Lecture 3 Climate Fundamentals

Gang He

September 5, 2023

Climate and Weather

Climate is the average weather conditions of a region over a long period of time, usually at least 30 years. Weather refers to short-term atmospheric conditions. Climate change refers to long-term changes.

Weather refers to short-term atmospheric conditions. Climate change refers to long-term changes.

GHG effect

Greenhouse Gases(GHG)

GHG	GWP-100	Lifetime (Years)
Carbon Dioxide (CO2)	1	hundreds
Methane (CH4)	29.8±11	11.8 ± 1.8
Nitrous Oxide (N2O)	273 ± 130	109 ± 10
Hydrofluorocarbon-32 (HFC-32)	771 ± 292	5.4 ± 1.1

Other:

• Sulphur hexafluoride (SF6)
• PFC-14 (CF4)
• Water vapour

From emissions to warming

Warming since measurement

Warming in context of geological history

Warmer and Warmer

Climate spireal

Temprature anomaly distribution

Human vs nature

Human component is the major driver of warming

Scientific understanding: climate systems

Scientific community and process

• What is the IPCC?
• How does the IPCC select its authors?
• What literature does the IPCC assess?
• How does the IPCC review process work?
• How does the IPCC approve reports?
• How does the IPCC deal with alleged errors?
• What is an Expert Reviewer of IPCC?

Five stages of climate denial

• Stage 1: Deny the Problem Exists
• Stage 2: Deny We’re the Cause
  • Stage 2b: Consensus Denial
• Stage 3: Deny It’s a Problem
  
• Stage 4: Deny We can Solve It
  
• Stage 5: It’s too Late

A five points “climate haiku”

1. It’s warming
2. It’s us
3. We’re sure
4. It’s bad
5. We can fix it

References

Hansen, James, Makiko Sato, and Reto Ruedy. 2012. “Perception of Climate Change.” Proceedings of the National Academy of Sciences 109 (37): E2415–23. https://doi.org/10.1073/pnas.1205276109.

Koomey, Jonathan, and Ian Monroe. 2022. Solving Climate Change: A Guide for Learners and Leaders. IOP Publishing. https://iopscience.iop.org/book/mono/978-0-7503-4032-8.