Merged Global Warming Discussion II: Heated Conversation

[jobberone]

We're actually in an interglacial period at the moment, and have been for about 10,000 years.


The current interglacial is set to be an unusually long one, with the next change in insolation that might be great enough to precipitate another period of glaciation not due for at least 23,000 years.

http://en.wikipedia.org/wiki/Milankovitch_cycles

Yes we are in an interglacial and are still in the Quaternary glaciation in an overall ice age between 2-3 million years old set in the backdrop of significant glaciation beginning about 23 million years ago. So I think I have the beginnings of some basics.

I'm concerned about rising greenhouse gases but I'm even more concerned with the pH of our oceans. I'm still trying to set those basics in memory.

I haven't meant to ignore you or others I've just been busy. I don't really have the time for this topic but I'm going to attempt to make some time for it anyway.

 

[aleCcowaN]

I see this schtick all the time. Not impressed. I'll respond to one of your verbal barbs. The earth has had substantial glaciation for the last 2.56 million years. We are in an interglacial which may or may not last a long time.

Now is there something erroneous about that?

Your previous post (#592) took many words to say basically nothing. Now you dropped the outmost mask. Your assertion would be correct for a very narrow definition of substantial, a plural for glaciation and a perfective use of the English present perfect and not a perfect one. I'm afraid you are again applying sales rhetoric and retouching your speech to wedge in things there are not there . Your assertion about the "may or may not" part is only valid in a context of "the future hasn't happened yet" and for an extremely wide definition of "a long time". And all of that barely relates with anthropogenic global warming in this narrow period of the Anthropocene. If you haven't noticed yet, you're almost off topic.

And do me a favor?? You have no idea how I feel about 'global warming' because I don't have a position only concerns. So stop trying to be cute and read my mind. And since you don't know me or my background including education then you have no right to question my intellect or intellectual abilities or honesty.

Why would your background and education be important? The problem here is what you say here. You seem to think you have to be respected more than a garbage collector just because you have some sort of "polishing", "cultural varnish" or whatever. You have a 100% of my respect, and what you've said and the way you said it couldn't have had less of 100% of my objection.

By this time you should have realised that the science of AGW is strong and evolving, and that this is not the place to disprove it -though you're welcome to believe you're trying- but the place to be sceptic and analyse how rhetoric is used to confound the masses. All of that in the context of dissecting epistemological hedonism in front of those very masses. AGW, because of its complexity and range, is a subject that fosters epistemological hedonism in subjects that otherwise would be more centred.

 

[ideogram]

jobberone, the theme I'm getting from you is "we don't know". This could happen, that could happen, therefore all we can say is "we don't know". I am guessing you don't really understand probability.

Let me try to explain it this way. You are playing blackjack. There are hundreds of cards you haven't seen yet. How much money do you bet? You could just say "we don't know" and bet whatever you feel like. But if you've been counting cards, you know most of the face cards are gone. Do you know for sure the next card is not a face card? No. But is that the same as saying "we don't know?" No.

You can make a lot of money by knowing the difference.

This is the kindergarten version. Now imagine people have been "counting" all the cards in the climate change deck for decades. And they are saying, don't bet the next card is a face card.

 

[lenny]

dear old-timers on this thread,

Yes, you seem to be denying it. We only need confirmation.

it seems to me that attacking every new poster here as if they are part of the antiscience lobby is an unfortunate approach. those that are soon reveal themselves, those that are not fail to learn the basics of climate science and understandably respond to being attacked, painting themselves into a logical corner, no doubt, but not accepting the evidence as most scientists see it. that counts as a loss for us, no?

