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Archive for the ‘Musings’ Category

If you haven’t yet watched the television series Game of Thrones or read George R. R. Martin’s A Song of Ice and Fire books on which the show is based, I would urge you to get started (unless you are a small child, in which case I would urge you to wait a few years). The show and the books are both absolute masterpieces (although, as I alluded, definitely not for kids). I’m not usually a big fan of high fantasy, but the character and plot development of this series really pulled me in.

One of the most interesting parts of the series – maybe just for me – is the way the seasons work in Westeros and Essos, the continents explored in Game of Thrones. Winter and summer occur randomly, and can last anywhere from a couple of years to more than a decade. (Here a “year” is presumably defined by a complete rotation of the planet around the Sun, which can be discerned by the stars, rather than by one full cycle of the seasons.)

So what causes these random, multiyear seasons? Many people, George R. R. Martin included, brush off the causes as magical rather than scientific. To those people I say: you have no sense of fun.

After several lunchtime conversations with my friends from UNSW and U of T (few things are more fun than letting a group of climate scientists loose on a question like this), I think I’ve found a mechanism to explain the seasons. My hypothesis is simple, has been known to work on Earth, and satisfies all the criteria I can remember (I only read the books once and I didn’t take notes). I think that “winters” in Westeros are actually miniature ice ages, caused by the same orbital mechanisms which govern ice ages on Earth.

Glacial Cycles on Earth

First let’s look at how ice ages – the cold phases of glacial cycles – work on Earth. At their most basic level, glacial cycles are caused by gravity: the gravity of other planets in the solar system, which influence Earth’s orbit around the Sun. Three main orbital cycles, known as Milankovitch cycles, result:

  1. A 100,000 year cycle in eccentricity: how elliptical (as opposed to circular) Earth’s path around the Sun is.
  2. A 41,000 year cycle in obliquity: the degree of Earth’s axial tilt.
  3. A 26,000 year cycle in precession: what time of year the North Pole is pointing towards the Sun.

These three cycles combine to impact the timing and severity of the seasons in each hemisphere. The way they combine is not simple: the superposition of three sinusoidal functions with different periods is generally a mess, and often one cycle will cancel out the effects of another. However, sometimes the three cycles combine to make the Northern Hemisphere winter relatively warm, and the Northern Hemisphere summer relatively cool.

These conditions are ideal for glacier growth in the Northern Hemisphere. A warmer winter, as long as it’s still below freezing, will often actually cause more snow to fall. A cool summer will prevent that snow from entirely melting. And as soon as you’ve got snow that sticks around for the entire year, a glacier can begin to form.

Then the ice-albedo feedback kicks in. Snow and ice reflect more sunlight than bare ground, meaning less solar radiation is absorbed by the surface. This makes the Earth’s average temperature go down, so even less of the glacier will melt each summer. Now the glacier is larger and can reflect even more sunlight. This positive feedback loop, or “vicious cycle”, is incredibly powerful. Combined with carbon cycle feedbacks, it caused glaciers several kilometres thick to spread over most of North America and Eurasia during the last ice age.

The conditions are reversed in the Southern Hemisphere: relatively cold winters and hot summers, which cause glaciers to recede. However, at this stage in Earth’s history, most of the continents are concentrated in the Northern Hemisphere. The south is mostly ocean, where there are no glaciers to recede. For this reason, the Northern Hemisphere is the one which controls Earth’s glacial cycles.

These ice ages don’t last forever, because sooner or later the Milankovitch cycles will combine in the opposite way: the Northern Hemisphere will have cold winters and hot summers, and its glaciers will start to recede. The ice-albedo feedback will be reversed: less snow and ice means more sunlight is absorbed, which makes the planet warmer, which means there is less snow and ice, and so on.

Glacial Cycles in Westeros?

I propose that Westeros (or rather, the unnamed planet which contains Westeros and Essos and any other undiscovered continents in Game of Thrones; let’s call it Westeros-world) experiences glacial cycles just like Earth, but the periods of the underlying Milankovitch cycles are much shorter – on the order of years to decades. This might imply the presence of very large planets close by, or a high number of planets in the solar system, or even multiple other solar systems which are close enough to exert significant gravitational attraction. As far as I know, all of these ideas are plausible, but I encourage any astronomers in the audience to chime in.

