Week 8 - Looking ahead

Our final week was all about what we might do about climate change in the future.

I was hoping we'd finally get a look at some potential solutions but instead we were asked to calculate our carbon footprint and figure out what we could do to help.

Disappointing to say the least.

The average man on the street, if they ever think about it, feels overwhelmed by the scale of the climate change problem. This is exemplified by the rate at which China is currently building coal fired power stations (1 a week isn't it?). How on earth can we hope to reduce emissions in the face of China's staggering economic growth?

The fact is though, it can be done. Even the Chinese are acutely aware of the effects of their growth and working hard to reduce their impact.

As I said in one of my answers on the course, things like carbon capture, energy storage, smart grids, super-grids, and energy efficiency will be key to our fight against climate change.

Also investment in R&D on renewables; bringing down the price of renewables, whilst raising the cost of fossil fuels to encourage rapid development and deployment of new forms of clean energy.

Replacing coal stations with nuclear, or gas would be a useful stop-gap until cleaner, cheaper forms of power take over.

Re-forestation is essential. We also need to stop cutting down forests/replacing food crops with biofuel crops. We need to make more effective use of farmland by using more of it for crops rather than livestock. That means we need to eat less meat (Our family has at least one 'veggie' day a week).

We need to put an end to consumerism for the sake of it. Not only does it waste energy, it wastes raw materials and even precious water (Yes everything has it's own water footprint).

We need to de-couple carbon emissions from economic growth.

And so on.

My point is that there are loads of things we can do to reduce emissions to the required levels even with current technology. It doesn't have to be financially crippling. In fact, it would be far cheaper than having to deal with the consequences of business-as-usual.

All we need is the collective will to do it.

Week 7 - Adaptation & Mitigation

The poorest week by far.

A video supposedly about adaptation and mitigation focuses on a new build school that's been built to be zero carbon, stay cool in summer, and generate it's own power.

All very nice but how does it mitigate climate change? Yes, if it were applied to all new builds, it might just scratch the surface of the problem, but we all know that's not going to happen any time soon. Every building would cost a fortune for a start.

What would have been better would be to show an old school being retrofitted with cost efficient carbon cutting and adaptation measures. That would have been far more interesting, realistic, and on topic.

And then, to compound things, we were asked to 'browse' a 75 page document on mitigation and adaptation in, would you believe, new build houses.

ARGHHHHHH!! The UK alone has 25 million existing homes, very few of which are even close to zero carbon. They're the problem! How do we get them sorted out?

Then we get the classic "Decarbonising energy is all very well but what about..." argument in the form a video about NIMBYs. Yes, I've heard it all before, so where are the SOLUTIONS?

If we are to have any chance of keeping climate change below 2 degrees C, global carbon emissions have to level off (and fall quickly thereafter) by 2020. We need effective, cost efficient solutions now and that may mean we have to make some tough choices.

If we want things to stay the same, things are going to have to change.

Week 6 - Effects of climate change on Humans

This week we covered the topics of urban heat island and food security.

Urban heat islands
Here we looked at the way cities tend to be several degrees warmer than the surrounding countryside making heatwaves all the more dangerous. Heat islands are caused by large and/or densely packed buildings absorbing and re-radiating heat, whilst there's little to cool things off (like open spaces, woodland, circulating air, and evaporating water).

70,000 people died in Europe's 2003 heatwave. Most deaths occured at night near the top of tall buildings. At night, because people would normally get the chance to cool down then but can't during a heatwave. At the top of tall buildings because they store more heat and heat rises...

Given that the world's population is tending to migrate towards cities (I believe some 50% or more will be living in cities by mid-century) this problem can only get worse in a warming world unless some way of reducing the effect is found.

Food security
Pests and diseases are on the increase thanks to climate change. We depend on 3 main crops, if these pathogens sweep through any one of these (in a similar way to Ash Die-back, Dutch Elm Disease, and Acute Oak Decline) and there'd be mass-starvation, food riots and, in the developed countries food inflation.

This too is set to be more of a threat as the world population increases to around 9.2 billion by mid-century: We may need to double crop yields by then to keep up with the demands of the increasing population, especially the growing middle classes.

Climate change, rising sea levels, mass extinctions, urban heat islands, ocean acidification, over population, water scarcity, and mass starvation. That's what our kids have got to look forward to.

Week 5 - The impacts of climate change

This week we covered the effects on the cryosphere and ocean acidification.

