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Posts Tagged: Climate Change

Thinking about climate change

Wednesday 23rd November 2011

Climate change is a significant topic that affects the lives of pretty much every living human. As such, discussions about the subject can often get quite heated, with two distinct camps. One side says that climate change is caused by carbon dioxide emissions, and that the consequences for humanity will be absolutely dire. The other side seems to claim that the climate isn’t changing, or that the other side are making things up. To stoke up their claims both sides resort to bad science, misrepresentation of good science, and lots of good old ad hominem attacks. Here are a few things which we know to be true, at least as far as we can be sure about these things:

  1. Climate is changing. It always has, it always will.
  2. Global temperatures have risen.
  3. CO2 levels in the atmosphere have risen in the last circa 200 years, driven by industrialisation.
  4. CO2 is a greenhouse gas. Its presence in the atmosphere does have a warming effect (we’re dependant upon this for our survival!)

Sensible discussion of the topic has to start from at least these facts, as they represent the state of our current knowledge. It is ridiculous to claim that any of these 4 are untrue, because as far as we know all the evidence suggests that they’re not. But equally, sensible discussion of this topic cannot simply stop here. Because these facts raise some questions which need to be answered before we can devise any meaningful response to this issue:

  1. To what extent does CO2 cause changes in temperature? If there is x amount of CO2 added to the atmosphere, what is the corresponding change in temperature?
  2. To what extent is this a problem? What is the cost of doing nothing to stop climate change?
  3. If we can find ways to reduce/stop CO2 emission, what are the costs of doing so?

To think about those three questions, I’ll break them down into the appropriate subject areas. Question 1 is about the science, about working out what’s happening with the climate. Question 2 is about how we can deal with the effects of climate change and the cost of doing so, and so is really about engineering. And the heart of the third question is about reducing the reliance on energy sources which cause CO2 to be emitted (as energy use is the principal cause of CO2 emissions).

Science

When we’re talking about climate, we’re talking about a huge, chaotic system. To start to understand how it works, we’re talking about modelling the flow of fluids (namely water and air) across the entirety of the Earth’s surface, taking into account countless different variables and the way they interact with each other. This is really hard to do, at least with any accuracy. And it’s really hard to look at such a system and to derive the effect that one particular variable has (namely CO2 concentration). So to come back to the first question I posed. Do we know the extent to which CO2 causes warming? No, we don’t. We can run all kinds of models to find some sort of estimate, yes, but finding out whether that model is accurate is not a trivial problem.

There’s lots of confusion about this, it seems. One side of the climate debate tries to make out that climate change is caused by anything but the activities of mankind, whilst the other is pretty set on the idea that it’s all down to CO2. Both sides vilify the other, and that doesn’t really make any sense. We can’t yet say – with any certainty – what effect the CO2 generated by our activities is having on the environment; but CO2 is a greenhouse gas, so it really isn’t a leap to say it’s having some effect.

A good example of this problem can be found when we examine the temperature change over the last decade, and compare it with the change in CO2 concentration in the atmosphere:


Temperature data are global averages from the HadCRUT3 dataset of temperature records. CO2 concentrations recorded at Mauna Loa Observatory, Hawaii.

The basic theory is that CO2 is causing mean temperatures to increase, and yet looking at the above graph, it’s rather hard to find such a relationship. HadCRUT and BEST both show that there has been no warming in the last decade (in fact, the HadCRUT data used here show that mean temperatures have decreased very slightly), even though CO2 concentration has steadily increased. More than likely, we can’t draw too many conclusions from this; 10 years is quite a small period of time when discussing climatic events which take place over a significantly longer amount of time. But at the very least, it causes us to question the claims about the significance of CO2. Because if CO2 really is as dangerous as we’re told, has such a dominant effect that we need to make drastic steps to reduce the amount we emit, we really should have seen accelerated warming in this period.

Now, for the sake of clarity, I am most definitely not saying that CO2 does not cause warming at all; simply that we haven’t properly quantified the warming effect that’s caused by our CO2 emissions. And that, whilst the temperature rose during the 20th century, we probably don’t know the whole story of why that happened; most likely it’s been caused by a number of things, and human activity could be a large or a small component (for instance, we know that solar activity has increased during the last few decades). Climate is variable, it always has been and it always will be, and so there isn’t a steady baseline to make comparisons from. We can’t say that CO2 and temperature have both risen, therefore increased CO2 has caused the temperature rise; it simply isn’t that straightforward. And it’s rather foolish to dedicate lots of resources to the cessation of CO2 emission, when we don’t know whether that really is causing unnatural climate change.

Engineering

So. For the sake of argument, let’s ignore everything I’ve just said. Let’s make the assumption that CO2 is driving climate change, and that if we continue to pump it into the atmosphere it’ll cause a global temperature rise that will cause the environment to change. How could we deal with that?

