[QUOTE=Martin Hyde]
You unfortunately seem to be quite uninformed on the facts for someone who came in to “set things straight.”
[/QUOTE]
You know what, some others have chosen to ridicule you, but I have to admit, you have pointed out a few things that I’ve gotten wrong. Instead of simply discounting what you’re saying, I’m going to debate you. I have some sense that perhaps I was a little too personal saying you were uninformed. You can clearly throw around links like the best of them, and you state some valid facts. So I’m going to debate because I believe I might convince you.
[QUOTE=Martin Hyde]
This is a very inaccurate statement. The earliest information I have on CO2 concentrations start about 500 million years ago. Several different geochemical modeling estimates exist.
…
To say that the “last 500 million years” was a period of “great evolutionary change” and “many extinctions” is very disingenuous. Any period covering that amount of time is going to be one of great evolutionary change and many extinctions. That’s the nature of life on earth, what is known is that throughout that 500 million year period is that there have been periods defined as ice ages in which CO2 concentrations were almost 10x as high as they were today.
[/QUOTE]
That’s what I get for watching TV. I saw a documentary about a warming period in earth’s past in which a great number of species perished because of overall warming. Probably this was oversimplified. Shame on me. Score one for you.
[QUOTE=Martin Hyde]
The period ~475-425 million years ago was a glacial period. CO2 concentration in the atmosphere is estimated to have been around 4,000 ppm around this time, and this is during a glacial period. The people who try to explain CO2 as “causing” global warming, in my opinion, have a hard time explaining how we can have CO2 concentrations of 4,000 ppm during a glacial period 475 to 425 million years ago when today we have CO2 concentrations within the 350-380 ppm range.
The period from 225-325 mya was likewise a glacial period, as was 110-175 mya and present day back to 50 million years ago.
Right now, we’re arguably simply in an interglacial period of an ice age. The presence of large, permanent ice on the globe isn’t necessarily the regular state of things. Outside of the major ice ages (one of which we’re still in, and possibly at the tail end of) there is exceptional evidence that there is no polar ice whatsoever. There’s also evidence of extremes when it comes to ice ages, with the present ice age being very mild and then one that occurred from 850 mya to 630 mya possibly the most extreme, being theorized as causing a “snowball earth.” It has been theorized that the population explosion in life around 500 mya is because of the end of that extreme ice age.
[/QUOTE]
Uh…you spend a great deal of effort here with a lot of data, but it’s unnecessary, because I wouldn’t challenge that bit. You ask…how can we have glacial-periodic colder temperatures and higher CO2 concentrations if CO2 causes global warming? And then lower amounts of CO2 interglacially?
First, ice ages are caused by things that are massively stronger than CO2 concentration. The wobble of the earth’s axis and the wobble of its orbit, mostly.
Second, natural CO2 concentrations are directly affected by ice ages, and contribute to the way the cycles work by mitigating them. When an ice age begins, more CO2 is released into the atmosphere, but as the earth goes interglacial, more land mass is available for plant life, which begins to soak up the CO2.
But before you assume that I must now agree with any other parts of your argument, the difference this time is that the time scale for such things is thousands of years longer than what we are experiencing now.
[QUOTE=Martin Hyde]
A more accurate phrasing of your statement would be that in the past, for HUNDREDS OF MILLIONS OF YEARS, CO2 levels were vastly higher than they were now,
[/QUOTE]
But not continuously, looking at the data. Sometimes it was less.
[QUOTE=Martin Hyde]
and that that period of hundreds of millions of years was characterized by:
-Vibrant explosion in the number of species on the planet
-Drastic ice ages which have within them glacials/interglacials periods
-Periods of extreme global warming, with near-tropical weather and extensive animal life at the poles
-Periods of mass extinction
-Periods of drought
-Periods of flooding
Basically pretty much the entire gamut, from drought to deluge, freezing to warming.
[/QUOTE]
As I said…whoops…trusted the TV. I shoulda known better. But also…changes over millions of years, not 100 years…
[QUOTE=Martin Hyde]
You seem to be working from the assumption, already, that greenhouse gases are the only explanation for climate change, no one I’m aware of in the serious scientific field of climate change believe that.
[/QUOTE]
No, I’m not assuming that. And I can tell that you’re just chomping at the bit to seethe with this particular complaint. But I’m not being that simple.
I would give you the possibility that there is a small effect caused by something natural. But the point of all this is this debate is whether or not a natural process could make it happen so quickly, or whether it’s the result of human activity. As I see it, CO2 is just the main culprit as a part of human activity.
[QUOTE=Martin Hyde]
I don’t recall calling it speculation that CO2 is a greenhouse gas.
The science behind CO2 concentrations being an agent in warming is sound but the conclusion that “higher CO2 concentrations cause warming” is not as sound. I believe that paleoclimatology firmly shows an incredibly complex system of which atmospheric changes are only one part and CO2 only a part of that aspect of it.
[/QUOTE]
Okay, maybe that time I put words in your mouth. Sorry.
But otherwise, what nonsense. CO2 is an agent in global warming because it traps more heat than oxygen or nitrogen. More of it will trap more heat. The only possible reason you could have to say something that ridiculous is that you are betting that natural negative feedbacks are stronger than the known thermal properties. Well, at least you agree that CO2 is a greenhouse gas.
[QUOTE=Martin Hyde]
I think the questions that are most aptly asked are:
- What causes Ice Ages?
-The answer to that is controversial within the scientific community. The general consensus is that there is not one answer, but many. Atmospheric changes, Milankovitch Cycles (changes in the Earth’s rotation around the sun), movements of the tectonic plates, eruption of supervolcanoes, variations in solar output, and even possibly changes in the Sun’s position in the galaxy.