The Cryosphere
i.e those areas of the Earth covered in ice or show such as ice sheets, glaciers, permafrost, and snow fields.

Most of the world's ice is contained in the Antarctic and Greenland icesheets. These are so big that, were they to melt completely, sea levels would rise by 65 metres. If you want to get an idea of what that would mean to your part of the world try here.

Unfortunately, the Greenland sheet is losing mass at an accelerating rate and parts of western Antarctica are showing signs of vulnerability too. We learnt about some of the things that influence this including how melt water can accelerate the rate of flow of glaciers and buttressing (which can slow mass loss down).

Ocean Acidification
The oceans act as a CO2 sink, absorbing around half of our carbon emissions. Unfortunately, this is leading to the oceans becoming more acidic. The pH has decreased by 30% since pre-industrial times. This could seriously compromise the ability of marine organisms to build and retain shells and skeletons. They may even have problems getting rid of CO2 from their bodies leading to acidosis.

These problems may result in the extinction of many shell forming organisms. If any of these are near the bottom of food chains it may lead to the collapse of the whole food chain. Mass extinction anyone?

Why should we care? Because the sea provides us with a significant part of our diet. For many of us, fish and shellfish is a nice-to-have not an essential, but for some populations, it is a staple part of their diet.

Week 4 - Climate Models and Geoengineering

Two controversial areas this week.

Climate models are computerised simulations of the Earth's climate which can be used to predict future climate based on a given set of variables.

The principle is fine and can be tested and tuned against past climates. It's important to realise that they don't predict precisely what will happen but give a general idea of where things are likely to head.

For this reason they are considered controversial by climate sceptics/deniers. The rest of us see the models for what they are: A useful tool.

By contrast, Geoengineering is controversial for good reason: It's playing god.

You see, if you accept that computers can never truly model all the complexity of the climate down to the finest detail, how can you expect to use something like stratospheric aerosols on anything other than a wing and a prayer? It's nuts.

But there are lot of vested interests out there who want and need a silver-bullet, so don't be surprised if geoengineering gets deployed anyway.

That's when we'll KNOW we're screwed.

Week 3 – Signs of Climate Change

Ships of the desert

Do the 'discussions' work for you?
Okay, so one of the core ideas on this course is that we watch a video, or read something off the web then enter into a discussion via posts on the course forum.

Trouble is you end up with literally hundreds of posts to trawl through for each discussion. It just doesn't work.

The problem is the sheer number of people on this course (and over 500 more have joined since it started). If the majority try to make contributions, the discussions become too unwieldy.

It would be better if the course organisers either limit the numbers or, run the course for everyone at once (as now) but divide them into separate groups running in parallel.

Longer videos?
I must admit I was a bit disappointed that the video 'lectures' weren't a lot longer. Instead there's more emphasis on discussions (which don't work - See above).

I think I've worked out what they wanted to do here though. The videos are just a quick heads-up on a given theme, whilst the research/discuss sections are meant to be the main method of education: You look at the data and you work out what it means e.g. I was really surprised this week when I discovered that the UK's wettest year (2012) was part of a 40 year trend towards wetter weather. I just thought we'd had a bit of bad luck lately!

The difference between Obliquity and Precession

Earth (with axis shown) orbiting the Sun

I don't know about you but I was confused by week 2's video description of Obliquity (Axial tilt) and Precession.

The video's description made them sound the same with only the period of time different.

So, after much research, here's the actual difference:

Obliquity is about the angle of tilt of the Earth's axis relative to it's orbit round the Sun. This tilt gives us our seasons e.g. In June to August, the northern hemisphere leans towards the Sun giving us Summer. In December to February, the southern hemisphere tilts towards the Sun giving them their Summer.

If you ignore all other effects, this tilt changes from 21.5 to 24.5 degrees over a 41000 years period. The more the angle, the more pronounced the seasons


Precession is a wobble the axis gets from the pull of the Moon and the Sun. If you ignore all other effects, this wobble makes the Earth's axis trace out a circle over a 23000 year period. On it's own it would also give us our seasons.

So yes, Obliquity and Precession are very similar but subtly different.

What makes a gas a greenhouse gas?

A water molecule

Something the course hasn't gone into yet is why certain gases behave as greenhouse gases (GHGs). So I thought I'd have a go at it myself :)

There are 2 requirements for a GHG:

1) The gas needs a frequency of vibration mode that matches the frequency of infra red light (IR). In other words it needs to be capable of vibrating in tune when IR hits it.

