that this was a greater divergence than normal (as far as I can tell from the many charts I have seen).

I think this is a large chunk of the problem here....people do think this is the case, but it isn't. They can't tell what temperatures were on a century by century basis, because that's really hard to find out. So we're essentially comparing a single data point against no other data points.

We know the past variance in Earth's temperature is over 24 times the one we've seen in the past century...but we just have no way to know how quickly these changes normally occur. There's no frame of reference to say 0.8 degrees in 100 years is fast, slow, or perfectly normal.

We know it Dropped further than that in 200 years prior to 1600...If it could drop more than 0.8 degrees with no interference from us, why would it be unusual if it rose it too?

Also, look at our method of measuring really old temperatures...we literally use the gases we find to determine what the temperature must have been. We can't actually detect the temperatures.

In more recent history, where we use Geological, Astronomical, Biological and Dendrochronological analysis to try and figure out the past few thousand years, we see big differences in predicted temperatures.

http://en.wikipedia.org/wiki/File:1000_Year_Temperature_Comparison.png

If you look at the different lines and methods, you see a large disagreement between methods, but even within individual methods...you see big jumps and drops.

in fact, following the Moberg et al. study, (The Red Line) they concluded:

According to our reconstruction, high temperatures—similar to those observed in the twentieth century before 1990—occurred around ad 1000 to 1100, and minimum temperatures that are about 0.7 K below the average of 1961–90 occurred around ad 1600. This large natural variability in the past suggests an important role of natural multicentennial variability that is likely to continue.

Their main observation is that this stuff seems to jump around and varies a lot on a century by century basis.

Honestly, if this wasn't a political/feel-good topic, and someone presented this to you as a simple mathematical stats and causality issue...I doubt anyone here would believe it.

Everyone would point out that it's a misleading presentation of data, rife with recency bias, confirmation bias and that the data itself is constructed using methods that actually rely on its own conclusions being true.

The world took 10 dice, rolled then and came up with a total of 38...we said 'Oh that seems high' and we've set out to fix the dice.

[Vash]

The Weather Channel has plenty of reason to play up hurricanes. It's not at all analogous to climate scientists.

You don't see the benefits of this to those scientists?

Positive results mean more research money, but that's always true. There would be more dissenters. There is literally not one scientific paper in the field that calls these finds into question. There is also nothing politically to gain for these scientists.

There's a nice list of a lot of the leading dissenters,

http://en.wikipedia.org/wiki/List_of_scientists_opposing_the_mainstream_scientific_assessment_of_global_warming

Do you not get this? This is completely exasperating. Almost all of those scientists don't know the climate research. Most probably have not even read it. Does training in a field not mean anything to you?

There are some researchers in relevant fields, according to Wikipedia, which is citing the Heartland Institute (a political organization). I also remember reading that in at least one list of dissenting scientists the scientists had not consented to be on the list. In other cases they were misquoted. Citing Wikipedia on any controversial issue generally comes with a great deal of bias (having edited Wikipedia, I've had to deal with this exact problem). Unless you can find some peer-reviewed papers, I'm going to consider this a closed issue. You can debate with yourself, if you want.

There really just is no evidence of this, its all anecdotal and guesswork, and a lot of real scientists have called it out as such. It's rather be with the smarter minority than a group-think majority on this one.

Predictive models are all there are in this case. Of course it's not perfect, but one wouldn't assume that they are completely wrong, either.

By the way, I used to be on the skeptical side of this issue.

There is extreme benefit for pretending this crap is real, and no benefit to denying it.

Corporations not having to pay out the ass to meet environmental standards? Please. There is a two-sided political debate that we should both be ignoring. Only one of us seems to be.

Can you honestly listen to a scientist say "It's going to rise 6 degrees in 50 years" and not laugh in their face for the level of ridiculous that is? The level of hyperbole involved in this is just insane. And there are So many scientists who are in the 'Global Warming exists' column who are like 'well...yeah...and in 10,000 years this may be a problem'
but You hear from the '20 Years your dog will literally burn to death in the park!' people, 'cause its more sensational.

Now don't get extreme in reaction to the frustrations of your opponents. I've watched some of those shows, as well. How it is often said is closer to "It is possible that it might rise 6 degrees in 50 years. That is the worst case scenario." Some researchers, from what I have seen, take a more extreme bent and say that it will.

I think this is a large chunk of the problem here....people do think this is the case, but it isn't. They can't tell what temperatures were on a century by century basis, because that's really hard to find out. So we're essentially comparing a single data point against no other data points.

