CLIMATE AND CLIMATE CHANGE - Chapter 12
Glacier
A large mass of flowing ice that moves downslope under its own weight and persists from year to year; formed, at least in part on land by the compaction and recrystallization of snow.
Aerosol
A suspension of microscopic liquid and solid particles, such as mineral dust and soot, in the atmosphere.
How do aerosols influence climate? Where do they come from? (pp. 409-411)
Aerosols are colloidal particles that are dispersed in gas, smoke, and fog, and are important in cloud formation. They act as the nuclei around which water droplets condense to form clouds. Their presence can lead to either cooling or warming of the air.
El Niño
An event in the atmosphere and ocean during which trade winds weaken or even reverse, the eastern equatorial Pacific Ocean becomes anomalously warm, and the westward moving equatorial ocean current weakens or reverses; this change in ocean temperature can cause anomalous weather in adjacent landmasses.
Climate Forcing
An imposed positive or negative change of Earth's energy balance measured in Watts per meter squared (W/m²).
What is an interglacial? (p. 411)
An interglacial is a period of less glaciation to no glaciation, when the glaciers have retreated back toward the poles.
Weather
Atmospheric conditions, such as air temperature, humidity, and wind speed, at any given time and place.
List the major greenhouse gases and their natural and anthropogenic sources. Which gases are enhancing the greenhouse effect the most? (pp. 420-423)
Carbon dioxide, methane, nitrous oxide, and halocarbons are referred to as greenhouse gases. Carbon dioxide accounts for around 56 percent of the anthropogenic greenhouse effect. Carbon dioxide is released into the atmosphere naturally through volcanic activity, plant and animal respiration, and decay of organic material. Human sources have primarily been the burning of fossil fuels and cement production, and indirectly through deforestation, because fewer trees are available to remove carbon dioxide from the air. Methane occurs naturally from bacterial decay in moist places that lack oxygen, such as marshes and swamps. Anthropogenic sources of methane include coal mines, oil wells, leaking natural gas pipelines, rive cultivation, landfills, and livestock. Natural sources of nitrous oxide include microbiological processes in the soil and ocean and wildfires. Anthropogenic sources include fertilizer use and burning fossil fuels. Halocarbons are entirely anthropogenic. They are used in industrial processes, firefighting, and as fumigants, refrigerants, and propellants.
How will climate change affect the biosphere? (p. 435)
Changes in the biosphere include shifts in the range of plants and animals as well as changes in the habitat where a plant or animal lives. Warmer water temperatures and ocean acidification threatens coral, shellfish, and other reef invertebrates.
Climate
Characteristic weather at a particular place or region during many seasons, years, or decades.
How is drought related to global warming? (p. 433)
Climate change will likely exacerbate the phenomenon known as desertification—the conversion of land to land resembling desert—in areas that are already becoming warmer and drier. An increase in drought events will result from global warming, thus putting pressure on food and water supplies. If climate zones shift, it is likely that areas with no significant history of droughts will have to cope with them.
What is climate forcing and how does it work? (p. 423)
Climate forcing is defined as an imposed change of Earth's energy balance. The units for the forcing are and they can be positive if a particular forcing increases global mean temperature or negative if temperature is decreased. For example, if the energy from the sun increases, then Earth will warm (this is positive climate forcing).
What is climate proxy data and why is it important? (p. 414)
Climate proxy data refers to data that is not strictly climatic but can be correlated with climate, such as temperature of the land or sea. Paleoclimate proxy data preserved in the geologic record provide the best evidence of change that predates the historical and instrumental records.
What is the distinction between climate and weather? (p. 409)
Climate refers to the characteristic atmospheric conditions at a given location over long periods of time, whereas weather refers to conditions over short periods of time such as days or weeks.
Explain El Niño and its effects. (pp. 430-433)
El Niño may start with a slight reduction in trade winds, which causes warm water in the western equatorial Pacific Ocean to flow eastward. This eastward flow further reduces the trade winds, causing more warm water to move eastward until an El Niño event is established. The El Niño brings heavy rains to northern South America and Central America, and the warm surface waters disrupt the normal coastal upwelling of nutrient-rich cold deep water, destroying the fish population and all that rely on it (birds, people, etc.). El Niño is associated with storms and landslides in these regions, although its effects are felt globally.
Earth Climate System
Emphasizes the interactions among the atmospheric, cryospheric, and terrestrial, and marine biospheric processes that affect the climate of Earth.
Pliestocene Epoch
Geologically recent interval of Earth history characterized by widespread continental glaciation and commonly referred to as the "Ice Age"; the subdivision of the Quaternary Period before the Holocene Epoch.
How can glaciers be hazardous? (pp. 412-413)
Glaciers are huge, actively flowing masses of ice and rock debris whose movement and melting have been responsible for property damage, injuries, and deaths. Their irregular surface, including crevasses, provides hazards to those exploring over the terrain. One of the biggest hazards of glaciers is when icebergs calve off of glaciers or ice shelves and enter shipping lanes, forming a hazard to shipping.
Describe the natural hazards associated with climate change.
