Arguing that Global Warming exists

[mosaix]

NickB has contributed two excellent posts - many thanks.

 

[Dave]

NickB has contributed two excellent posts - many thanks.

Agreed except that his post appears to tar all environmentalists with the same brush.

Most of my colleagues get really frustrated with environmentalists exaggerating climate change (frankly, it's bad enough without needing to exaggerate it) - this is counter productive, and reflects badly on scientists because people wrongly lump us together with environmentalists - something about us apparently being on the same side, hmm. This doesn't stop us loathing the people at the other extreme who are bent on perverting the science for ideological or economic reasons. Frankly the statement that we've teamed up with environmentalists is verging on slander as far as I'm concerned.

I agree almost entirely, many people see the green movement as communism under a different coloured banner, and sometimes they are, but I would ask that isn't the real reason for all of this to be:

1) the lack of research itself.
2) the woeful scientific ignorance of journalists.

On the lack of research: the picture is becoming clearer now, but until very recently you could easily argue for and against the man-made warming, or even that there was no warming at all, and have enough flimsy scientific evidence to back it up because it was so unclear. With a lack of research you do have to make a subjective judgement based on your own world view. That will quite obviously be different for different people because of their backgrounds and political affiliations. It would be different for someone living on a floodplain who is currently living in a caravan, from someone who's whole town is employed by the local energy-inefficient factory. This is an important and emotive issue, the future livelihood of your family could not be more important. I work in a customer driven environment, I can tell you that customers always exaggerate issues.

You also appear to think of this is a modern development. Take a look at the research into the effects of acid rain pollution in England in the late 1960's and 1970's. Look at who paid for the research and then match it up to the results which the different research papers found. That doesn't mean that the scientists were in the pockets of the CEGB, nor that they were in league with anarchist environmentalists, "perverting" science as you called it. It is simply a vital part of the scientific method. Each piece of research brought in different variables that had never been thought of before, not because they had been deliberately hidden. Peer review of all the current research then brings a consensus of opinion, (although the British government continued to argue with the Scandinavians about the effects on their lakes right up until the 1990's.)

We still have not reached that point on climate change where a consensus is possible and only more research is the answer. Worrying to me is that I've seen commentators in the US saying research into climate change is a waste of money.

 

[NickB]

Agreed except that his post appears to tar all environmentalists with the same brush.

Guilty as charged! I have no quibble with the aims of many environmentalists, by which I mean activists who aren't necessarily expert in the science (although many are very well informed). But there is a tendency to exaggerate, which is counter-productive. I was really trying to make the point that there are tensions between scientists and environmental activists, whereas the media and public often fail to differentiate between the two groups.

As for there being a lack of research, I'd say there has been an enormous amount of relevant research since the early 1990s (and indeed before, although this wasn't all framed by the "global warming" paradigm). I think it has been quite a number of years since there was any serious doubt that we are affecting the climate. It is only since 2001 that scientists have become more confident about how sensitive the climate is to increased greenhouse gas concentrations (it is now thought a doubling of atmospheric greenhouse gas concentrations, which we will reach in the middle of this century at the current rate) will increase global mean temperature by around 3 degrees C. In 2001 there was a lot more uncertainty, with estimates ranging from around 1.5 degrees to 4.5 or more.

As for people "perverting" the science, of course there is lots of room for interpretation and disagreement. But this is really in terms of the details - magnitudes and rates of warming, the nature of impacts and the role of feedbacks in the climate system - not on the existence of human-induced climate change. There are always questions to be answered, and one should never be dogmatic about the science. But there are certainly people out there (most of who are not bona fide scientists, and almost none of who have a background in climate science) who deliberately distort and misinterpret the science for their own ends. Most of the public uncertainty, and most of the public perception of disagreement in the climate research community, is the result of deliberate campaigns to confuse the public and reduce support for action to mitigate manmade climate change. A strong claim, but one I'd stick by. Google "climate change myths" and you will find a lot of material here - some attacking the science and some defending it. You can also google my blog (Sand and Dust) - there are some posts here on this issue, plus links.

