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Extras: Basic Components of Life | Philosophy of Science | An Inconvenient Truth

Chapter 29
Global Environmental Change

Required Reading Additional Reading (2-3 Quiz questions from these sources)

  • Chapter 29 in Elements of Ecology

  • Text, pictures and captions on this page

Links for Enrichment and Further Learning

an inconvenient truth The film, An Inconvenient Truth, boldly presents the case that the activities of a single species can powerfully affect the global surface environment. Global climate in particular. The scientific community no longer is debating global warming. And neither are insurance companies. This film should be of interest to all but the willfully ignorant. It persuasively presents a scientifically accurate case that it is imprudent and unwise for policymakers to ignore the certain prospects of a rapidly warming planet.
Student Learning Outcomes. Lessons in this chapter are intended to help students to:
  1. Recognize that the so-called "controversy" about global warming primarily is a journalistic controversy and a political controversy -- not a scientific controversy.
  2. Grasp the immense scope of scientific efforts to predict global climate change.
  3. Recognize that characterizations of long-term trends achieve greater reliability as the number of observations increases.
  4. Explain the greenhouse effect in terms of electromagnetic radiation and atmospheric gases.
  5. Distinguish between "greenhouse effect" and "global warming."
  6. Intellectually perceive the possible connections between increases in global temperature and increases in atmospheric CO2.
  7. Describe the few, main logical components of climate modeling.
  8. Preview the possible impacts of global warming on the Earth's environments and on civilization.

Study Questions / Quiz Prep. (Consult Required Reading and lecture notes for answers.)

  1. There are many ways to take a planet's temperature. Describe three of those ways.
  2. In taking the planet's temperature, what interesting observation have scientists made?
  3. Starting in 1958 in Mauna Loa, atmospheric CO2 has been systematically measured and recorded. Yet scientists have plotted atmospheric CO2 for the last 300 years. How do scientists do this?
  4. What interesting observation have scientists made about the amount of atmospheric CO2 over the last few centuries?
  5. What is the greenhouse effect? How does it work?
  6. What has been the percentage increase of atmospheric CO2 between the year 1800 and the year 2000? HINT: Derive values from Figure 29.2 and calculate the answer yourself.
  7. Make a general statement that describes how plants respond when exposed to increased atmospheric CO2.
  8. In studying the effects of increased CO2 on a tallgrass prairie ecosystem in Kansas, C.E. Owensby plants grew larger during years of average or below-average rainfall. Explain.
  9. What are the main greenhouse gases? For each gas, which human activities add them to the atmosphere?
  10. What are GCMs?
  11. How do scientists develop general circulation models? Do they guard their secret code from other scientists, or do they share their code?
  12. Is there only one authoritative general circulation model? If not, how many models are in use today?
  13. How do general circulation models represent the Earth?
  14. What is the ultimate aim of general circulation model development?
  15. Study the results of the CSIRO-Mk2 that depicts a CO2-doubled world (below). Compare warming between the tropics and high latitudes in the northern hemisphere.

  1. Consider the comparison of general circulation models from different labs (Figure 29.11). Although the models predict slightly different climate futures, what do they all indicate?
  2. Refer to the “Annual Temperature Change Difference” simulation results for a CO2 doubled world by the General Fluid Dynamics laboratory (GFDL) pictured in Figure 29.12(a). According to this model, which three states will experience the greatest increases in annual temperature? Which five states will experience the smallest increase in annual temperature?
  3. Refer to the “Annual Precipitation Change Ratio” simulation results for a CO2 doubled world by the General Fluid Dynamics laboratory (GFDL) pictured in Figure 29.12(b). According to this model, will the northeastern United States be wetter or drier? Will the southwestern United States be wetter or drier?
  4. What is the major source of soot and sulfate particles? Where are the greatest concentrations of soot and sulfate particles on the planet?
  5. Regard the United Kingdom Meteorological Office general circulation model (UKMO GCM) results presented in Figure 29.13(a). How do sulfate particles in the atmosphere influence global temperature?
  6. Important findings were reported in Jim Hansen's (et al.) paper of April  2005, Earth's Energy Imbalance: Confirmation and Implications. How did this work increase the level of confidence about his model's accuracy?
  7. If the oceans are taking in more heat today, why won't that heat fully influence global climate until 100+ years in the future?
  8. How might global warming transform the distribution of ecosystems?
  9. How might global warming threaten and destroy coastal environments?
  10. How might global warming disrupt current patterns of food production?
  11. How might global warming influence the distribution of warm-weather diseases?
  12. Your friend lives in Fargo, North Dakota. She says that the winters have been getting colder, not warmer. Wouldn't that mean that all this talk about global warming is nothing but a bunch of liberal propaganda?
  13. A famous novelist disagrees with thousands of trained and experienced scientists on the possible onset of global warming. The novelist writes good fiction. Shouldn't you believe him when he says that global warming is a hoax?
  14. The president of an international oil company presents carefully prepared studies that show the Earth isn't warming at all, but cooling instead. What do you think?
  15. A noted climate scientist presents a paper arguing that his climate model of the previous year had several coding errors. What does this tell you about the reliability of climate models?
  16. Britney Spears gives a concert in Alaska to raise awareness of the effects of global warming on Polar Bears. Are you ready to sign on now?
  17. A salesguy calls you offering soon-to-be-coastal property in San Bernardino, thanks to global warming. Buy now before everybody else discovers this secret. Or should you?

