Download The Science of Global Warming

9/25/2016
The Science of Global Warming
http://www.ethlife.ethz.ch/e/articles/sciencelife/klima
interview.html
Scientific Knowledge- Ranney
Some solar
radiation is
reflected by
atmosphere,
clouds &
Earth surface:
103 W/ m2
Sun:
343
W/m2
- Most Americans do not know the basic
science of global warming
- Ranney’s experiments show that when
people learn it, the knowledge changes
their attitudes
Some thermal
radiation is emitted
by atmosphere,
clouds & Earth
surface:
239.15 W/ m2
Atmosphere
Earth’s Surface
- Ranney’s research:
https://gse.berkeley.edu/people/michael-ranney
Solar Radiation
1. Michael A. Ranney and Dav Clark, “Climate Change and Conceptual Change: Scientific
Information Can Transform Attitudes.” Topics in Cognitive Science 8(2016): 49-75.
Thermal Radiation
Sources: James Hanson et al., "Earth's Energy Imbalance: Confirmation and
Implications." Science 308 (3 June 2005): 1431-35; Houghton, Global Warming, ch 2
Electromagnetic Spectrum
Solar radiation
Thermal radiation
78% nitrogen
20.6% oxygen
< 1% argon
0.4% water
vapor
0.036% carbon
dioxide
traces gases:
Ne, He, Kr, H, O3
Methane, Nitrous
Oxide
http://academic.engr.arizona.edu/HWR/B
rooks/NATS101sec48/lectures/2-62003.ppt
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Selected Greenhouse Gases
Absorption Spectra of Atmospheric Gases
UV
Visible
Infrared
CH4
• Carbon Dioxide (CO2)
– Source: Fossil fuel burning, deforestation

Anthropogenic increase: 30%

Average atmospheric residence time: 500 years
N2O
O2 & O 3

– Source: Rice cultivation, cattle & sheep ranching, decay
from landfills, mining

Anthropogenic increase: 145%

Average atmospheric residence time: 7-10 years
CO2
H2O
atmosphere
Methane (CH4)

Nitrous oxide (N2O)
– Source: Industry and agriculture (fertilizers)

