Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Facts, Myths, and Givens in Anthropogenic Climate Change (ACC) 36

Status
Not open for further replies.

zdas04

Mechanical
Jun 25, 2002
10,274
I have been repeatedly accused of refusing to accept the basic "facts" of Anthropogenic Cimate Change (ACC nee AGW, nee Global Warming, nee Global cooling). I think we really need to define terms.

In the following I'm going to rely heavily on The Shattered Greenhouse: How Simple Physics Demolishes the "Greenhouse Effect". I've linked the article in for anyone who wants to check my interpretation of the story. It has an extensive bibliography at the end for further reading.

Greenhouse Effect
The basic idea of a greenhouse gas comes from Arrhenius' in 1896 representing (some say misrepresenting) the work of Fourier from 1827
Arrhenius (1896 said:
"Fourier maintained that the atmosphere acts like the glass of a hothouse, because it lets through the light rays of the sun but retains the dark rays from the ground."
In other words, visible light can traverse the atmosphere more easily than infrared can traverse the atmosphere back into space. Fourier actually said nothing of the kind, but it has entered our collective culture that he did.

This idea ignores the fact that in greenhouses, the glass acts to prevent the heated air from mixing with the ambient air outside the box (i.e., prevents mass transfer) and has nothing to do with different wave lengths of light. The ACC concept says that the heating is due to energy absorption and disregards the fact that hot gases rise and there is no physical barrier to how far they can rise.

The linked article ends with:
Consulting Geologist said:
In the real physics of thermodynamics, the measurable thermodynamic properties of common atmospheric gases predict little if any influence on temperature by carbon dioxide concentration and this prediction is confirmed by the inconsistency of temperature and carbon dioxide concentrations in the geological record. Moreover, when the backradiation "Greenhouse Effect" hypothesis of Arrhenius is put to a real, physical, material test, such as the Wood Experiment, there is no sign of it because the "Greenhouse Effect" simply does not exist. This is why the "Greenhouse Effect" is excluded from modern physics textbooks and why Arrhenius' theory of ice ages was so politely forgotten. It is exclusively the "Greenhouse Effect" due to carbon dioxide produced by industry that is used to underpin the claim that humans are changing the climate and causing global warming. However, without the "Greenhouse Effect", how can anyone honestly describe global warming as "anthropogenic"?

If the thermodynamic underpinning of the "Greenhouse Effect" is absolutely missing, ACC does not have a leg to stand on.

Carbon Dating
Much has been made about the "fact" that atmospheric CO[sub]2[/sub] must have come from geologically old sources because of the lack of Carbon-14 in the atmospheric CO[sub]2[/sub]. The idea of carbon dating is the result of very creative work in 1946 by Willard Libby at the University of Chicago. His concept is that Nitrogen-14 in the atmosphere is bombarded by solar radiation and that some proportion of the impacts will cause the stable nitrogen to lose a neutron and become radioactive Carbon-14 (radiocarbon). He further postulated that the number of collisions is relatively constant and that as animals breathed the C14 a portion of it would be absorbed into their systems and decay to Carbon 12 over time. This means that as long as the animal is breathing they will be ingesting C14. When the animal stops breathing they will stop ingesting C14 and the inventory of radiocarbon in their bodies will decay with a half life of 5730 years. So if you find a sample with 1/4 as much C14 as you expect then it is something like 11,460 years old. There are a large number of assumptions that go into this calculation, and many of them are invalid for any given biological sample, and the uncertainty in dating cam be millennia.

The big question is what sources of fuel have zero C14? Of course hydrocarbons that haven't been alive for 300 million years likely have zero C14. Same with CO[sub]2[/sub] from volcanoes. What about biological material that has been frozen under the permafrost since the last ice age (2.58 to 0.012 million years ago)? That stuff has been through a lot of half lives of C14. So if the climate is warming, and if the permafrost is retreating, then biological action on the newly thawed material would have zero C14. This means that C14-free CO[sub]2[/sub] in the atmosphere does not necessarily have to come from industrial activity.

