APES Chapter 19 review questions
Pick three of these factors and describe how each can become part of a positive feedback loop leading to climate disruption.
-As droughts increase and spread, the growth of trees and other plants declines, which reduces the removal of CO2 from the atmosphere. As forests and grasslands also dry out, wildfires increase in frequency, and this adds CO2 to the atmosphere. Climate scientists project that these combined effects from the projected increase of prolonged droughts are likely to accelerate atmospheric warming in a positive feedback loop. (droughts) -The resulting increase in CH4 and CO2 emissions would cause more warm- ing, which would in turn melt more permafrost in yet another positive feedback loop. (permafrost) -atmospheric warming, could increase the size and strength of Atlantic storms and hurricanes and their storm surges due to the warming of the ocean's surface water. (extreme weather)
6) List seven examples of climate tipping points that we could be approaching.
1) Atmospheric carbon level of 450ppm 2) Melting of all artic summer sea ice 3) Collasp and melting of the Greenland ice sheet 4) Severe ocean acidification, collapse of phytoplankton populations, and sharp drop in ability of oceans to absorb CO2 5) Massive release of methane from thawing artic permafrost 6) Collapse and melting of most of western Antarictic ice sheet 7) Severe shrinkage or collapse of Amazon rainforest
Describe three problems associated with capturing and storing carbon dioxide emissions.
1. Any large-scale leaks caused by earthquakes or other shocks, as well as any number of smaller continuous leaks from CO2 storage sites around the world, could dramatically increase atmospheric warming and climate disruption in a very short time. 2. Removing all or most of the CO2 from smokestack emissions and transporting and storing it takes a lot of energy. 3. This would greatly reduce the net energy yield and significantly raise the cost of burning coal to supply electricity
What are three major prevention strategies and three major cleanup strategies for dealing with projected climate disruption?
1. Improve energy efficiency to reduce fossil fuel use, especially use of coal. According to climate scientist James Hansen, phasing out coal use is "80% of the solution to the global warming crisis." 2. Shift from nonrenewable carbon-based fossil fuels to a mix of low-carbon renewable energy resources based on local and regional availability. 3. Stop cutting down tropical forests and plant trees to help remove more CO2 from the atmosphere. 1. by implementing, on an emergency basis, a massive, global tree-planting program 2. Restore wetlands where they have been drained for farming. Wetlands are very efficient at taking up CO2, and they provide other valuable natural services as well 3. plant large areas of degraded land with fast-growing perennial plants such as switchgrass, which remove CO2 from the air and store it in the soil
What are five factors that make it difficult to deal with the problem of projected climate disruption?
1. it's a global issue 2. long term political issues 3. projected harmful and beneficial impacts of climate disruption not spread eveningly 4. Many proposed solutions are contraversial 5. A growing number of social scientists contend that humans aren't hardwired to respond to long term threats
List the major human activities that add CO2, CH4 and N2O to the atmosphere.
1. lower atmosphere is warming, especially since 1960, due to increase of CO2 and other greenhouse gases 2. Increase of these gases is due to human activities, such as the burning of fossil fuels and deforestation. 3. These human-induced changes in the chemical composition and the temperature of the atmosphere are beginning to change the earth's climate. 4. The earth is likely to experience rapid atmospheric warming and climate disruption during this century, if levels increase. 5. Rapid and significant climate disruption will likely cause ecologica1, economic, and social disruption by degrading food and water supplies and terrestrial and aquatic ecosystems, flooding low-lying coastal communities and cities, and eliminating many of the earth's species.
How have human activities affected atmospheric greenhouse gas levels during the last 275 years and especially in the last 30 years?
70% of methane (CH4) emissions in the past 275 years are the result of human activities such as raising cattle and sheep, extracting fossil fuels, creating landfills, and flooding land to create reservoirs (levels in the atmosphere have tripled). Emissions are expected to rise in the future if the atmosphere warms as projected and melts some of the permafrost in the arctic tundra, which will release CH4 into the atmosphere. Nitrous oxide (N2O) levels rose 20% during the last 275 years, as a result of the increased use of nitrogen fertilizers. Accounts for 9% of greenhouse gas emissions, but each molecule of N2O has 298 times the warming potential of a molecule of CO2. Fertilizers and other sources of nitrogen have greatly increased nitrogen inputs into the environment
Describe atmospheric warming and cooling over the past 900,000 years and during the last century. How do scientists get information about past temperatures and climates?
