Chapter 14: Global Climate Change
Greenhouse Effect
Natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases.
Radiative forcing
The amount of change in thermal energy that a given factor causes
Earth's climate ________. A) has been stable over the history of the planet B) is changing as a result of natural and human processes C) will stabilize over the next century, according to the predictions of most scientists D) has changed only once due to the evolution of green photosynthesizing plants E) history is undeterminable because there is no method of studying climatic history of the planet
is changing as a result of natural and human processes
Geoengineering
manipulation of earths climate system to counteract the effects of climate change caused by greenhouse gas emissions. -suck carbon dioxide out of the air -block sunlight before it reaches the Earth
Carbon footprint
measure of the impact human activities have on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide
Table 14.2 - predicted impacts of climate change in the U.S.
-Average temperature will rise 2.2-6.1 degrees C (4-11 F) -Droughts and flooding will worsen -Longer growing seasons and enhanced CO2 -Snowpack will decrease in the West -Cold-weather illnesses, tropical diseases will spread -Sea-level rise and storm surges will erode beaches and destroy coastal wetlands and real estate -Alpine ecosystems and barrier islands vanish -Drought, fire, and pest outbreak - Northeast forests will lose sugar maples, Southeast forests will be invaded by grassland -Melting of permafrost will undermine Alaskan buildings and roads
Table 14.3 - ways to eliminate carbon emissions
-Double fuel economy of cars -Halve the miles driven by cars -Maximize efficiency in all buildings -Double the efficiency of coal-powered plants -Switch from coal to natural -Capture and retore Carbon from 800 coal plants -Adopt tillage conservation
Excuses
-cutting emission will hurt the economy (in spite of success in Europe and California) -"cap and trade" won't work (look at example from Chapter 5) -carbon taxes will hurt the economy (petroleum prices in U.S. are heavily subsidized compared to other countries) -carbon offsets seem to be somewhat popular, though
Kyoto Protocol
-the commitment of a large number of developed countries to reducing their greenhouse gas emissions 5% below their 1990 levels by 201
Changes Predicted
1) Temperatures will rise 3.2 to 7.2 oF in next 100 years 2) Sea level will rise 7-23 inches in next 100 years 3) Carbon uptake by ecosystems will peak in < 50 years (80% chance) 4) Dry areas will become drier (66-90% chance) 5) Decrease of GDP of 1-5% for each 7.2 o F rise in temperature 6) Greater swings in precipitation and strong storms 7) Crop failures 8) Loss of fresh water 9) Huge impact on human health 10) About 20-30% of species face extinction risk if temperatures rise more than 2.7-4.5 oF (50% chance)
Mitigation
Aims to mitigate or alleviate the problem Ex: Improving energy efficiency, switching to clean and renewable energy sources, preventing deforestation, recovering landfill gas, and encouraging farm practices that protect soil quality
Global Warming
An increase in Earth's average surface temperature
Figure 14.17 - expected temperature rise
Average temperatures are predicted to rise 4-6 degrees fahrenheit (low) 7-11 (high)
Figure 14.15 - shift in species
Birds moving north Pikas are being forced upslope
Figure 14.13 - shrinking of glaciers and effects on fresh water supply
Browner shades indicate less precipitation Bluer shades indicate more precipitation
4) Which of the following are market mechanisms for addressing climate change? A) international treaties from global conferences B) carbon taxes and fee-and-dividend benefits C) cap-and-trade and carbon offsets D) mitigation and adaptation
Cap-and-trade and carbon benefits
Table 14.1 - major greenhouse gases
Carbon Dioxide Methane Nitrous oxide Hydrochlorofluorocarbon
Carbon Sequestration (carbon storage)
Carbon is stored under pressure in deep salt mines, depleted oil or gas deposits or other underwater reservoirs
Milankovitch cycles
Changes in the shape earth's orbit and tilt that cause glacial periods and interglacial periods.