Temperature Record
The temperature record is not just one thing.
[ul]
[li]Data from 2005 might be from digital instruments that self-report or from satellite surrogates.[/li]
[li]Data from 1970 likely comes from analog instruments manually recorded[/li]
[li]Data from 1900 likely comes from spotty coverage at universities and on ships.[/li]
[li]Data from 1800 comes from ice cores, sea floor samples, and tree ring analysis[/li]
[li]Data from thousands of years ago to about 1.5 million years ago come from ice cores[/li]
[li]Data older than that comes from analysis of the fossil record (i.e., what kind of plants were growing? how big were they?)[/li]
[/ul]

We have no way to directly measure temperature. We can't do it today. We couldn't do it 100,000 million years ago. We can measure the impact of a given temperature on a material with very good accuracy and repeatability and very low uncertainty. That mercury thermometer that your mum stuck up your bum didn't measure your temperature, it measured the thermal expansion of the mercury in a constrained channel. All temperature data is the result of an evaluation of the impact on something physical to a temperature change. To turn ice core data into temperatures the scientist melts the ice then boils the water in a tightly controlled space and evaluates the gasses that come out of the sample. A computer model is used to convert the mix of gases into a temperature. These models are very clever and quite involved. If you assume that CO[sub]2[/sub] forces temperature change, you get one set of temperature numbers. If you assume that changes in CO[sub]2[/sub] are a result of temperature change you get a very different set of temperature numbers. When people plot CO[sub]2[/sub] concentration on the same graph as "temperature" data they are being purposely misleading since everyone with the ability to run this calculation knows that they have selected "cause" or "effect" before they generated the temperature numbers and in spite of having different scales they are actually the same number.

The oldest data has a temporal uncertainty of no less than ±10,000 years. The Ice core data is probably ±200 years. Data from the 1800's is certainly ±1-2 years. Data from the early 1900's is around ±6 months. More contemporary data has a better temporal uncertainty.

Contemporary data is collected from thousands of weather stations and stored in a database. The database (actually there are several, each its own format) contains one record per station per time period. No indication that the data is anything but true and accurate like scientific data is supposed to be. It is anything but that. "Everyone" understands that temperature on a blacktop surface is higher than temperature on a grassy field. As urban populations have expanded to formerly rural spaces, many weather stations have shifted from rural to urban. If you look at the data for the station, there is a step change in the output. To be able to compare a station that is currently urban to data from when it was rural, requires some "adjustments". These adjustments are done destructively without even a flag in the database. Also many of the stations have been broken for months or years and just receive "estimates", without any explicit definition of the estimating technique.

Finally, the historical record can be modified. Luckily several "outsiders" made copies of the databases at various times. Comparing those copies to the "official" records indicates some distinct trends. Several warm periods from the past are no longer included in the historical record. Data from 2000, show the 1930's to have been as much as 5°F warmer than the current string of "warmest on record years". Many of those record-breaking years were warmer by less than 0.05°F when the contemporary records have an uncertainty of ±0.1°F, but "Warmest Year on Record" gets headlines.

Impact of Climate Change
The list of things that ACC is going to cause has been widely published. It includes wildfires, more hurricanes, more tornadoes, floods, droughts, more deserts, reduced biodiversity, rising sea level, etc. This list was generated by a group of grad students sitting around a table throwing out ideas. Things like "when it is hotter it feels like the desert, I bet deserts will grow". In fact the geological record shows that in general during a warm epoch there is additional moisture in the atmosphere and deserts shrink--this is happening today all over the world. The list of consequences is not part of the "science" of ACC, but the scientists involved have rarely spoken out against the list. The scientific theories of ACC talk about physical reactions, but they can't even predict clouds or rotating systems let alone wildfires.

