More on Greenhouse effect and Climate Change

If the Earth's climate has sometimes naturally been warmer in the past, then why is global warming considered to be a bad thing?

Because human societies are adapted for the climate that we have now.

If you removed the atmosphere's natural greenhouse effect, and everything else stayed the same, Earth's temperature would be: A. 10 to 20°F (6 to 11°C) warmer B. 30 to 40°F (17 to 22°C) warmer C. 10 to 20°F (6 to 11°C) cooler D. 50 to 60°F (28 to 33°C) cooler

D. 50 to 60°F (28 to 33°C) cooler The greenhouse effect is a naturally occurring physical process that warms the Earth's surface with energy from the atmosphere. Without the effect, Earth's average surface temperature would be well below freezing.

How do scientists collect evidence about climate? A. Using remote sensing from space with satellites B. By ground-based measurements of surface temperature, carbon dioxide concentration and sea level C. By collecting "proxy data" from tree rings, ice cores and historical records D. All of the above

D. All of the above For the past few decades, scientists have had the benefit of global satellite data. We have accurate ground-based measurements that reach back just over a century. "Proxy" methods, such as tree ring and ice core analysis, are used to reconstruct climate records before the rise of modern instruments.

Which of the following gases does not trap heat? carbon dioxide, nitrogen, water vapor or methane

NITROGEN - Heat-trapping greenhouse gases absorb and emit radiation within the thermal infrared range. Water vapor, carbon dioxide and methane are Earth's most abundant greenhouse gases. Nitrogen, which makes up 80 percent of Earth's atmosphere, is not a greenhouse gas. This is because its molecules, which contain two atoms of the same element (nitrogen), are unaffected by infrared light.

Geologic records provide evidence that Earth was sometimes warmer in the past than it is now. TRUE or FALSE

TRUE

The discovery of fossils of tropical organisms such as palm trees in Antarctica indicates that Antarctica used to much warmer than it is now. TRUE or FALSE

TRUE

Some kinds of pollution in the atmosphere can act to cool the planet by reducing the amount of solar radiation that reaches Earth's surface. TRUE or FALSE

TRUE - Air pollution can take the form of fine particles called "aerosols," which both absorb and scatter the sun's radiation. Both natural and man-made aerosols, such as dust, sea salt, soot and sulfates, affect the climate by reflecting radiation that is transmitted through the atmosphere.

Earth has been warmer in the past than it is today. TRUE or FALSE

TRUE - Global temperatures during some of the past interglacial periods have exceeded the average temperatures we observe today, although you would have to go back more than three million years to find a period that was clearly warmer than today. Temperatures in the most recent decade have now exceeded the warmth of the previous Eemian interglacial.

No place on Earth is colder today than it was 100 years ago. TRUE or FALSE

FALSE - Although most locations on the planet have recorded increased temperatures since 1900, changes in global ocean and atmospheric circulation patterns have created small-scale temperature decreases in a few local regions.

As average global temperature rises, average precipitation decreases. TRUE or FALSE

FALSE - Average precipitation increases. Higher temperatures give rise to a more active water cycle, which means faster and greater evaporation and precipitation and more extreme weather events.

The strongest and earliest impacts of global warming occurred in the tropics. TRUE or FALSE

FALSE - In northern latitudes Some of the fastest-warming regions on the planet include Alaska, Greenland and Siberia. These Arctic environments are highly sensitive to even small temperature increases, which can melt sea ice, ice sheets and permafrost, and lead to changes in Earth's reflectance ("albedo").

Compared to other greenhouse gases, carbon dioxide is the most effective at trapping heat near the Earth's surface. TRUE or FALSE

FALSE - Water vapor actually has more heat-trapping power than carbon dioxide. It is also more abundant. But carbon dioxide and water vapor interact in crucial ways: More carbon dioxide means the atmosphere gets warmer, which then creates more water vapor, which traps heat and warms the atmosphere even more.

Earth's climate has changed due to changing amounts of CO2 in the atmosphere. TRUE or FALSE

FALSE - aside from the changing amounts of CO2 in the atmosphere, other causes are continental drift and breaking up of landmasses

If Earth had no greenhouse effect, it would be hotter. TRUE or FALSE

FALSE - greenhouse effect warms the Earth at a certain extent. without it, then Earth will be colder

If the climate becomes warmer, sea levels will fall because hot water evaporates faster. TRUE or FALSE

FALSE - sea levels would rise, both because of ice melting AND because of water expanding when it gets warmer