We're not writing all of that down again just for you. Do you think that after 20,000 or 40,000 posts on the matter your concern hasn't been extensively explained and backed here?

no, i do not suggest writing it all down again. but the E in JREF might suggest posting a link, as macdoc did, rather than yelling at someone for asking a naive question. even pointing them to a specific post amongst those 40,000 posts.

i really have had the experience of engaging with someone i was certain was an antisicence lobbyist in hiding, only to learn later it was a 14 year old with real concerns and questions... and eventually happy to follow the basic arguments to their 'good as it gets' conclusions...

i do not understand why those on this forum who know the science don't happily give newcomers more rope, lots and lots of rope! (my understanding is not all that important, but the strategy might have other benefits )

 

[lenny]

... how does one tie any specific or even group of events to AGW? It remains a controversial contention in my understanding

this is not controversial, it is merely an ill-posed question.

when discussing a change in the distribution, no attempt is made to tie a specific event to the change in the distribution. when discussing a change in distribution, given only observations (that is, unless one has knowledge of the two distributions themselves) one can only make statements of probability, this is not a shortcoming of the science but the nature of the appropriate answer to the question asked. does that make sense?

in the same manner, it makes no sense to assign any particular home run to steroid use of the player...

While one cannot tie any particular weather event to AGW with absolute certainty.

but then science NEVER provides (or claims to provide) absolute certainty. only religion claims to do this.

firm foundations and forecasts regarding the impacts of increasing CO2 levels date back to the 1920s.

questions which ask climate science to do things that science does not do can be clarified without reference to climate change. repeatedly asking them in the context of climate change after they have been established as ill-posed or unscientific is difficult to interpret charitably.

 

[aleCcowaN]

dear old-timers on this thread,

it seems to me that attacking every new poster here as if they are part of the antiscience lobby is an unfortunate approach. those that are soon reveal themselves, those that are not fail to learn the basics of climate science and understandably respond to being attacked, painting themselves into a logical corner, no doubt, but not accepting the evidence as most scientists see it. that counts as a loss for us, no?

no, i do not suggest writing it all down again. but the E in JREF might suggest posting a link, as macdoc did, rather than yelling at someone for asking a naive question. even pointing them to a specific post amongst those 40,000 posts.

You mean like dozens of posts I did one, two, three or four years ago? I'm now letting you pals deal with nice newcomers, as most of them are, even those who distrust AGW, because you do it very well.

I think you didn't understand the situation. There is enough evidence in every case to have done it that way. In one of the cases, the poster started with a speculation based on the geological register in a scale of aeons. Later, I asked him -or her- about the use of a famous denialist iconic figure; this person replied defyingly and I provided all the information needed. The result was silence and new attempts to follow the previous line. To make the story short, the poster increased his careful word selection in his posts without changing a bit the original line. The last reincarnation of his posts is the old trick of presenting his own idea as if it is some intermediate common position, and that is that we are supposedly in a glaciation and colder is around the corner while warmer is the long term normal. Those together with the "we're not sure" bull prepare the ground to sell inaction about the whole business, and the "we have to be careful" nails it. Chemically pure rhetoric.

The other case, well, the poster already posted this (yes, your past haunts you, skeptsci):

You know how funny (and cynical) AGW alarmists sound when they talk in the name of science? The vocabulary and argumentation are those of fundamentalists ("deniers" "flat earth believers" producing propaganda films and winning Oscar and Peace Nobel Prizes). With IPCC reports serving as their Bible. Many times, in this forum system, I have read sentences such as: " so you claim that all these scientists at the IPCC are wrong…." ?. Those who have been using science as a tool for facilitating the advancement toward (long sought after) political goals of some politicians or movements should well expect to be answered by the same token. The damage to the trustworthiness of science in the public eye caused by the revealed bad science and problematic scientific behavior of scientists in climatology related fields will take long time to heal.
And GreNME how can you even start comparing the enormous explanatory power, theoretic soundness and body of evidence of the theory of evolution to that (AGW) level of scientific argumentation?!

or this:

About this increase in ice area, this could be a misleading fact. It may not be linked to a "cooling" effect. Quite the contrary.