Consensus
Before you say you "believe" in ACC remember:
Belief is the acceptance of a theory in the absence of data
For every Michael Mann there is a Judith Curry. For every Al Gore there is a Jim Imhoff (U.S. Senator from Oklahoma). For every David Suzuki there is a Lord Monkton. For every Bill Nye there is a Jack-in-the-Box Clown. For every IPCC report there are contributors who claim their statements were misrepresented. The 97% consensus was made up from whole cloth. Before this subject got so political and began having so much money thrown at it, there were frank and honest discussions among the scientific community and people of varying views could get published or get on the podium at conferences. Not today. There are a large number of scientists who have actually lost tenure for holding opinions that the ACC story does not hold up to scrutiny, and getting published with papers outside the mainstream is nearly impossible. Not the "science" of my youth.

[bold]David Simpson, PE[/bold]
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
 
Replies continue below

Recommended for you

Mongrel,
The whole "poison the earth for thousands of years" mantra from the e-NGO's has not proven to be true. Even something as awful as Chernobyl has ecosystems thriving in the high-radiation area. When the Chicago River was so polluted you could smell it from Michigan, there were still fish in the river. Life was thriving. Pretty fish, fish we would want to eat, fish we would want to put on the wall were dead, but other fish were still there metabolizing the gunk. When people stopped dumping raw sewage and industrial waste in the river it didn't take long for it to be gone. BTEX (benzene, tolulene, ethylbenzene, and xylene) is some nasty stuff that is often produced with crude oil. When you put any of this stuff in the sun, it begins rapid decomposition into more benign substances. Most of it evaporates quickly and leaves the biosphere. The remaining components are metabolized by organisms evolved to metabolize these natural substances. "Poison the earth for thousands of years" really means "we can't hold a Memorial Day picnic there this year". When you think in global scale and geologic time, nothing can be done that won't be undone by natural processes. If we really really want to hold the picnic at that location this year then we spend money and energy to speed up the natural processes, but all too often our efforts are absolutely counter productive (e.g., the cleanup of the Exxon Valdez spill had thousands of people with Dawn dish soap scrubbing otters and sea birds--independent studies after the event showed an order of magnitude more dead creatures from having the natural oils scrubbed from their fur or feathers than would have died from the oil contamination).

The 2008 BP Macondo disaster is s great example of the hyperbole surrounding this crap. It was a tragedy because people died. It was a tragedy because the Coast Guard ignored advice from actual Oil-Field fire mitigation experts and caused the platform to collapse (losing many billions of dollars of infrastructure that could have been saved). It was not an environmental disaster. Oil is always getting to the beaches of the gulf from those seeps that I talked about in my last post. I've been to several of them and there is always oil or tar on the beaches before the trucks come along and groom them for the day's tourists. Nature has strategies and techniques for dealing with free oil, and they have evolved over hundreds of millions of years to become incredibly effective. A lot of oil spewed out of the casing that the Coast Guard broke, but very very little of it reached the shore. The microbes captured and consumed it. The Plankton and Krill ate the microbes. Other sea critters ate the plankton and krill. Other than loss of tourism business from the hysteria (my son went to the beach in Destin, FL at the height of the hysteria and other than the lack of other tourists could not see a single impact on that beach), the biggest result was a number of years of record shrimp crops and depressed prices for shrimp consumers. Nature deals with stuff in nature very effectively.

And remember that the Clean Air Act explicitly prohibits the EPA from classifying CO[sub]2[/sub] or Methane as "pollutants". The sue-and-settle strategy of the Obama EPA and the e-NGOs (e.g., the Wild Earth Guardians sue the EPA over methane leaks from pneumatic controllers in Oil & GAS, the EPA notifies the court that they have reached an amicable agreement with the Guardians and submits a consent decree to the court, the consent decree requires the EPA to write rules on methane emissions and the industry spends many billions of dollars complying with the regulation that the court would have said was illegal without the consent decree) has illegally classified both CO[sub]2[/sub] and methane as "substances of concern" and are requiring mitigation activities.

