Man Based Global Warming....

This is one of those things the deniers don't seem to understand. It really doesn't matter what the normal cycle is without our influence. The difference is that we are adding the CO2 on top of everything else, upsetting the correlation. CO2 is unlikely to be causal (at least initially) for the cyclical temperature rise absent man's large influences today.

All else being equal CO2 will trap more heat. There is really no doubt about it as it gets down to wave physics and atomic structure. Or perhaps you are disputing that CO2 is a greenhouse gas?

 

No, no. The difference between those two arrows is the temp increase in this decade. You said it was el niño. Why?

I gave you the most important one, Milankovitch cycles. What's important is that no other cause for temperature increase has been found.

 

What an incredibly poor assumption. Various species on this planet have indeed had a direct impact on our climate Ever wonder why we have an oxygen rich atmosphere? It isn't "natural" in the sense that it would not be here without the rise of life.

And what we are doing is now is throwing the stored decay products of millions of years worth of climate changing critters into the atmosphere all in a few generations.

We also had a major impact on the ozone layer in a much shorter period of time through our "paltry daily activities." But we addressed the man made source of the problem. So yes, we have proven that we can impact the climate through our activities.

Or you can talk to any living relatives who experienced the dust bowl. We certainly had some impact on the climate then. (And had some before that in wiping out the buffalo and the native grasses.) We've altered our agricultural processes as a result.

 

I haven't claimed CO2 is not a greenhouse gas nor have I claimed it cannot contribute to some level of temperature rise. But AGW believers (like Alric) imply that past correlations demonstrate that CO2 drives temperature, meanwhile glossing over the fact that CO2 lags temperature in such reconstructions.

My dispute is with the argument that CO2 is the primary climate driver and that the temperature increase from CO2 are likely to be catastrophic.

That said, I think I've said about all I can say on this. Obviously you, Alric, and Fibb are of different opinions - and that is fine. I stand about as much chance of convincing you to change your mind as you me.

So rather than waste any more time on this thread, I am going to sign off.

 

It is not normally the primary climate driver. What we are doing isn't normal. Our activities and resultant CO2 are demonstrating a capacity to override underlying cycles, of which we are only dimly aware of at present.

 

Nicely put. CO2 can be both a cause of global warming *and* a trailing indicator, depending on circumstances. When the climate is heated by some other cause, such as Milankovic cycles, CO2 can be a trailing indicator because higher average global temperature can cause it to be released (from melting permafrost, for example). When there is a CO2 release mechanism operating mostly independent of average global temperature, such as human activity, CO2 can both cause warming and then amplify it, because those "trailing indicator" mechanisms can also operate and release additional CO2 and other greenhouse gasses.

Some people have been honestly confused about this. Some may have been deliberately confusing about it to further their agenda.

 

You mean for Milankovic-driven global cooling? Check out that Pravda article that all the deniers are crowing about. Oh, you mean, references for the fact that global warming is occurring now; but you've already rejected those.

 

I'll bite.

1. Evidence for an alternative explanation for temperature rise.
2. 30 years or more without warming in the face of continued increased atmospheric C02.

 

Dubya admitting global warming was real was the biggest bit of doubt that has crossed my mind on the matter in 10 years.

If we see "normal" weather patterns again for about 10 years running. (That doesn't mean no extreme weather.) When I was undecided about global warming about 15-18 years ago there was an excellent discussion about the sort of weather patterns one might expect from a warming Earth. The most interesting aspect was more sustained loops/kinks in the jet stream. This would then produce abnormally long seasonal/non-seasonal weather patterns.

I made note of their explanation and have been amazed at how well it has described the weather I've observed for most of the years since then. Rather than having a drought/deluge season every few years I've experienced "100 yr. events" back-to-back several years in a row where I've lived. When we've gotten rains it has been in short flooding bursts that do little good, and then we get six months of drought. On average it is both warmer and drier in all three of the widely dispersed locations I've lived over the past two decades. (The swamps actually dried up and burned while I was living in the Southeast.)

The frequent weather extremes and the magnitude of the extremes (hot or cold) reinforce the global warming argument.

What cracks me up is every time there is a cold spell somewhere, the denialists begin trashing global warming as if a single front moving through decides everything. It's like a gambler who loses most of the time and has lost everything, but only remembers the winning hands.

Another thing that would bring some doubt is if the "permafrost" would refreeze and glaciers begin returning to conditions of about a century ago (this would take at least a decade to confirm.) Northwest passage not opening again in my lifetime would be a start...