In June 2006, there was already a case of a misread publication. The scientists found an increase of polar ice thickness in a specific region. Of course, GW deniers jumped on it.
I learned it on the radio. "It's not melting! Do you hear me, (insert bad word - sic). It's thickening!" It was pleasant to have a DJ calling you names early morning.
An editorial in the journal Nature (mid-June 2006) set it back on perspective. It turned out this patch of ice was deep inland, and was not receiving much rain or snow. The thickening was the result of more precipitations making in inland.
And what causes an increase of precipitations? More water in the atmosphere, meaning more sea evaporation. Meaning higher temperatures.

To this extend, "global warming" could be a bit misleading. From that I understood, it's more like "warmer summers, colder and more rainy/snowy winters". I think I will wait next Summer to decide if the global warming is over.

Adding a little bit of drama made it more interesting especially when used as a mean to belittle the opinions you didn't like. But hey you did reach the reasonable conclusion highlighted (by me) in yellow.

and that's just the tip of the iceberg as there are more along the same lines, so, a little too much for a naive newcomer, don't you think?

It's still pending more research on the sockpuppety nature of these kind of newcomers. But in the meantime I suggest you to look more into climate models as you are needed of much more study on that subject and take into account that the educational purpose of a forum is with the occasional reader, and not necessarily the poster, who is naturally committed to do so, otherwise compelled. That elemental goal has long been neglected here in such a way that even an angelologist is using forums.randi.org as a sort of backing for his quackeries.

 

[DC]

yes new posters are mostly not welcomed nicely here. especially when they are not informed about the topic.
i can understand why many react the way they do to new posters here, but its contraproductive and does indeed make an impression like the inquisition.

but also the newcomers often come in the wrong way, often they already have opinions and speculation without being informed about the science. and often they want to debate and then those that are informed have to explain all the thngs we all explained a 100 times already to others over the years.

But how do you start informing yourself? i still think the media in general does a pretty bad job in infomring people. often they present the case as if the science is still debating the basics. often the media gives the deniers the same amount of time to present theyr myths. most other topics this is unthinkable. when they talk about astrophysics they don't invite geocentrics or electric universe nutters or however they call themself.

when they talk about earthquakes they talk plate tectonics, and no holow world, no growing world etc etc.

So one has to do alot of reading to get informed. and most people do not want to read the IPCC reports. Wich is a very very good summary of the science, but its huge and time concuming, alot of aditional reading is needed to understand it properly etc etc.

and then the internet is full with denier blogs that make convincing arguments when you are not propertly informed about the science. and one can easely be misled.

but here some links for "beginners" that are really interested in getting informed about the science in this topic.

http://www.epa.gov/climatechange/basics/

http://www.epa.gov/climate/climatechange/kids/basics/index.html

http://climate.nasa.gov/evidence

http://climate.nasa.gov/

http://www.esa-cci.org/

more detailed sources:

http://www.realclimate.org/

debunks alot of deier myths:

http://www.skepticalscience.com/

https://www.youtube.com/playlist?list=PL82yk73N8eoX-Xobr_TfHsWPfAIyI7VAP

the best and most detailed summary of the science:

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html

 

[lenny]

but also the newcomers often come in the wrong way, often they already have opinions and speculation without being informed about the science. and often they want to debate and then those that are informed have to explain all the thngs we all explained a 100 times already to others over the years.

i do not disagree. i merely point out the damage "blaming the young" can do, in any educational forum.

i can understand why many react the way they do to new posters here, but its contraproductive and does indeed make an impression like the inquisition.

getting the discussion restricted to a single thread gave advantages to the antiscience side. as does (in my view) provoking others to give the impression of the inquisition. i too can understand the reaction, it just appears very counterproductive: raising the noise level is an effect approach of the anti-science campaigner, both online and in public. what are the effective responses to this?

but here some links for "beginners" that are really interested in getting informed about the science in this topic.

thanks for the list. i think things like this, and macdoc's long running dedication to his list, really help.

it is a shame there is no way to make such things "sticky" on this thread. or that threads on individual topics are not allowed, so that an introduction to each "beginners" question could be easily archived and then pointed too.

 

[macdoc]

I really think this thread should and has been moving beyond any question of if it's occurring - there is lots of sites dedicated to the ill informed.

