My belief in Global Warming is getting shaky

[Grains]

Originally Posted by InfiniteNow

Water vapor only stays in the atmosphere for up to 2 weeks, whereas CO₂ stays in the atmosphere for more than a century.

Also, water vapour accounts for only a tiny fraction of the issue, as it's not a radiative forcing, but is a feedback. You can't successfully argue against what you don't understand.

cool thanks for posting that I was just out looking around the net! very informative...

you said I can't successfully argue what you don't understand.....i wasnt arguing the fact that it was true???

1. I posted link
2. You posted link providing more information
3. I said I didn't see anything in that about vapor
4. You posted good information that was helpful

Never said it was true or not true....jeez

[modest]

Originally Posted by Grains

i cant see this chart to well but I think the blue line is the logarithmic trendline correct? which is trending down correct?

This doesn't inspire confidence. Blue is temp, red is trend, error bars are error bars.

~modest

[Grains]

Originally Posted by modest

This doesn't inspire confidence. Blue is temp, red is trend, error bars are error bars.

~modest

modest the chart is still in a downward trend

regardless of what you say red is not a trendline, it cant be....it looks like the mean/average to me after looking at the graph and your excel sheet..for a trendline to be perfectly parallel to the x axis their would have to be no changes in data over the whole time period...


Trend Lines - StockCharts.com

[Grains]

I just felt like recapping the last 6 pages of posts because I think somewhere their has been a miscommunication between myself and the rest of the mob

1. I posted link and graph
2. Infinatenow said pop a trend line on it
3. I popped a trend line on a graph
4. Infinatenow said the trendline was wrong
5. I said a trend line cannot be wrong granted you are doing along with definition of the trend line and not making green streaks across a graph for no particular reason.

Trend Lines - StockCharts.com

6. Others and infinatenow begin to say my graph is of a short time period (which I have never strongly supported the time period I just popped a trendline like he asked me to and simply was stating my trendline was not wrong)

In between all that their was other discussion but I just wanted to get my main point out there because it has been lost through the thread. Regardless if you like the period of 1988-2008 or 1998-2008 or 2007-2008 or you just don't think it's a good pool of data the trend line on that particular chart is still going down. We can talk about 10,000 year graphs or 600 million year graphs but that has nothing do do with what I originally posted. My original statement was from 1988 to 2008 the trend is going down. I don't care if you think its going to start going back up, stay the same, or go down. The trendline as of right now has nothing to do with any of that. Nothing more than that......the trendline is still going down on that time period...

[modest]

Originally Posted by Grains

regardless of what you say red is not a trendline, it cant be....it looks like the mean/average to me after looking at the graph and your excel sheet..

Well, you're not arguing with me, you're arguing with excel. That's the most accurate trend it can generate.

Originally Posted by Grains

for a trendline to be perfectly parallel to the x axis their would have to be no changes in data over the whole time period...

"no changes in data over the whole time period" is a flat line. So, that's wrong. If you really want to convince yourself its correct look at how much area the data points make above the trend and below. If they are equal then that's a good indication the trend is accurate. They look equal to me.

~modest

EDIT:

also, to change the type of trend line in excel you can right click on the trend line and click format trendline.

~modest

[Grains]

Originally Posted by modest

Well, you're not arguing with me, you're arguing with excel. That's the most accurate trend it can generate.

no

"no changes in data over the whole time period" is a flat line.

exactly!!!!!!!!!!!!!!!! and your saying thats your trendline...

So, that's wrong. If you really want to convince yourself its correct look at how much area the data points make above the trend and below. If they are equal then that's a good indication the trend is accurate. They look equal to me.

not a trendline

Again....
Trend Lines - StockCharts.com

[Grains]

here....

all you have to do is connect the peaks...regardless of where the peaks are thats where the trend lines go..

[modest]

Ok, Sir, no need to get excited. We're just discussing the finer points of trendlines is all. Let's see if we can track down our differences here.

I don't object to your method of drawing a trend (except that you should also draw a line on the bottom points and you've accidentally put one on the error bars). But, it's not as accurate as my computer generated trend. The top and bottom 4 points don't and can't represent all the data like a computer can. That's not to say there's anything abnormal about what you're doing - people have been doing it for a long time. It's just not as accurate.

So, would you object to the trend excel puts on the last 50 years of data:



~modest

[Grains]

Originally Posted by modest

Ok, Sir, no need to get excited. We're just discussing the finer points of trendlines is all. Let's see if we can track down our differences here.

I don't object to your method of drawing a trend (except that you should also draw a line on the bottom points and you've accidentally put one on the error bars). But, it's not as accurate as my computer generated trend. The top and bottom 4 points don't and can't represent all the data like a computer can. That's not to say there's anything abnormal about what you're doing - people have been doing it for a long time. It's just not as accurate.

So, would you object to the trend excel puts on the last 50 years of data:



~modest

no i would not argue with that...

i have enclosed a chart showing an increasing trend as well just different than excel...

on this chart yes the trendline is increasing...

I have never argued that it would not increase over different time periods.... in fact I have viewed a 100 yr chart as well and the trendline is increasing.

Regardless, from the 1998-2008 period the trendline is decreasing...your absolutely correct...there is nothing abnormal about what i am doing...thats why i am so confused on why it has been so hard to get that across

and your also correct on that spot trendlines are not as accurate but they still move in the same direction regardless..you mentioned i should have drawn trend lines on the bottom of my last chart and i did and they continue to show downward trend...would be impossible otherwise....

my sincerest thank you to you...i finally feel like someone is actually reading what i am saying and working with it....there is life on the other side of the forum...