Anthropogenic increase: 15%

Average atmospheric residence time: 140-190 years
WAVELENGTH (micrometers)
Anthes, p. 55
http://academic.engr.arizona.edu/HWR/Brooks/NATS101sec48/lectures/2-6-2003.ppt
http://academic.engr.arizona.edu/HWR/Brooks/NATS101sec48/lectures/2-6-2003.ppt
Global Carbon Cycle
Carbon Pools
Pool
Atmosphere
Terrestrial Plants
Soil Organic matter
Ocean
Fossil Fuel Depos its
Marine Sediments and Sedimentary Rocks
Amount in Billions of Metric Tons
578 (as of 1700) - 766 (as of 1999)
540 to 610
1500 to 1600
38,000 to 40,000
4000
66,000,000 to 100,000,000
Carbon is stored on our planet in the following major pools:
Carbon is exchanged among the active pools due to various processes –
photosynthesis and respiration between the land and the atmosphere, and
http://cliveg.bu.edu/courses/estoni
diffusion between the ocean and the atmosphere.
3/12
a/myneni-carbon-01.ppt
Climate
Change
• as organic molecules in living and dead organisms found in the
biosphere;
• as the gas carbon dioxide in the atmosphere;
• as organic matter in soils;
• in the lithosphere as fossil fuels and sedimentary rock deposits such as
limestone, dolomite and chalk;
• in the oceans as dissolved atmospheric carbon dioxide and as calcium
carbonate shells in marine organisms.
http://cliveg.bu.edu/courses/estonia/mynen
i-carbon-01.ppt
2/12
From Horse & Buggy to the
Moon
2
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Scientific Consensus Oreskes
“The Scientific Consensus on Climate
Change”
- Naomi Oreskes
- Analysis of 928 papers published in
refereed scientific journals between 1993
and 2003
- None of the papers disagreed with the
consensus on climate change
1. IPCC, Climate Change 2014 Synthesis Report Summary for
Policymakers [http://www.ipcc.ch/pdf/assessmentreport/ar5/syr/AR5_SYR_FINAL_SPM.pdf]
Scientific Consensus on 4 Key Facts
1. Global warming is real.
-The global temperature rose a total of 4 to 7 degrees
Celsius over about 5,000 years.1
-In the past century alone, the temperature has climbed
0.7 degrees Celsius (1.4° F), roughly ten times faster than
the average rate of ice-age-recovery warming. 1
-Since 1975, the warning rate is roughly 0.15-0.20°C per
decade. 2
1.
2.
Global Warming Trend
1.
Source: http://data.giss.nasa.gov/gistemp/graphs/
http://earthobservatory.nasa.gov/Features/GlobalWarming/page3.php
http://earthobservatory.nasa.gov/Features/WorldOfChange/decadaltem
p.php
2016: Warmest Year So Far
1.
2.
Source: http://data.giss.nasa.gov/gistemp/news/20160816/
http://www.nytimes.com/2016/07/20/science/nasa-global-temperatures2016.html?_r=1
Scientific Consensus on 4 Key Facts
2. Global warming is caused by human
activity.
- “Anthropogenic greenhouse gas emissions have
increased since the pre-industrial era, driven largely by
economic and population growth, and are now higher
than ever.”
1
- “Their effects, together with those of other
anthropogenic drivers, … are extremely likely to have
been the dominant cause of the observed warming
since the mid-20th century.”
1. IPCC, Climate Change 2014 Synthesis Report Summary for
Policymakers [http://www.ipcc.ch/pdf/assessmentreport/ar5/syr/AR5_SYR_FINAL_SPM.pdf]
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Scientific Consensus on 4 Key Facts
3. Even if greenhouse gas emissions
completely stop, global warming will continue
because of the buildup of greenhouse gases
in the atmosphere.
- If greenhouse gas emissions continue, global warming will
grow at an escalating pace.
- If current trends continue (business as usual), the IPCC
predicts that Earth's surface temperatures will increase
between 2.5° and 10.4° F by the year 2100, and will
continue to increase after that
1. IPCC, Climate Change 2014 Synthesis Report Summary for
Policymakers [http://www.ipcc.ch/pdf/assessmentreport/ar5/syr/AR5_SYR_FINAL_SPM.pdf]
Impacts - Sea Level Rise
Scientific Consensus on 4 Key Facts
4. Global warming will have substantial,
harmful impacts on human society and the
environment
-
Sea level rise
Droughts
Excessive rain
More powerful storms
Ecosystem damage
Diseases spread
1. IPCC, Climate Change 2014 Synthesis Report Summary for
Policymakers [http://www.ipcc.ch/pdf/assessmentreport/ar5/syr/AR5_SYR_FINAL_SPM.pdf]
Florida
• Rising sea levels (~20 inches by 2100)
– Lots of uncertainty (20-90 cm by 2100)
– Combination of melting glaciers & thermal
expansion of ocean
• Subsidence of land
– River delta losing sand & sinking
– Reduced ground water causing compaction
• Impacts
– Bangladesh may lose 10-20 % of its habitable land by
2050, displacing 6 to 15 million people
– Egypt's Nile delta, Maldive Islands, Marshall Islands,
China's east coast, Mississippi River delta
Climate Change Impacts - Water
• Rainfall patterns will change
– Some areas more; most less
– California: 15-30% less rain; earlier rain
– Proposals to build dams & restore Delta system
• Droughts more frequent
– In U.S.: southwest & MINK (MO, IA, NE, KS)
• Desertification: deserts spread
Climate Change Impacts - Ecosystems
• Plant & animal ranges shift toward poles or
to higher elevations in response to warming
– e.g., Pikas moving up mountains
– Bark beetles moving north into Rockies
– Boreal forests threatened
• Animals tend to move faster
– Animal-food syncronization
• Earlier springs
• Disease threats to humans
• Food supply: with adaptation, not much
change
– Change in crops raised (CO2 feeds plants)
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Climate Change Impacts - Weather
• Hurricanes are predicted to be more
powerful
− Their energy
source is
sea
temperature
5