Steve Gardner
Ethics and Global Climate Change
(originally Ethics, 2004, updated 2009)
1. Climate change is fundamentally an ethical issue
2. WHY “CLIMATE CHANGE”=CC RATHER THAN “GREENHOUSE EFFECT” OR “GLOBAL WARMING”
3. Greenhouse effect
a. Gasses (GHG) allow short-wave incoming solar radiation in but reflect some of earth’s outgoing long-wave radiation back to surface
i. Band of gases only a few miles wide
b. Like glass in greenhouse, a blanketing effect
c. Humans increasing concentration of GHG via industrialization
d. Expect an overall warming effect
e. How does increase in low frequency radiation play out in overall climate system?
4. Global warming
a. Effects of GHG increase are of concern, and increase in temperature is one of them
i. But gradual warming at global level could cause and coesiat with dramatic cooling in some regions
b. Temperature is not the core problem or most important impact of CC
i. Warmer world might be a better world.....
c. Core problem is unprecedented rapidity of the changing climate
i. Warmer world might be better, but not one brought on so quickly that species can’t adapt.
d. Temperatures might go down due to increase GHG but this still serious problem
i. So rapid that harm species
ii. Cause of cooling might be shutdown of THC (thermohaline circulation) which supports Gulf Stream going got norther Europe
5. Climate change
a. **Interference in climate system is crucial issue, not what the specific effects of that interference might turn out to be
b. Fundamental problem: Now possible for humans to alter underlying dynamics of planet’s climate and therefore the basic life-support system for themselves and all other life forms on planet
c. Skeptics: Earth been much warmer in past
d. Reply:
i. Humans not around during those times
ii. Climate been extremely stable during rise of civilization
iii. We have never experienced a climate change as swift or as large as one projected by IPCC
6. CLIMATE SCIENCE
7. Should listen to scientists
a. Jamieson: “Almost no one would deny that in principle our actions and policies should be informed by our best scientific judgments, and it is hard to deny that our best scientific judgments about climate change are expressed in the IPCC reports.”
8. IPPC (Intergovernmental Panel on climate change)
a. Established in 1988 by World Meteorological association and U.N. Env Program
b. Submitted 4 reports, fairly consistent, with increasing levels of confidence
c. IPCC main conclusions endorsed by all major scientific bodies (E.g., National Academy of Science)
d. Findings
i. Global average temp increased .6C 29th century
ii. Increase in temp in 29th century largest of any century in last 1000 years
iii. Snow cover/ice extent decreased
iv. Global average sea level risen
v. Ocean heat content increased
vi. Increases in amount of precipitation some places
vii. Increased heavy precipitation events
viii. Humans increased GHG 31% since 1750
ix. Present CO2 not exceeded during last 420,000 years
x. Current rate of increase is unprecedented during past 20,000 years
xi. Main source burning of fossil fuels (75%) and deforestation (removing carbon sinks)
xii. Very likely (90% confidence) that most of warming over last 0 years due to increase GHG
e. Not observed
i. Increase on tropical storm intensity/frequency
ii. Frequency of tornadoes, thunder, hail
iii. Extent of Antarctic sea ice
f. Predictions
i. CO2 rise from 280 ppm (pre-industrial levels) to 540-970 ppm by 2100
ii. Surface temp increase 1.4C to 5.8C (w/o precedent in 10,000 years)
iii. To stabilize CO2 at (1) 450, (2) 650 or (3) 1000 ppm require human emissions of CO2 to drop below 1990 within (1) few decades, (2) a century, or (3) 2 centuries and continue to decrease thereafter
(1) CO2 today 391ppm (March 30, 2011)
9. Catastrophic possibilities/ threshold effects
a. Collapse of West Antarctic Ice Sheet raise seal level 4-6 meters
b. Shut down of ocean conveyor: Deep circulation that drives world ocean currents and distributes huge amounts of heat around planet and plays fundamental role in earth’s climate and water distribution
i. 12,700 years ago Conveyor slowed and saw drop of temp in North Atlantic 5C in 10 years
ii. Would be rich countries, not poor who are most affected by this!
iii. Winters twice as cold as the worse winters on record in eastern U.S. in past century and last 100 years
10. SCIENTIFIC UNCERTAINTY
11. Better to think about this as risk than uncertainty
a. Uncertainty suggest we don’t know and cannot reliably estimate probabilities of climate change
b. But we have considerable information here
12. Doing nothing is not appropriate response to uncertainty/risk
a. We have lots of information, not totally ignorant
b. Do nothing may make sense only if we have as much reason to believe climate change will be good as bad
13. Temperature record alone does not show that increase in temperatures last century due to humans, as temperatures have fluctuated naturally over long term
a. But have other evidence
i. All agree
(1) GHG increase raises global temperatures (assuming other things equal)
(2) Humans significantly increased GHG
(3) Enhanced greenhouse effect to be expected
14. Scientific dispute (such as is) concerns complexity of climate system and whether there are mechanisms that would moderate effect of more GHG or exacerbate them
a. Positive feedbacks water vapor, show, and ice
b. Negative feedbacks clouds, ocean currents
15. Scientific uncertainty not a reason to fail to act
a. Gardner: no more reason to assume will be saved by unexpectedly large negative feedbacks than that warming will be much worse than we expect due to unexpectedly large positive feedbacks.
16. Conceivable (but not likely) CC problem will turn out to be not real, also possible that it may be much worse than anyone anticipated
Here (p. 10)
17. ECONOMICS
18. Skeptics argue yes CC is real, but costs of prevention (mitigation) are much greater than costs of adaptation, so we should accept CC and try to live with it
a. Money spend on prevention better spent on helping world’s poor