The Importance of Climate Change – part 2

In my previous post I discussed some of the evidence for climate change and why there is some scepticism. The main point of contention is the hockey stick graph which shows a sudden rise in temperatures starting around 1900 and becoming particularly fast after 1950. The criticism is that there were problems with the analysis that first produced this graph. However, it has been reproduced many times using other methods and so the scientific consensus is that it correctly represents temperature variations over the last 1000 years. Possibly the most surprising thing I found was the possibility of a medieval warm period (around 1000 AD) that may have been as warm as it is today. It’s not clear that it was (not all analyses suggest this) and it’s not clear that it’s relevant.

Here’s why. The figure below shows temperature variations and variations in CO2 over the last 400000 years. There is clearly a relationship between temperature and CO2. This is thought to be a consequence of Milankovich cycles which cause the eccentricity (ellipticity) of the Earth’s orbit and tilt of the Earth’s axis to vary with time. This results in a variation in the total amount of energy that the Earth receives from the Sun and, more importantly, causes where it is deposited to vary with time.

ice core data

Variations in temperature and CO2 levels – determined from ice core samples – over the past 450000 years (Petit et al., Nature, 1999).

Over the course of a Milankovich cycle the Earth will at times receive more energy from the Sun than at other times. Furthermore, where the energy is deposited on the Earth’s surface also varies during the cycle. This will, of course, cause the Earth’s temperature to vary. The variation shown in the above figure is, however, much bigger than can be explained by variations due to the Milankovich cycle. What is thought to happen is that when the polar ice caps melt they release CO2 into the atmosphere. This produces a feedback cycle. The increased CO2 increases the temperature through greenhouse warming which then releases more CO2. Later in the Milankovich cycle, the Earth will start to cool, the ice caps start to reform, the CO2 levels drop, greenhouse warming reduces and the Earth’s temperatures reduces. As can be seen from the above figure, each cycle lasts about 100000 years, the CO2 varies from about 180 parts per million (ppm) to about 280 ppm, and the temperature varies by about 10o C.

There are a number of interesting things about the above graph. It’s fairly easy to show that in the absence of an atmosphere, the Earth would have an average temperature of about -15o C. Instead, today, it has an average temperature about 30o higher than this. Today the CO2 levels are about 300 ppm, which might suggest that each 100 ppm of CO2 produces 10o C of warming. The above figure would seem to be consistent with this since the CO2 level varies by 100 ppm and the temperature varies by about 10o C. I suspect that this is a little simplistic as there are many other greenhouse gases (methane, water vapour) but I suspect that variations of 100 ppm in CO2 must produce variations in temperature of at least a few degrees. That CO2 produces greenhouse warming is irrefutable, as is the fact that the Earth is 30o C degrees warmer than it would be in the absence of greenhouse warming.

Here’s where things gets even more interesting. In the past 400000 years the CO2 levels varied from between 180 ppm to 280 ppm. If you look at the extreme right of the above figure, you see the red line suddenly shoot up to about 350 ppm. This is shown in more detail in the figure below which shows the CO2 levels since 900 AD till today. It’s clear that it was at about 280 ppm until just after 1800 and increases rapidly after 1950, reaching almost 350 ppm today. This rise in CO2 levels is almost certainly associated with our increasing use of fossil fuels.  What’s more, the CO2 levels started rising before the temperature started rising.  One can’t then argue that the rising CO2 levels has lead to the rise in temperature, and not the other way around (i.e., the increased CO2 is not because of a natural increase in the temperature).

CO2 concentration

Atmospheric CO2 levels from 900 AD till today.

This increase of 70 ppm over what the levels would have been had we not been using fossil fuels could – using my simple estimate – lead to 7o C of warming. Interestingly, a recent report suggests that the world is on track for 6o C of warming if we don’t cut carbon emissions. Maybe my crude estimate is not that wrong.

Here’s where it gets scarier. Since about 1950 we’ve increased the CO2 levels by 1 ppm per year. This means we could easily get to CO2 levels significantly higher than those seen over the last 500000 years. If so, we could reach a tipping point where the process runs away and doesn’t stop until the atmosphere is almost exclusively CO2, and the temperature is well above what would be suitable for life of any kind. This may seem extreme but such a process (known as the Runaway Greenhouse effect) has indeed happened on the planet Venus, which today has an atmosphere almost exclusively consisting of CO2 and a surface temperature of 500o C, almost 500o C warmer than it should be based on the energy it receives from the Sun.

This post has got slightly long, but here is my basic summary of the situation.