It's akin to dropping into an evolution discussion and questioning it.... non-factual position that cannot be supported so earning an instant diss.

Want to discuss the "pause", regional forecasting, speed of onset of consequences, all those discussions are predicated on the established reality of AGW. Regular posters here are not much tolerant of the poorly informed - wilfull or not.

What we did successfully at another forum is to split the Climate Science thread and restrict to those that accept the consensus view and then give the deniers their own thread and enforce it.
Working so far tho not much left in the denier arsenal of nonsense....couple of blind Aussies one of whom drives a coal train....no conflict of interest there...

There is lots to go over that is not clear while still shifting any "open mind" to the deniers to bring evidence and theory that can counter AGW theory effectively.
Lots of big money like Koch and Exxon have been trying....entirely dishonestly in terms of results..to discredit the science .....spending millions in the attempt to influence public and politicians.

Fed up with it comes to mind.....

Climate Change Deniers Banned From Major Newspaper

politix.topix.com/.../8426-climate-change-deniers-banned-from-...‎
by Mary Noble
Oct 14, 2013 - Climate Change Deniers Banned From Major Newspaper: LA Times won't even print letters from climate change skeptics,

no tolerance for factually incorrect.....no tolerance here either.
I've asked numerous times for a Climate Sources sticky at the top like evolution has.

Management here creates it's own set issues regarding climate including JR himself....for which he got thoroughly excoriated by the science community ....and deservedly so....prompting a weak retraction.

So if you sense disgruntlement and weary of nonsense....it's with good reason.

This is sufficient to get up to speed for someone willing to make the effort.
http://www.realclimate.org/index.php/archives/2007/05/start-here/

Gavin feels aerosols are the biggest enigma facing climalogists and modelers....very very complex issue.

 

[aleCcowaN]

it is a shame there is no way to make such things "sticky" on this thread. or that threads on individual topics are not allowed, so that an introduction to each "beginners" question could be easily archived and then pointed too.

I think that is no longer the rule at forums.randi.org. The solution I envisage is very good opening posts with an addendum about a few rules to follow in the thread. Pretty much a slightly improved version of Ben's threads about Arctic sea ice which were a success.

One recurrent problem in these fora have been the denialists, among many a zealot, opening thread after thread with defying content. The typical thread started by, say, Muchahontas, asserting "one year of cooling wipes out a century of global warming" and adding some twisted figure with instructions to read it in the way the thread's title proposes. After that a lot of people would jump in and some quarrels would start. Of course, Muchahontas no longer would participate in the thread, saving efforts to start another thread elsewhere. The antidote to those techniques propaganda offers is the kind of threads I explained above and a general thread -in fact, this one already is it- labelled "Anti global warming propaganda goes here". A thread that can be on moderated status or not, according to the forum weather.

 

[macdoc]

I see the anti-evo and anti-agw have joined forces....

http://www.slate.com/articles/healt...hange_political_union_of_science_critics.html

•••

This is the lead off at Ratskep for climate news and science discussion

GENERAL MODNOTE
This thread is for discussing the science of climate change. It has the operating assumptions that climate change is happening, and that it has an anthropogenic origin. From the 2007 IPCC Summary for Policymakers:

The Intergovernmental Panel on Climate Change wrote:
Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level...

Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases...

Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations...

Discussions of the pros and cons of the science go here.

Climate change denial does not go here.

Members wanting to post general remarks denying climate change or its anthropogenic basis, or off-topic references to what your favourite journalist, politician or 'radio personality' says about it all, should post them in the Climate Science Denial thread, which can be found here.

This thread will be strictly moderated. Off-topic, inflammatory, irrational or non-science based posts will be either binned or moved to the Denial thread as appropriate. Continuing to post OT or inflammatory posts will invite moderator attention, guidance, and corrective action as required.