[bold]David Simpson, PE[/bold]
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
 
Hmm, I'm not sure I can agree with you fully there. Granted, there's always something that can eat whatever. Anaerobic microbes, lichens, whatever. Probably even for radioactive waste? I don't know. Plenty of old minesites out there, for instance, that were once poisonous but are now green and thriving.
But it kinda comes across as a dismissal of the damage done short-term; plant and animal life killed, crops destroyed, whatever. Just because nature can deal with it eventually, surely shouldn't mean we can just dump whatever we want?
 
Where the majority of the extra CO2 in the atmosphere came from is not at all controversial in the scientific literature on the subject.

As to the magnitude of the natural flows- it's not the magnitude of the flows that matters, but only the difference. Input minus output equals accumulation. Things were in balance until about 1700, as evident from a measured near constant CO2 concentration in the atmosphere. Those huge up and down flows were in balance, then CO2 started to spike. That's not a supposition based on a model- it's based on measurements. The isotopic balance measurements demonstrates where the majority of the extra CO2 came from. So zdas04, are you arguing that there was some spike in natural seeps etc. that happened to correspond with human industrial-scale exploitation and combustion of fossil fuels? A huge increase that we just missed? Or do you have some other explanation?
 
moltenmetal,
Are you really and truly saying that CO[sub]2[/sub] levels were constant over geological time up until the industrial revolution????? Really??? The whole argument for your belief system is that CO[sub]2[/sub] is a precursor to temperature variations, and we know that there have been times where ferns grew in Greenland and times when Ice sheets reached nearly to the equator. Graph after graph after graph from the IPCC, many universities, and most climate researchers (hell, even Al Gore's propaganda piece) shows CO[sub]2[/sub] levels varying from lower than today to much higher than today over every timeline selected. Every single one of them.

The so-called "balance of nature" is actually a "slide towards minimum maximum entropy punctuated with events (earthquakes, volcanoes, asteroid strikes, sun spots, and whatever it is that turns a normal storm into a tornado or hurricane, etc.) that cause an upward downward step change in the overall entropy level, and then entropy starts bleeding off building up again. You are truly grasping at the plastic straws that have been banned in California to support an unsupportable argument. CO[sub]2[/sub] concentrations that can be attributed to man are 0.0006% of the total inventory of so called greenhouse gases. Not even close to being within the uncertainty of the significant contributing elements.

The "extra" CO[sub]2[/sub] that a rise from 170 ppm to 480 ppm has resulted in significant reduction of the areal extent of the world's deserts. Yep, new sinks develop to use extra resources, just like they always do.

[bold]David Simpson, PE[/bold]
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
 
Clearly nobody is going to change zdas04's mind on this issue. Folks, don't be distracted- David is just plain wrong on this one. It absolutely isn't in dispute in the scientific community.

I'll leave you with this piece, which eloquently and briefly describes the bases of our understanding in this area, which is measurements not models.


For those of you who won't click on the link, I've extracted the text from the transcript on the issue in question:

"Proof that the atmosphere's excess CO2 is human generated
You might think that carbon is carbon, and that if we find there's more CO2 in the atmosphere, its source can't easily be proven. But chemistry is a bit more complicated than that; there are different kinds of carbon, as there are of most elements. They're called isotopes. One isotope of carbon is carbon-14. Cosmic rays bombard the Earth at a rate that is more or less constant over time. When they do, they strike atoms in the upper atmosphere, kicking out neutrons. These neutrons then collide with the most common atoms in our atmosphere, nitrogen. This collision kicks a proton out of the nucleus and turns the nitrogen into carbon with two neutrons too many: the unstable and radioactive carbon-14, instead of the normal stable carbon-12.

You've heard of carbon dating; this is done by comparing the relative amounts of carbon-12 and carbon-14 in a sample. Living things, like animals and trees, are in equilibrium with the atmosphere. As they eat and breathe and interact, they contain the same proportions of carbon isotopes as the atmosphere. When they die, that carbon-14 decays over a long time, and since the organism is no longer eating and breathing, no new carbon-14 comes in, and eventually the only carbon remaining is carbon-12 (and some carbon-13). Fossil fuels like oil and natural gas come from plants that died millions of years ago and have no carbon-14 left. The CO2 produced by burning fossil fuels contains only carbon-12.