  • Despite criticism, the hockey stick graph – first determined by Mann, Bradley and Hughes (1999) – is essentially correct.  It has been replicated by others using different techniques.
  • There is definitely a relationship between temperature and CO2 levels  and CO2 definitely acts as a greenhouse gas with variations of 100 ppm producing variations in temperature of as much as 10o C.
  • The CO2 levels today are 80 ppm (~ 30 %) higher than they have been for the last 500000 years.  This is certainly a consequence of our extensive use of fossil fuels.  This increasing CO2 level started prior to the increase in temperature.
  • It is therefore clear that the increased temperatures (climate change/global warming) is causes by the CO2 being released by our excessive use of fossil fuels.
  • If we don’t do something soon we could reach a point where the planet undergoes a runaway greenhouse process which won’t stop until the temperature is too high for life to exist.

I think that pretty much says it all.  This is extremely serious and I think it is probably time we all started acting to encourage our governments to start taking this seriously and to start doing something about it.  The consequences of doing nothing are quite likely be catastrophic.


The Importance of Climate Change – part 1.

A comment on another blog made me think that I should write again about climate change. The basic comment was that we should all be campaigning to get governments to take climate change seriously and to act to do something about it. It is, however, an extremely controversial topic with many feeling that even if global warming is taking place, it is not yet clear that it is due to the action of man and that it is probably just part of a natural cycle. The controversy seems to often focus on the Hockey Stick graph, shown below. This is taken (I believe) from a paper published in 1999 by Mann, Bradley and Hughes (GeoRL, 26, 759-762). I say, I believe, because I couldn’t actually access the paper, even when running my university’s VPN.
Hockey Stick Graph
The graph covers the period 1000AD-2000AD and shows the variation in temperature relative to some mean. There’s a gradual cooling from 1000 AD till about 1800 AD and then quite a sudden rise starting just before 1900 AD. The interpretation is that much of this rise in temperature (especially from the mid 1900s onwards) is driven by the large amounts of CO2 we have been pumping into the atmosphere through the burning of fossil fuels.

The criticism is, however, that variations in temperature are natural and also, that there were problems with the analysis carried out by Mann, Bradley and Hughes (1999). It turns out that there were indeed some issues with their statistical technique. Many climate change sceptics use this to then claim that it shows that the hockey stick graph is not suitable for determining if climate change is being driven by man-made activities. What they fail to mention is that even though there are some issues with the analysis (and this if often true when very complicated techniques are used for analysing complicated data sets) it doesn’t appear to make any substantive difference. Furthermore, other methods for determining temperature variations over the last millennium produces results that are largely consistent with that of Mann, Bradley and Hughes (1999).

What I thought I would then do is look through some of the papers that have cited Mann, Bradley and Hughes (1999) to see if there was any evidence that serious scientists were questioning their work. It wasn’t an exhaustive or particularly systematic search, but I did find a number of recent papers that produced long-term temperature variation trends that largely matched that found by Mann, Bradley and Hughes (1999). I did find one particular result from a 2012 paper (Christiansen, B. and Ljungqvist, F.C., 2012, Climate of the Past Discussions, 7, 3991-4035) which is shown in the figure below.

It is clearly consistent with Mann, Bradley and Hughes (1999), showing quite a rapid rise in temperature starting at about 1900. It also, however, shows an additional peak at about 1000 AD. This is known as the medieval warm period and some also use this to argue that today’s climate change is simply part of natural variations. Some analysis does indeed show that it was as warm in about 1000 AD as it is today. Others show less of a peak at about 1000 AD and that the warmest period in the last 2000 years has been since about 1950.

Basically, it appears as though most serious scientific studies do produce temperature variations over the last 1000 – 2000 years that are consistent with the hockey stick graph produced by Mann, Bradley and Hughes (1999). The last 50 years has seen a substantial rise in temperature and the general consensus is that it is driven by the action of man. The only real issue I can find is the existence of the medieval warm period, when it may have been as warm as it is today. I don’t, however, think that is necessarily particularly relevant. Given that this post has got a little long, I thought I would carry on in a second post where I will try to explain why I think the current warming trend is driven by man and why it is crucial that we invest in developing alternative energy technologies that reduce how much CO2 we put into the Earth’s atmosphere. Having said that, I am not an expert on climate change and am simply expressing my views based on my understanding of what is happening. As always, happy to take comments and corrections. Given the type of rhetoric typically surrounding the climate change debate, I may regret that offer.

Talking about Open Access

Just finished reading a post by Stephen Curry called We need to talk about open access. It essentially highlights the recent Research Libraries UK (RLUK) 2012 conference. Three of the speakers were Dame Janet Finch, Mark Thorley, and himself. The talks are all on youtube and are linked from Stephen Curry’s post.

