Week 2 - Palaeoclimate

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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.