All the best

Nick

 

[Dave]

Most of the public uncertainty, and most of the public perception of disagreement in the climate research community, is the result of deliberate campaigns to confuse the public and reduce support for action to mitigate manmade climate change.

That's where my second point comes in.

2) the woeful scientific ignorance of journalists.

Most people never read a science magazine, even less a research paper. They get their knowledge from the TV and newspapers. And as you rightly point out, the Internet with it's very dubious authenticity, and more than it's fair share of wackos. That's why I'm not sure that I agree with you on banning those two films from schools. Yes, they are both propaganda, but they balance each other and it is important that children learn to differentiate facts from fiction. They are certainly not going to be shielded from it when they leave school.

 

[NickB]

That's why I'm not sure that I agree with you on banning those two films from schools. Yes, they are both propaganda, but they balance each other and it is important that children learn to differentiate facts from fiction. They are certainly not going to be shielded from it when they leave school.

I'm not dogmatically in favour of banning them. On the one hand I think we should avoid using school kids as pawns in ideological battles. Maybe this is hopelessly utopian of me - kids can't help but be exposed to all the unexamined ideological assumptions of their teachers and those who make education policy. But perhaps we should avoid the more explicit, deliberate exposure of children to propaganda, whether we sympathise with it or not.

On the other had I have no problem with school children being shown either (or preferably both) films, as long as they are presented as representing particular points of view, and not as works of science. In fact they would make very good departure points for a discussion about science versus ideology in the context of climate change. The trouble is, I'm not sure that most teachers (even science teachers) are well enough versed in the science to be able to really tackle the issues raised in the films and the reality of what the science does and doesn't say. I haven't examined the treatment of climate change in the national curriculum - maybe I'm not putting enough faith in the system to deliver education on this issue that reflects the state of the science.

 

[jackokent]

I agree that the government is wrong in trying to push the responsibility for tackling climate change onto the individual when they are doing very little apart from talking about the need to address it. Most governments that acknowledge a problem with climate change are self-righteous, lazy, hypocritical and cowardly when it comes to tackling it. .

I hear a lot of complaint about Government in-action on this and other threads. I agree in part. However, I wonder what it is we expect Governments to do and how.

We, Joe public, through our media, are the very first to shoot down anything radical that a politician suggests. We do not like restraint... we call it control and use phrases like Big Brother. We do not like inconvenience, we feel we have a right to our cars, our mod cons, our bin collections etc etc.

People really really want the Government to do something... as long as it doesn't put them out.

I am critical of the Government.... but I am also very critical of the people who do not let them act. If we want our Government to take massive / radical action we have to be prepared for restraint and control... and we just don't put up with it.

 

[Coolhand]

Interesting title of this thread, but I don’t think anyone is arguing that global warming hasn’t happened. The thrust argument now seems to be how much of it is down to us and how much is natural, and how bad is it going to get i.e. bad enough to spend the trillions of pounds it’s been estimated to cost to “fix.”

I’m just an average dude in the street with no real scientific training. But I’ve learned not to trust journalists or pressure groups at all when it comes to this kind of issue, and so I tend to just listen to the scientists argue and then make up my own mind as to who’s data and theories come out the most reliable. As a result, I’ve followed the whole “anthropogenic climate change” debate with interest but also with frequent confusion, and irritation with both sides.

The thing that really annoys me is the time and effort spent by both sides accusing the other of having agendas, rather than addressing the actual data and theories. People interviewed for news items tend to be notably bad for this.

At the end of the day, a scientist could be Captain Evil, who’s hobbies include selling his soul to Satan and whipping puppies with barbed wire, but if his research and data is accurate, then it’s accurate. So people should spend their time attacking the data, and not the fact that their opponents have jumped into bed with Shell Oil or Greenpeace.

A few responses to Ray from a climate scientist who also works in the field of archaeology.

Ooh, cool! A climatologist! I was wondering if I could pick your brains for a second on subjects that I keep hearing argued back and forth? I try to keep an open mind on it all.

What’s your opinion of the Mann Hockey Stick Graph?

