Atmospheric Processes Involved in Global Warming
Jan 01, 2016
Top issues in science
Nanoscience and nanotechnology
Genetically modified plants
Using animals in research
The public ignores many science issues
Pluto is NOT a planetFirst face transplant
Element 118 discovered
Global Cooling fears
“There are ominous signs that the earth’s weather patterns have begun to change dramatically and that these changes may portend a drastic decline in food production ...”
Newsweek, April 28, 1975
Extreme high temperatures
Not one of the world’s highest temperatures has occurredin the past 30 years!
U.S. National Oceanic and Atmospheric Administration
The Deadliest Hurricanes
Rosenberg Library, Galveston
Galveston hurricane, 1900: 8,000 killed
Bangladesh cyclone, 1970: 300,000 killed
• Yangtze River flood, 1931: 3.7 million killedYangtze River flood, 1931: 3.7 million killed• Vietnam flood, 1971:100,000 killedVietnam flood, 1971:100,000 killed• Great Iran Flood, 1954: 10,000 casualtiesGreat Iran Flood, 1954: 10,000 casualties• China typhoon 1912: 50,000 killedChina typhoon 1912: 50,000 killed• China typhoon 1922: 60,000 killedChina typhoon 1922: 60,000 killed• India drought 1914: 250,000 diedIndia drought 1914: 250,000 died• Chinese famine 1907: 24 million diedChinese famine 1907: 24 million died• Soviet Union drought 1921-1922: 3 million diedSoviet Union drought 1921-1922: 3 million died• Great Drought in western Sahara Desert 1968-Great Drought in western Sahara Desert 1968-
1973: 100,000 died from starvation and disease1973: 100,000 died from starvation and disease
Source: World Meteorological Organization
Deadly weather disasters
Big Questions
•Why do scientists disagree about the causes and effects of global warming?
•Why is the issue so complicated?
Kerry Emanuel: Phaeton’s Reins: The human hand in climate change
Boston Review, 2006 http://bostonreview.net/BR32.1/emanuel.html
Climate Change
• The earth is 4.5 billion years old.
• During the past 3,000,000 years, the earth has had both mild climates and ice ages.
Ice ages
Eccentricity (shape) of the earth’s orbit: 100,000 year cycle
Precession (wobbling) of the earth’s axis: 23,000 year cycle
Obliquity (tilt angle) of the earth’s axis: 100,000 year cycle
Greenhouse gases
H2O: • The most important greenhouse substances (liquid and vapor).• H2O vapor absorbs infrared radiation warming• H2O liquid reflects sunlight into space cooling • H2O is constantly recycled between the atmosphere and the oceans• The concentration of water vapor is limited by temperature
CO2: • 2nd-most important greenhouse gas• absorbs infrared radiation warming• lifetime up to 200 years
Feedback processes
Positive feedback: an amplifying process
Negative feedback: a process that reduces itself
body heat
evaporation, cooling
REDUCED
Negative feedback: a reducing process
Ice-Albedo Feedback
Albedo: % of sunlight reflected.
White surfaces: large albedo. Dark surfaces: small albedo.
Ice-Albedo Feedback
Atmospheric temperatures increase
Sea ice melts
Albedo decreases
Earth absorbs more energy
Cloud feedbacks
Clouds reflect sunlight cooling
Clouds absorb IR radiation warming
Polluted clouds reflect more sunlight cooling
Sulfate (SO4) aerosols
sulfate aerosols reflect sunlight coolingsulfate aerosols cause more clouds to form coolingsulfate aerosols reduce the size of cloud droplets cooling
So what should we do?• Elect politicians who understand science• Conserve the earth’s resources as much as you can• Pollute as little as you can• Remember that popular movies and books like
The Day After Tomorrow and State of Fear are entertainment,
not science.