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.