What’s your opinion of the claim that ice core records show a link between CO2 rises and temp rises?

What’s your opinion of the sun’s influence on climate?

What kind of sea level rise do you think we’re going to see?

Which of the climate computer models do think holds the most reasonable predictions for the future changes?

What kind of effect will warming have on the spread of insect based disease such as malaria?

I’ve heard many conflicting claims about the recent increase in global temperature, including some that it actually hasn’t gone up for the last couple of years and others claiming that it has? What are the actual measurements saying? And how many separate measurements are getting taken?

Thanks in advance, NickB, for any of those you choose to answer.

 

[Overread]

"Which of the climate computer models do think holds the most reasonable predictions for the future changes?"
Well I can answer this one from one of my lecturers - none of them, they all mostly start breaking or taking such wild guesses/estimations at the global scale that they cannot truly be expected to produce accurate modelling of the future.

 

[Coolhand]

"Which of the climate computer models do think holds the most reasonable predictions for the future changes?"
Well I can answer this one from one of my lecturers - none of them, they all mostly start breaking or taking such wild guesses/estimations at the global scale that they cannot truly be expected to produce accurate modelling of the future.

So, err, at the risk of asking a dumb question, what's the point of them then?

 

[Rawled Demha]

id guess because any model, however vague is better than no idea. these models can then be refined to make better ones, and so on.

as long as you're aware that its a model, and not telling te future without any doubt.

 

[Coolhand]

Well yeah, but as you pointed out in the parrallel universe thread, flawed maths isn't maths at all. I mean, what's the point of a model that just takes vauge wild guesses? I can take vauge wild guesses, I don't need a computer for that. I thought the whole point of these computer models was that they were supposed to be a very good indicator of what's going to happen 20, 50, 100 years from now.

You could argue that a model that gives you the WRONG data is actually WORSE than no model at all, coz it sends you off in the wrong directions.

Or am I being thick?

 

[Overread]

"I can take vauge wild guesses, I don't need a computer for that."

scientists can also make wild guesses and also make conclusions based upon collected data; however whilst our current data and understanding of the world is strictly to limited to produce the perfect answer, the data we do have is to vast for people to be able to work with one their own, or even in groups. Thus computer models allow the use of larger data pools to draw conclusions, however it has to be strongly recegnised that they are flawed results. They will let you make connections between events and devise theories to expline those connections, but these have to then be tested in the real world. In the case of global warming theories, the only way to test them is to go through global warming itself

 

[Coolhand]

Thus computer models allow the use of larger data pools to draw conclusions, however it has to be strongly recegnised that they are flawed results. They will let you make connections between events and devise theories to expline those connections, but these have to then be tested in the real world. In the case of global warming theories, the only way to test them is to go through global warming itself

Yeah, that sounds logical.

The problem seems to be that we’re expected to form wide-ranging and serious international policies at great cost to ourselves (financial and otherwise) based on models that most people seem to agree are seriously flawed and may not in fact reflect the future at all.

I heard a great idea from someone a while back about sorting out all this doubt about the reliability of the models. I think it was from Michael Crichton and, regardless of what you think of his general stance on climate change, this idea is pretty hard to argue against.

It was basically to run all the models publicly for a ten year period, and compare what the models predict will happen to what actually happens in the real world. If the models show a good, solid ability to generate data that closely matches what actually happens in the real climate, then the question will have publicly been answered to a large degree, and we know that when the models say "Eeek, Doomsday unless we slash our CO2" we should probably pay attention. But if the models are shown NOT to be accurate over this ten year period, then maybe it's time to think a little harder before we sign the multi-trillion pound check for emergency carbon slashing.

As far as I know, (and I’m open to correction) this has never been done, and the models were run in the past show a very poor level of reliability when compared with what actually happened over that timeframe.