When a forest fire burns, the CO2 in the smoke came from living or recently dead fuel, so the smoke contains the same proportions of carbon-12 and carbon-14 as the atmosphere. This is the case with nearly all natural sources of CO2. We can carbon date the CO2 in the atmosphere, and tell exactly how much of it comes from humans burning fossil fuels. It's a direct measurement. It leaves no room for interpretation.

There is one natural source of CO2 that contains only carbon-12, and which is often pointed out by climate deniers as the real source of all of this new carbon-12: volcanoes. Volcanoes worldwide constantly erupt, both on land and under the sea. They do so at a fairly constant rate. We measure their output, and we know that annually, worldwide volcanic activity averages about 200 million tons of CO2 added to the atmosphere, all with carbon-12, which is indistinguishable from the carbon-12 produced by burning fossil fuels. However, each year, we measure a total of about 29 billion tons of CO2 added to the atmosphere. That's more than 100 times the amount volcanoes can account for. The only possible source of all the rest of that new CO2 is fossil fuel burned by humans.

This, in short, is the "smoking gun" that proves the increase in CO2 in the atmosphere is caused by humans burning fossil fuel. It's not a conjecture or a model or a prediction, it's a measurement that anyone can reproduce, and isotopes are isotopes, and don't have alternate explanations.

Some have said that 29 billion tons is not a problem, because of how small that is compared to the atmosphere's total existing carbon load. It's true that 29 billion tons is a drop in the bucket compared to the 750 billion tons that moves through the carbon cycle each year, which is our name for the natural processes by which carbon is exchanged between the atmosphere and the oceans and vegetation. Each year, of that 750 billion tons, the ocean absorbs a net gain of about 6 billion, and vegetation absorbs a net gain of about 11 billion. They're only able to absorb about half of the 29 billion we're adding. The other half — about 15 billion tons each year — remains in the atmosphere, after maxing out the Earth's ability to absorb it into its system. These numbers, too, are reproducible measurements; not conjectures, models, or predictions. The system is provably absorbing all it can, but still unable to keep up."
 
Moltenmetal, it seems you're also guilty of closed ears, perhaps? 😎
Nobody is really debating whether we're producing extra CO2, as far as I can see. To my mind, the debate is more centred around the reliability of the "experts", who are yet to produce a single model or prediction that's even close to true, in the experience of myself, and many others. And then there's the general hysteria that's been carefully created around it, and the fact that proponents of AGW use terms like "belief" and "denial" with complete lack of irony.
Or, put another way - it's not whether we produce it, it's a question of how much risk there actually is?
I have a friend who's extremely religious, and also believes the Earth is flat. He tends to throw up Web addresses with the same sort of names, using words like "denier", "debunk", etc. I've quickly come to expect little in the way of rational discourse from such literature. We still debate sometimes on the subject, and it can be quite a good way to pass time. But the only way he'll ever be convinced is probably to actually orbit the planet. Sometimes, people become so attached to a theory, you have to show them incontrovertible proof before they'll even consider changing their minds.
And that's the problem with the AGW argument. Yes, there's proof we're creating CO2. Yes, like most pollution, it would be a good idea to stop, or slow it down. For efficiency's sake, if nothing else.
But where's the proof that excess CO2 will *definitely* cause runaway warming of the planet?
It's just another unproven theory. It's logical, and believable, but by now there have been way too many fearmongering predictions that have just been flat out wrong. So, is there any wonder that people have little trust in the "experts"?
 
Moltenmetal,
Just the flat statement "David is wrong on this one. It absolutely isn't in dispute in the scientific community". And then you go into an inept rehash of carbon dating. Methane form seeps has no C14. Methane and CO[sub]2[/sub] from hydrates under the permafrost have no C14. The organic material that has been frozen in the permafrost for 100 million years has no C14. Carbon from volcanoes has no C14. Carbon dating has a long long list of assumptions to get from an isotope measurement to an elapsed time. In fact you are so very wrong on this one, no one will ever change your mind, and the scientific community has many many disputes on all of these issues.