Climate
Describes an area's long term atmospheric conditions, including temperature, precipitation, wind, humidity, barometric pressure, solar radiation, and other characteristics
Ocean Acidification
Decreasing pH of ocean waters due to absorption of excess atmospheric CO2 from the burning of fossil fuels.
fee-and-dividend
Funds from the carbon tax paid to the government by polluters are transferred as a tax refund or dividend to tax payers -consumers will be reimbursed by the tax refund they receive
Figure 14.9 - observed impacts of climate change
Global physical indicators Social indicators Regional physical Biological
Carbon tax
Governments charge polluters a fee for each unit of greenhouse gases they emit
Figure 14.3 - contributions to rise in carbon dioxide
Green- Natural fluxes Down (photosynthesis) Up (respiration) Red- Anthropogenic Down (Absorption) Up (Release)
Important concepts
How we know that carbon dioxide levels are rising Why carbon dioxide levels are rising Natural causes of warming/cooling Physical observations of climate change (temperature, sea level, acidity of ocean) Regional impacts of climate change (droughts, severe storms) What climate models predict: temperature rise, sea level rise, maxing out of carbon uptake by ecosystems, drought, severe storms, crop failures, loss of fresh water, impact on human health, extinction of species GDP will decrease by 1-5% for each 7.2 degree F rise in temperature Why scientists think we are responsible for climate change Why many people in U.S. deny climate change Solutions to problem: mitigate, adapt Why best solutions in U.S. may include economic incentives and consumer driven change, rather than regulation
Global climate change
Modifications in aspects of Earth's climate, such as temperature, precipitation, and storm frequency and intensity. (not to confuse with Global warming)
The atmosphere around Earth can cause global warming because ________. A) warm air cannot escape, as in a greenhouse B) molecules in the atmosphere are warmed by radiation from Earth and retain that heat C) fossil fuels release heat D) plants absorb CO2 E) plants release CO2
Molecules in the atmosphere are warmed by radiation from Earth and retain that heat
Figure 14.12 - expected change in precipitation
Landmasses are expected to warm more than oceans, and the Arctic will warm the most
Aerosols
Microscopic droplets and particles can have either a warming or cooling effect
How certain are scientists that humans are causing global climate change? Describe the language used by scientists and some of the particular climate trends they have identified as changing.
Nearly all environmental scientists agree that Earth's atmosphere and climate are changing. Most environmental scientists have concluded that human activity, particularly the emission of greenhouse gases, is the primary reason for this change. Scientists express conclusions as probabilities, so reports are often written in language that the lay public may interpret as uncertain. Particular climate trends include changes in surface temperature, snow and ice cover, rising sea level and warmer oceans, and alterations to precipitation intensity and patterns. Scientists debate some of the exact mechanisms, how the mechanisms interact in making predictive models and extent of the effects of global climate change on humans.
Explain how human health may suffer or benefit from global climate change.
People may face increased likelihood of exposure to some health risks due to global climate change. These risks include heat stress, infectious diseases resulting from flooding and failed sewage systems, the movement of disease vectors such as malarial mosquitoes into new warmer and wetter areas and injuries due to increased storm frequency and intensity. A warmer world might, however, present fewer cold-related diseases and injuries such as hypothermia and famine. Then, there are the obvious health problems that will arise as agriculture and water supplies gradually fail in some populated areas producing refugees and the logistics of supplying them with basic health crises such providing food, water and medical treatment.
Climate models
Programs that combine what is known about atmospheric circulation, ocean circulation, atmospheric-ocean interactions, and feedback cycles to simulate climate processes
Figure 14.4 - human impact on atmosphere
Red bars- positive forcing (warming) Blue bars- negative forcing (cooling) X-axis: Emitted gases Y-axis: Radioactive forcing
Figure 14.2 - increase in carbon dioxide
Red- Carbon Dioxide Green- Methane Blue- Nitrous Oxide X-axis: Year Y-axis: Carbon Dioxide
Global Warming potential
Relative ability of one molecule of a given greenhouse gas to contribute to warming
Intergovernmental Panel on Climate Change (IPCC)
Scientific intergovernmental body set up by the World Meteorological Organzation and UNEP to provide an objective source of information about the causes of climate change
Fourth Assessment report
Summarized many thousands of scientific studies, documented observed trends in surface temperature, precipitation patterns, snow, and ice cover, sea levels, storm intensity, and other factors.