Members are invited to contact a forum moderator if they need further clarification, or to use the report system if posts need to be reviewed by staff.

http://www.rationalskepticism.org/earth-sciences/climate-change-science-t988.html

and the accompanying Denial padded room

Climate Change Denial
#1 Postby Nicko » Sep 17, 2012 11:14 am


!
GENERAL MODNOTE
This thread is for posting and discussing climate change denial.

This might include general remarks denying climate change or it's anthropogenic basis, or what a columnist, politician, 'radio personality' or stand-up comedian says about it all. If you wish to discuss the science of climate change - pro or con - you are welcome to do so here, but please read the moderation note in the OP of that thread, and restrict yourself to discussion of the science.

Members are invited to contact a forum moderator if they need further clarification, or to use the report system if posts need to be reviewed by staff.

This was a carry over from a long battle at RDNet to get the trolls out of the science thread .....it mostly worked as the leadin post stated participation in the thread acknowledged the consensus view on climate change.

That tended to keep them at bay.

The headaches arise when you get a mod who thinks there is valid science behind the denialists qnd wants to give "equal opportunity" .....gets old.

 

[jobberone]

jobberone, the theme I'm getting from you is "we don't know". This could happen, that could happen, therefore all we can say is "we don't know". I am guessing you don't really understand probability.

Let me try to explain it this way. You are playing blackjack. There are hundreds of cards you haven't seen yet. How much money do you bet? You could just say "we don't know" and bet whatever you feel like. But if you've been counting cards, you know most of the face cards are gone. Do you know for sure the next card is not a face card? No. But is that the same as saying "we don't know?" No.

You can make a lot of money by knowing the difference.

This is the kindergarten version. Now imagine people have been "counting" all the cards in the climate change deck for decades. And they are saying, don't bet the next card is a face card.

Under those circumstances I'd bet with you. And I'd bet that CO2 levels rising are going to raise temps. I'm not sure how much but only a fool would not be concerned. The winters in general here are warmer than the 50s were. I had to have a coat as a child/young person most days. Now that's anecdotal but still an observation that appears to ring true.

I don't believe you are at the point to start making certain predictions. That's a far cry from you don't know enough so you don't know anything.

I'm sure you guys see a lot of different types coming thru here. It's a mistake to think they are all alike. And it's a mistake to think you are at the point of being predictive within a high degree of certainty.

 

[macdoc]

How could you possibly "predict" when the major unknown is the amount of C02 humanity will emit.
That's why the scenarios are laid out in a range of outcomes from controlled to BAU extreme consequences.

The other unknown is timing and consequences for various regions. The tropics expand and don't get much hotter at the core but the band expands towards the poles.

The Arctic is the smoking gun for rapid change....in all aspects of geophysical changes and biome changes the pace is stunning even for the scientists engaged with the region.
Species never seen in the region, species under stress from change, ridiculous high temp records being set and entire biomes ( small lakes ) being eliminated entirely.

Each year the changes are document by an internation cross discipline team.

http://www.arctic.noaa.gov/reportcard/

The body of knowledge of aerodynamics is not complete but we still build and fly in aircraft.
We know "enough" to act.

We know enough to act on climate change.

We don't know what is best course of action.

We don't need more "predictions" - the changes are in progress and documented.
We don't know exactly the impact of 5% more moisture in the atmosphere and greater swings of weather but we can see the trends and the insurance companies can as well.

They are acting
http://www.triplepundit.com/2013/11/climate-change-insurance-industry/

They must or face going broke....too bad society as a whole is not informed, motivated and taking action in the same manner.

 

[Reality Check]

Now is there something erroneous about that?

Nothing erroneous about being in an interglacial period.
But little to do with the current global warming which will have an effect over the next century. Have a look at Are we heading into a new Ice Age?

 

[ideogram]

Under those circumstances I'd bet with you. And I'd bet that CO2 levels rising are going to raise temps. I'm not sure how much but only a fool would not be concerned. The winters in general here are warmer than the 50s were. I had to have a coat as a child/young person most days. Now that's anecdotal but still an observation that appears to ring true.

I don't believe you are at the point to start making certain predictions. That's a far cry from you don't know enough so you don't know anything.