I'm not sure it is quite that impossible, but the temperatures are indeed more poorly measured far in the past.

We know it Dropped further than that in 200 years prior to 1600...If it could drop more than 0.8 degrees with no interference from us, why would it be unusual if it rose it too?

Where are the citations? I'm pretty sure this is not accurate.

In more recent history, where we use Geological, Astronomical, Biological and Dendrochronological analysis to try and figure out the past few thousand years, we see big differences in predicted temperatures.

I am pretty sure there were always large variations in temperatures. The thing about that is that these variations had a huge effect on living organisms, even if natural.

Their main observation is that this stuff seems to jump around and varies a lot on a century by century basis.

Even the Wikipedia chart doesn't include all of the various versions of the temperature data.

Honestly, if this wasn't a political/feel-good topic, and someone presented this to you as a simple mathematical stats and causality issue...I doubt anyone here would believe it.

That's the thing. I did a lot of reading a while ago (not on political websites), and I was convinced.

Everyone would point out that it's a misleading presentation of data, rife with recency bias, confirmation bias and that the data itself is constructed using methods that actually rely on its own conclusions being true.

That's certainly how it seems presented sometimes, but if you read the actual research I think you'll come back with a much more interesting idea of what it actually means. I am summarizing it poorly. You can give it a shot yourself, if you want. It's the only way to really know.

[adho]

Read all of these, then come back here.
The IPCC was formed by the WMO and the UNEP (parts of the UN). They concluded in 2007:

Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.

These natural variations in global climate are known to them. They have modelled them time and time again. The increases that we are seeing and are being projected lie well outside the natural curve. Don't try and tell them how to do their job, they are experts. You are not. There is no single major scientific body which denies anthropogenic climate change.

It's an issue, and it's an issue now. Get a degree in climate science, do years of research and then I might listen to your ramblings about temperature variability.

[Posthumane]

While I'm not going to deny that the climate may be changing for the warmer (in spite of my region having the longest and coldest winter and wettest spring in many decades this year), I have to agree with Iceman on the fact that it is probably not something to panic about. Temperature variations have occurred in the past and the earth has survived, as have people. The issue, as someone pointed out above, is simply an economic one rather than an ecological one.

Even if the worst case scenario occurs, what we end up with is a small redistribution of natural resources. Equatorial lands will become less habitable and arable, but polar lands more so. Some areas will become drier due to the increased temperatures, but other areas will get more rainfall due to increased evaporation. There will be some coastal cities which will become flooded, but since this will be happening over the course of decades (at the quickest) or centuries rather than weeks people will simply move slightly further inland or build up infrastructure to deal with it.

Yes, there will be many people who will not be able to cope with the changes and will suffer/die as a result. This is an economic effect though; people in poorer countries will suffer, just as they are now, while people in wealthier countries will cope with some inconvenience. There are plenty of people starving to death already in those countries and we're not doing anything about it, so let's not pretend that their welfare is the reason we should implement drastic changes.

That being said, I do agree that we should reduce our use of fossil fuel use and energy use in general. However, the problem with wild speculation and fear imposed by people who are adamant that we HAVE to do something NOW leads to poorly thought out schemes which either do not work or trade one problem for another. One example that always bothers me is when people condemn me for driving an old car because they think it's "not environmentally friendly" since new cars have tighter emission standards. Then they cite global warming, carbon, etc. What they don't take into account is that my car has lower fuel consumption (and therefore CO2 emissions) than most newer cars, and that producing new cars uses as much energy as the car itself over its lifetime. Some regions have mandated that people drive newer cars based on this logic.

[Trasvi]

While I'm not going to deny that the climate may be changing for the warmer (in spite of my region having the longest and coldest winter and wettest spring in many decades this year), I have to agree with Iceman on the fact that it is probably not something to panic about. Temperature variations have occurred in the past and the earth has survived, as have people. The issue, as someone pointed out above, is simply an economic one rather than an ecological one.

Even if the worst case scenario occurs, what we end up with is a small redistribution of natural resources. Equatorial lands will become less habitable and arable, but polar lands more so. Some areas will become drier due to the increased temperatures, but other areas will get more rainfall due to increased evaporation. There will be some coastal cities which will become flooded, but since this will be happening over the course of decades (at the quickest) or centuries rather than weeks people will simply move slightly further inland or build up infrastructure to deal with it.

