Global Warming

 

            Because I’m working towards becoming a scientist (or something like that) in a field that’s related to our Earth and the climate at least tangentially, I decided to take it upon myself to learn about this issue.  This is not only because it is interesting, but also because I realized I knew very little about a subject that could govern everything about human existence for the rest of the future. 

What I have found is rather astonishing (to me anyway).  The fact is that it is really hard to learn anything concrete about this issue.  You might think that this is just because the Earth’s climate is an incredibly complex system that we do not fully understand even today (it is), or because it is difficult to make good measurements of all of the variables involved (it is), or maybe because we’ve only been seriously trying to take these measurements for such a small fraction of human history (we have).  But really, the main problem is that I don’t really trust any of the information presented.  Both sides of this issue seem to have demonstrated a willingness to use bad information - data that’s either presented in a clearly misleading way, is in some way tampered with, or is just blatantly wrong or outdated - in order to make their case seem better to the public (who don’t have access to the raw data, and might not be able to interpret it even if they did).  By doing this, they are undermining their believability and honestly I’m not sure what to believe at this point.  This is really frustrating, because it has the effect of polarizing the issue completely – proponents of either side immediately point out a few obvious flaws in the others’ thinking and use that to discredit the other side’s entire argument which may be partially valid.  Anyone who seems to know anything about global warming has a staunch opinion – either they’re sure that we need to act now regardless of the consequences, or they think it’s all a load of crap.  And yet, as far as I can tell, and despite the fact that everyone thinks they do, the fact remains that we really don’t know the answer for sure.. 

My goal here is to provide an unbiased summary of what I have found – I really have no desire to cause you to believe any one thing over another.  I have no ties to any political party that I know of, nor do I even claim to know the answer myself – so I really have no preferred direction in which to lead you.  I will do my best to note where I’m especially suspicious of the data I found, or where I think things are more concrete.  We’ll start with the latest official information on the topic. 

 

The IPCC Reports

 The IPCC (Intergovernmental Panel on Climate Change) submitted a new report this February (2007), updating their 3rd report, which was made in 2001.  The report presented a consensus of 2500+ scientists who concluded that it is 90% likely that we are responsible for the current global rise in temperature, which is up from the 80% likelihood concluded by the 3rd report.  I will admit I did not read both actual reports cover to cover (I did read the summaries for policymakers that were part of the reports), nor did I check all the sources within them (has anybody?).  The summaries cite numerous computer simulations of the climate which conclude that we can’t explain the temperature change without a contribution from anthropogenic causes. 

  There are a few things I don’t like about these reports.  One is the testimony of scientist Paul Reiter, who resigned from the IPCC, yet his name still appeared on the 2001 draft when he received it.  He asked it to be removed, and they claimed he had contributed and refused.   He reminded them that he had resigned because they didn’t listen to anything he had said and demanded they remove it.  They refused again.  Finally, they succumbed after he threatened legal action.  He claims that he knows of others who also resigned, and he expects this is not uncommon.  Now, I suppose he could be making this all up, but this really doesn’t sound like the kind of thing you just make up.  Certainly if it’s true, it’s probably not an isolated case, and it has to make you question the validity of this list of 2500+ scientists who agree with this report, which is one of the major claims they make.  If the scientific consensus is so strong, why would they risk undermining their credibility through actions like that?  Having people who disagree with you is a normal part of science, and should be welcomed. 

Next, here is a page from the 2007 report:

 

 

 

Above is the last page of the IPCC summary to policymakers, which describes the storylines that were used to make models of future human greenhouse gas emissions, land use, and other factors that might affect the climate in the future.  Am I the only one to whom this doesn’t sound like hard science?  Since when does science need a storyline?  Why aren’t they specifying the ranges of the parameters they used and why they used them?  Why are they wasting their time and our time concocting and explaining these scenarios that never should have been made – science doesn’t need this.   Besides this, the fact is that we have no idea what the world will be like in 50 years.  Somebody might discover something tomorrow that eliminates the need to burn fossil fuels.

            Besides this, nearly all of the data used for this report comes from computer models, although the report covertly admits that many of the processes involved are very poorly understood.  Look at this plot:

 

This describes the radiative forcing, which is a measure (as best I can tell) of the effective increase in the intensity of radiation to the Earth based on other factors.  Essentially the greenhouse effect traps radiation and prevents it from escaping out into space, thus effectively making it seem as though more radiation were actually coming down.  If you’ll notice, the last column of this plot is called LOSU.   This stands for “level of scientific understanding,” as the caption points out.  As you can see, our self-diagnosed level is rather low for many of the factors included.  The caption also says “Additional forcing factors not included here are considered to have a very low LOSU.”  So, wait a tick.  There are things that we don’t understand at all, and they might be important, but they are not included because we don’t understand them well enough.  This sounds like something important that maybe shouldn’t be in a caption – not to mention that they should be addressed when talking about the uncertainty of the reports (which it’s not).  Maybe it isn’t important at all, but this seems like it should be addressed up front, rather than slipped in through a caption as though they were trying to hide it. 

