Global warming is not real... right?

[PDIII]

So when I was in my sophomore year at hopkins I took an atmospheric science class. The prof had taken several trips to Antarctica where he drilled ice cores for the purpose of measuring historic co2 levels.  almost every class he would go off topic and go on and about his ice cores.  he had massive amounts of data and several power point presentations about historic co2 levels along with corresponding temp data. He  came to the conclusion  that spikes in co2 level/ correlations in global temperature have been happening since the last ice age. Furthermore he pointed to case after case where changes in global temperature were several times more drastic than what we have experience over the last century and ocured over shorter periods... so whenever I here people raise doubt about human impact on global warming I tend to agree with them... and generally dismiss global warming as a myth.   Now days however... it seems like if you don't believe in global warming it is almost as bad as being a racist.  so I don't know what to believe.  I mean  the dude went to Antarctica and drilled the holes himself... and he is like a publish/ well respected scientist.  I tend to believe  in science.... I have always been afraid to even mention  global warning here because every time someone does... they get yelled at... I know this is not a climate forum.. but I want to hear what people think.   

[Roger Smith]

I think it's somewhere in between the IPCC-Al Gore type of concern for our very survival and the outright skeptical nothing to see all made up Chinese hoax. 

We are warming the atmosphere. The question is, how does that warming interact with natural variability which could, in theory be in a cooling phase, or static, or in and of itself responsible for some of the observed warming.

And I also believe that we are currently in a situation where the southern hemisphere is (at least south of the subtropical zones) not warming and actually cooling near the south pole. But the northern subarctic is showing the strongest warming effects. Ice margins are definitely a lot further north in the North Atlantic sector in the past thirty years, and have shown more variability in the Siberian-Alaskan sectors. 

The effect that all this has on regional climates in the eastern U.S. is probably not very great because of the high variability factor. The temperatures at reliable stations for comparison (DCA not included) are edging upward when viewed in the time frame of 30-year normals, but extremes are not necessarily doing the same. This slightly warmed up climate (in the temperate zones) seems to be cloudier too, and that has some balancing effect on daytime temperatures. I did an extensive study of Toronto temperatures from 1840 to present and found two things, the largest temperature increases were in April and October-November, and also generally speaking at night rather than in the daytime hours. Then looking at a longer period of record in central England, the effects are quite variable and almost chaotic. But they probably reflect the fact that the Atlantic is warmer and the ice margins further away. For example, June has warmed the least of all months, March and November have warmed the most. 

So for the time being I think we are in a rather subtle period of warming, but I don't discount the idea that we could quickly move to a more dramatic warming and also a more rapid ice loss from Greenland and other places in the northern hemisphere. I don't think there is necessarily going to be any correlation to the southern hemisphere which has actually seen some increase in sea ice in modern times. 

[PDIII]

15 hours ago, Roger Smith said:

I think it's somewhere in between the IPCC-Al Gore type of concern for our very survival and the outright skeptical nothing to see all made up Chinese hoax. 

We are warming the atmosphere. The question is, how does that warming interact with natural variability which could, in theory be in a cooling phase, or static, or in and of itself responsible for some of the observed warming.

And I also believe that we are currently in a situation where the southern hemisphere is (at least south of the subtropical zones) not warming and actually cooling near the south pole. But the northern subarctic is showing the strongest warming effects. Ice margins are definitely a lot further north in the North Atlantic sector in the past thirty years, and have shown more variability in the Siberian-Alaskan sectors. 

The effect that all this has on regional climates in the eastern U.S. is probably not very great because of the high variability factor. The temperatures at reliable stations for comparison (DCA not included) are edging upward when viewed in the time frame of 30-year normals, but extremes are not necessarily doing the same. This slightly warmed up climate (in the temperate zones) seems to be cloudier too, and that has some balancing effect on daytime temperatures. I did an extensive study of Toronto temperatures from 1840 to present and found two things, the largest temperature increases were in April and October-November, and also generally speaking at night rather than in the daytime hours. Then looking at a longer period of record in central England, the effects are quite variable and almost chaotic. But they probably reflect the fact that the Atlantic is warmer and the ice margins further away. For example, June has warmed the least of all months, March and November have warmed the most. 

So for the time being I think we are in a rather subtle period of warming, but I don't discount the idea that we could quickly move to a more dramatic warming and also a more rapid ice loss from Greenland and other places in the northern hemisphere. I don't think there is necessarily going to be any correlation to the southern hemisphere which has actually seen some increase in sea ice in modern times. 

So you have done research... and if I am reading this correctly... temperatures have increased slightly.  additionally sea ice in the northern hemisphere has decreased... and this has all been over the last 30 years... 

The question is why? and do people have anything to with it.  I would argue no.  the reason for this is that over the last 30 years industrial nations have instituted regulation that has resulted in significant decrease in pollution output.... and during the same period sea ice has been receding. 

 

One could argue that we are simply seeing a delayed effect; that we are paying for the pollution out put from 1880 to 1980... but it has been a really long time since regularly action has taken hold.  additionally there is the argument that other countries such as china do not have the same regulatory requirements.

 

[Roger Smith]

Yes we have reduced pollution but greenhouse gases continue to increase, they are not really pollutants but naturally occurring constituents of the atmosphere. Carbon dioxide and methane would be in the atmosphere even on a human-free planet earth. Their proportions might be variable too. Carbon dioxide in particular would depend on percentage of the planet ice free and vegetated. 

My research really has no sure-fire method of separating out natural variability from human signal, but the fact that the warming signal is not uniform month to month suggests to me that the climate zones are shifting slightly, catching months that are transitional more than months that are core-seasonal. 

The only way we could separate human and natural signals would be in the wake of some demonstrated accurate model that correlated almost 1:1 with past values with some sort of gradual adjustment required for perfect fit. Let's say for sake of argument that a warm month like March 2012 (+10 to +12 anomalies) was predicted to be +9 by the model with near perfect fit from 1800 to 1950 and errors like that since 1950 on an increasing slope, then you would have some cause for saying that the human modification factor was +1 degree. 

We don't have anything like that available to us, but if the average temperature is higher in the recent past than any historical period, most climate scientists are bound to suppose that this must be a sign of human modification. However, for the sake of argument, there is no absolute reason why the last 30-50 years could not be the naturally warmest period in the centuries of record. What would make that argument more plausible would be a drifting down of global and regional temperatures to values that were mid-range for the longer term or even below normal. So far we are not seeing that (anecdotal evidence is sometimes quoted on skeptic-friendly blogs but these are not widely supported in climate science, usually it's something like "this past month was very cold in Europe" (true) but thirty year averages keep on drifting up except when you get a slight fluky reset by dropping a very mild year for a very cold one. 

My personal opinion is that the recent warm period is at least half natural variability, possibly three-quarters, and the remnant is human modification. The fact that the Sun was very active for most of the 20th century probably means that the late 20th century averages should be higher than anything since 1700. There is a known lag time between solar activity and temperature response. If there is going to be natural variation cooling from the current downturn in solar activity, it likely won't be too impressive until the decade 2021-2030. So it's wait and see on that. A flat line response from this decade to that one would probably indicate natural cooling balanced by human modification warming. 

[WxUSAF]

We have a complete climate change sub-forum folks.  I'm going to lock this thread, but feel free to continue the disco there.