Tester 'll Never " Satisfied "

1) "Global warming" is a real phenomenon: Earth's temperature is increasing. (True/False)

Correct Answer: True

Today's temperature is probably higher than it's been in at least 1300 years - mostly due to human activities.

2) The "Greenhouse Effect" is real. (True/False)

Correct Answer: True

A background greenhouse effect is natural to the Earth. Without it, the Earth's average temperature would be an uninhabitable 0°F. But human activities have increased the greenhouse effect, causing rapid global warming.

3) The main cause of Global Warming is:

a) pollution from factories and automobiles
b) orbital eccentricities of Earth and variations in the Sun's output
c) the Greenhouse Effect

Correct Answer: a) pollution from factories and automobiles, and c) the Greenhouse Effect

Today's rapid global warming is caused by increased concentrations of greenhouse gases in the atmosphere. The additional greenhouse gases come from human activities such as industrial pollution and tropical deforestation. It is not caused by orbital eccentricities or variations in the Sun's output.

4) The Greenhouse Effect is caused primarily by:

a) water vapor
b) carbon dioxide
c) ozone-destroying aerosol sprays

Correct Answer: b) carbon dioxide

Although water vapor traps more heat than carbon dioxide (CO2), increasing greenhouse gases like CO2, not water vapor, is what drives global warming. Air warmed by CO2 holds more water vapor, enhancing the effect. To interrupt this vicious cycle and stop global warming, we must control the emission of greenhouse gases like CO2.

5) Which most accurately describes the effects of Global Warming in the United States over the last 100 years?

a) temperatures have risen > 5° C
b) temperatures have risen > 2° C
c) temperatures have risen < 1° C

Correct Answer: c) temperatures have risen < 1° C

Global temperatures have increased by about 0.75°C over the past 100 years (see this chart from NASA). U.S. temperatures have risen by nearly the same amount.

It may sound like a small number, but the impacts on Earth systems and global climate are already dramatic. Scientists predict much more warming in the future unless we cut greenhouse gas emissions.

6) How much carbon dioxide (CO2) is in Earth's atmosphere today?

a) 10% or greater
b) 2% to 10%
c) less than 1/10th of 1%

Correct Answer: c) less than 1/10th of 1%

CO2 is about 0.038 percent of the Earth's atmosphere. This sounds insignificant, but even small concentrations of greenhouse gases can have a large effect.

Since the start of the industrial revolution, CO2 levels have risen about 33 percent, and the level of methane (a more potent greenhouse gas) has more than doubled.

7) Carbon dioxide from coal-fired power plants damages forests. (True/False)

Correct Answer: True

Nearly 20 percent of global CO2 emissions come from cutting down forests, which certainly counts as damage!

Rising levels of CO2 from industrial emissions have a complex effect on forests and other plants. In the western U.S., warming and drying have encouraged widespread beetle outbreaks and increasing wildfires. Some plants respond to CO2 by growing more rapidly, but scientists also have found that many crops grown in high CO2 conditions have lower nutritional value.

8) Which answer below provides the best explanation for the following temperature record?

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a) Industrial pollution from factories, power plants, and cars caused global warming
b) Natural variations in global temperatures may occur in roughly 500-years cycles
c) Global cooling occurred as a result of the Renaissance Period

Correct Answer: N/A, data in graph not accurate

The actual temperature record is not depicted in this graph. The "Medieval Warm Period" wasn't as warm as temperatures are today, and it may not have been a global phenomenon. Like the "Little Ice Age", it's most prominent in records from Europe. Scientists think the cooler temperatures between the 14th and 19th centuries may have been caused by changes in solar energy and/or the Gulf Stream. But natural factors like these have not contributed much to today's warming trend.

9) Which of the following is not true about an increasing greenhouse effect?

a) the consensus of scientists is that the problem warrants drastic action
b) nighttime temperatures may increase, but daytime temperatures will not
c) the coldest, driest regions of the planet will warm first

Correct Answer: b) nighttime temperatures may increase, but daytime temperatures will not, and c) the coldest, driest regions of the planet will warm first

Both daytime and nighttime temperatures are already increasing. Northern areas are warming more quickly, but global warming is evident around the world. Scientists are calling for prompt action to cut greenhouse gas emissions.

10) Which temperature measuring method most accurately measures global warming?

a) ground-based thermometers
b) orbiting weather satellites
c) weather balloons

Correct Answer: a) ground-based thermometers, and b) orbiting weather satellites
Labels: Global warming
Global warming

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-twentieth century, and its projected continuation.

The average global air temperature near the Earth's surface increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the hundred years ending in 2005. The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic (man-made) greenhouse gas concentrations" via the greenhouse effect. Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward.

These basic conclusions have been endorsed by at least thirty scientific societies and academies of science, including all of the national academies of science of the major industrialized countries. While individual scientists have voiced disagreement with some findings of the IPCC, the overwhelming majority of scientists working on climate change agree with the IPCC's main conclusions.
Global mean surface temperature anomaly relative to 1961–1990
Global mean surface temperature anomaly relative to 1961–1990
Mean surface temperature anomalies during the period 1995 to 2004 with respect to the average temperatures from 1940 to 1980



Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century. This range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels are stabilized. The delay in reaching equilibrium is a result of the large heat capacity of the oceans.

Increasing global temperature will cause sea level to rise, and is expected to increase the intensity of extreme weather events and to change the amount and pattern of precipitation. Other effects of global warming include changes in agricultural yields, trade routes, glacier retreat, species extinctions and increases in the ranges of disease vectors.

Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.