Of the following greenhouse gases, which have actually decreased in atmospheric concentrations during the past 30 years?

Of the following greenhouse gases, which have actually decreased in atmospheric concentrations during the past 30 years?

methane (CH4)

carbon dioxide (CO2)

chlorofluorocarbons (CFCs)

nitrous oxides (N2O)

Fossil fuel burning accounts for over ________ percent of CO2 emissions.

20

50

70

85

The 16O evaporates ________ easily than 18O, and condenses ________ easily.

less; more

less; less

more; less

more; more

Which scenario predicts the lowest level of warming during the 21st Century?

A1F1-continued use of fossil fuels

B1-use of greater amounts of new and clean energy technologies.

B2-lower levels of economic growth and technological change, emphasis on local solutions.

A2-continuous population growth and lower level of economic growth and technological change.

Which of the following has not been sited as a possible cause of ice sheet darkening?

ice melt has exposed darker land surface, water, and vegetation

black carbon accumulation from wildfires

sunspot activity

snow metamorphism

The general term for glacially deposited sediments is alluvium.

 True

 False

During the height of the Pleistocene ice age, the glaciers extended as far south as the Ohio and Missouri river systems.

 True

 False

If a glacier does not have debris embedded in its base, it is not a very effective agent of abrasion.

 True

 False

In terms of pedogenic regimes, the process that concentrates salts in soils in climates with high evapotranspiration is ________

laterization.

salinization.

calcification.

podzolization.

gleization.