Lecture

Radiative Forcing & Climate Sensitivity

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Description

This lecture covers the concepts of radiative forcing, climate sensitivity, and feedback mechanisms in the context of climate change. It discusses how clouds, aerosols, and greenhouse gases impact the Earth's energy balance and temperature. The instructor explains the difference between radiative forcing and effective radiative forcing, emphasizing the role of various components like CO2, methane, and nitrous oxide. The lecture also delves into the evolution of climate models and the methods used to derive climate sensitivity, including equilibrium climate sensitivity and transient climate response. The importance of paleoclimate records and emergent constraints in constraining climate sensitivity is highlighted.

Official source

Ontological neighbourhood

Environmental science

Climate: Climate change, Climate change mitigation

Related concepts (32)

Climate change

In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices increase greenhouse gases, notably carbon dioxide and methane.

Climate model

Numerical climate models use quantitative methods to simulate the interactions of the important drivers of climate, including atmosphere, oceans, land surface and ice. They are used for a variety of purposes from study of the dynamics of the climate system to projections of future climate. Climate models may also be qualitative (i.e. not numerical) models and also narratives, largely descriptive, of possible futures.

Climate sensitivity

Climate sensitivity is a measure of how much Earth's surface will cool or warm after a specified factor causes a change in its climate system, such as how much it will warm for a doubling in the atmospheric carbon dioxide () concentration. In technical terms, climate sensitivity is the average change in global mean surface temperature in response to a radiative forcing, which drives a difference between Earth's incoming and outgoing energy.

Radiative forcing

Radiative forcing (or climate forcing) is the change in energy flux in the atmosphere caused by natural or anthropogenic factors of climate change as measured in watts per meter squared. It is a scientific concept used to quantify and compare the external drivers of change to Earth's energy balance. These external drivers are distinguished from climate feedbacks and internal variability, which also influence the direction and magnitude of imbalance. Positive radiative forcing means Earth receives more incoming energy from sunlight than it radiates to space.

Climate change feedback

Climate change feedbacks are effects of global warming that amplify or diminish the effect of forces that initially cause the warming. Positive feedbacks enhance global warming while negative feedbacks weaken it. Feedbacks are important in the understanding of climate change because they play an important part in determining the sensitivity of the climate to warming forces. Climate forcings and feedbacks together determine how much and how fast the climate changes.

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