I think you are seriously underestimating the effect that rising sea levels would have on the population of the world. You are correct that the earth has survived, but humans (at least, agricultural/industrial humans) have not. Taking a conservative average of google results, somewhere around 70% of the world's population live within 100 miles of the coast. I know if sea levels rose by 5 metres, most of my state (Western Australia) would be submerged. If (as scientists are suggesting) the rate of temperature increase is accelerating, then we almost definitely do not have centuries. Billions of people would need to be relocated to smaller areas on less productive land (both food and other resources - WA alone produces about 20% of the worlds alumina and iron ore) and hundreds of millions would die. Perhaps that is just nature and the Earth obviously doesn't care that a species settled down and built massive infrastructure in certain areas and multiplied far beyond the population of any other large species on the planet, but we certainly care and need to do something to preserve our lives.


My issue with the science I've seen (and I'll admit that I haven't read many papers) is that we are comparing an incredibly short time scale (10/100/1000 years) against incredibly long time scales (hundreds of millions of years). We actually don't know what was happening on a 10 year time scale 100,000,000 years ago so why are we saying 'temperature rises this quickly are unprecedented?'.
In the end though, I have to admit that indeed I am not a climate scientist nor a statistician and as such I am leaving the scientific conclusions up to those who are qualified. I just hope we don't look back in 100 years when we have more data and see ourselves as stupid.

[Posthumane]

I think you are seriously underestimating the effect that rising sea levels would have on the population of the world. You are correct that the earth has survived, but humans (at least, agricultural/industrial humans) have not. Taking a conservative average of google results, somewhere around 70% of the world's population live within 100 miles of the coast. I know if sea levels rose by 5 metres, most of my state (Western Australia) would be submerged. If (as scientists are suggesting) the rate of temperature increase is accelerating, then we almost definitely do not have centuries. Billions of people would need to be relocated to smaller areas on less productive land (both food and other resources - WA alone produces about 20% of the worlds alumina and iron ore) and hundreds of millions would die. Perhaps that is just nature and the Earth obviously doesn't care that a species settled down and built massive infrastructure in certain areas and multiplied far beyond the population of any other large species on the planet, but we certainly care and need to do something to preserve our lives.

Many people have been displaced over much shorter time scales than what is predicted for the worst case of climate change without dying out. The estimate of 70% living within 100 miles of the coast is misleading - the coast line would move less than a mile or two on average given your 5m rise. Even looking at an elevation map of Western Australia, which is much flatter than many other places, reveals a 100m contour line within a mile of the coastline. It's true that a lot of cities and towns are right on the coast, but the reason people settled there is simply because it is on the coast. When the coastline moves in a few hundred metres, people will move inland a few hundred metres as well. This will happen over the course of several generations, not a few months, so it will have a lot less impact than many of the "political" relocations of people that have happened over the last few centuries.

The amount of usable land would not decrease significantly. The world's bread bowl does not lie withing a couple miles of the ocean, so the land that people would be settling on would not be any less productive. The reason people settled near the coast is that these are the places that were the most accessible when they settled. They will continue to be as accessible when the coastal settlements move as well.

Even if your prediction that some hundreds of millions would die were true, that may be alarming from a political/humanities standpoint but from an ecological standpoint it is a drop in the bucket. Even if a billion people die, we will be back at 1990 population levels, which is hardly on the brink of extinction.

[Habz]

Anyone else read this paper Understanding the Thermodynamic Atmosphere Effect?

I'm not an expert in thermodynamics though, but I think he makes more than a few good points against the popular view of the climate change.

Thoughts?

[adho]

I'm not an expert in thermodynamics though, but I think he makes more than a few good points against the popular view of the climate change.

He doesn't. First off, he's an astronomer and astrophysicist. This is like taking advice about your lungs from an optometrist.
He puts huge generalisations onto a extremely complex system - the entire Earth. Even assuming his initial values are correct (no citations throughout), the logic is poor. He works out, sort of, what the suns output should kind of be, guesses the Earth's absorption and re-emission and comes to a value for the average temperature of the Earth and it's atmosphere. He then says that this value is the same (not close to, exactly the same) as the observed average temperature. Hence, no global warming.

The Venus comparison is silly. Many of the things he says greenhouse theory states, it does not state. I'm not going to bother deconstructing the entire thing but it would be good to realise that this is not a scientific article, it is an opinion piece.

Either the greenhouse effect is bunk, thermodynamics is bunk, or the writer of this article has entirely misapplied it.

