Lecture 4

An entity composed of diverse but interrelated parts that function as a complex whole.

It is made up of a number of sub-systems (or components) that perform vital functions. The respiratory system for Oxygen in and CO2 out, cardiovascular system that carries oxygen throughout the body, digestive system that turns food into energy, and the nervous system that senses environment and controls other sub-systems

It is self-regulating

It has the atmosphere, hydrosphere, biosphere, and lithosphere that make the planet livable and are self-regulating

The set of important attributes that characterize a system at a particular time.

Body temperature, nutrition level, and blood pressure

Couplings, and they allow for regulation of a system

A positive coupling is a change in the same direction. If the system is composed of blanket temperature and body temperature, when the blanket temperature rises, so does body temperature.

A negative coupling is a change in the opposite direction, represented by a line with a dot. If you get too hot and turn the blanket off, the blanket temperature goes down while the body temperature is still rising

It is a combination of positive and negative couplings that minimizes disturbances, leading to stability

It is a combination that ultimately results in a positive coupling, that amplifies the initial distubance causing instability.

Because even a small initial change can be amplified via positive feedback and can cause disproportionately significant damage to the Earth

It ultimately results in a poistive feedbakc loop amplifying global warming because more CO2 causes a positive coupling with the temperature in the atmosphere, which causes a positive coupling with the temperature of the oceans, which causes a negative coupling between the amount of CO2 that can be taken up by the oceans, which causes a negative coupling between the amount of CO2 in the atmosphere

It is a measure of the reflectivity of a surface

Ice and clouds are lighter and more reflective, reflecting 70-90% of incident light, and the ocean is dark and absorbs more heat. Forests and land also absorb heat, reflecting closer to 10% of the incident light

Temp rises, causing a positive coupling between the amount of ice melting, which causes a positive coupling between the amount of dark surfaces, causing a positive coupling with atmospheric temperature

There is a positive coupling between temperature and rate of evaporation, causing a positive coupling between evaporation and cloud cover, causing a negative coupling between the amount of cloud cover and the amount of solar radiation absorbed, causing a positive coupling between solar radiation and the temperature

Rocks decompose due to chemical or physical processes. There is a positive coupling between atmospheric CO2 and atmospheric temp, causing a positive coupling between temperature and rates of rock weathering, causing a negative coupling between the rate of rock weathering and atmospheric CO2.

50 million years ago there was a peak in global temepratures, but it was reveresed from long-term warming to cooling because the Himalayas were formed as Inidian and Asia colided causing rocks to be kicked up that could weather and erode taking CO2 out of the atmosphere

A passage formed 35 million years ago when South America broke off from Antarctica.

Antarctica went from being ice-free to being covered in ice because of the circulate ocean current called the Antarctic Circumpolar Current (ACC) that circles it.

The lithosphere changed as the plates moved apart, the hydropshere as the circumpolar current was started, the energy system as heat can’t get to antarctica, the atmosphere as it was also isolated from hear causing it to get cold, and the hydrosphere as glacier ice being to form. Starts the ice-albedo feedback and antarctica keeps getting colder and colder