 

[Overread]

From what you say you want the models to run either in real time, or to predict the next year - well first off, this would reuire serious computing power (most computer models take years to run - by which time they are also out of date). Plus, we all ready know tat this will not work to produce accurate results - we can't even be certain about what the weather will be tomorrow, but we can do it a lot better now than in the past.
Also, after those 10 years, there will be new data and new models - should those then be ignored? The problem is that we do not know, but also that government must be seen to act, thus they select models/data and then use this to produce policies - however there is always the feeling with these at the moment, that much is done for show - e.g. wind farms and all those differnet bins they make us put our rubbish into

 

[Rawled Demha]

Well yeah, but as you pointed out in the parrallel universe thread, flawed maths isn't maths at all. I mean, what's the point of a model that just takes vauge wild guesses? I can take vauge wild guesses, I don't need a computer for that. I thought the whole point of these computer models was that they were supposed to be a very good indicator of what's going to happen 20, 50, 100 years from now.

You could argue that a model that gives you the WRONG data is actually WORSE than no model at all, coz it sends you off in the wrong directions.

Or am I being thick?

crude models are not based on flawed maths. they are based on insufficient data. when we can get a hold of this data, the models that we have been using can be refined to make a more accurate one - NOT the final model. there is no such thing as a right answer with modelling, they are all based on approximations and assumptions.

the guesses only become vague and wild because we are missing some crucial data, specific to that model.

yes you could take vague wild guesses, and sometimes they may be as good as a computers guess. but you are only human, and where you may forget to take into account any given factor, if a computer is told to, it will not. even if it isnt told to consider certain data, when we refine it, it will. and also, the computer computes a hell of a lot quicker than any human could. i think.

and yes, there can be instances when certain models are so bad that we are better off without them - but then, nothing is infallible.

ps. the flawed maths in the multiverse thread is in the "proof" of 1=0, where you divide by zero. i dont think there is anything along these lines in the models we are talking.

 

[Coolhand]

ps. the flawed maths in the multiverse thread is in the "proof" of 1=0, where you divide by zero. i dont think there is anything along these lines in the models we are talking.

Whoops! I apologise for the misquote. I get the wrong end of the stick sometimes, as you can probably tell.

crude models are not based on flawed maths. they are based on insufficient data. when we can get a hold of this data, the models that we have been using can be refined to make a more accurate one - NOT the final model. there is no such thing as a right answer with

modelling, they are all based on approximations and assumptions.

the guesses only become vague and wild because we are missing some crucial data, specific to that model.

I agree with the insufficient data problem, but there’s also the assumption that there are no flaws in the actual mechanics of the model itself. If the mechanics that drive the model are flawed or contain incorrect assumptions, then even the correct data is going to give you mangled results.

The conclusion that everyone seems to agree on is that the models give you a vague idea of a future that may or may not be true. Which as Overread quite rightly points out doesn’t sit well in the political arena.

The problem is that we do not know, but also that government must be seen to act, thus they select models/data and then use this to produce policies

Ah well. I mostly walk to work anyway so my CO2 footprint's pretty damn low...

 

[Sabina]

In the case of climate change the computer models are more sophisticated and they have another forty years of statistics to build predictions upon. But predictions are based upon current trends.
Perhaps because they suggest certain doom, they are popular amongst a vocal group of fatalists, who think that because we are involved in it, we might be able to do something about it.

 

[NickB]

First apologies - I've been away for a bit, and will be disappearing again soon. But while I'm here...

The thing that really annoys me is the time and effort spent by both sides accusing the other of having agendas, rather than addressing the actual data and theories. People interviewed for news items tend to be notably bad for this.

All parties have an agenda. The non-scientist pro and anti (mitigation through reducing greenhouse gas emissions) lobbies certainly have economic and ideological agendas (more ideological for the green looby groups, a mixture of both for the contrarians). Hopefully the agenda of most scientists is the improvement and dissemination of our scientific understanding of climate change.

Now briefly, as this could take up pages....

What’s your opinion of the Mann Hockey Stick Graph?