Fundamentally, this is a problem about the maintenance of the natural and built environment. That’s not a new issue, we’ve been doing this for millennia, and engineers have been doing it using a scientifically rigorous approach for centuries. It’s what Civil Engineering is all about, and we’ve gotten pretty good at it by now. So, let’s look at one particular issue that is likely to be a problem, should global temperatures continue to rise: higher sea levels.

The first step in solving an engineering problem is to work out what exactly the problem is, so we’ve got to find out how much the sea is likely to rise. At the moment, the consensus seems to be that the sea level will rise between 75cm and 2m in the next 100 years. It’s quite hard to visualise what that looks like, what that really means for us. Happily it’s quite easy to model this, to see which bits of land will be flooded after a given change in sea level:


Map of British Isles with 2m rise in sea levels. Areas of land which are below the increased sea level are shaded blue. Source: geology.com.

Not a particularly significant change, actually. The worst-affected area is landlocked anyway, so I guess it might not be encroached by the sea, although flooding may become more likely. But if we really wanted to, these are problems which we can easily solve. If a place is under threat from a 2m sea level rise, then we can build a dyke (or similar) to stop it from being flooded. If flood risk in a region is increased, then there are lots of techniques we can use to deal with that too. Or, in some cases it might be best to simply move away from the areas which are likely to flood, as there’s still plenty of higher land left. None of these approaches should really be that costly, certainly in comparison to some of the alternatives.

These problems can be solved, and in many cases are already being solved. It’s also worth mentioning that on the global scale, climate change might actually cause positive effects in some locations, for example by moderating the climate of places which are currently very cold. And so when we examine these issues to try to think about how to deal with the possible effects of climate change, it quickly becomes apparent that this is something that we know how to do, and that climate change really isn’t the end of the world.

Energy

Now let’s go even further with our assumptions by saying that we’ve decided that we should try to reduce the amount of CO2 we emit. The largest cause of anthropogenic CO2 emission is the burning of fossil fuels for energy. Therefore to make a meaningful reduction in emissions, we must use alternative sources of energy as much as possible.

Several countries have agreed to targets to reduce their CO2 emissions, and there are several policies which are in place to try to achieve this. Firstly, there are high taxes on CO2 emission, in order to discourage activities which cause pollution. There are also subsidies available for the production of certain (supposedly) sustainable sources of energy – wind power, solar power, etc. – to encourage people to install these facilities. And to try to make current fuels “greener”, a certain amount of bio-ethanol is blended with petrol and diesel used for transport.

There are problems with this: it’s expensive, and often grossly unfair. Taxes on energy affect everyone; directly in the price we pay for transportation, heating and electricity, and indirectly in the price we pay for goods. You might argue that, well, we’re wealthy, and we can afford it. And we probably can. If we think it’s an acceptable trade-off, then we can probably afford to sacrifice some luxuries, or lose a certain amount of investment – and jobs – even with the current state of the economy. It makes life difficult for ourselves, but not impossible.

Subsidies are less excusable. It’s the classic argument that subsidies distort the market and make it less efficient. Which is a good argument; we want to use alternative sources of energy when it’s actually efficient to do so, not just because we think we should, as that simply makes energy more expensive than it needs to be. This is also deeply unfair, as it benefits those who can afford to invest in “green” energy, at the expense of those who cannot. Frankly, I think it’s inexcusable to drive up energy prices for the majority with a scheme to provide cheap energy to the minority who are wealthy enough to buy into the scheme.

On the subject of unfairness, there’s also a broader point to be made. Firstly, we’re telling poorer parts of the world that they need to not emit CO2, but often the only affordable sources of energy available in such parts of the world are those which cause lots of CO2 to be emitted. So in a way, we’re asking less developed parts of the world to stay undeveloped, to stay poor. Which limits access to things like healthcare and education in those parts of the world, and so undoubtedly causes a huge amount of damage (or rather, it would if they all listened to us).

On top of this, we impose “green” policies which directly cause actual damage. For example, the requirement that fuels be blended with bio-ethanol has had the effect of raising the price of some foods. This increased price has meant that some people simply haven’t been able to afford to eat, which is thought to have caused at least 192,000 extra deaths last year. Some of the poorest people in the world are being starved because we want to burn their food to reduce our CO2 emissions. Whatever your views on climate change, that should make you mad.

What should we do?

The point that I’m trying to make is that our approach to climate change needs to be more intelligent. The science is very complicated, and probably not well-understood enough to be the basis of policy decisions which can have profound effects. We cannot say with confidence that we are the cause of the changes in climate that we observe.

Given this, it seems sensible to have a different approach to dealing with climate change: to analyse the costs and the benefits of the situation, to work out what really is the best course of action.