- What causes glacial/interglacial periods?
-The answer to this is also not something fully understood or explained. Right now we’re in an interglacial period of an ice age. In the past, ice ages have come and gone, periods of no glaciation and extreme glaciation have come and gone. Periods with much greater glaciation have existed millions of years ago with much higher CO2 concentrations.
[/QUOTE]
There is SOME debate about what causes these things, but it’s about the MARGINS of the effects. The strongest effects are generally agreed-upon. The tilt of the earth becomes more or less radical, and the orbit of the earth becomes more or less eccentric. These things correllate well to known ice ages. The outlyers to that correllation are the things of some controversy. But even if that were a significant issue, the time frames are still vast.
[QUOTE=Martin Hyde]
This is the problem with the CO2 story. Over the past 140 years, there has been a general period of global warming. Over the past 140 years, there has been a rise in CO2 production. That’s correlation. There’s also evidence that the rise in CO2 concentration is part of the causation where I have a problem is when people argue it is an overwhelming part of said causation. Paleoclimatology suggests that while CO2 plays an important part in climate change, the climate isn’t near as sensitive to CO2 to cause the sort of warming we have seen over the past 140 years over a relatively miniscule rise (in the context of hundreds of millions of years of CO2 concentrations) in CO2 in the atmosphere.
[/QUOTE]
“Correllation, not causation…” Yeah, I have heard that one before. The problem, though, is not that it’s ludicrous to say there’s a connection, because it’s actually the SIMPLEST explanation. The simplest explanation is usually the right one. If we’re going to throw around idioms about debate it doesn’t give you a clear win.
[QUOTE=Martin Hyde]
There’s not any consensus like you’re suggesting.
[/QUOTE]
Yes there is. IPCC, 99% of scientists, etc. etc. If you don’t believe this you need a better source of information. Didn’t you notice that there is a loud minority of paid robots parroting anti-global-warming theories for the benefit of CO2-emtting industry?
[QUOTE=Martin Hyde]
that’s akin to saying climate change is driven by one thing, CO2, and that’s ludicrous and any serious climatologist would laugh in your face if you suggested that.
[/QUOTE]
You’d love me to suggest that, because then global warming wouldn’t be the fault of the humans. Sorry, I think you just put those words in my mouth.
[QUOTE=Martin Hyde]
I’m not really sure I’m sold on ‘startling disasters’ nor am I entirely sure I buy into the same definition of “startling disasters” that everyone else buys in to.
[/QUOTE]
Well, if the temperature rises, maybe you won’t be startled. Sorry. You are one steeled human being. The sea levels rising to cover nearly all island nations and coastal areas…oh yeah, not startling.
Not a single piece of ice has to melt for the seas to rise. Temperature change alone will cause the sea to expand. That startles me, at least.
[QUOTE=Martin Hyde]
The thing is we can certainly adapt but there’s no certainty whatsoever we can stop climate change. In fact, I believe the idea that we have the technology to stop global warming is as ludicrous as the idea that we have the technology to blast humans to Pluto at light speed.
[/QUOTE]
I’d actually agree with you, IF I thought humans weren’t to blame. In the end, yes, we can’t stop an ice age. But we could change our behavior. So whatever.
[QUOTE=Martin Hyde]
So ultimately, I come very close to agreeing with the thread title. I’d change it slightly to say that “man-made CO2 is probably not causing global warming, but is contributing to it.”
[/QUOTE]
And I’d say, “Human-caused release of more-than-natural amounts CO2, methane, and other greenhouse gases is the main cause of global warming.”
[QUOTE=Martin Hyde]
I believe that right now, we’re in a natural interglacial period of an ice age, or even possibly the end of an ice age. I believe that ice ages, glacial/interglacial periods come and go with no human involvement (the historic record suggests this is true.) I also believe that the rise in industrialization came at the worst possible time. If human society had become industrialized 25,000 years ago, during a glacial period, I doubt our industrial emissions would have been significant enough to have seriously altered the natural glacial period we were in. But since we are in a natural interglacial period, human contributions to global warming can and are more significant than they would be in another general climate period, and that our contributions to GHG concentrations and global warming while quite possibly very small compared to other things is upsetting a delicate system in such a way as to cause a greater degree of change than would otherwise happen.
My belief isn’t proven by any means, it’s just what I think from all that I’ve read. I believe people are probably fooling themselves if they think we don’t have a hand in climate change. I also think it is human arrogance to believe we are the prime engineers of climate change. I also think it is human arrogance to describe the worst case scenarios as “disasters” they are disasters because we have built entrenched cities in coastal areas and have an incredibly intricate global trade network and agricultural network. Ancient man would not have seriously been bothered by these changes at all, nor would many animals who routinely survive transitions from glacial to interglacial periods. Ancient man would just move his camp a few miles back from the shore, or move farther north or south to deal with warmer or colder climates.
[/QUOTE]
You should read some more. Most predictions I’ve read say that we’re just as likely headed for another ice age rather than into an inter-glacial period. Again, not proven. Fair enough.
We’ve caused acid rain. We’ve caused the oceans to get over-fished. We’ve spread organisms all over the place. We’ve defoliated vast tracts of jungle, forest, and plains. A few degrees of climate change in an earth practically smothered with our effects…doesn’t seem so arrogant to me.
I’m not sure what else to say about your speculations. You’re admitting you’re speculating, so I don’t feel I should probably debate it too much. I know that, if this was a natural occurrence, we wouldn’t feel guilt, so adapting really is the answer. Too bad for us humans. But if it IS our fault, it doesn’t make much sense to “adapt” to a climate the earth and all its life haven’t seen for millions of years. We arrive at these two conclusions from different assumptions, so I’ll give it to you.
So there it is. Thanks for the opportunity to debate.