Given the climates of various regions in Game of Thrones, it’s clear that they all exist in the Northern Hemisphere: the further north you go, the colder it gets. The southernmost boundary of the known world is probably somewhere around the equator, because it never starts getting cold again as you travel south. Beyond that, the planet is unexplored, and it’s plausible that the Southern Hemisphere is mainly ocean. The concentration of continents in one hemisphere would allow Milankovitch cycles to induce glacial cycles in Westeros-world.

The glacial periods (“winter”) and interglacials (“summer”) would vary in length – again, on the scale of years to decades – and would appear random: the superposition of three different sine functions has an erratic pattern of peaks and troughs when you zoom in. Of course, the pattern of season lengths would eventually repeat itself, with a period equal to the least common multiple of the three Milankovitch cycle periods. But this least common multiple could be so large – centuries or even millennia – that the seasons would appear random on a human timescale. It’s not hard to believe that the people of Westeros, even the highly educated maesters, would fail to recognize a pattern which took hundreds or thousands of years to repeat.

Of course, within each glacial cycle there would be multiple smaller seasons as the planet revolved around the Sun – the way that regular seasons work on Earth. However, if the axial tilt of Westeros-world was sufficiently small, these regular seasons could be overwhelmed by the glacial cycles to the point where nobody would notice them.

There could be other hypotheses involving fluctuations in solar intensity, frequent volcanoes shooting sulfate aerosols into the stratosphere, or rapid carbon cycle feedbacks. But I think this one is the most plausible, because it’s known to happen on Earth (albeit on a much longer timescale). Can you find any holes? Please go nuts in the comments.

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Recently I was lucky enough to pay a visit to the South Island of New Zealand. I am actually a Kiwi by birth (that’s why it’s so easy for me to work in Australia) but grew up in Canada. This was my first visit back since I left as a baby – in fact, we were in my hometown exactly 20 years to the day after I left. We didn’t plan this, but it was a neat coincidence to discover.

Among the many places we visited was Aoraki / Mt. Cook National Park in the Southern Alps. It was my first experience of an alpine environment and I absolutely loved it. It was also my first glacier sighting – a momentous day in the life of any climate scientist.

There are 72 named glaciers in the park, of which we saw two: the Hooker Glacier and the Mueller Glacier. The latter is pictured below as seen from the valley floor – the thick, blue-tinged ice near the bottom of the visible portion of the mountain. As it flows downward it becomes coated in dirt and is much less pretty.

Along with most of the world’s glaciers, the Mueller is retreating (see these satellite images by NASA). At the base of the mountain on which it flows, there is a large terminal lake, coloured bright blue and green from the presence of “glacial flour” (rock ground up by the ice). According to the signs at the park, this lake has only existed since 1974.

In the photo above, you can see a large black “sill” behind the lake, which is the glacial moraine showing the previous extent of the ice. Here’s a photo of the moraines on the other side, looking down the valley:

It’s hard to capture the scale of the melt, even in photos. But when you stand beside it, the now-empty glacial valley is unbelievably huge. The fact that it was full of ice just 50 years ago boggles my mind. Changes like that don’t happen for no reason.

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Me: Hello?
Caller: Hello?
Me: Yes, hello?
Caller: Hi, I’m from the local paper.
Me: Okay. (We get these calls several times a week. It’s getting kind of tiresome.)
Caller: Do you currently receive the paper?
Me: No.
Caller: Would you like to become a subscriber?
Me: No, thank you.
Caller: Well, have you ever read it?
Me: Yes, and that’s why I don’t want to buy it.
Caller: Say again?
Me: I’m not happy with your science coverage.
Caller: Science?
Me: Yes. I’m a scientist and I’m not happy with the quality of science journalism in the paper.
Caller: Well, I didn’t write it.
Me: I know. I’m just telling you why I don’t want to buy it.
Caller: Is it anything in particular? I mean, you say “science”…
Me: Climate science, in particular.
Caller: Climate science.
Me: Yes.
Caller: Was it a specific article?
Me: No, it was a pattern of articles over several years, relating to climate change. I’m a climate scientist and your coverage of this issue was so far off base that I could no longer support the paper.
Caller: Oh.
Me: Thanks for your interest. Please don’t call again.
Caller: My…interest?
End of call