[bold]David Simpson, PE[/bold]
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
 
It seems that zdas04's implied hypothesis is that, coincident with the increases in fossil CO2 being dumped to the atmosphere which we know about, but entirely unrelated to it, methane seeps etc. suddenly started dumping huge amounts of fossil carbon into the atmosphere and raising the atmospheric CO2 concentration with C14-free CO2, and we somehow failed to notice. Not volcanoes, mind you, because we know about those- we don't miss them, and when they happen they don't even make a blip in the atmospheric concentration. These natural sources weren't increasing the atmospheric CO2 concentration significantly before 1700, but they started doing it with gusto when we started to burn coal, and increased their rate of emission in locked step to the amount we generated by burning fossils over the same period. Have I got that right?

Here's the data on historical CO2 concentrations in the atmosphere:


co2-graph-021116_q8ermy.jpg


Granted, those prehistoric CO2 concentration estimates are going to have a much lower precision than those we can measure from indicators during the more recent past:


CO2_concentrations_versus_time_from_withouthotair_a7d6js.png


It seems that zdas04's alternative hypothesis for the cause of this CO2 concentration increase is some kind of a planetary conspiracy theory. Nothing to look at here folks- it isn't us that caused it, it's just nature messing with us!

And you accuse me of having closed ears!

I'll leave it to readers to figure out which point of view is better supported by the data. I'm trying my best to stop beating my head against this particular wall, since it is clearly a wall and isn't moving- but of course I'm failing. I can't stand back when such obviously settled matters keep coming up as if they're in doubt- letting those assertions go unchallenged is corrosive to the public discourse, especially on a site such as this which is supposed to have at least some scientific credibility.

It would be so much more productive if we could focus on the things we can all agree to be in doubt, within a range of certainty at least. I'm all ears to practical suggestions of how we might accomplish that goal, assuming others share that view.
 
and again the medieval warm and cold periods disappear,
or are changes unrelated to CO2 ?
or are localised events (so what does a global average mean ?) ?

and (surely) no-one credits a "hockey stick" graph anymore ? surely this has been discredited ? surely ??

and (surely) the only conclusion that can be drawn is "we're doomed" ... the levels are So alarmingly unnatural that no remediation can save the situation. If we stop adding CO2 today how long would it that to return to "normal" levels (from the graph normal seems to be low 200s) ?

another day in paradise, or is paradise one day closer ?
 
Molten it appears you have not bothered to watch the documentary I posted in the other thread. Granted, it is an hour long, but if you want to argue one side you should at least be aware of what the other side has to say. Things like, while CO2 and temperature do have a strong correlation over the millennia, CO2 has lagged temperature increases by 800 years. The data does not show that CO2 causes temperature increases, but that temperature increases cause CO2 increases. Or that both are caused by something else because, as we all know correlation does not mean causation. All of the people interviewed are climate scientists.
 
Folks: the data I've posted is the concentration of CO2 in the atmosphere versus time. Please don't conflate it with other issues. We need to get zdas04 to concede a point here on this subject for the very first time EVER. We're trying to put to bed something that, frankly, isn't in dispute: a) that the concentration of CO2 in the atmosphere has risen, suddenly, since about 1700 (a measured fact) and b) the source of that CO2 is, predominantly, the burning of fossil fuels and roasting of fossil carbonate rocks. In my view, on the basis of everything I've personally read on the subject from authoritative sources, a) and b) above are not suppositions or model predictions but rather solid facts based on measurement with a firm theoretical underpinning.