 

 
Will Ferrell talks about Global Warming...

Apple QuickTime viewer required.

 

Dealmakers sometimes can't deal with unwelcome scientific findings
Environmental issues are always party spoilers for deal makers.

Taking a planet's temperature

Direct measurements from land and sea indicate a warming trend

Direct temperature measurements using thermometers from land and sea locations. Trend is upward when compared to 1800s and early 1900s.

Global temperatures using satellites

global temps using satellites
Combined temperature measurements from Microwave Sounding Units aboard several NOAA satellites.

Glaciers in retreat indicate a warming planet

Mountain glacier thinning
This image indicates changes in glacier thickness since the year, 1970. Note that the colors yellow, gold and brown represent glaciers that are getting thinner. The overwhelming majority of glaciers are getting thinner. Scientists attribute this thinning as a consequence of a warming planet.

 

An example of recent glacier retreat between the years 1985 and 2003. Easton Glacier on Mount Baker, Cascades, Washington.

Discovering long-term trends in atmospheric CO2

Ancient Air is trapped in the ice. Scientists drill for it.
Scientists dig in the ice for clues about the chemical composition of ancient atmospheres. Tiny bubbles in Antarctic ice store remnants of ancient atmospheres. Scientists extract ice cores, determine their age, then crush them in a vacuum. Liberated air from bubbles is sampled for gas composition.

 

Bubbles in a section of ice from an ice core. The bubbles are filled with air from an ancient atmosphere. Scientists crush the ice in a vacuum. The freed air is analyzed for the ancient mix of atmospheric gases.

 

National Ice Core Laboratory, University of Nevada, Reno.

Scientists use ice records to discover historical CO2 levels in the atmosphere

Global CO2 concentrations over the last 300 years. Blue dots represent direct instrument measurements. Gold dots represent values determined from Antarctic ice cores.

Is there a connection between increasing global temperature and increases in atmospheric CO2?

The Greenhouse Effect: CO2 and other gases act to trap infrared radiation -- warming the planet

Earth's surfaces, warmed by absorbing incoming sunlight, re-radiate energy toward space in the form of infrared radiation. Some gases like CO2, methane, chlorofluorocarbons (CFCs) and nitrous oxide trap outbound infrared causing the planet to retain more heat.

 

General Circulation Models

The steps that scientists must take in order to understand and model the global climate system

1. Characterize the system. That is, be able to describe objective components of the system like temperature, atmospheric pressure, wind speed, wind direction, cloudiness and the like. The global network of weather stations, oceanographic sampling and satellites provide the data for this task.

2. Understand the physics of the system. Based on this comprehensive characterization of the global climate system, learn to understand the physics of the system. For example, explain the physics of cloud formation, or the physics of the greenhouse effect, or the physics of hurricane formation and oceanic heat transport. Explain how and why individual components of the system work.

3. Develop a conceptual model of the climate system. Based on an understanding of the physics of the components that make up the system, develop a conceptual model that shows how all of the components spontaneously interact to produce our global climate (General Circulation Model).

4. Write computer programs to represent the General Circulation Model (FORTRAN). That is, represent the model mathematically, and write computer programs that deal with the matematics in a sensible and efficient manner.

5. Design and build supercomputers. Dedicate these computers for the purpose of running the programs representing the General Circulation Model.

6. Run General Circulation Model programs and evaluate results. Calibrate models by predicting the past and the present. Then attempt to predict the future.

 

Scientists characterize the system by launching hundreds of weather balloons everyday and by constantly monitoring the weather with satellites.

launching a weather ballon
Launching a weather balloon at sea.

 

GOES-N weather satellite
GOES-N weather satellite

 

Scientists develop conceptual models of the global climate -- GCMs

6-box climate model
Flow diagram for a 6-box climate model. This zonal energy balance model, although apparently complex, has been superceded by the more sophisticated and more complex General Circulation Models of today.

 

Cartesian grid approach to modeling the atmosphere. Computations are performed on each box which in turn influence the properties of adjacent boxes. New generation, spectral GCMs achieve more realistic, fluid interactions by applying wave properties to large groups of boxes.

Scientists use computer programs to organize the thousands of components in their climate simulation models

This is a tiny section of a large computer program used for climate simulation at the Goddard institute for Space Studies. The computer program is a quantitative representation of their conceptual model for the operation of the global climate. The language is the old FORTRAN.