I'm sure you guys see a lot of different types coming thru here. It's a mistake to think they are all alike. And it's a mistake to think you are at the point of being predictive within a high degree of certainty.

Sorry, you still don't get it.

How many face cards are left in the deck? Twenty? Ten? One? It matters.

Probability isn't a "belief". It's a number.

You say maybe a higher CO2 level will be better for us. What is the probability of that being true? You don't have a number. You don't know.

You say you want a "high" degree of certainty. What does "high" mean? 90%? 95%? 99.99%? You don't know.

 

[lomiller]

There's also consequences of some species of plants invading areas not normally habitable for them or at least relatively so. .

Global warming will force virtually all species and to move thousands of miles over a few hundred years. This is so far beyond the issues around a single species moving you can’t compare the two. This is why there is a real risk of global mass extinction.

For comparison 18000 years ago the northern great planes were covered with half a mile of ice, South Dakota was taiga and most of the southern US was desert or steppe. Warming of 6 degrees changed the world to what we know now, but that warming took over 5000 years. Even the “good” scenarios have us warming 3 degrees in a mere 200 years.

OTOH, if we can grow crops in areas not previously favorable for the same then food production would likely increase.

Did you read what I wrote? We can’t grow corps in previously unfavorable regions because there is either no soil or unsuitable soil/drainage even if temperatures warm.

I'm more concerned about unforeseen consequences than worrying about making non-arable land fit for crops.

The foreseeable changes are bad enough that we should be seriously concerned. The unforeseen paints an even grimmer picture.

As a pure amateur in this field of climate all I can do is speculate from a biological standpoint. However, I believe there are so many variables that most everyone is speculating.

Didn’t you just say you wanted to worry about unforeseen changes? Worrying about the unforeseen is by definition speculating. What I’m talking about is all very well documented so no speculation is required.

What I'd like to see is arid areas receive more rainfall although I suspect that is wishful thinking. Unless the greenbelt expands my guess is arid areas may in the main on balance become more arid.

Mainly this is true. Some arid areas will become wet due to changes in monsoon patterns, but this will be offset by wet areas becoming arid. In other cases, wet areas dominated by rainfall should become even wetter, while dry areas dominated by evaporation will become dryer. Some regions like the Amazon are known to dry out as global temperatures rise but for the most part specific regional forecasts can’t be made with high confidence.

 

[lomiller]

not sure exactly what you mean by "indefinitely": if a model is generating regional weather at very low fidelity, then eventually it cannot be expected to get a changing climate usefully even on larger scales..

Regional forecasts require predicting what heat energy is doing in the atmosphere, global forecasts only require you to know how much heat energy is present, not how it ends up being distributed. The latter is a much easier task.

the more rain argument with 2xCO2 has been clear since the 1920's, the intensity/frequency question is still pretty open. i'd take 10:1 the balance there will change again.

A warmer planet means both precipitation and evaporation increase globally. This should be obvious that these two things are linked. What’s less obvious is when/where this precipitation ends up occurring and if a given region will be dryer or wetter even with more rainfall.

 

[lomiller]

We're in a glacial age and have been for some time. So if I say we don't really know what's going to happen over the next 1000 years then I think I'm on solid ground. If you tell me the methane and CO2 levels are going to rise exponentially over the next 100 years then I will wonder how that reconciles with the idea we should be at some point entering into a colder period.

If you're only interested in the next few decades then I really don't bring much to the conversation other than to remind it has been thought we should be getting colder, it has gotten colder in the very recent past and been warmer in the recent past, and it is getting warmer now but not as predictably as we'd like to know in advance.

There are unpredictable changes coming. Nuclear fusion and possible mass desalination. Advances in aging and increasing medical knowledge. Vaccines esp one for malaria. Use of solar radiation esp lunar.

So I'm not trying to step on the experts toes.

You are not on solid ground. The only real unknowns are what human activity will be over that time and whether we will cross some tipping point. The major forcings are all reasonably well qualified for the current climate range and we have reasonable projections for what the natural forcings will be over that time period. While crossing a tipping point would be bad, there is plenty to worry about even if this didn’t happen.