I believe there were some problems with the methodology with which the first version was produced, but these were addressed by the authors. I think this represents the best reproduction of past temperatures we have at the global level. Once we get back past a century or so there is more reliance on proxy data (i.e. inferred temperature from ice cores, pollen, etc etc) as there are few instrumental records. As we go back centuries the coverage of the record becomes sparser, and by the time we go back some 1200 years (you can see such a reconstruction in the latest IPCC report) there is quite a bit of uncertainty - most records come from a few northern hemisphere sites and the temperature reconstructions are not strictly global. That said, the people who work on this particular issue are pretty confident that temperatures are now higher than at any time in the past 500 years, and think they are probably higher than at any time in the past 1200 years, but with much lower confidence. I know some of these people and they're not eco loonies. Far from it Going back to the hockey stick, I think it's been criticised more than is justified by people determined to undermine the science. It's not perfect and we can't be 100 % confident in all aspects of it, but I'd say it's highly credible.

What’s your opinion of the claim that ice core records show a link between CO2 rises and temp rises?

Throughout much of the ice core record temperatures do rise before CO2 levels, but this is to be expected as the driving mechanisms of climate change during past glacial cycles are changes in the Earth's orbit. These lead to warming which releases greenhouse gases which further amplify the warming. So the fact that warming precedes CO2 increases suggests that once warming is started it is then amplified further by feedback processes. This is not encouraging. If anything the ice core data make me more pessimistic! But the mechanisms evidence in the ice cores are different to those driving climate change today - there is much to be learned here but to invoke the ice core data to "demonstrate" that rising greenhouse gas concentrations don't cause temperatures to rise is disingenuous, and indicates a lack of understanding of the science.

What’s your opinion of the sun’s influence on climate?

The sun does seem to have an influence on climatic variations, e.g. there are good correlations between solar activity and African lake levels in the past. It appears that the sun was driving part of the warming in the early 20th century, but its importance was overtaken by increases in greenhouse gases as as the century progressed. Apparently trends in solar activity are now such that we'd expect a cooling of the Earth if this was the major driver. While there is more work to be done on uncovering links between solar behaviour and climate, it's also worth pointing out that greenhouse gas increases represent the best way of explaining what we observed happening to the climate, based on our understanding of the basic physics, on observations, and on modelling studies. For a treatment of solar variability see Chapter 2 of Working Group I of the 2007 IPCC report - free to download from the IPCC website (I can't post links here, but it's ipcc and the country is ch).

What kind of sea level rise do you think we’re going to see?

The IPCC has "downgraded" its estimate to up to around 60 cm by 2100 (from a maximum of, if I recall correctly, around 88 cm in 2100). However, it emphasises that this is very uncertain, and does not attempt to put probabilities on different estimates (as it has with temperatures). More recent work by Stefan Rahmstorf suggests a possible increase of up to 1.4m by 2100. In the longer term it looks like we're very likely to be committed to the loss of the Greenland Ice Sheet, which would add 6-7 m to global sea level. If we lose the West Antarctic Ice Sheet that's another 5-6 m. And it's possible other ice from Antarctica could be lost. The ice dynamics of Antarctica are not well understood, and some elements of these dynamics are not considered by the IPCC because they cannot be quantified. Many climate scientists, including at least some (maybe all - I don't know) of those who authored the sections on sea level in the IPCC, view the IPCC estimates as conservative. My advice to planners wanting to adapt to climate change is plan for at least a metre by 2100, and (if any were to look further ahead) at least 1m per century for the next few hundred years. I think this is pretty plausible - I wouldn't be surprised to see a rise of up to around 15 m by sometime between 250-3000, although that is no doubt too far ahead to be of more than passing interest to most people.

Which of the climate computer models do think holds the most reasonable predictions for the future changes?

I wouldn't single any particular models out. The best way of looking at the most plausible futures is to look at a collection of models and see what degree of agreement there is. The more consistent the projections, the more faith I'd put in them. Consistency varies from region to region, and there is always the possibility that something important has been missed in the way the models are parameterised. For example, most climate models have difficulty in reproducing past "abrupt" climate change, and it is very plausible that the projections we are getting are underestimating the possibility of abrupt atmospheric, oceanic, or ecological transitions in the future.

What kind of effect will warming have on the spread of insect based disease such as malaria?