Hazards associated with global warming include climate change, rising sea level, intensification of storms, shifting of climate and agricultural zones, changes in the biosphere, and desertification and drought.
How have international agreements dealt with ozone depletion and climate changes?
International agreements have attempted to capture and store carbon dioxide, but have been hampered by lack of cooperation.
What are the proposed methods for carbon sequestration? What methods hold the greatest promise and why? (pp. 438-439)
Of the three major options for sequestration, biological, oceanic, and geologic, the geologic option is the most promising. Biological sequestration, such as by planting more trees, is a much slower process and pales in comparison to the amount of carbon dioxide that must be removed from the atmosphere. Fertilizing ocean plankton with iron is limited in its capacity to remove carbon dioxide and has unknown side effects in the marine environment. Injecting carbon dioxide in the oceans would further acidify the ocean and potentially wreak havoc on marine ecosystems. Geologic sequestration holds the most promise because the residence time of carbon in the geologic environment is potentially thousands to hundreds of thousands of years.
Proxy Data
Refers to data that is not strictly climate in nature, but can be used to infer, indirectly, changes in the climate record.
What changes should individuals, the private sector, and government make to reduce greenhouse gases? (pp. 437-441)
Regulatory, technological, and behavioral changes will have to be made at individual, community, national, and international levels. The best solutions include a reduction of our dependency on fossil fuels and a switch to clean-energy alternatives.
Explain solar, volcanic, and anthropogenic forcing. (pp. 426-427)
Solar forcing is the evaluation of the change of intensity of the sun as a reason for possible climate change. Volcanic forcing is the evaluation of the change in global temperature based on volcanic particles floating through the air—eruptions can change the temperature of the Earth for years by a few degrees. Anthropogenic forcing is the evaluation of how humans have changed the temperature of the Earth.
What is the Milankovitch effect? What are the three changes in the Earth's orbit that cause this effect? (p. 421)
The Milankovitch effect is a theory of climate change that accounts for the orbit, tilt, and wobble of the Earth relative to its rotation around the sun. Cyclical changes in these orbital parameters, with different time periods, cause systematic variations in the amount of incoming solar radiation, and thus causes changes in climate. The different periodicities of each orbital parameter cause a complex pattern of cycles with different strengths and periods.
What is the basis for climate classification? (p. 409)
The basis is temperature and precipitation.
What are the potential causes of continental glaciation?
The causes of major global glacial events are unknown, but they appear to be related to the position of the continents, which significantly affects both ocean circulation and global climate. Once a glacial event has begun, changes in the amount of solar radiation reaching Earth's surface influence the advances and retreats of continental glaciers. These changes are influenced by astronomical or orbital cycles known as Milankovitch cycles in which the Earth's orbit around the sun and the tilt and wobble of the Earth's axis or rotation change.
Explain or diagram the greenhouse effect. Describe the types of radiation that are involved and the wavelength of the radiation. (pp. 419-421)
The greenhouse effect is caused by several gases that trap energy in the form of heat in the atmosphere. Energy enters the atmosphere in short wavelengths that can penetrate the clouds and gases in the atmosphere. However, when this radiation is re-reflected from the Earth it is reflected at longer wavelengths that cannot penetrate the clouds and atmospheric gases, so it remains in the atmosphere as heat energy. Carbon dioxide, nitrogen dioxide, nitrogen oxides, and chlorofluorocarbons absorb the infrared radiation and increase the air temperature.
Global Warming
The increase in the mean annual temperature of the lower atmosphere and oceans in the past 150 years, primarily as a consequence of burning fossil fuels that emit greenhouse gases into the atmosphere.
Which processes are contributing the most to rising sea level? (p. 433)
The primary cause of current sea level rise is the thermal expansion of water due to the temperature increase from global warming. The secondary cause is icecaps melting.
Earth System Science
The study of Earth as a system.
Which parts of our planet are experiencing the greatest effects of climate change? (p. 428)
These areas include coastlines with elevations close to sea level and areas which are already experiencing frequent drought, such as the Sahel of Africa.
Greenhouse Effect
Trapping of heat in the lower atmosphere by the absorption of infrared energy by water vapor, carbon dioxide, methane, nitrous oxides, halocarbons, and other gases.
What are the projected changes to our climate for the remainder of this century? (p. 438)
Two possible scenarios exist for global warming and sea-level rise during the next 100 years. In the first scenario, more efficient technologies are introduced, but the energy system remains fossil-fuel intensive. The average global temperature is predicted to rise around 4.5° (8°F) and sea level may rise as much as 1.4 m (4.6 ft.). In the second scenario, economic structures have changed, reducing material intensity and introducing clean resource-efficient technologies. In this scenario, average global temperature is predicted to rise only about 2°C (3.6°F), and sea level rise will be under 0.5 m (2 ft.).
How is climate change likely to affect the weather?
Weather patterns shift as climate changes. Changing climate patterns will alter the location of agricultural zones, and affect weather patterns; melting glaciers and ice sheets will contribute to the continuing rise in global sea level, and species may lose some of their habitat; and global temperature increases may lead to desertification of arid lands, droughts, and an increase in frequency and intensity of wildfires.