Edit: Found the original "paper" here. More of the same. The Principia Scientific International organisation, from what I can gather, sounds like a made up name because it is. It's released two papers, both of which are directly opposed to the greenhouse effect and climate change. (The other is here.)

[Hawknc]

The greenhouse effect is based on thermodynamics. I'm using my phone so I can't deconstruct in too much detail, but most of his assumptions about what the greenhouse effect does are wrong. His fundamental argument seems to be that it violates the first law because the sun-earth system is at a steady state, and therefore the earth's average temperature must be the same. That's true if you consider the earth as an isotropic mass with no internal variation, but as he admits, it isn't. My (admittedly limited) understanding of the greenhouse effect is that greenhouse gases increase the overall absorptivity of the atmosphere, meaning that the average temperature increases. The system might be transient temporarily but would return to a steady state average over the long run, with the earth at a slightly higher average temperature.

...This is hard to explain without equations and graphs.

[SummerGlauFan]

I'm not an expert in thermodynamics though, but I think he makes more than a few good points against the popular view of the climate change.

He doesn't. First off, he's an astronomer and astrophysicist. This is like taking advice about your lungs from an optometrist.

I've never bought the argument that just because a person works in one field means they can't have something useful to contribute in another. I work in healthcare, but I know far more about dinosaurs than almost anyone. Would you discount my knowledge because I am not a paleontologist?

Much more telling than a persons background is their evidence/reasoning:

He puts huge generalisations onto a extremely complex system - the entire Earth. Even assuming his initial values are correct (no citations throughout), the logic is poor. He works out, sort of, what the suns output should kind of be, guesses the Earth's absorption and re-emission and comes to a value for the average temperature of the Earth and it's atmosphere. He then says that this value is the same (not close to, exactly the same) as the observed average temperature. Hence, no global warming.

This is why the person's paper is bad; terrible logic, little to no evidence to back up his arguments, and rampant guessing. I would bet he also makes a bad astrophysicist if this is any indication of the effort he puts into a project.

I only point this out because too often in history, someone who tries to turn against the status quo (with good reason) was dismissed out of hand merely for not being a paid professional in said field. Look at the validity of the argument, not at who wrote it (this also avoids putting prominent figures in a field up on a pedestal of infallibility).

[adho]

I get where you are coming from, it's just one of the things that bugs me about media and public presentation of the climate change debate. Any scientist, whether they are trained in that field, published and backed by an institute or not, is given equal weight to any other. It gives an illusion of a far greater difference of opinion than there actually is. I'm not about to write someone off because they're from a different field, but when they start trying to disprove a widely tested and widely accepted theory with no experimental backing...

Ok, it's an entirely different situation, but still.

[yurell]

I work in healthcare, but I know far more about dinosaurs than almost anyone. Would you discount my knowledge because I am not a paleontologist?

I know I would if it disagreed with the consensus in palaeontology, unless you had some damned convincing evidence that could be brought to palaeontologists to convince them — knowing nothing about dinosaurs beyond the fact that they're extinct, I simply don't know enough to have an opinion, or to accept the opinion of 'some random'* over that of the experts in the field.

*I mean that in general, it's not intended as a disparaging remark to you, Summer.

[SummerGlauFan]

I get where you are coming from, it's just one of the things that bugs me about media and public presentation of the climate change debate. Any scientist, whether they are trained in that field, published and backed by an institute or not, is given equal weight to any other. It gives an illusion of a far greater difference of opinion than there actually is. I'm not about to write someone off because they're from a different field, but when they start trying to disprove a widely tested and widely accepted theory with no experimental backing...

Yes, giving equal weight to anyone regardless of their data is bad. I agree with you there. I just want an argument to be measured on the merit of it's evidence and reason, not because of who presented it. I also think that we can agree that media coverage of any scientific topic is going to be inaccurate as heck.

Good comic btw.

I work in healthcare, but I know far more about dinosaurs than almost anyone. Would you discount my knowledge because I am not a paleontologist?

I know I would if it disagreed with the consensus in palaeontology, unless you had some damned convincing evidence that could be brought to palaeontologists to convince them — knowing nothing about dinosaurs beyond the fact that they're extinct, I simply don't know enough to have an opinion, or to accept the opinion of 'some random'* over that of the experts in the field.

*I mean that in general, it's not intended as a disparaging remark to you, Summer.

You would be right to ask for my data, you would be wrong to require an extra burden of proof just because I don't get paid for the hobby*. As a sidenote, paleontology is a great example of my ideal, because even other paleontologists have an incredibly hard time presenting new theories to their colleagues**.