Some areas will become more suitable for malaria transmission, and others will become less suitable for it (same for other diseases). But malaria and other diseases aren't controlled deterministically by climate - their transmission depends on all sorts of other factors, principally how they are managed, but also with factors such as land management. I'd guess that in some places malaria will be exacerbated by climate change, and in others the situation might improve.

I’ve heard many conflicting claims about the recent increase in global temperature, including some that it actually hasn’t gone up for the last couple of years and others claiming that it has? What are the actual measurements saying? And how many separate measurements are getting taken?

Not sure precisely how many measurements are being taken - thousands, certainly. These go into large gridded datasets (such as those held at the Climatic Research Unit in Norwich, UK), which are then processed in order to look at global and regional average temperatures. No-one expects each year to be progressively hotter than the last - the global mean temperature varies due to all sorts of factors such as El Nino. The warming trend is superimposed on these year-to-year variations. 1998 is still the hottest recorded year, followed by 2005. See Chapter 3 (p 242) of Working Group I of the 2007 IPCC report.

Thanks in advance, NickB, for any of those you choose to answer.

No worries - hope that helps. All a bit rushed so probably not as articulate as it could be. For more information, you could try the UK Met Office "Climate Change Myths" page, or the "Realclimate" website. Both are run by climate scientists and are reputable. New Scientist Magazine also has a page listing 26 "climate change myths", and there are quite a lot of other decent sources addressing the confusion and disinformation. The Royal Society also has something.

Cheers

Nick

 

[NickB]

It was basically to run all the models publicly for a ten year period, and compare what the models predict will happen to what actually happens in the real world. If the models show a good, solid ability to generate data that closely matches what actually happens in the real climate, then the question will have publicly been answered to a large degree, and we know that when the models say "Eeek, Doomsday unless we slash our CO2" we should probably pay attention. But if the models are shown NOT to be accurate over this ten year period, then maybe it's time to think a little harder before we sign the multi-trillion pound check for emergency carbon slashing.

As far as I know, (and I’m open to correction) this has never been done, and the models were run in the past show a very poor level of reliability when compared with what actually happened over that timeframe.

This is essentially what is being done - if anything the models seem to give conservative projections of future changes, at least for some phenomena. Modellers are desperate to see if their models are getting it right.

Models represent the best, educated, quantitative guesses of future change. They are far from perfect, but they are continuously assessed for accuracy, for example by seeing how well they "predict" observed climate over the past century or more. They have their flaws, but are not just wild guesses of the future that are treated as gospel. Anyone treating a single model projection as a true prediction of the future needs their head examined, but results from a group of models can be used to assess plausible future changes, and perhaps likely future changes if the projections are consistent with emerging observed trends. Model output is used more for what is known as "scenario planning" in which a range of possible future outcomes are examined, and existing or planned policies are assessed for their robustness under these plausible futures. Well, that's the idea - in reality not much attention is paid at the government level to how climate change will impact development, despite the fine words.

 

[NickB]

In the case of climate change the computer models are more sophisticated and they have another forty years of statistics to build predictions upon. But predictions are based upon current trends.
Perhaps because they suggest certain doom, they are popular amongst a vocal group of fatalists, who think that because we are involved in it, we might be able to do something about it.

See my earlier piece about models generally being poor at reproducing past episodes of abrupt climate change that we know have occurred from the palaeoclimatic record.

Models are not just based on current trends. If this was the case they wouldn't have to be so computationally powerful and sophisticated. If we were just extrapolating current trends we could do that with a pencil and a piece of graph paper. Extrapolating current trends would give us much smaller values of future warming than the models are projecting.

Models are based on physics, and while statistics is important in representing the physical behaviour of the climate system within models, they attempt to represent the dynamics of the climate system, so that we can examine how it might evolve under different external forcings. It's good to be critical of models, and I generally am, but I think they're getting short changed here - people seem to think they are much more simplistic and arbitrary, and run and interpreted much more sloppily, than they actually are. The guys at Realclimate might have more to say on this - they're much more expert in the area of modelling than I am.