If you’re new to climate systems, meteorology, or biophysical science in general, take a look here to get some good background knowledge: www.physicalgeography.net

The major components in the climate system is an interlocking relationship between the following:

• Atmosphere
• Hydrophere (oceans, lakes, rivers)
• Cryosphere (snow and ice)
• Lithosphere (land surface and “deep” Earth)
• Marine and terrestrial biosystems

What connects them are fluxes, flows and transfers of mass, energy and momentum. These relationships are extremely complex and do not form linear relationships, aka their relationship cannot be explained along a straight line on our graphs.

Terminology of the Climate System’s Relationships

Relationships are hard, right? There’s a lot of give and take, compromise and reactions that play out between two people. Climate’s got it hard too!

Forcing versus Response

Forcings: Factors that drive or cause change

Response: The effects (e.g., climatic changes that occur)

Response or relaxation time: The time it takes for a system to re-equilibrate to a new state after a small perturbation has been applied. These changes that occur over short time periods are still seen in effects caused over longer time periods (just like holding a grudge and acting out about it later!)

Feedbacks

This is not a typo, I promise. Feedbacks describe the cycle of a forcing causing a response (i.e., the effect) on a climate system. There are positive and negative feedbacks.

Negative feedbacks have a stabilizing influence. This seems counter intuitive, since the word negative evokes something bad and therefore bad to worse. However, think of it like this: a forcing creates a response in the climate system, which then overcomes or reduces the influential power of the effect and remains stable (rather than acting out).

Positive feedbacks lead to pronounced instability. As the forcing creates a response within the climate system, the effect triggers a gut reaction in the system that amplifies the instability. Think of food poisoning, in this case. You have a digestive system that experiences a forcing (spoiled food) and a response (upset stomach). This would cause a positive feedback; you’d not only get sick, but your system would become greatly unstable.

Yes, food poisoning was just used to explain a positive feedback. Gross, I know.

Common climate forcings over time include:

• Tectonic processes: Earth’s internal heat affects the surface by altering topography
• Earth orbital changes: Earth’s orbit around the Sun does change slightly over time, altering the amount of solar radiation received by Earth
• Changes in the Sun’s strength: the amount of solar radiation may change intensity
• Anthropocentric: people effect the climate too!