I watched both Janet Finch’s and Stephen Curry’s talks. Stephen Curry’s talk was very amusing and balanced. Made a number of very good points, in particular that we really should get rid of Impact Factors. Janet Finch came across well and certainly laid out the reasoning behind their decision to propose that we should move towards a system of Gold Open Access. For those who aren’t aware of what this is all about, the government has decided (quite correctly) that publicly funded research should be accessible to anyone. Dame Janet Finch headed an independent commission that recently published a report suggesting that the solution was that we (the publicly funded researchers) should pay upfront for the cost of publishing and that the papers that we publish would then become accessible to anyone. Their prediction was that this would cost about £60 million per year, a small fraction of what the UK spends on research.

At the moment, we have what is called a subscription model. We can only access journals if our university library is paying a subscription fee to the publishing company. According to this Guardian article, we currently spend £200 million per year on Journal subscriptions. I had thought the idea behind Gold Open Access was that by paying up front, and hence making papers accessible to all, subscriptions charges would no longer be needed. How can we replace £200 million of subscription charges with £60 million of author charges? Fantastic if we could, but it does seem unlikely. It also seems like we’ve started funding Gold Open Access while subscription charges still exist. Seems like, for the moment at least, we’re just paying more for the same thing.

What really wasn’t addressed in either of the talks (although Stephen Curry did hint at this) was that many publishing companies are making extremely large profits. In some cases, 20% – 30% of revenue. If we are spending £200 million per year on subscription charges and profits are 30%, that means the actual cost is closer to £130 million per year (and this too is probably an overestimate). What Janet Finch openly admitted was that one of their remits was to make sure that they didn’t damage the publishing industry. I really don’t understand why this should be given so much importance. We have a government that seems to think that a free market and increasing competition should be used to drive down costs, but for some reason thinks we should protect an industry whose income comes, primarily, from the public sector. Even in the private sector, 5% profits is generally regarded as quite good. Why should we be happy with what is essentially a service provider making 30% profits from public money.

As Stephen Curry pointed out, one of the problems is the use of Impact Factors. In each field there are a couple of Journals with high Impact Factors and we are encouraged (largely because of REF2014) to publish in these Journals. This gives them what might be regarded as an unfair advantage. It’s difficult for other, newer, journals to compete. Impact Factors are, however, an extremely poor measure of the quality of a particular paper. We have a metric of quality that is extremely poor, but essentially allows existing journals to maintain a profit level significantly higher than many other industries with similar revenue levels. I think they’ve really missed an opportunity to both find a way to provide open access to publicly funded research and put pressure on the publishing industry to come up with a model that still provides all the useful services, but at a cost that produces reasonable and fair profit levels for their investors.

How could they have done this? One way would have been to have made Green Open Access a more acceptable option. This is where you publish your papers on some kind of free-to-access repository as well as in a peer-reviewed journal. One criticism is that the copy on the repository may not be identical to that in the published journal, but that’s largely nonsense. The formatting might be different, but the content is almost always identical. The other thing they could have done was to not make protecting the publishing industry one of the remits of the independent commission headed by Janet Finch. The goal should have been simple. Provide a way to make peer-reviewed journal papers accessible to the public at a cost that is optimal. I have no problem with these companies making a decent profit for their investors. Quite how one decides what is reasonable is difficult, but actively protecting this industry is clearly going to largely guarantee that it is higher than it could be.

Council for the Defence of British Universities (CDBU)

I thought I should write something about the recently launched Council for the Defence of British Universities. This is a group who’s goal is to protect academic values and to resist the “short term, pragmatic, and narrowly commercial” views that currently appear to persist in UK Higher Education.

I find the name a little militant and could imagine, in a Monty Python type of way, another group called the British Universities Defence Council who have the same aims, but instead of joining forces with the CDBU, end up fighting each other.

There is an article in the Times Higher Education suggesting that the CDBU is too narrow. Essentially suggesting that it is mainly “middle-aged, pale, male Oxbridge professors or Lords of the realm”, or at least almost. That was one of my first impressions too, but I do agree whole-heartedly with the aims of the CBDU, which you can find here. I have, in the past, complained that senior members of the community are unwilling to fight against the changes that are taking place in Higher Education, and here they are. Even if it is dominated by “middle-aged, pale, male Oxbridge professors or Lords of the realm”, at least they are attempting to make a stand against changes that could do immense damage to UK Higher Education. The Steering Committee does also seem more balanced, so maybe there is hope that it will be an organisation that is inclusive.

I don’t really know what else to say. I’ve been complaining for quite a while now about various aspects of UK Higher Education (introduction of tuition fees, emphasis on research over teaching driven mainly by REF2014, university management that thinks HE is a business and that generating income is a priority) and so it is very good to see a group like this starting and aiming to fight to protect more traditional academic values. Makes me think that maybe I don’t talk complete nonsense all the time. Then again, maybe we’re all wrong.