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Sometimes I look back to 2010 and wonder how we all got through it. I remember the stomachache I’d get every time I opened a newspaper, wondering what awful lies had been printed about climate science that day. I remember the disdain with which people treated the science I love and the scientists I look up to. 2010 was the year when climate change conspiracy theories went mainstream, and the year when the whole issue was a lump of dread I carried around in my pocket.

Things are easier now. The climate system is in really bad shape (and it can only get worse from here), but somehow I find this fact easier to deal with than the judgement of well-meaning, but highly misinformed and misled, people. Maybe this is because I find human conflict scary but graphs and numbers comforting. Or maybe I am just too good at thinking of model simulations as hypothetical.

In my own way I am in denial, because when I think about my future I always picture a world without climate change.

Regardless, the attacks on our integrity have largely abated, and everything feels so peaceful in comparison. Part of this, of course, has to do with policy: the misinformation campaign “ClimateGate” was clearly timed to derail the Copenhagen talks, the likes of which won’t happen again for another few years. I think there is another factor, though, which will protect us the next time around: the scientists are now officially pissed off.

As scientists, we are shy creatures by nature (remember what I said about human conflict and graphs?) but even we can be provoked. Recall that we have discovered important information that could be vital to the future of our civilization, and yet there are many who seek to discredit us and make sure this information is not taken seriously. When those people go so far as to slander and harass individual researchers, nearly to the point of suicide, they have stepped on all of our toes. We are mad scientists, but not in the cartoon sense.

Now, when deniers attempt to construct a scandal, it doesn’t get off the ground. Scientists are there immediately to set the record straight, and the media realizes it is a non-story. When shady politicians try to press charges against researchers, those researchers hire accomplished lawyers because there is a fund for that now. Geoscience conferences  feature so many communications workshops that you could attend nothing else if you chose to. Scientific societies are publishing handbooks on how to respond if your research is publicly attacked, you face charges of fraud, or you fear for your safety.

I like this new attitude of climate scientists. Forget the old paradigm that scientists should steer clear of political speech and stick to pure research. We didn’t give up our rights as citizens when we decided to be scientists. Maybe 2010 was a necessary evil, because it made us realize that we have a responsibility to fight for truth.

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And now for something completely different: this is one of my favourite poems by the brilliant Pablo Neruda, translated from the original Spanish by Alastair Reid.

It reminds me of all the bickering and politics that get in the way of climate science, and all the trials and tribulations of climate change communication.

Given that now perhaps
we are seriously alone,
I mean to ask some questions -
we’ll speak man to man.

With you, with that passerby,
with those born yesterday,
with all those who died,
and with those to be born tomorrow,
I want to speak without being overheard,
without them always whispering,
without things getting changed
in ears along the way.

Well then, where from, where to?
What made you decide to be born?
Do you know that the world is small,
scarcely the size of an apple,
like a little hard stone,
and that brothers kill each other
for a fistful of dust?

For the dead there’s land enough!

You know by now, or you will,
that time is scarcely one day
and a day is a single drop?

How will you be, how have you been?
Sociable, talkative, silent?
Are you going to outdistance
those who were born with you?
Or will you be sticking a pistol
grimly into their kidneys?

What will you do with so many days
left over, and even more,
with so many missing days?

Do you know there’s nobody in the streets
and nobody in the houses?

There are only eyes in the windows.

If you don’t have somewhere to sleep,
knock on a door and it will open,
open up to a certain point
and you’ll see it’s cold inside,
and that that house is empty
and wants nothing to do with you;
your stories are worth nothing,
and if you insist on being gentle,
the dog and cat will bite you.

Until later, till you forget me -
I’m going, since I don’t have time
to ask the wind more questions.

I can scarcely walk properly,
I’m in such a hurry.
Somewhere they’re waiting
to accuse me of something
and I have to defend myself;
nobody knows what it’s about
except that it’s urgent,
and if I don’t go, it will close,
and how can I hold my own
if I knock and nobody opens the door?