*Also not a personal attack, it's just for the sake of this hypothetical.

**This may be the same in other scientific circles, I just know a lot more about paleontologists than I do about, say, the physics community.

EDIT: As a disclaimer, I do believe that humans are causing environmental changes, because of the data. This is just one of those things where, I believe, people tend to take a rather dogmatic view. I just like to maintain an objective viewpoint in discussions, I think it is important.

[yurell]

You would be right to ask for my data, you would be wrong to require an extra burden of proof just because I don't get paid for the hobby*. As a sidenote, paleontology is a great example of my ideal, because even other paleontologists have an incredibly hard time presenting new theories to their colleagues**.

Oh, I wouldn't expect extra burden of proof ^.^ I just presumed that anything that is commonly accepted would have lots of papers behind it (I'm not a palaeontologist so I've no idea what their papers are like) and so the burden of someone claiming something contrary would be to explain why they're right and the sum of peer-reviewed literature is wrong (or misinterpreted). In the case where there are no papers published ... well, I've never had to handle that ^o^

[Azrael001]

I'm just going to leave this here.

[BattleMoose]

I would like to see a predictive model that is capable of estimating the Rate of Greenhouse gas emission AND Absorption, that includes some of these other factors external to the gas as well.

If we could see 100 year increments, over a reasonable period of time...say 100,000 most recent years, and this was the First time we ever saw a 0.8 degree change in 100 years, That'd be at least something, 1000 sample periods. But just in the past 2000 years, it seems like we've had 0.4, 0.6, 0.7 degree changes occur up and down, So it leads me to believe that the change we see as 'alarming' may be reasonably common.

I think this is a large chunk of the problem here....people do think this is the case, but it isn't. They can't tell what temperatures were on a century by century basis, because that's really hard to find out. So we're essentially comparing a single data point against no other data points.

We know the past variance in Earth's temperature is over 24 times the one we've seen in the past century...but we just have no way to know how quickly these changes normally occur. There's no frame of reference to say 0.8 degrees in 100 years is fast, slow, or perfectly normal.

We know it Dropped further than that in 200 years prior to 1600...If it could drop more than 0.8 degrees with no interference from us, why would it be unusual if it rose it too?

Also, look at our method of measuring really old temperatures...we literally use the gases we find to determine what the temperature must have been. We can't actually detect the temperatures.

In more recent history, where we use Geological, Astronomical, Biological and Dendrochronological analysis to try and figure out the past few thousand years, we see big differences in predicted temperatures.

http://en.wikipedia.org/wiki/File:1000_Year_Temperature_Comparison.png

If you look at the different lines and methods, you see a large disagreement between methods, but even within individual methods...you see big jumps and drops.

You have said a lot that should be responded to, but, I don't quite have the time so just picked these bits out.

Measuring the temperature of the planet is an incredibly arduous task and our ability to do so is improving. As a consequence of this, especially in going back many thousands and even hundreds of thousands of years, we use every possible method we can devise in order to gain a better understanding of the over temperature and most importantly, the trends in the temperature.

Also, look at our method of measuring really old temperatures...we literally use the gases we find to determine what the temperature must have been. We can't actually detect the temperatures.

This comment I found particularly odd. Why is it inappropriate to analyze isotope ratios of the gases within the bubbles to then infer the temperature? Is this method inaccurate? Do you know its inaccurate? Can you prove its inaccurate? Does this method have a sound theory on why it should work? These are not questions you ask but you seem to flippantly disregard this methodology because to you it sounds, ridiculous? There is also the slight awkwardness that the inferred temperatures correlate very strongly to CO2 concentrations, which we would expect, because we have a very sound theory on why we expect CO2 concentrations to effect global temperatures. Everything matches up beautifully with our current theories, so yeah, we have an effective CO2 record and temperature proxy dating back for more than 400 000 years. That's some achievement.

In more recent history, where we use Geological, Astronomical, Biological and Dendrochronological analysis to try and figure out the past few thousand years, we see big differences in predicted temperatures.

http://en.wikipedia.org/wiki/File:1000_Year_Temperature_Comparison.png

I also found this very odd, different proxies will work differently, some better than others and in potentially different areas, and we can argue about how well they match to each other till the cows come home, however, since 1900 they all show a strong warming trend consistent with actual directly observed temperature records.