Rachel Maddow and getting a grip on reality

I’ve been posting quite a lot recently and have quite enjoyed it, but am now finding it difficult to think of something to write. Part of that is just that I’ve been busy, but part of it is because I would like to write something positive and cheerful and am struggling to find something positive and cheerful to write about. Maybe I’m getting old and grumpy, but it just feels like we’re living in an incredibly divisive age when sensible debate about important issues isn’t really possible and in which we’re dominated by those with vested interests and who have the power and influence to make their views heard.

Instead of saying more I thought that I would post this clip of Rachel Maddow, the anchor of MSNBC’s The Rachel Maddow Show. It was just after Obama’s re-election and I found it brilliant and incredibly moving. It encapsulated pretty much exactly what I feel about what appears to be happening in the world. I really recommend watching. It isn’t very long.

The Impact of REF2014

I thought I would highlight a recent article, Dodgy dealings in UK Higher Education, posted on the Guardian Blog, Occam’s Corner by Jenny Rohn. Jenny Rohn also write a blog called Mind the Gap on the Occam’s Typewriter blog portal. What I particularly liked in the article was the quote by Einstein, “Strive not to be a success, but rather to be of value.”. If you’ve read any of my earlier posts (The Negative Impact of REF), you’ll know that I’m not a fan of what is proposed for REF2014. Einstein’s quote, to a large extent, highlights my main issue with the process. There are likely to be some measures of success and the goal is to appear as successful as possible. There is, however, no guarantee that what we measure as successful has any intrinsic value. A highly cited paper isn’t necessarily right, or even valuable. Furthermore, those who are perceived to not be successful are not necessarily doing things that don’t have value.

The system may, therefore, measure some people as being unsuccessful and hence doing work that doesn’t have value. This could have a hugely negative effect on their careers, but may be completely wrong. Ideally we want to publish our research and for it to be noticed. However, we can’t always be certain that it will be noticed. I’ve published a number of papers that I’ve really thought would be of great interest, that have generated very little interest. I’ve also published a number papers that take a while to generate interest. One in particular is starting to have quite a lot of impact now, but was published in 2006. The article by Jenny Rohn was highlighting – in particular – the use of Impact Factors. The Impact Factor of a Journal is the average number of citations per paper. What is well known is that a small fraction of the papers typically have most of the citations. Using this as a measure of how good an individual’s papers are is largely nonsensical. Some argue that if you publish a paper in a high impact journal then that implies the paper must be good, even if it doesn’t get many citations. What you’ve really done is convince an editor and a few (sometimes only one) reviewers that your paper is worth publishing in that journal. Not necessarily a statistically significant sample.

Anyway, the point of this post was mainly to highlight Jenny Rohn’s article. There is also an associated poll. If you haven’t already done so, you could also take the poll I set up a while ago.

Unconscious bias

I attented, today, a very interesting presentation that was essentially about gender balance in academia, specifically in the sciences. There are a number of schemes, such as Athen SWAN and the Institute of Physics’s Project Juno, aimed at improving the gender balance in academia. These are schemes where a university department/school can qualify for a certain award if they satisfy certain criteria. There are different levels in each of the schemes and so a department can start with a basic award and build up to a higher award over time. Although the goal, in some sense, is to improve the gender balance in the physical sciences, ultimately it is meant to encourage a working environment and working practices that should benefit both men and women.

What I found interesting was a discussion about unconscious biases. Two researchers (Michelle Hebl and Randi Martin) from Rice University studied 624 reference letters for 194 applicants for junior faculty positions at US universities. They classified certain words as communal (social or emotive) and others as agentic (active or assertive). They found that communal words were used more often in reference letters for female applicants while agentic terms were more commonly used in letters for male applicants. What they then found is that communal terms were not valued by those assessing the applicants. The basic conclusion was that those writing reference letters unconsciously associate communal characteristics with women and agentic characteristics with men and that this then disadvantages women when their applications are assessed by those on hiring panels (whether those on the hiring panels were male of female).

The one interpretation that I have heard is that this means that we should be more careful, when writing reference letters, not to unconsciously use terms that have a gender bias. Of course, if we are unconsciously describing two equivalent people differently just because one is a women and one is a man, then I would agree. My personal view is slightly different. There is no reason why someone who is more communal (kind, sympathetic, tactful, agreeable) wouldn’t be an excellent academic. If these terms fairly describe someone, then it’s not clear that reference letter writers should describe them differently. It’s the job of those on hiring panels to not undervalue such characteristics.

It’s certainly my opinion that the reason that agentic characteristics (ambitious, aggressive, daring) are more valued than communal characteristics is not because they are better characteristics for an academic, it is simply because these have been – and still are – the characteristics of the typical academic (in the sciences at least). I would much rather see us recognise that the ideal academic department is made up of people with a wide range of different characteristics (communal and agentic) rather than suggesting that those who want to become academics should become more agentic.