We are already in what should be a cooling phase. IIRC this was set to continue for another few thousand years, followed by a warmer period and eventually another cooling period with a possible, glaciations some 18K years from now. If that glaciation is avoided than the next natural glaciation would have been ~50K years from now.

If you tell me the methane and CO2 levels are going to rise exponentially over the next 100 years then I will wonder how that reconciles with the idea we should be at some point entering into a colder period.

The changes humans are causing are at least an order of magnitude larger forcing than the ones that trigger the start/end of a glaciation. The natural factors that were causing long term gradual cooling are completely overpowered by what humans are doing.

With the “long tail” lifespan of CO2, both of these glaciations are already unlikely to occur, and there will still be some level of elevated temperatures 100K years from now.

If you're only interested in the next few decades then I really don't bring much to the conversation other than to remind it has been thought we should be getting colder,

This isn’t the case. There are some human induced cooling effects as well, but the bulk of the scientific community always though the warming influences were greater than either the human cooling influences or the natural cooling influence.

If you're only interested in the next few decades then I really don't bring much to the conversation other than to remind it has been thought we should be getting colder, it has gotten colder in the very recent past and been warmer in the recent past, and it is getting warmer now but not as predictably as we'd like to know in advance.

it has gotten colder in the very recent past

There was cooling of perhaps 0.5 degrees over a period of 300 years in period sometimes called “the little ice age”. Some of this may have been related to human activity as well but this could also be the natural ups and downs overlaid on a longer term cooling trend. Current changes are MUCH larger than either the natural ups and downs or the natural trend.

and been warmer in the recent past, know in advance.

What do you mean by recent past? The Holocene optimum 8000 years ago may have been warmer, but even that isn’t certain. In multiple places globally artifacts frozen for 5000+ years are now thawing out. The last period clearly warmer than today was ~125 000 years ago, and we are expected to match or exceed these temperatures in the next 100 years.

it is getting warmer now but not as predictably as we'd like to know in advance.

Again what do you want in terms of predictability? The overall trend is ~0.2 degrees er decade but any given decade can be above or below this trend. In some extreme cases a decade could be +/- as much as 0.2 degrees. Due to chaotic effects, the time horizon for looking at the trend is 20-30 years but what it’s really the trend that is important.

 

[lomiller]

To me you "sound" like the Inquisition of the church. This is not a religious debate, haven't you noticed?

On the basics, the scientific debate ended decades ago with the conclusion the earth is warming and humans are causing it. If someone chooses to take another stance without some extraordinary evidence to support it, I think characterizing their position as one based on belief rather than facts is fair.

Please give me compelling evidence that the anthropogenic increase in CO2 and/or other GHGs is an important cause of the observed GW and I'll be on my way.

So if we provide you with the hundreds of thousands of pages published in the scientific literature on the subject is a simple clear forum post you will accept the reality of global warming and be on your way? Isn’t that a bit like saying no amount of scientific evidence we could present will ever convince you?

The summary version of what’s in the scientific literature goes like this.
- Greenhouse gases block IR radiation from leaving the atmosphere
- Less IR leaving the atmosphere causes an energy imbalance than warms the planet until a new stable equilibrium is reached.
- Human emissions have raised the amount of greenhouse gas in the atmosphere
- The earth has warmed by the amount predicted from this increase
- The rate of warming is very high, much higher than any natural change that has occurred for many millions of years.
- There are no significant natural factors that can explain this change

 

[macdoc]

Originally Posted by jobberone View Post
If you're only interested in the next few decades then I really don't bring much to the conversation other than to remind it has been thought we should be getting colder,

by who??
Indeed according to the Milankovich position it should be cooling slowly and was until we came along.
I suspect however you are referring to global dimming which you can look up.

This wiki chart leads left to right past to present and the slow cooling is clear until we got industrialized...

and the rise has gotten steeper since the 80s.