Having the coral recover would be a factor as well, I can tell by my own temp. gauges and records that the water is too warm in many dive sights compared to a decade before. The stress on the coral is obvious and painful to observe.

Seeing water return to rural streams/springs back home that were filled year round when I was a kid (with the exception of once/twice in a decade summer drought.) I haven't seen some of these flowing properly in the past 15 years--and they've gotten worse each year.

Reduced propensity for massive Category 5 hurricanes whipping up overnight in the Gulf. The warm water and stable weather patterns seem to have worked together to create fast developing monster storms over and over again. Personally seeing 600 miles of trashed coastline across 5 states from several storms in a single year focuses your attention. (And much of this same stretch was hit again last year.)

The lack of history/time of understanding and predicting cycles without man's influence. There is no control to compare to, so the overall temperature change due to increased CO2 is uncertain. But there is no doubt that there is man based global warming, CO2 undeniably has that influence--the question is only how much and on what sort of cycle is it overlaying. (Afterall, half the argument here has been that global warming is preventing a new Ice Age--an argument that is completely fatal to the denialist camp, but they use it anyway.)

 

I really doubt that 30 years of cooling would convince you that global warming is not primarily driven by CO2. You will most likely just say it is an anomaly like the 20 years from 1950 to 1970 when CO2 and temperatures when in opposite directions.

A couple pages back I asked:

You replied:

And then later you said:

So:
When temperature happens to match CO2 levels it is proof of man made global warming caused by CO2.

When temperature doesn't correspond to CO2 levels this is caused by other natural factors and does nothing to disprove a direct correlation of temperature to CO2.

 

I would need compelling evidence that the past 200 years of observed global average temperature rise was not caused by the observed increase in atmospheric CO2 (or that either of those observations are incorrect, which now seems about as likely as discovering that the universe is not actually expanding). The fact that it is cold on a January day in New England is not sufficient, just as the current record high temps in California are by themselves not good evidence for global warming. Other uncompelling alternatives include:
- changes in Solar activity. There is no clear theory explaining why an increase in Sunspots should cause global warming.
- Milankovic cycle. This would by itself now be causing global cooling, not warming.

 

A 1:1 relationship between CO2 levels and global temperature is not expected because global temperature is affected by many factors. What you would expect is a trend of increased temperature over time with increased CO2 concentrations., which is exactly what we see.

We've discussed this before. Unique or short term data does not invalidate a much larger trend.

 

Correct me if I'm wrong but a 800 year trend is 4 times longer than the current 200 year trend. The last 2000 years have had warming and cooling trends but the overall trend is down.

If 20 years of contrary evidence in the 50's and 60's had no effect on your belief I don't see how 30 years will. I predict that even if temperatures continually dropped for the rest of your life, will say the decrease is only temporary.

 

Ok. I'll correct you. This is historical temperature data using 16 different proxies. What you describe is the argument for AGW. There was cooling and all of the sudden since the industrial revolution temp started rising. As you can say in the last 200 years the trend is decidedly upward and climbing rapidly. Moreso than it has in the past 2k years.

 

The above appears to be an intentional attempt to mislead. It also appears to be an intentional misstatement of the global warming argument. Unfortunately, it is all too common from the denial camp.

Nobody denies that there are other cycles occurring, some poorly understood, some yet unknown. Some are dependent, some independent. CO2 is but a single factor but one over which we have a direct and measurable contribution. The change in CO2 concentration over each year is small enough that I would expect it to be swamped on annual or even decade long scales by other factors. Nevertheless, small concentration changes will still raise the temperatures above what they would otherwise be during those times.

This claim you are making that climatologists require a 1:1 correlation with CO2 is a fabrication of your own making. It's a pretty standard strawman tactic: try to force an opponent to defend a position they are not taking. (Karl Rove is pretty darned good at it.)

If I wanted to play the same game I would require that you prove that we are presently experiencing global cooling and that CO2 is saving us (the most ironic of the denial arguments because it inherently accepts global warming.)

Engineers should generally not take the inherently unsafe approach: see the shuttle disasters and the Apollo pad fires for examples why the approach doesn't work. Generally it is required to prove something is safe or at least not detrimental, instead of forcing others to prove it is detrimental while the activity continues. This is why we have drug testing, etc.

 

One of the two will happen on the present course:
1) There will be a level of CO2 reached that will affect the climate with no room for doubt.
2) We will run out of stuff to burn.

Edit-Actually both could happen.

 

Could happen????

Icarus