900,000 years--prolonged periods of global cooling and warming, known as glacial and interglacial (between ice ages) period. 10,000 years--live in an interglacial period, fairly stable climate based mostly on a generally steady global average surface temperature (beneifical to humans) 1,000 years--remained fairly stable but began to rise during the last century, more people began clearing more forests and burning more fossil fuels. Temperatures are estimated through analysis of radioisotopes in rocks and fossils; plankton and radioisotopes in ocean sediments; tiny bubbles of ancient air found in ice cores from glaciers; pollen from the bottoms of lakes and bogs; tree rings; and temperature measurements taken regularly since 1861.
5) Briefly describe how projected climate disruption is likely to affect: (a) drought, (b) ice cover, (c) permafrost, (d) sea levels, (e) extreme weather, (f) biodiversity, (g) crop yields, and (h) human health during this century.
A) Droughts caused by decreased rainfall are related to changes in weather patterns such as high pressure sys- tems and jet streams. Droughts in some parts of the world are also related to shifts every few years in trade winds known as El Niño-Southern Oscillations (ENSO). These weather (not climate) events typically alter Pacific Ocean cur- rents for about a year or two. This temporarily increases droughts and alters other weather conditions over much of the globe B) The atmosphere above the poles to warm faster than it does at lower latitudes, as projected by all major climate models. This in turn can cause more ice and snow to melt, which would lead to more atmospheric warming C) If the permafrost in soil and in lake bottoms in parts of the rapidly warming Arctic melts, significant amounts of CH4 and CO2 will be released into the atmosphere, and this will accelerate projected climate disruption D) Sea levels are rising faster than IPCC scientists had reported, a 2008 U.S. Geological Survey report concluded that the world's average sea level will likely rise 0.8-2 meters (3-6.5 feet) by the end of this century and will probably keep rising for centuries. This rise is due to the expansion of seawater as it warms, and to the melting of land-based ice. E) Atmospheric warming will increase the incidence of extreme weather events such as severe droughts and heat waves in some areas, which could kill large numbers of people, reduce crop production, and expand deserts. At the same time, because a warmer atmosphere can hold more moisture, other areas will experience increased flooding from heavy and prolonged snow or rainfall F) Climate disruption upsets ecosystems, decrease biodiversity, and degrade ecosystem services in areas of every continent. The rain forest dries out and becomes more prone to burning and the resulting conversion to tropical savanna G) Crop productivity is projected to increase slightly at middle to high latitudes with moderate warming, but decrease if warming goes too far. But this effect may be limited because soils generally are more lacking in sufficient plant nutrients in these northern regions. H) Prolonged heat waves in some areas will increase numbers of deaths and illnesses, especially among older people, people in poor health, and the urban poor who cannot afford air conditioning
What do a number of climate models project about temperature changes during this century?
According to the 2007 report, based on analyzing past climate data and the use of 19 climate models, it is very likely that human activities, burning of fossil fuels, have played an important role in the observed atmospheric warming of the past 30 years. Studies suggest that it is very likely that the earth's mean surface temperature will increase by 2-4.5Co (3.6-8.1Fo) between 2005 and 2100 (Fig- ure 19-B), with about 3Co (5.4Fo) being the most likely rise, unless the world halts deforestation and makes drastic cuts in greenhouse gas emissions from fossil fuel-burning power plants, factories, and cars. The lower temperature in this range is likely only if global greenhouse gas emissions fall 50-85% below 5.0 2000 levels by 2050. These models, like all scientific models, 4.5 are not perfect.
Describe the contribution of waste heat from energy-conversion devices to projected climate disruption.
Applies to low-carbon energy alternatives such as solar cells (waste about 80-90% of the solar energy) and wind turbines (waste 50-60% of the energy). Thus, a key component must be a global energy efficiency revolution, in which the world's scientists and engineers work to make every energy conversion device as energy efficient as possible.
How can positive feedback loops affect future temperature changes and thus global climate? Give two examples of such loops.
First, with current temperature changes, the permafrost layer has started to slowly melt. As it does, methane is released into the environment. As this happens, the greenhouse effect may increase, causing higher temp and more melting and on and on. Second, As glaciers and ice caps melt, the acidity of the ocean changes drastically. If the ocean becomes more acidic it will lose the ability to absorb CO2 and hence contribute to the greenhouse effect and cause more melting.
