The Greenhouse Effect

The Carbon Cycle and Climate Change

In this course, Professor David Archer (University of Chicago) explores the greenhouse effect, the carbon cycle, and climate change. In the first module, we think about the Earth’s energy balance – the relationship between energy coming in through solar radiation and leaving via infrared light – and how this is disrupted by greenhouse gases. In the second, we look at how greenhouse gases work, focusing particularly on their capacity to absorb infrared radiation. The third and fourth modules consider the carbon cycle, firstly examining its fast and slow cycles as they exist without human impact, before turning to the ways it has been disturbed and altered by fossil fuel emissions. In the fifth module, we outline past changes in climate and their causes, including variations in Earth’s orbit and plate tectonics. We conclude with a sixth module on global warming today, the impact it is predicted to have on humanity, and strategies for limiting its effects.

The Greenhouse Effect

In this module, we think about the Earth’s temperature and how it is influenced by the greenhouse effect. We focus on: (i) solar radiation as the planet’s energy source; (ii) the Earth’s energy balance – the equilibrium between incoming solar radiation and energy shed from the planet through infrared emissions – and its role in creating a stable climate; (iii) the impact of greenhouse gases – they disrupt this balance by impeding infrared light leaving the Earth, leading to a rise in temperature; (iv) how the effect of greenhouse gases is estimated using climate sensitivity models; (v) how warming on Earth is exacerbated by amplifying processes known as climate feedbacks.