Until later, we’ll speak before then.
Or speak after, I don’t remember,
or perhaps we haven’t even met
or cannot communicate.
I have these crazy habits -
I speak, there is no one and I don’t listen,
I ask myself questions and never answer.

- Pablo Neruda

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Since I last wrote, I finished my summer research at Andrew Weaver’s lab (more on that in the weeks and months to come, as our papers work through peer review). I moved back home to the Prairies, which seem unnaturally hot, flat and dry compared to BC. Perhaps what I miss most is the ocean – the knowledge that the nearest coastline is more than a thousand kilometres away gives me an uncomfortable feeling akin to claustrophobia.

During that time, the last story I covered has developed significantly. Before September even began, Arctic sea ice extent reached record low levels. It’s currently well below the previous record, held in 2007, and will continue to decline for two or three more weeks before it levels off:

Finally, El Niño conditions are beginning to emerge in the Pacific Ocean. In central Canada we are celebrating, because El Niño tends to produce warmer-than-average winters (although last winter was mysteriously warm despite the cooling influence of La Niña – not a day below -30 C!) The impacts of El Niño are different all over the world, but overall it tends to boost global surface temperatures. Combine this effect with the current ascent from a solar minimum and the stronger-than-ever greenhouse gas forcing, and it looks likely that 2013 will break global temperature records. That’s still a long way away, though, and who knows what will happen before then?

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Tonight is Earth Hour, when people across the world turn off all their lights and electronic devices (except the necessary ones – I don’t think you’re required to unplug the freezer) from 8:30 to 9:30 local time. This is meant to generate awareness about climate change and conservation. It’s really more of a symbolic action, to my understanding – I doubt it adds up to a significant dip in carbon emissions – but I take part anyway. I find that a lot of interesting conversations begin when there’s nothing to do but sit in the dark.

It was during the second official Earth Hour, when I was sixteen years old, that I agreed to babysit for friends of the family. Great, I thought, how am I going to get a five-year-old boy and a two-year-old girl to sit in the dark for an hour? I ended up turning it into a camping game, which was really fun. We made a tent out of chairs and blankets, ate popcorn, and played with a flashlight powered by a hand crank.

The girl was too young to understand the purpose of sitting in the dark – she just liked waving the flashlight around – but I talked to the boy a bit about why we were doing this. I told him how we needed to take care of nature, because it can be damaged if we don’t treat it well, and that can come back to bite us. I explained the purpose of recycling: “You can make paper out of trees, but you can also make paper out of old paper, and that way you don’t have to cut down any trees.” His face just lit up, and he said, “Oh! I get it now! Well, we should do more of that!” which was really great to hear.

Halfway through the hour, the kids went to bed, and I sat in the dark on my own until 9:30, when I turned the lights on and started to do homework. And that was the end of it…or so I thought.

Apparently, at some point during that hour, a neighbour had noticed that the house was in darkness and flashlights were waving around. He thought there was something wrong with that situation, and came over to knock on the door, but we were in the basement in our tent and didn’t hear him. So then he called the police.

It was 11 pm by the time they showed up. Suddenly someone was pounding on the door, and I, convinced that someone was trying to break in, was terrified. I froze in my seat, and contemplated hiding under the desk, but whoever was at the door refused to go away. Eventually I crept over to a side window and looked outside, where I saw a police car.

My first thought when I opened to the door to two police officers was, “Who got in a car accident? My family, or the kids’ parents?” The concept of police coming to investigate a house that had its lights off was completely foreign to me.

“It’s Earth Hour,” I said when they told me why they were there. They replied, “Yeah, we know, but we have to answer all our calls.” They took my name and my birth date, so this incident must be mentioned somewhere in the city police records. I imagine there is a note next to my name saying, “Attempted to indoctrinate children with environmentalism.”

Luckily the kids didn’t wake up, but they heard about the incident later from their parents. I still babysit these kids, albeit less frequently now that I’m in university, and the boy often asks, “Can we turn off all the lights again? I want the police to come. That would be fun.”

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