What are geoengineering schemes (give two examples) and what is the major problem with most of them?
Geoengineering schemes -- trying to manipulate certain natural conditions to help counter an enhanced greenhouse effect. 1. 1991 eruption of Mount Pinatubo in the Philippines and the fact that the average global atmospheric tempera- ture cooled for about 15 months after the eruption 2. 2008 study by atmospheric scientist Sim- one Tilmes suggests that chlorine released by reactions involved in this scheme could speed up the thinning of the earth's vital ozone layer This short-term technological fix would allow CO2 levels to continue rising and adding to climate disruption. Increase the acidity of the oceans, decreasing ability to absorb CO2. Scientists would deal with this ocean acidity problem by building a global network of thousands of chemical plants to reduce its acidity. Quite costly and could have unpredictable and possibly harmful ecological effects on ocean ecosystems.
Describe the roles that climate scientist James Hansen has played in improving our understanding of climate and projected climate disruption.
He was 99% certain that atmospheric warming was a grave threat made worse every day by large and growing emissions of carbon dioxide and other greenhouse gases resulting from human activities. He also helped to promote the idea of creating the Intergovernmental Panel on Climate Change (IPCC) in 1988 to organize climate experts with the goals of studying this issue and reporting their findings to the world. Used his decades of experience as a climate scientist and head of NASA's Goddard Institute for Space Studies to help develop several climate models. He has made many important contributions to the science of atmo- spheric warming and projected climate disruption. Rising levels of greenhouse gases will likely lead to catastrophic climate disruption during this century unless those levels are drastically reduced.
What is carbon capture and storage (CCS)?
Remove CO2 from the smokestacks of coal-burning power and industrial plants and to store it somewhere.
How do scientists use models to make projections about future temperature changes?
Scientists develop complex mathematical models, which simulate interactions among the earth's sunlight, clouds, landmasses, oceans, ocean currents, concentrations of greenhouse gases and pollutants, and positive and negative feedback loops within the earth's complex climate system. Then they run these continually improving models on supercomputers and compare the results to known past climate changes, from which they project future changes in the earth's average temperature.
Describe John Sterman's bathtub analogy as it applies to CO2 emissions.
The bathtub represents the atmosphere. Inputs of CO2 are now entering the bathtub at nearly twice the rate at which the tub can drain. The tub drains into three major reservoirs: plants and soil, which absorb about 30% of daily outputs; the oceans, which take 25%; and sediments and rocks, which absorb less than 1%. Together, these reservoirs can absorb only about 55% of what is put into the tub every day by human activities. The other 45% is added to the tub, which is steadily filling—at a rate that some scientists say is beyond the level that is safe for most of life on earth.
How did scientists arrive at these two general conclusions, and why was this such a rare event?
This high level of general agreement among the world's top scientific experts on the subject of climate change or on any scientific subject is extremely rare.
Describe the interactions among science, politics, and climate.
To many analysts, the answer lies in the deliberate politicizing of the climate change issue by certain parties that sought to create doubt about the reliability of the scientific research and to accuse climate scientists of exaggerating the seriousness of the issue. One tactic used in the political campaign is the general public's lack of knowledge about how science works. The idea is to argue that scientists have not provided absolute proof that projected climate disruption is real, threatening, or caused mostly by human activities. A second tactic plays on the general lack of knowledge about the difference between weather and climate. But consumers, along with most weather forecasters and many scientists in a variety of fields, know very little about the much more complex science of climatology.
2) Explain why weather and climate are not the same. What are the differences between them?
Weather consists of short-term changes in atmospheric variables such as the temperature, precipitation, wind, and barometric pressure in a given area over a period of hours or days . Climate is determined by the average weather conditions of the earth or of a particular area, especially temperature and precipitation, over a long period of time ranging from decades and centuries to thousands of years.
What is the greenhouse effect and why is it so important to life on the earth?
greenhouse effect warms the earth's lower atmosphere and surface, and affects the earth's climate. Without this life on earth wouldn't exist.
3) After studying past climate change and the nature of the earth's climate system for almost three decades, what two general conclusions did most of the world's climate scientists agree on about atmospheric warming over the past 30 years?
the earth's climet has warmed by about 0.6 C, that human activities played a major role in this warming, and that human activities are likely to alter the planets climate during this century