[Overdog]

Originally Posted by InfiniteNow

And they successfully model past climates, how exactly? Did they just throw a bunch of garbage into a bin, shake it up, and wind up with successful reconstructions of past climates by chance?

Show me which model specifically is wrong and where. Until then, you are waving your hands about and expecting the rest of us to take you seriously.

I'm not picking out specific models, again, I question all of them.

Global climate model - Wikipedia, the free encyclopedia

According to the IPCC, the majority of climatologists agree that important climate processes are imperfectly accounted for by the climate models. Scientists point out that there are specific flaws in the models, such as albedo errors, and external factors not taken into consideration that could change the conclusion above. GCMs are capable of reproducing the general features of the observed global temperature over the past century

And

Dr. David Wojick, an expert in climate science, recently wrote in Canadaʼs National Post, “The computer models cannot decide among the variable drivers, like solar versus lunar change, or chaos versus ocean circulation versus greenhouse gas increases. Unless and until they can explain these things, the models cannot be taken seriously as a basis for public policy.”

In short, these general circulation models, or GCMs as theyʼre known, create simulations that must track over 5 million parameters. These simulations require accurate information on two natural greenhouse gas factors - water vapor and clouds - the effects of which scientists still do not understand.
Even the IPCC conceded as much: “The single largest uncertainty in determining the climate sensitivity to either natural or anthropogenic changes are clouds and their effects on radiation and their role in the hydrological cycle...at the present time, weaknesses in the parameterization of cloud formation and dissipation are probably the main impediment to improvements in the simulation of cloud effects on climate.”

Because of these and other uncertainties, climate modelers from four separate climate modeling centers wrote in the October 2000 edition of Nature that, “Forecasts of climate change are inevitably uncertain.” They go on to explain that, “A basic problem with all such predictions to date has been the difficulty of providing any systematic estimate of uncertainty,” a problem that stems from the fact that “these [climate] models do not necessarily span the full range of known climate system behavior.”

This means the models do not account for key variables that influence the climate system.

http://epw.senate.gov/repwhitepapers/ClimateChange.pdf

And from the wiki link:

All models have shortcomings in their simulations of the present day climate of the stratosphere, which might limit the accuracy of predictions of future climate change.
There is a tendency for the models to show a global mean cold bias at all levels.
There is a large scatter in the tropical temperatures.
The polar night jets in most models are inclined poleward with height, in noticeable contrast to an equatorward inclination of the observed jet.
There is a differing degree of separation in the models between the winter sub-tropical jet and the polar night jet.
For nearly all models the r.m.s. error in zonal- and annual-mean surface air temperature is small compared with its natural variability.
There are problems in simulating natural seasonal variability.( 2000)
In flux-adjusted models, seasonal variations are simulated to within 2 K of observed values over the oceans. The corresponding average over non-flux-adjusted models shows errors up to about 6 K in extensive ocean areas.
Near-surface land temperature errors are substantial in the average over flux-adjusted models, which systematically underestimates (by about 5 K) temperature in areas of elevated terrain. The corresponding average over non-flux-adjusted models forms a similar error pattern (with somewhat increased amplitude) over land.
In Southern Ocean mid-latitudes, the non-flux-adjusted models overestimate the magnitude of January-minus-July temperature differences by ~5 K due to an overestimate of summer (January) near-surface temperature. This error is common to five of the eight non-flux-adjusted models.
Over Northern Hemisphere mid-latitude land areas, zonal mean differences between July and January temperatures simulated by the non-flux-adjusted models show a greater spread (positive and negative) about observed values than results from the flux-adjusted models.
The ability of coupled GCMs to simulate a reasonable seasonal cycle is a necessary condition for confidence in their prediction of long-term climatic changes (such as global warming), but it is not a sufficient condition unless the seasonal cycle and long-term changes involve similar climatic processes.

Coupled climate models do not simulate with reasonable accuracy clouds and some related hydrological processes (in particular those involving upper tropospheric humidity). Problems in the simulation of clouds and upper tropospheric humidity, remain worrisome because the associated processes account for most of the uncertainty in climate model simulations of anthropogenic change.

Temperature predictions from some climate models assuming the SRES A2 emissions scenario.The precise magnitude of future changes in climate is still uncertain [20]; for the end of the 21st century (2071 to 2100), for SRES scenario A2, the change of global average SAT change from AOGCMs compared with 1961 to 1990 is +3.0 °C (4.8 °F) and the range is +1.3 to +4.5 °C (+2 to +7.2 °F).

Forecasts of climate change are inevitably uncertain. Even the degree of uncertainty is uncertain, a problem that stems from the fact that these climate models do not necessarily span the full range of known climate system behavior

But this is from your post:

Information about climate and how it responds to increased greenhouse gas concentrations depends heavily on insight gained from numerical simulations by coupled climate models. The confidence placed in quantitative estimates of the rate and magnitude of future climate change is therefore strongly related to the quality of these models.

So these are problems with ALL the models.

Further, you are making a strawman by suggesting that the ONLY thing we have to go on for these conclusions is computer models. I think we can all pretty well reject that assertion on its face.

What conclusions? I'm not sure what I said about any conclusions...sorry if I wasn't clear, my intent was to question the predictive accuracy of the computer models.

Your assertion that the models work is unconvincing. I ask again, which ones predicted the current cooling trend?