Welcome back to the penultimate episode of the Habitable Planet course. Fantastic job on getting this far. Sad to see it end? Well, then, don't worry too much as you still have two exciting weeks to go.  Last week we added a new species to our model and saw how humans arose here in Africa. For most of our history there was more than one human species on the planet (usually 5-10), but recently all the others appear to have been wiped out by homo sapiens - us. We call ourselves the thinking apes, but perhaps we should be the murderous apes! 

Focusing on modern humans now, JZ told us last week that the industrial and agricultural revolutions have enabled humans to sustain and employ a greater number of people than ever before. The results are putting a severe strain on the planet. Our model of the Earth's systems is now complete, but it has become immeasurably complex, and includes seven billion people going about their everyday lives. No computer has the power to predict what they will do, say or think. In fact, no computer programme could even manage to model just my own brain patterns, and succeed in predicting the last letter of this sentencb!! So we are left with just a conceptual model of humans as part of life and the Earth's Systems we have discussed. Because of this we have left pure science behind and are forced to work in a world of feelings, emotions, ethics and politics. Tricky stuff indeed, and far more complicated than the simple physics of the early course (how I miss the simple physics).

But never fear, our experts are here to make sense of it all! This week we look in more detail at the problem of climate change with Nadine. Climate change is yet another problem that has resulted from too many people on the planet, and it is possibly the most alarming problem of all those facing mankind (with emphasis on possibly, as we shall see later). Luckily, there is a solution to all these problems; sustainable development. Like our knight in shining armour, Tumelo will tell us how we can attempt to resolve these issues. 

1. This Week's Lectures

2. This Week's Reading

Some useful reading resources around climate change can be found here:

• Climate Change Basics Made Simple

3. Special South Africa

This section is very small this week. Not because there is too little to say, but because there is so much to say we dedicated next week to it. Also this week is very busy so you guys need breathing space. Two things to say briefly:

1. The responsibility for climate change lies with rich. The impacts will affect mostly the poor. South Africa is almost unique in the world in that we have the super rich living next door to those who are unable to meet their basic needs. Although this is certainly not a good thing in general, it does make South Africa a microcosm of the climate change political problem. South Africans are therefore best placed to debate a solution that is fair to all.

2. As noted, many South Africans are struggling financially. The way the richer nations became wealthy was by burning coal for cheap energy to fuel industrialisation, and this remains the only tested route to end poverty. South Africa has much coal. Leaving it in the ground will help mitigate climate change and improve the lives of future South Africans. Burning it on the other hand may help the economy and reduce poverty and suffering now. How do we balance the needs of the present again those of the future?

More next week!

4. Critical Eye from a Science Guy

This week we would like you to challenge yourself by engaging with some perspectives and ideas that many environmentalists may find unusual, unpalatable or, downright dangerous.  In each case, the challenge is to think critically. This means uses what you have learned in HPW to engage with and critique the information presented. However, it also means being open to being wrong, and learning something new!

6. This Week's Test