The cost of doing something about the possible threat of anthropogenic climate change is massive, as it calls for a fundamental change in the way we do things. It calls for us to abandon the sources of energy which allow us to access many of the resources we need to maintain our standard of living, and it calls for us to deny poorer parts of the world the opportunity to grow and develop and improve their basic standard of living. That is a massive cost. Given that the modest things we’ve already done have resulted in hundreds of thousands of deaths, it’s scary to consider the possible cost of doing more.

Additionally, the potential benefits of reducing CO2 to combat climate change are comparatively small. All we’d do is avoid a certain amount of engineering work which would be required to adapt to the changing environment. It’s not clear that we’d save all that much; the built environment will need to be maintained in the coming years regardless of climate change, and so all we’d do is change the parameters of problems that need to be solved anyway. But solving those problems becomes infinitely easier if we maintain our access to cheap, abundant energy.

Fundamentally, it seems to me that our response to the possible threat of anthropogenic climate change is wholly disproportionate. We’re causing more harm than we could ever hope to stop; we’re spending lots of money (and causing lots of deaths) for solutions that might not work, for a problem that probably isn’t that severe. Whatever way you slice it, that isn’t an intelligent trade-off.

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Climate Control

Monday 21st December 2009

I’ve said before here that I don’t know much about climate change. In fact what I said was “I don’t know whether it’s happening and really I don’t care, because it’s irrelevant”, which taken out of context says something which I didn’t intend to say, but ho hum.

Anyhow, I was reading up on the science behind climate change the other day. I was reading up on how human activity causes it, and it’s fairly interesting. It also gave me a fairly large headache, because I don’t really understand it. I understand the argument thats being made, but I don’t see how the evidence which is being presented supports that argument.

Before I continue, I’m not writing from a “boo climate change isnt happening” standpoint, because thats stupid. I just don’t understand the science. That could be (probably is) because I’m missing something, and that’s ok because I’m not a climatologist. I’m kinda hoping that by writing this, someone will write a comment which says “ah, but you’re forgetting this…” and it’ll suddenly make sense.

Ok. So looking at the data from ice cores or wherever for CO2 in the atmosphere and comparing it with the temperature of the Earth, does show a clear correlation. Historically, when there’s been an increase in the Earth’s temperature, the increase in CO2 levels comes after the temperature increase. Now this makes sense, because theres lots of CO2 stored in ice and water, so when the temperature goes up (due to, say, fluctuations in the Earth’s orbit), obviously CO2 is going to be released. And CO2 is a greenhouse gas, so clearly increased levels of CO2 help to warm the Earth’s surface, amplifying the temperature increase which has caused the extra CO2 to be released. Eventually the thing which caused the Earth to warm up in the first place stops having such an effect, so eventually the temperature of the Earth goes down again. As the temperature goes down more CO2 is dissolved in water and ice, so there’s less in the atmosphere. As I understand it, that’s the science which explains the relationship between CO2 and temperature, right upto mankind having any appreciable effect on either.

Ok, some facts which I think everyone will agree on.In the last 150-200 years, humans have put a lot of CO2 into the atmosphere. More CO2 in the atmosphere will help warm the Earth up. The Earth has warmed up – more than it has in the “recent” past – in the last  few hundred years.

However. We’re told that the current increase in the Earth’s temperature is entirely due to the increase in CO2 emissions. I don’t see where the evidence is which suggests that CO2 is such a large driver of the temperature of the Earth. If CO2 in the atmosphere plays as important a part in this as people claim it does, how come the Earth’s temperature has dropped in the past when CO2 levels were high? If a lot of CO2 in the atmosphere was that catastrophic, surely in the past when there were high levels of CO2, the temperature would have remained high once the original warming action was removed?

Why are we so sure that the current increase in temperature is purely down to CO2? Why have we ruled out the possibility that other – perhaps natural – phenomena are taking place, as they have done for thousands of years?

(Ego, perhaps?)

This isn’t to say that CO2 doesn’t play a role or that we should ignore what we’re putting into the air. If natural processes are responsible for some of the increase in temperature, then clearly we’re responsible for the rest of it. I just think that perhaps simply focussing on CO2 as the silver bullet is a really silly – maybe even dangerous – thing to do. As I’ve written before, the thing which really scares me is the fact that we’re running out of energy. Distracting ourselves with jollies to Copenhagen may make us feel like we’re doing something, but does it really solve the problem? Irrespective of whether the science is right, it annoys me that so many people have simplified the issue so much, to the point that they’re not even trying to solve the right problem. Stop CO2 emissions with sustainable fuels. Problems solved. As I said in the last post, that should be our Apollo…

In a comment on Callan’s blog, I likened Copenhagen to rearranging deckchairs on the Titanic. That’s not true – it’s more trying to pump the water out to keep the ship from sinking. I mean it’ll work, albeit at great expense and inconvenience. But it doesn’t really solve the problem of the holes beneath the water, does it?

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