Compositepro: your documentary link was from something like a decade ago, was it not? Do any of these people dispute either the rise in CO2 concentrations or its origin? I am fairly aware of the arguments being made by the denialists, but few of them debate either the fact of the [CO2] or its origin- except the idiots who make specious claims about volcanoes etc. that are obviously and patently false. Otherwise, your post talks about something which is absolutely up for debate and discussion, i.e. how severe the climactic forcing resulting from the increased [CO2] might be, and inferences to be made from past [CO2] vs past estimates of global mean temperature. That is absolutely fair game for debate and discussion- while the climate science community has an overhwelming opinion that the (geologically) recent [CO2] increase is very worrisome with respect to climactic forcing, there is no absolute consensus on how bad it will get, how quickly etc.

rb1957: you looked at a graph of the concentration of CO2 in the atmosphere versus time and somehow jumped to the conclusion that it was a graph of temperature versus time. It isn't.

 
@mm ...
umm, no I didn't "jumped to the conclusion that it was a graph of temperature versus time."

I made no reference to temperature. I made no comment on the data (there are IMHO as many CO2 graphs as there are people working the field).

I mentioned two historical events where temperature were perceived to have changed, but there's no indication of a change in CO2 level ... no appreciable change. Then I supposed two other reasons why this could happen.

The conclusion I did come to from the graph presented was that CO2 levels are far higher than they've (almost) ever been and trending higher, hence the conclusion "we're doomed". I asked how can we possibly retrieve the situation, even by the most draconian measures (stop burning FFs, entirely, today) ? To me this a apparent from the graph.

Then I also asked "isn't the hockey stick "debunked" (to use a word bandied about here) ?" I believe it has been. I don't particularly care if other people are created their own hockey stick graphs ("ok, Mann manipulated the data and got his hockey stick, but I haven't and get the same result" ... "what, you mean Mann didn't have to manipulate the data ? why would he risk his professional statue if he didn't have to ?".

another day in paradise, or is paradise one day closer ?
 
rb1957: OK, sorry, a re-reading of what you wrote with the explanation you're giving makes your point a little clearer, but only a little. I guess you're alluding to arguments on the part of some that CO2 concentrations are a result of some other climactic driver, or that CO2 concentration changes arising from some or other driver were responsible for previous climactic events like warm and cold periods in recorded history, or am I yet again missing your point here?

CO2 concentrations have in fact increased- a lot- over the pre-industrial mean. Does that mean we're doomed? That's a huge leap in my opinion. I think that natural sinks (the ocean has taken half of the fossil CO2 we've emitted so far) and heat capacity give us some time to react. What can we do about it in time that is feasible and worth doing? Fair topic for further discussion.

Again, can we please just focus on this one simple point, and see if we can get anywhere? If we can't, the whole discussion is pointless unless the participant list changes.
 
@mm,

1) the graph shows no changes (in atmospheric CO2) during two well documented climate events (the medieval warm and cold periods) so either ...
a) these changes were unrelated to atmospheric CO2 (that'd be odd given today's opinions), or
b) these changes were localised to Europe (that'd be "odd" for two quite extreme events and also should question the meaning of a global mean temperature or global CO2 level).

2) I repeat, the level of CO2 is so much higher than "ever" that how can this not have a dire effect on the environment ? I mean, it is clear that we'll soon have levels of 500 ppm (if the trend continues for a short time unabated). The only way (IMHO) that the atmospheric level of CO2 can come down is if we stop (or drastically slow down) producing it, and even then I'd expect the level to increase for a while and then start to come down. And this is not being talked about, only small 1/2 measures (get back to 1990s level for instance is possibly the most dramatic proposal) and with these I'd expect the trend shown to continue though possibly not to accelerate (and so we'd hit 500 ppm a few decades later). I don't see new sequestration mechanisms suddenly becoming active, but who knows ? I think it's fair to say that the atmosphere is still in a state of flux from the CO2 added previously.

But in any case, what would you propose to mitigate this trend ? Constraining ourselves to 1990s levels would only slow the inevitable rise at an enormous cost (particularly to the developing economies). If we stopped producing CO2 I'd expect it'd take something over 100 years for the level to decline to "normal" 250s.