Besides this, there are other uncertainties and pieces of evidence that are not addressed at all in the report.  The suggestion that sunspots and cloud formation may affect the global temperatures on Earth is not mentioned at all – in fact, the only natural cause included in this radiative forcing plot is the small variability in the sun’s luminosity, which over short periods of time is essentially nothing.  Here is a paper (a random one I picked from Wikipedia’s sources that investigates the connection between cosmic ray intensities and cloud cover on the Earth, which have been suggested to be linked to sunspots).  I stress that I really picked this paper at random since I didn’t want to read a whole bunch of papers.  The paper concludes that “when [our research is] combined with the additional forcing by the solar irradiance change, we get predicted global temperature anomalies with some similarity to those from observations, however an upward trend in temperature still remains.” This seems to conclude that this by itself isn’t enough to explain the warming that we’ve see.  But, the paper goes on to say that “[t]he extent of this residual warning is crucially dependent on the climate sensitivity assumed – a higher value for this parameter would reduce the discrepancy.  On the other hand, the residual warming could be due to greenhouse gas warming, with contributions from [natural factors].”  Quotes like this bother me.  I know this wasn’t in the IPCC report, but here is a (admittedly random) study whose computer simulations reported that they varied “crucially” on the assumed value of a parameter.  The fact that they used the term “assumed” tells me that we don’t know it and we can’t measure it.  They didn’t say “if our value for this is wrong.”  Unknown parameters like this lead to bias – if we’re guessing, then why is one value better than another?  The authors picked the value 0.53 for this parameter from an accepted range of 0.3-1.0 (which seems rather substantial), and cited that they were compensating for the fact that some other parameter values they got from another paper were challenged to be a little too high.  This doesn’t sound like good science to me.  Now, again, this was only one paper, and others may well be better.  But, if some simulations are showing that we can explain the warming without anthropogenic causes if we change the value of a parameter we don’t know within its known range, then maybe there’s a little more than 10% uncertainty here.

            Overall, the IPCC report seems somewhat flawed to me – it brushes over the fact that our understanding of many of the processes involved in this is admittedly low, while considering only one natural factor in the variability of global temperatures.  Computer models that are built without a knowledge of all the processes involved are almost always useless.  Maybe this is the best we can do right now, but then they need to stipulate that it’s more uncertain. 

 

The Great Global Warming Swindle

The Great Global Warming Swindle is a documentary by a British news channel which argues that it’s all complete nonsense.  They make a few good points, but they just plain tried to do too much – they used some information which is highly in question at best, used some false logic, and instead of merely calling global warming into doubt they tried to prove it false.  If you just watch this and don’t think really critically, you’ll probably end up believing it, because it sounds good.  It really pisses me off when people do this, because they end up completely polarizing the issue.  The station who made it has even admitted that it was made to stir things up and to be controversial.  It’s bad enough that politicians do this shit, but when scientists are involved it really annoys me.  The problem is that everyone has lost sight of the goal.  The goal is no longer to find the truth – the goal is to convince everyone that your point of view is correct.   This documentary is probably worse in this regard than the IPCC reports are (they may be just as bad, it’s just more difficult to tell because it’s all written in long scientific papers). 

 

Here are the good points they make which are undisputed as far as I know:

1)      The testimony of Paul Reiter was taken from here.

2)   Cloud formation is complicated, not well understood, and we aren’t able to model it, and it changes what % of the sun’s radiation is reflected back into space without ever reaching the surface, which is important.

3)   There is a whole lot of money being poured into the industry and people whose jobs are dependent on global warming being a major issue in the future.  In the last 20 years, the amount of money being spent on it has gone from tens of millions to tens of billions - thus many people in science, government and the media have a huge incentive to find that it’s real.  This certainly doesn’t prove anything, of course, but it does provide an incentive for scientists to find extreme results. 

4)   There still seems to be a controversy over the temperatures in the troposphere.  The theory suggests that if we are causing the warming, then any temperature increase here on the surface should be seen 1.2-1.5x amplified in this region of the atmosphere.  We still seem unsure that we are seeing this.  After reading this Wikipedia article on it, I’m still not sure what’s going on, but it seems like we’re not sure about this.