Scientists run their General Circulation Models on the world's fastest super computers

IBM's Blue Gene/L supercomputer capable of performing 280 million million floating point operations per second (FLOPS). By comparison, mainstream desktop computers perform about 10,000 FLOPS. In other words, this supercomputer is 28 billion times faster than your sexy gamer's box.

Scientists from many different laboratories around the world cooperate/compete with each other to develop the most useful General Circulation Model

Comparison of results from several different general circulation models from different laboratories. Despite differences, all predict a warming planet.

CGCM1 - Coupled Global Climate Model - Canadian Centre for Climate Modeling and Analysis, Victoria British Colummbia.

CCSR - Center for Climate System Research, Tokyo, Japan.

CSIRO - Commonwealth Scientific and Industrial Research Organisation, Australia.

ECHAM3 - Max-Planck-Institut für Meteorologie, Hamburg Germany.

GFDL_R15 - General Fluid Dynamics Laboratory, Princeton, NJ.

HadCM2 - Hadley Centre for Climate Prediction and Research, Exeter, England.

DOE PCM - Parallel Climate Model - National Center for Atmospheric research, Boulder, CO.

 

How reliable are computer models?

A recent report (April 2005) makes the convincing argument that the Earth is absorbing more heat than it is giving off.

James Hansen Dr. James E. Hansen, director of the NASA Goddard Institute for Space Studies in Manhattan. His recent investigation makes it harder to doubt that the planet is getting warmer and that humans are responsible.

 

ocean heat increases
Validating the model by predicting the past. The Global Climate Model (NASA Goddard Institute for Space Studies) predictions closely match actual observations of oceanic heat content. Warming oceans persuasively indicate a warming planet. Models (such as this one) that closely match empirical observations can be used with greater confidence to predict the future climate.

From Earth's energy imbalance: Confirmation and implications.

 

ocean warming
Validating the model by predicting the past. These maps show observed (top) and modeled (bottom) energy imbalances in the top 750 meters (2,461 feet) of the world's oceans from 1993-2003. Areas where there was an energy surplus are shown in shades of yellow to red, while areas where there was an energy deficit are in shades of green to purple. Taken from web page at Earth's Energy Out of Balance

So, what's the problem?

Heat absorbed by the oceans today might not exert its fullest impact on climate change for hundreds of years

ocean conveyor
Currents carry warm tropical surface waters to the North Atlantic Ocean. There it becomes colder, denser and sinks to the ocean bottom. This cold water travels along the ocean bottom for 1000 years until it finally picks up enough heat to rise to the surface in the Indian Ocean and the North Pacific Ocean. The implication is that heat absorbed by the oceans today becomes entrained and stored in the oceans for hundreds of years. This large scale thermal inertia means that when climate effects finally are recognized, it may take hundreds of years for countermeasures to produce a result.

What the models predict

 

General Circulation Models predict that the north polar regions will experience the fastest warming

Global temperature changes for CO2 doubled world. General Circulation Model of the Commonwealth Scientific and Industrial Research Organization (CSIRS), Australia.

 

Global Climate Simulation Models predict substantial melting of Artic ice this century -- as a result of a warming planet. Ice melt from Greenland could produce significant sea level rise.

General Circulation Models predict that some areas will become wetter, other areas will become drier

Annual precipitation change results for a CO2-doubled world, by the General Fluid Dynamics Laboratory GCM. A value of 1.0 means no change. Values above 1.0 mean increases. Values below 1.0 mean decreases.

General Circulation Models predict that some areas will experience more warming than others

Annual temperature changes in a CO2-doubled world,  by the General Fluid Dynamics Laboratory GCM.

Global warming could transform the distribution of ecosystems

climate change and tropical ecosystems
General circulation models predict drier conditions for places that now are rainy. In the tropics, this result could significantly reduce the size of rain forests, especially in west Africa.

Rising sea levels could threaten and destroy coastal environments

Storm surf crashes into a coastal community. Modest rises in sea level pose little threat under calm conditions. But higher sea levels will allow severe storms to push deeper into coastal environments.

Global warming will disrupt current patterns of food production


Current location of the grain belt.


Predicted migration of the grain belt north as a result of global warming.
Global warming could cause centers of food production to shift. Local and regional economies could experience substantial instabilities.

Global warming could increase the spread of warm-weather disease

Shifting climate zones could be accompanied by their resident diseases, infesting new frontiers.

 

Malaria-spreading mosquito

Isn't there any GOOD news about the effects of air pollution?

Sulfate aerosol pollution above industrial cities has a cooling effect

Areas that receive less solar radiation due to the presence of high concentrations of sulfate aerosols in the atmosphere. Sulfate aerosols are produced above urbanized areas where large amounts of fossil fuels are burned. The presence of these aerosols has a cooling effect that , to a certain degree, counteracts the warming effects of fossil fuel emissions.

Too bad sulfate aerosols are toxic...

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