Climate sensitivity

Definition

Climate sensitivity is a measure of how much the Earth's average surface temperature will increase in response to a doubling of atmospheric carbon dioxide (CO2) concentrations, typically expressed in degrees Celsius. It helps scientists understand the relationship between greenhouse gas emissions and temperature rise, and is crucial for predicting future climate scenarios and evaluating the impacts of climate change.

5 Must Know Facts For Your Next Test

1. Climate sensitivity is usually estimated to be between 1.5°C and 4.5°C for a doubling of CO2, with most estimates clustering around 3°C.
2. Higher climate sensitivity suggests greater potential warming for any given increase in CO2 levels, emphasizing the importance of reducing greenhouse gas emissions.
3. Different climate models may produce varying estimates of climate sensitivity due to differences in how they simulate feedback processes and radiative transfer.
4. Observational data, including historical temperature changes and paleoclimate records, help refine estimates of climate sensitivity by providing real-world evidence of climate responses.
5. Climate sensitivity plays a key role in shaping global climate policies by informing targets for limiting greenhouse gas emissions to meet international agreements like the Paris Accord.

Review Questions

• How does climate sensitivity relate to radiative forcing and the overall energy balance of the Earth?
  • Climate sensitivity is directly linked to radiative forcing, as it quantifies the temperature response to changes in greenhouse gas concentrations caused by radiative forcing. When CO2 levels double, increased radiative forcing alters the energy balance of the Earth, leading to warming. Understanding this relationship is essential for assessing potential temperature rises associated with different emissions scenarios and helps inform mitigation strategies.
• Discuss the significance of feedback mechanisms in determining climate sensitivity and their impact on future climate predictions.
  • Feedback mechanisms are crucial for understanding climate sensitivity because they can either amplify or mitigate warming effects. For instance, positive feedback from melting ice reduces Earth's albedo, leading to further warming. In contrast, negative feedback from increased cloud cover can reflect more sunlight back into space. Accurately accounting for these feedbacks in climate models affects predictions about future temperatures and influences policy decisions aimed at reducing greenhouse gas emissions.
• Evaluate the implications of varying climate sensitivity estimates for global climate policy and future scenarios.
  • Varying estimates of climate sensitivity have significant implications for global climate policy because they inform how much warming can be expected from different levels of greenhouse gas emissions. If climate sensitivity is high, even modest increases in CO2 could lead to severe temperature rises, necessitating more aggressive emission reduction strategies. Conversely, lower estimates might suggest that current policies could suffice. Understanding these nuances helps policymakers prioritize actions and set realistic targets for mitigating climate change impacts.

Related terms

radiative forcing: Radiative forcing refers to the change in energy balance in the Earth's atmosphere due to factors like greenhouse gas emissions, land use changes, or volcanic eruptions, which can influence temperature and climate.

feedback mechanisms: Feedback mechanisms are processes that can amplify or dampen the effects of climate change; positive feedbacks, like ice melt reducing albedo, can increase warming, while negative feedbacks, like increased cloud cover, can help cool the planet.

climate models: Climate models are complex computer simulations that represent the interactions between the atmosphere, oceans, land surface, and ice, helping researchers predict future climate conditions based on different greenhouse gas emission scenarios.