2) The vibration needs to perturb the gas molecule's electric field, creating a dipole. Dipoles are where a molecule has a positive and negative pole (like a battery).

When you accelerate and decelerate a dipole (i.e. vibrate it) electro-magnetic radiation - in this case IR - is created.

In summary, IR hits a GHG, the gas vibrates in tune with it and therefore fires off IR in all directions including back to the ground.

More here.

Week 2 - Palaeoclimate

Home

Palaeoclimate (past climates) is a particular interest of mine as a geology graduate, so I was especially pleased about this week's content.

The use of 'Snowball Earth' was particularly clever as it expanded upon the ideas of feedback mechanisms and a self-regulating planet from last week.

I was already aware of Snowball Earth as I'd already seen the Horizon program featured when it first aired (and from various sources since), but it was good to see more detail on how the planet managed to escape it (Nice work you volcanoes!).

I was also aware that the sun had been less bright in the past but didn't realise how our self-regulating planet had scaled back the CO2 (through chemical weathering and sequestration in the oceans) as the sun got brighter. Wow.

Goldilocks zone: Another concept I knew but it was interesting to know that Earth will have a runaway greenhouse effect eventually like Venus. I thought the physics were all wrong (Must dig out a reference for that some time).

Again, proxy climate data and the effects of the Earth's orbit and axial tilt weren't news to me but it was great to get more detail.

The proxy data allows us to learn lessons from the past whilst the influences on solar input help us understand the climatic changes they show us. All very clever stuff.

Week 1 - Principles of Climate Change

Jack Russells: Aren't they great?!

As mentioned in my previous post here are my reflections on the first week of the course based on the Uni's suggested questions:

What are the key scientific principles that explain climate change including the greenhouse (blanket) effect?
When the sun's light hits the Earth, about 30% is reflected back into space and the rest of the energy is absorbed and radiated back into the atmosphere as heat.

Greenhouse gases like water vapour, CO2, methane, ozone, and nitrous oxide, in turn, absorb this heat and re-radiate it in all directions including back towards the ground.

As a result, heat is trapped in the lower atmosphere. This is the greenhouse effect.

The climate system of our planet is made up of 5 elements:

• Atmosphere.
• Cryosphere (Snow & ice)
• Lithosphere (Solid rock)
• Biosphere (Living things)
• Hydrosphere (Water )

These all interact with each other to provide our ever-evolving climate. These are influenced by external factors known as 'forcings' (e.g. volcanoes, solar variation, and we humans).

Closed loops of cause and effect can develop called feedbacks. For example, when temperature rises, more water evaporates, which traps heat in the atmosphere, so raising the temperature and so on. This amplifying effect is called positive feedback. The opposite effect, which reduces the temperature, is called a negative feedback.



What are the key feedback mechanisms that help to explain why our climate is able to “self-regulate”? 

• water vapour feedback (described above)
• ice albedo (a positive feedback)
• Radiation (a negative feedback)

How can our climate be conceptualised as a system containing a series of components that interact with one another?
See my answer to the first question.

What are the most important themes you have learned this week?
That the climate is a very complex, constantly evolving and self-regulating system. And we humans are unbalancing it.

What aspect of this week did you find difficult?
Finding the time to fit in reading through all the forum comments.

What did you find most interesting? And why?
Seeing how all the elements of the climate fit together and feed off each other.

Was there something that you learned this week that prompted you to do your own research?
I started looking at some of the chapters in the latest IPCC report and noticed they had one on palaeoclimate i.e. climate in the past. Apparently climate models can be tested against palaeoclimate and successfully 'predict' the past.

Beginnings

Our cat: Not a happy bunny

I'm doing what's called a 'Massive Open Online Course' with Exeter University at the moment. It's the one called Climate Change: Challenges and Solutions. And it's free, which is always a bonus.

As part of the course, you're asked to 'reflect' on what you've learnt through something like a blog. So here we are.

The course lasts 8 weeks and every week you're set up (online) with a new bunch of videos, course material, and questions that allegedly take between 2 and 3 hours to complete. Well, yeah, but if you want the full social media experience, you need to read through all the comments posted by your classmates. That kind of takes a while. Lucky they're worth reading then.

Why am I doing the course? Well, as I commented on the course forum "I'm doing this course because I'm concerned about the sort of world my kids will be growing up in. Will they be part of the first generation to KNOW their world is in decline, or part of one that's finally going to turn it all round? Or will climate change turn out to be nonsense, and the joke will be on us".