The Science of Climate Change: Practice Questions

In the context of natural factors influencing the Earth's climate system, what is the term for the large-scale ocean circulation driven by global density gradients created by variations in surface heat and freshwater fluxes?

The enhanced greenhouse effect is a central focus of human influence on climate. Which statement accurately describes the physical mechanism by which increased atmospheric concentrations of greenhouse gases like \(CO_2\) lead to global warming?

In the context of the climate system, how does the ice-albedo feedback function when global temperatures increase, and what type of feedback does it represent?

Which of the following proxy indicators is primarily used by scientists to reconstruct past atmospheric \(CO_2\) concentrations and temperature variations over hundreds of thousands of years?

Identify the two physical variables that determine the density of seawater and drive the thermohaline circulation, which acts as a natural factor influencing the global climate.

Explain how the water vapor feedback mechanism operates and identify whether it is a positive or negative feedback in response to an initial warming caused by higher \(CO_{2}\) concentrations.

The study of the Quaternary period provides insights into the natural and anthropogenic drivers of climate change.

(a) Explain how thermohaline circulation (THC) contributes to global heat redistribution and analyze how the melting of ice sheets can lead to a weakening of this circulation. (3 marks)

(b) Discuss the sources of uncertainty in future climate projections made by the IPCC. In your answer, reference the challenges posed by positive feedback mechanisms and the lack of in-situ data in regions like the polar ice caps. (4 marks)