3) I have deliberately not questioned the data presented, I have just drawn my conclusion from it.

another day in paradise, or is paradise one day closer ?
 
moltenmetal,

I for one will concede that CO2 levels are increasing, but think that is "pointless" to the climate change discussion(s).
 
rb1957: the first step in a process of reversing a trend in the wrong direction is to stop it. And before you can stop it, you must reduce the magnitude of the trend in the wrong direction. For heaven's sake, we're not even THERE yet- not really. We haven't even established the basic economic conditions necessary to make such a reduction come about over time- not worldwide anyway. Even comparatively progressive, wealthy nations like Canada are just getting there now, 30 years after we had a strong suspicion about what was going on and what we needed to do about it. We're taking baby steps, but I do see us at least starting to take steps in some of the right direction. It is incredibly difficult, it will take time, and effort, and money, but that doesn't make it any less necessary in my opinion.

What is a key reason we haven't even properly done what is necessary? People like zdas04, creating controversy even in the parts of this difficult problem that are NOT in dispute! People see these "debates" and say, "Hell, even the propellorheads can't agree that there's a problem. Guess I'll just gas up the SUV and go for a drive."

Hokie: pretty much every reasonable person agrees that CO2 concentrations are rising and that human activities are the cause of that rise. It's tough to debate that, given both of those statements arise from measurements, not models. And nobody who actually understands the physics will debate that more CO2 closes the infrared wavelength window into space, hence resulting in climactic forcing- that too can be and has been measured. Reasonable people absolutely can debate the extent of the net forcing, the evidence about how bad it will get, how quickly it will get bad, and what if anything is both sensible and effective to do about it. I assume that what you mean by saying that the increase in CO2 is "pointless to the discussion", what you mean is that you consider the radiative forcing resulting from the higher [CO2] to be insignificant to the climate, whereas the people who study the subject for a living are pretty much in unanimous disagreement with you. Or maybe that's not your point at all- fair enough, either way, we can get to that later.

What we're looking for here is to establish a baseline for useful further discussion- establishing points of agreement. We have to bring zdas04 across that line on this very obvious point of fact or else I'd argue that he should really have no further part in the discussion.

While I hope I'm wrong, honestly, I don't think he's capable of conceding this point. His whole identity seems to be tied up in denying the whole AGW thing- every piece of it- in fact, recent posts indicate that he also denies that DDT has any significant environmental consequences (something else for which there is also good scientific evidence), and he also denies that CFCs destroy ozone in the upper atmosphere (again, the chemistry there is both well known and has been measured in situ). And yes, if he fails to concede this point, I do think that should be weighed by readers when they are trying to determine his credibility on any aspect of this topic.
 
given the graph (and taking it as fact) there's no point, IMHO, to taking "baby steps". For what I know we haven't stablised CO2 output though we may have just reduced the rate of increase. CO2 level will continue to increase and will probably pass 500 ppm in the next couple of decades. What are the consequences of that ? I don't know. When the graph was produced it was already too late, if CO2 level implies CC. But if CO2 level doesn't imply CC, then what does it mean to have 500 ppm ?? why should we care ??

another day in paradise, or is paradise one day closer ?
 
If increased CO2 means climate change, we should do something about it. If increased CO2 means very significant climate change happening in the near term, we should do everything we can to eliminate our fossil CO2 emissions as quickly as possible. Just how much climate change will happen, and how fast? And what's worth doing about it? Fair points of debate and discussion. But I'd argue that increased CO2 inarguably leads to SOME climate change- it's tough to imagine how it would be otherwise, understanding the basic physics involved.

 
What does it mean that CO2 levels were so much higher several hundred million years ago (>2000 ppmv)?
Is this true?
How do we relate that to today 410 ppm?


Thanks,
Mark
 
What does it mean that CO2 levels were so much higher several hundred million years ago (>2000 ppmv)?
Is this true?
How do we relate that to today 410 ppm?

The short answer is that CO2 is not the only variable.

Longer answer:
[link]https://www.skepticalscience.com/co2-higher-in-past.htm[/url]

Doug Jenkins
Interactive Design Services
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor