Quiz 19

The global human population has been growing

(not shrinking) at an accelerated rate since the industrial revolution, and has been doubling over shorter and shorter periods of time. As standards of living improve, the growing population uses more resources per capita, not less.

Which of the following statements is true? a. Carbon dioxide concentration of the atmosphere has increased in the last century. b.The worst-case scenario predicts that if global warming continues at its present rate, by 2050 the average annual temperature will have increased from 15°C to 20°C. c.The Intergovernmental Panel on Climate Change (IPCC) has ruled that all future research use the one computer climate model that it has concluded is the best. d.Most climate scientists believe that current temperature increases are due entirely to natural cycles of short-term climate changes.

a. Carbon dioxide concentration of the atmosphere has increased in the last century.

Identify the statement that is true about mass extinctions. a.A mass extinction may happen when a comet or asteroid impact starts a chain of events that blocks sunlight for weeks or even years. b.The mass extinction of dinosaurs occurred at the Permian-Triassic boundary. c.Mass-extinction events are times in the Earth's history when few species evolve. d.The mass extinction of more than two-thirds of the species on the Earth was the result of large volcanic eruptions in Hawaii.

a.A mass extinction may happen when a comet or asteroid impact starts a chain of events that blocks sunlight for weeks or even years.

Which of the following statements is true? a.Human production of nuclear weapons, nuclear power plants, and radioactive medical materials has placed radioactive contaminants onto the Earth's surface. b.Acid runoff develops when precipitation flows through piles of silica-containing ores. c.The danger of the ozone hole is that it allows increased amounts of harmful infrared radiation to reach the Earth's surface. d.CFCs are produced by the action of sunlight on vehicle exhaust fumes.

a.Human production of nuclear weapons, nuclear power plants, and radioactive medical materials has placed radioactive contaminants onto the Earth's surface.

Which of the following changes is cyclic? a.small continents merging to become a supercontinent b. life on the Earth evolving c.ocean crust changing to continental crust by partial melting d. liquid iron alloy sinking into the Earth's interior

a.small continents merging to become a supercontinent

Carbon, oxygen, sulfur, ammonia, phosphorus,

and nitrogen also participate in biogeochemical cycles. The hydrologic cycle is a true cycle, happening over and over again, whereas a unidirectional change proceeds in one direction and never repeats. The hydrologic cycle can maintain a steady state for long periods but can also change the proportions of distribution and thus produce global change.

Sea-level changes

are cyclic, consisting of episodes of transgression and regression.

Which of the following statements has been asserted in IPCC reports? a. Sea level is falling. b.It is extremely likely that human activity has contributed significantly to global climate change. c. The Earth's climate system is cooling. d.The warming trends observed in the past 50 years can be explained by natural forcing such as cosmic-ray flux.

b.It is extremely likely that human activity has contributed significantly to global climate change.

a. phosphorus b. sulfur c. nitrogen d. carbon All of these elements are involved in

biogeochemical cycles, but only carbon cycles among solid, liquid, and atmospheric Earth reservoirs via all of these processes.

If global warming continues at current rates

by 2050 the average annual temperature will increase by 1.5° to 2°C, not from 15°C to 20°C. Researchers have used many different climate models that have produced conflicting scenarios of future climate. No single model has been proved to be the best, although all models suggest that significant temperature increases are expected by 2100. Very few climate scientists believe that the current temperature increases are due entirely to natural cycles that can be attributed to short-term climate changes.

The Earth's internal heat does which of the following? a. keeps the lithosphere warm enough to flow b. enables volcanism and mountain building c. all of the possible answers are correct. d. permits plate tectonics

c. all of the possible answers are correct.

Which of the following elements is released into the atmosphere by volcanic outgassing, animal flatulence, production of cement, and metamorphism of limestone?

carbon

Which of the following is a line of evidence that supports the assertion of global warming, especially over the past 30 years? a.The rate of ice loss on the Greenland ice sheet has decreased. b.The spatial area of permafrost regions in low latitudes has substantially increased. c.Sea ice has increased substantially, at a rate of about 3% per decade. d.Large ice shelves, such as the Larsen B in Antarctica, are breaking up.

d.Large ice shelves, such as the Larsen B in Antarctica, are breaking up.

Which of the following statements is true? a.Plate-tectonic movements will not alter the global map significantly over the coming millions of years. b.Five million years from now, as scientists believe, the Sun will begin to collapse and then swell to encompass the Earth. c.Shallow seas cannot ever again cover continental interiors because there has been sufficient sediment deposition to raise the average land surface high enough to prevent this. d.The near-term future of the world depends heavily on human activities.

d.The near-term future of the world depends heavily on human activities.

The greenhouse effect is caused by

greenhouse gases that absorb and re-radiate heat from the Earth's surface.

Global human population

has doubled at an accelerated rate since the industrial revolution.

Sunlight warms the Earth's surface, which radiates

heat. Greenhouse gases absorb and re-radiate that heat back into the atmosphere, trapping it like heat in a greenhouse. The Earth's albedo describes its ability to reflect light back into space without absorbing it. Clouds reflect light back into space before it can warm the planet. The ozone hole is a completely separate phenomenon from the greenhouse effect, and does not significantly contribute to global warming.

The Earth's early atmosphere, after the initial

hydrogen and helium from the solar nebula dispersed, consisted mainly of carbon dioxide and water vapor. The atmosphere acquired oxygen (not carbon dioxide) from the photosynthetic process, and it warms when its carbon dioxide concentration goes up, not down.

The thickness (not the color) of a tree ring

indicates the growth rate in any given year. Pollen is commonly preserved in lake sediment, and can be used to characterize climate change over thousands to millions of years.

Blankets of marine sediments that record sea-

level changes are called sedimentary sequences, not clathrates. Eustatic sea-level changes are those that are global, not local. Sea-level changes are a form of cyclic change characterized by repeated transgression and regression throughout the Phanerozoic, but sea-level changes were never as great as 3,000 m.

The Earth's albedo is its reflectivity, which has

nothing to do with the sunspot cycle. Volcanic eruptions release aerosols into the atmosphere that cool, not warm, the climate. Because the oceans transport heat, changing ocean currents can drastically affect climate. Methane is a potent greenhouse gas, and its release from a warming ocean would cause further warming.

The Earth's internal heat keeps the lithosphere

warm enough to flow, which permits plate tectonics, mountain building, and volcanism.

Extinction events are times in the Earth's history

when large numbers of species abruptly disappeared. Superplume activity in Siberia (not volcanic eruptions in Hawaii) coincides with the extinction of more than two-thirds of the species on the Earth during the Permian-Triassic boundary extinction event. Dinosaurs, however, became extinct at the end of the Cretaceous (K-Pg boundary), which was 65 million years ago and associated with the Chicxulub crater in Yucatán, Mexico.

What is true of the ozone hole?

It is caused by the destructive reaction of chlorofluorocarbons with ozone in the atmosphere.

The ozone hole is a zone of depleted (not

completely removed) ozone in the atmosphere that occurs over the poles, not the equator. It is caused by chlorofluorocarbon emissions into the atmosphere, which react with tiny ice crystals to destroy atmospheric ozone. Ozone blocks harmful solar ultraviolet radiation. The ozone hole does not cause global warming.

Natural, non-anthropogenic forcing cannot

explain the change in global climate that scientists have observed.

Ice shelves and sea ice are melting, and at an

increasing rate. Permafrost regions are decreasing, especially at high (not low) latitudes. (Even if you don't remember whether permafrost is increasing or decreasing, remember that it is not a low-latitude feature.)

The hydrologic cycle

is a biogeochemical cycle involving both physical and biological phenomena.

Plate-tectonic movements are cyclical; in the next

million years or more, the global map will change significantly. Sea-level changes are also cyclical; what has happened in the past will no doubt happen in the future, and interior land will become inundated by seawater. Scientists do believe that the Sun will begin to collapse, but not for another 5 billion (not million) years or so.

Which of the following contributes to long-term climate change?

tectonic uplift

CFCs (chlorofluorocarbons) destroy ozone, but

they are not produced when sunlight reacts with vehicle exhaust; photochemical smog is produced this way. Acid runoff can be created when rainfall flows through sulfide-bearing ores and minerals (not silica). Ozone shields the Earth's surface from harmful ultraviolet radiation, not infrared.

Which of the following is an accurate description of a method used to study short-term climate change? a. All of the possible answers are correct. b.The color of a tree ring indicates the rate of growth in a given year. c.The oxygen-isotope ratios of glacial ice record changes in global temperature for the past 800,000 years. d.Pollen is useful for studying modern-day climate but cannot be used to study ancient climate because pollen is not preserved in sediment.

The oxygen-isotope ratios of glacial ice record changes in global temperature for the past 800,000 years.

If significant global warming happens, the consequences will include

an interruption of ocean currents and the heat transfer they accomplish.

The Earth's atmosphere

became more oxygen-rich during the Proterozoic, after the evolution of photosynthetic organisms in the Archean.

Which of the following statements about short-term climate change is true? a.Warming seas may release frozen seafloor methane, causing global cooling. b.Large volcanic eruptions generally accelerate global warming. c. The planet's albedo varies with the sunspot cycle. d. Changing ocean currents can affect global climate.

d. Changing ocean currents can affect global climate.

Unidirectional changes are changes that never

repeat. Evolution of life on the Earth, ocean crust converting to continental crust, and iron sinking into the Earth's interior are all examples of unidirectional changes. Supercontinent formation is a cyclic change, meaning the same steps happen over and over again. Scientists believe a supercontinent has existed at least three times in the Earth's past.