5)   Making computer simulations of things we don’t 100% understand is kind of a sketchy undertaking.  To some extent you can manipulate your parameters to change your results.  I’m not accusing them of doing this, but I’m sure it would be possible.  And, if you combine this with a team of people who all believe in global warming (stereotypically, most people in academia are liberal), it becomes even more likely that some of the results are tainted.  Don’t get me wrong, I’m sure most scientists are honest enough to accurately report what they find, but I’m equally sure there are some who are not. 

 

After that, it sort of goes downhill for the documentary.  It makes a number of points that are blatantly false, use false logic, or are just ridiculously fantastic (like claiming that environmentalists are anti-human because they’re keeping Africa from industrializing).  Mostly, they’re trying too hard to prove global warming wrong, instead of simply calling into question some of the findings, as they should have.  Some of these I got from this, a lecture given by Chris Merchant at the University of Edinburgh, others from reading criticism of the documentary.  I feel like he actually doesn’t try and do too much, which is kind of refreshing.  A few examples:

1)      Their plot of temperature for the last 100 years has been admitted to have been from old data.  It claimed most of the warming happened before 1940, which isn’t really true – it’s about half and half.  Also the claim that CO­2 emissions would be immediately correlated with climate changes is also crap – so the fact that the global temperatures were falling from 1950-1970 during a time of increases emissions doesn’t show anything about climate change. 

2)      The claim that volcanoes produce more CO2 than humans is patently false and has been admitted to be so.  The claim that humans produce much less carbon dioxide than other sources is true, but completely irrelevant.  We are producing an excess as compared to the natural sinks into which CO2 goes, and thus the amount in the atmosphere is being artificially increased (and significantly, one of the few things of which I am sure).

3)      They say that it has been much warmer and cooler than today by citing the Medieval Warm Period and the Little Ice Age.  Their evidence of this data is poor, a guy rambling on about how people skated on the Thames in England when it was cold, and how cathedrals were built and vineyards sprang up in Northern England when it was warm.  Not to mention the fact that these temperature trends were in Europe and do not necessarily reflect temperatures globally.  In fact, global data shows that our best estimate is that these trends were substantially less globally (with fairly high error, though, so who knows).

4)      The plot given of sunspot # vs. temperature does not depict the last 20 years.  If you extend the plots, the relationship clearly breaks down.  Also the data given is very different from what other sources are getting (Merchant even says he suspects it was tampered with, but I’m not in the business of making such accusations). 

5)      Many of the attacks are against the people and not the science, which does not prove anything.  For example, supposedly the first research money for global warming came from Margaret Thatcher who wanted to reduce dependence on coal and switch to nuclear power, so she asked scientists for evidence that burning coal was harmful.   I agree this is not the way science should be done, but clearly that does not mean that current research is wrong. 

 

My take

      I figure I should actually make a point to express my overall thoughts, since I’ve spent the last while researching all this stuff.  Basically they run along the following lines:

1)   The amount of CO2 in the atmosphere is increasing rapidly, and is higher now, we think, than at any point in the last many hundreds of thousands of years.  This is a bad thing. 

2)  CO2 is known to be a powerful greenhouse gas, but it’s not the dominant greenhouse gas on this planet.  Clearly adding a greenhouse gas will have some effect on our climate over time.

3)  We don’t really know for sure what the magnitude of this effect will be - in particular how other factors in the climate cycle will enhance or diminish this effect.  For a while, some give in the system will likely help to diminish the effects, but we don’t know how much or for how long.

4)   We can’t be sure that natural factors in the climate cycle aren’t partially and/or totally responsible for the warming we’re seeing right now, because we simply don’t understand them well enough.  Thus, we can’t be sure that we’re seeing the results of the CO2 increase.  Our best guess seems to be that we are responsible. 
5)   Despite all this, we should put forth a good amount of our resources towards reducing CO2 emissions simply because we can’t afford to be wrong.  I don’t think we should wreck the economy, but we should be doing more than we are.  I don’t really believe the hype that both ice caps will melt by 2050, and the sea levels will rise by 50 ft, and there will be huge droughts and the world will end a la An Inconvenient Truth.  But, I think we should be spending more money on fuel economy standards, alternative fuels, etc.  Besides, money spent on this has the added benefit of reducing our need for fossil fuels, and this will come in handy whenever they do run out (apparently not anytime soon, but eventually they will).  So, even if we’re wrong about this whole thing, this money will still be helping us in the long run.