And quite bluntly, the best proxy for average global temperature is sea level, and here are two charts which show sea levels, take care to notice the timescales, because they are very different.

http://en.wikipedia.org/wiki/File:Post- ... _Level.png
http://en.wikipedia.org/wiki/File:Recen ... l_Rise.png

What we are experiencing is clearly an anomaly from the norm. Furthermore the Vostock ice core data shows that the temperature hasn't varied by more than 2 degrees over perhaps 10 000 years.

Again, this is timely associated with our greenhouse gas increases, which we expect to cause the changes which we are observing.

Moreover, we have what have been called, Dansgaard–Oeschger events, http://en.wikipedia.org/wiki/Dansgaard%E2%80%93Oeschger_event , which, to be blunt, are not well understood for a lack of data, but, these are events where the earth has rapidly changed temperature, as rapidly as 8 degrees over 40 years. Possibly indicating that there are some very powerful positive feedback loops.

Either which way, the Earth Climate system is not something we want to be messing with, and as a species we are, unapologetically and with reckless abandon.

Also, on the point of what is the right temperature, or the right CO2 level, the answer is, the levels that our species evolved under, perhaps more specifically, the levels under which civilization was allowed to flourish, so pretty much what the conditions have been for the past 10 000 years, any change from this, would be bad.

[Posthumane]

I'm confused. You say that the temperature hasn't varied by more than 2 degrees in the last 10k years, and then post a link to Dansgaard–Oeschger events which correspond with temperature variations of 8 degrees? Am I missing something, or is this a contradiction?

Also, on the point of what is the right temperature, or the right CO2 level, the answer is, the levels that our species evolved under, perhaps more specifically, the levels under which civilization was allowed to flourish, so pretty much what the conditions have been for the past 10 000 years, any change from this, would be bad.

But humans have flourished under a very wide range of temperatures. Even if we assume that the average global temperature hasn't varied all that much, regional variations in temperature are much greater than temporal variations. Humans have thrived equally well in mid-Northern areas as they have in equatorial areas, despite a 20+ degree difference in temperature. There are plenty of regions that are not settled on account of being too cold, but none that aren't settled because they are too hot.

Now, does that mean that the earth can sustain the current population level if there is a climate change? Maybe, but not necessarily. It's too soon to tell if the net effect of a change in climate would be negative, positive, or neutral for the species. However, you can't assume that current population levels are the "right" levels either. It's quite possible that the earth can't sustain the current population even in the absence of a change.

[gmalivuk]

I'm confused. You say that the temperature hasn't varied by more than 2 degrees in the last 10k years, and then post a link to Dansgaard–Oeschger events which correspond with temperature variations of 8 degrees? Am I missing something, or is this a contradiction?

Yes, you're missing the lack of any sort of claim that a D-O event has happened any time in those same 10k years.

But humans have flourished under a very wide range of temperatures.

Sure, but all this means is that humankind will survive.

Sorry, but some of us want more than that. For example, we want humanity to survive without millions of people dying in the meantime because of changing climates where they used to get their food.

[SummerGlauFan]

But humans have flourished under a very wide range of temperatures.

Sure, but all this means is that humankind will survive.

Sorry, but some of us want more than that. For example, we want humanity to survive without millions of people dying in the meantime because of changing climates where they used to get their food.

Or mass extinctions. Or wars that the mass human migrations would bring.

[Posthumane]

Yes, you're missing the lack of any sort of claim that a D-O event has happened any time in those same 10k years.

Fair enough.

Sorry, but some of us want more than that. For example, we want humanity to survive without millions of people dying in the meantime because of changing climates where they used to get their food.

This may seem like a cold hearted question, but for the sake of argument*... why? What is desirable about having an ever increasing population base? Millions of people die each day from a variety of causes, despite the fact that global mortality rate has been dropping over the last few decades, and upping that slightly would shift the birth-death balance closer to equilibrium.

The temporary culling of the human population can be considered a natural negative feedback mechanism. As the climate changes, people are forced to adapt to the changes. Some who cannot cope will die out and the remaining population will again thrive in their new environment. It should be noted that the ones who will die out are likely to be the same groups that are currently dying of starvation due to political and logistical reasons, even though there is plenty of food available world-wide.

*This is a devil's advocate argument. I'm all for reducing energy consumption and shifting away from things like coal power, but things have to be put into perspective. I.e. what amount of sacrifice/change/expenditure is reasonable with regards to the consequences of not doing it, compared to the amount of sacrifice/change/expenditure we are currently putting in to combat other sources of human death and suffering.