Climate Literacy Handbook: Principle 3
| Topics: |
Previous: Principle 2 | Table of Contents (Climate Literacy Handbook: Principle 3) |Next: Principle 4
| Principle 3. Life on Earth depends on, is shaped by, and affects climate. |
Organisms are both influenced by climate and have influencing it for billions of years, ever since microbes began altering the composition of the atmosphere. The effects of climate on organisms can be direct or indirect.
Essential Principle 3 is related to the dynamic dance between the biosphere and the climate system, including the annual flux of carbon dioxide in the atmosphere that occurs when vegetation in the Northern Hemisphere draws CO2 from the air through photosynthesis in the spring and summer months, releasing some of it through decay in the winter. We will also study how and when this content is presented in traditional educational settings, such as biology, history and social studies, examine relevant online resources, and design strategies for delivering the content and addressing misconceptions in effective ways.
|
Concept 3a. Individual organisms survive within specific ranges of temperature, precipitation, humidity, and sunlight. Organisms exposed to climate conditions outside their normal range must adapt or migrate, or they will perish. |
Articles in Depth:
Teaching Aids and External Resources:
- Project BudBurstA UCAR project gathering data from citizen scientists about the timing of seasonal changes in plants and the relationship of these to climate change.
- Project BudBurstA project gathering data from citizen scientists about the timing of seasonal changes in plants and the relationship of these to climate change. Coordinated by the U4niversity Corporation for Atmospheric Research (UCAR).
- Climate Change: Pushing Species to the BrinkAn article summarizing a comprehensive study of climate change impacts on species.
|
Concept 3b. The presence of small amounts of heat-trapping greenhouse gases in the atmosphere warms Earth's surface, resulting in a planet that sustains liquid water and life. |
Earth is the Goldilocks planet: “not too hot, not too cold, but just right” for liquid water to exist. If it weren’t for the planet’s greenhouse effect and what some scientists have described as its "self-regulating” nature, the planet would be frozen and life as we currently know it wouldn’t exist. Photosynthesis, which involves two heat trapping gases, CO2 and H2O, generates carbon-based sugars that form the base of the food chain. It also provided the starting material for the generation of fossil fuels . Photosynthesis is the often overlooked process linking carbon, climate and energy.
Articles in Depth:
Teaching Aids and External Resources:
- The Greenhouse EffectInformation and activities from UCAR’s Project Learn
- Global Warming: The Physics of the Greenhouse EffectNOVA video appropriate for classroom use and featured in a larger Teacher’s Domain lesson plan about the greenhouse effect.
|
Concept 3c. Changes in climate conditions can affect the health and function of ecosystems and the survival of entire species.The distribution patterns of fossils show evidence of gradual as well as abrupt extinctions related to climate change in the past. |
It is sobering to realize the planet has experienced at least five major mass extinctions in the past when the climate and/or environment shifted. Some scientists suggest we are in the midst of another mass extinction, this one caused by human activities that are altering the climate and changing ecosystems too quickly for organisms to adapt.
Over billions of years, organisms have proven able to adapt to and evolve with the changing circumstances. But changes, especially in terms of temperature and precipitation for land-based organisms, can spell the end of individual organisms and sometimes entire species.
Articles in Depth:
Teaching Aids and External Resources:
- Mass ExtinctionMultimedia resources about the Permian mass extinction and others. An interactive feature “Prime Suspects” presents possible causes of mass extinction, many of which involve climatic changes. Produced for the NOVA television broadcast ‘Mass Extinction’.Climate History: Exploring Climate Events and Human DevelopmentA NOAA article about the impact of sea level rise in the Black Sea area, 7600 years ago.
|
Concept 3d. A range of natural records shows that the last 10,000 years have been an unusually stable period in Earth's climate history. Modern human societies developed during this time. The agricultural, economic, and transportation systems we rely upon are vulnerable if climate changes significantly. |
Officially called the “Holocene,” the geological epoch which began roughly 11,700 years ago is an interglacial period in the current ice age. From the Greek words “holos” or “whole” and “kainos” meaning “new, the Holocene has been relatively steady in terms of climate. Human societies began to settle into communities, domesticating water for use in agriculture, then developing commerce, weapons systems, smelting metals, and harnessing animals. The rest, as they say, is history.
Humans have always been vulnerable to severe weather and changes in climate. The Vikings settled in Greenland during a brief warm period there but died off or retreated when the climate turned colder again. Droughts have been linked as a key component in the breakdown of entire societies, and there is some evidence that a megadrought in the 16th Century in Mexico triggered an epidemic of hemorrhagic fever that killed between five and fifteen million people: http://www.cdc.gov/ncidod/EID/vol8no4/01-0175.htm
During the Holocene the human population grew from a few million people around the planet as the ice retreated in the northern hemisphere to several hundred million people two thousand years ago. By around 1800 there were a billion people, in the mid 1950s it had risen to three billions, and in the past fifty years the population has more than doubled and will continue to grow until, whether by circumstances or design, there are fewer people being born than are dying.
The exponential population growth, fueled in part by the exponential growth in the use of fossil fuels, has also led to more people being put in harm’s way through “disasters by design,” such as building in floodplains and along coastlines. Today more than half the U.S. population live on or near the coasts, which are vulnerable to coastal storms and sea level rise.
Articles in Depth:
- Earth's climatic history
- Agriculture
Teaching Aids and External Resources:
|
Concept 3e. Life - including microbes, plants, and animals and humans - is a major driver of the global carbon cycle and can influence global climate by modifying the chemical makeup of the atmosphere. The geologic record shows that life has significantly altered the atmosphere during Earth's history. |
The biologic realm is an integral component of the Earth system, influencing climate in profound and subtle ways. Plants, photosynthetic protists like diatoms, and photosynthetic bacteria captured solar energy and transformed it into carbohydrates, removing CO2 from the atmosphere in the process. Under the right geologic conditions of time and pressure, these carbohydrates turned into hydrocarbons, which we use today for fuels. The combustion of fossil fuels, as super concentrated forms of “buried solar energy” in effect reverses the process of photosynthesis. Therefore, living things link to climates of the past while impacting climate in the future.
Living things also affect the reflectance of the Earth's surface, which can impact Earth's energy balance. This idea was used by James Lovelock to promote the idea of a self-regulating Earth. A hypothetical "Daisyworld" is used by Lovelock and others to illustrate the concept.
Articles in Depth:
Teaching Aids and External Resources:
- Life Makes a MarkThis website contains an article about how microbes have dramatically altered the chemistry of the atmosphere and, with it, the surface of the planet. The essay is accompanied by links to three other essays and additional multimedia resources, including a 7 minute video on the rise of oxygen and an interactive about rock layers of the Huronian Supergroup that contain evidence of this rise. From the American Museum of Natural History.
- Forest SolutionsThe role of forests in the carbon cycle and in possible solutions to global warming. The first article,"Tropical Forests and Global Warming", may be appropriate for secondary students. From the Union of Concerned Scientists.
- Animation: DaisyworldAn animation illustrating how different populations of organisms with different albedos can alter the energy balance of the Earth.
|
|
