The Snowball earth

So today's lesson was about the ancient climates. One of the additional reading mentioned was this: snowball earth After reading this - I was intrigued the research is quite recent (1998) - and Namibia (which is adjacent to my home country, South Africa) played a crucial role in this. I searched the timeline of the earth on Google and found this: The history of the Earth So the 600 Million years ago there was an Ice Age - actually lined up pretty well with the Biological evolutionary Data. It is truly fascinating. I've created a board to illustrate how this happened. I'm still uncertain about the "chemical weathering" part. My snowball earth

The Blanket Analogy

In the opening video the lecturer says the greenhouse analogy isn't really good, and that the blanket analogy should rather be used. I disagree strongly. The blanket analogy has the same problem as the greenhouse and more (being opague). He says "The problem is that what really warms the greenhouse up is the prevention of air flow, stopping the loss of heat by convection." Similarly, the blanket stops airflow over the body - stopping the loss of heat by convection. Also a blanket is really conduction related insulation and the problem is radiation, not convection or conduction. So, if you have a blanket over you - you have a twofold advantage over being naked - firstly the blanket provides a thermal insulation that prevents heat flow through conduction. The second advantage is that you don't have air flowing over your body at a quick rate, so the convection heat loss that you have is lower.

Reflection on the first week.

Having completed the first week's material in two days, I thought I could do some reflecting here. The new things that I've learnt are:

• The albedo effect - this is effectively a measure of the percentage of incoming energy that is reflected back from the earth's surface- the earth's albedo is about 30%
• the five "spheres" are
  • atmosphere- the hundreds of km of air above the surface - The international space station is still inside the "atmosphere"! - it is at 330-410 km above the earth's surface. I'm guessing from reading the article, that the most "reflection" back to the earth happens near the top of the troposphere (roughly 12km up)
  • hydrosphere- all the water in liquid form (and water vapour)
  • biosphere - all the life - interesting fact - there was also a biosphere 2 experiment in Arizona and the trees buckled under their own weight due to lack of wind in the biosphere 2 - space exploration here we come!
  • cryosphere- all the ice
  • lithosphere- the rocky crust
• There are some feedback loops - mainly the water loop (positive feedback with 3 elements), the ice melting (positive feedback with 2 elements, and the radiation outward - a negative feedback loop with 2 elements

Start of a new era

So I joined the free course at Futurelearn.com on Climate Change. Climate change is the major crisis of our time and we must try as hard as possible to minimise its impact. This is sort of a "hello world" post and I will continue to blog about my experiences as I embark on my first online course.