The sixth lecture in the philosophy of climate change. It covers ten basic points about climate science, offers one note of caution, and distills two key implications.

1. 6. Climate Science as a
Body of Knowledge
UNT Phil 4250
Climate Change
Adam Briggle
(he/him/his)
adam.briggle@unt.edu

2. 106 yesterday • Average 94

3. Ackbar
Approved!

4. Outline
•On science as a body of knowledge
•Ten climate basics
•One note of caution
•Two implications

5. What is
known?
• Bracket science from
process and context – a
passive corpus of
knowledge.
• Difficult, humbling, and
crude task to distill the
basics
• But necessary as a

6. Ten Climate Basics
1. Climate is long-term average weather. It is both real and a construct. A 30-year average is climate
to us, but it is weather from the perspective of the Triassic Period. (Long-term batting average vs.
your stats for a particular game or personality vs. mood).
2. The Earth’s climate system arises from the interactions of the hydrosphere, atmosphere,
lithosphere, biosphere, and cryosphere… and the anthropo-sphere. Along with variations in solar
radiation received by Earth.
3. Climate change is significant and lasting (at least on a period of decades) changes in the
distribution of weather patterns. For example, there were palm trees above the Arctic Circle 50
mya, where there is now ice (and now the ice is melting). Climate change can be change in
average weather and/or change in weather extremes.

8. Ten Climate Basics
4. An important feature of the climate system is the greenhouse effect: CO2 and other greenhouse
gasses (GHGs) trap heat radiating to space, warming the lower atmosphere and surface. The ocean
absorbs the vast majority of this heat.
5. Primarily by burning fossil fuels, but also through agriculture and land use changes, humans have
increased the concentration of GHGs in the atmosphere.
6. Atmospheric CO2 concentrations in 2020 are about 414 ppm, which is higher than at any time in
the past 800,000 years. Direct observations began in 1960 when concentration was about 309 ppm.

10. Ten Climate Basics
7. This increases radiative forcing, thereby raising global average temperatures. This is known as
global warming.
8. Climate change is a better comprehensive term for anthropogenic impacts (rather than global
warming), because different parts of the planet are warming at different rates. And due to complex
interactions, some parts of the planet may experience cooling (e.g., ocean circulation patterns).
Differential warming graphic

11. Ten Climate Basics
9. Anthropogenic (human-caused) climate change has current and projected impacts on earth systems
that are wide-ranging: for example, extreme weather events (drought, fire, storms, floods, heat
waves), biodiversity loss, ocean acidification, sea level rise, and species and disease distribution
patterns.
10. These changes have and will in turn impact humans in many ways: food security, access to water,
heat stress, infrastructure damage, infectious and zoonotic diseases, migration, war, and more.

13. One Note of Caution
1. Measuring these impacts and attributing them to anthropogenic climate change is
often difficult and requires care in following evidence, characterizing
uncertainties, and interpreting data.
Source: NSF
Source: IPCC

14. Weather-related losses as a
percent of GDP have
actually declined in recent
years.
• Of course, there is no
guarantee this trend will
continue, especially if current
emissions trends continue.

15. IPCC
https://www.ipcc.ch/site/assets/uploads/2018/03/SREX-
Chap3_FINAL-1.pdf

16. Two Implications
1. Scientists generally conclude that anthropogenic climate change poses risks to our collective
future and that aggressive adaptation and mitigation policies should be implemented. In short, we
know enough to act!
2. Climate policies bring climate science into the context of politics, where many values around
human development, sustainability, progress, and justice are adjudicated in systems shaped by
special interests, power, and money. In short, getting from knowledge to action is tricky! The
sentinel and the captains.