Carbon capture
Technologies or approaches that remove carbon dioxide from power plant emissions
If the scientific community is convinced of the evidence for climate change, why is there still debate?
The debate continues over how to address climate change in political and economic arenas. There is sometimes discourse among scientists, economists, business leaders, policymakers, and others over these issues because some critics of global climate change have a vested interest in continuing the widespread use of fossil fuels, and they may purposely cast doubt on scientific findings. Furthermore, some greenhouse skeptics and scientists are funded by industries such as the coal, petroleum and auto industries that benefit from fossil fuel use. Some of these "skeptics for hire" have considerable sway over policymakers, particularly in the United States. Finally, there is continuing confusion, often in popular media, between short term "weather" events and the long-term processes of climate change. So, for example, an unusually cold winter in some areas is often reported as a contradiction to scientific evidence for anthropogenic factors contributing to global climate change.
Explain how climate change can affect agriculture
The overall effect of a warmer climate on agricultural productivity is difficult to predict because the effect will vary regionally. Productivity might increase in some areas and decrease in others. Some croplands already stressed by heat and water availability could be pushed beyond their ability to produce food. If average temperatures increase by more than a few degrees, most tropical and subtropical areas will likely see decreased crop production, and farmlands in mid-latitudes may begin to see significant declines. Conversely, warmer temperatures could potentially lead to longer growing seasons and increase agricultural productivity at higher latitudes. In addition, temperate areas that begin to experience a more subtropical climate may see the invasion of more tropical crop pests into regions that have not experienced them before. Agricultural systems may also experience changes in pollinator populations (such as bees) which could affect the abundance and distribution of many plant species.
3) The greenhouse effect involves warming of Earth's surface and the ________. A) troposphere B) mesosphere C) stratosphere D) thermosphere E) ionosphere
Troposphere
Proxy indicators
Types of indirect evidence that serve as proxies, or substitutes, for direct measurement and that shed light on past climates
Carbon offsets
Voluntary payments intended to enable another entity to reduce emissions that one is unable to reduce oneself For ex: a coal-burning power plant could pay a reforestation project to plant trees that will soak up as much carbon dioxide as the coal plant emits
Greenhouse gases
Water vapor Ozone (O3) Carbon Dioxide (CO2) Nitrous Oxide (N2O) Methane (CH4) Halocarbons (CFCs) -after absorbing radiation emitted from surface, greenhouse gases re-emit infrared radiation in all directions
Figure 14.14 - sea level rise in past 100 years
X-axis: Year Y-axis: Sea level rise (mm)
Figure 14.10 - increase in temperature in past 100 years
X-axis: Year Y-axis: Temperature
Figure 14.1- influences on climate
Yellow Arrows Incoming solar radiation 342 (down) Absorbed by surface 168 (down) Reflected solar radiation 107 (up) Reflected by clouds, aerosols, and atmosphere 77 (up) Absorbed by atmosphere 67 (down) Reflected by surface 30 (up) Radiation emitted by surface 390 (up-bottom) Back Radiation 324 (down-bottom) Emitted by atmosphere and clouds 195 (up) Emitted by surface and passing through atmosphere 40 (up) Outgoing long wave radiation 235 (up top)
UN Framework Convention on Climate Change (FCCC)
agreement to reduce ghg emissions to 1990 levels by the year 2000; signed by the nations represented at the 1992 earth summit convened in rio de janeiro by the UN; fccc called for a voluntary nation by nation approach, but was unsuccessful. failure sparked by kyoto protocol