Climate Change

climatechange

Basics
Climate Change refers to any significant change in weather (temperature, precipitation, etc.) over an extended period of time.

Global Warming refers to the recent and ongoing rise in the average temperature around the world near Earth’s surface.

Earth’s climate has changed throughout history.  Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7000 years ago marking the beginning of the modern climate era — and of human civilization.  Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.  However, the current warming trend is of particular significance because most of it is very likely human-induced and proceeding at a rate that is unprecedented in the past 1300 years. — NASA

Global Warming is caused mostly by increasing concentrations of carbon dioxide and other gases in the atmosphere.  These “greenhouse gases” trap energy in the atmosphere and cause it to warm.  Over the past half-century, human activities, particularly the burning of fossil fuels to produce energy, have, in turn, produced greenhouse gases.  Other human activities (deforestation, industrial processes, agricultural practices) have also emitted greenhouse gases into the atmosphere.  The resultant global warming is causing climate patterns to change. — Environmental Protection Agency

Climate Change is an enormous subject, encompassing social studies, science, and many other areas.

As per climate.nasa.gov, what follows is a brief outline highlighting some of the issues associated with climate change.


Carbon Dioxide (CO2)

fossilfuelco2emission
Carbon dioxide levels are at their highest in 650,000 years.  As noted above, the burning of fossil fuels (oil, gas, coal) has been the main cause of ↑CO2.  Deforestation (e.g. cutting down trees in the Indonesian and Brazilian rainforests) worsens the problem, because plants naturally remove CO2 from the atmosphere through the carbon sequestration process of photosynthesis.

Ocean acidification (which harms marine life through oceanic carbon sequestration) is also related to the increase in atmospheric CO2.

Acid rain (highly acidic precipitation harming vegetation, surface water, and soil) and smog (urban air pollution) are related to the increased production of such other greenhouse gases as sulfur dioxide and nitrogen oxide.


Temperature
risingtemperature
2014 was Earth’s warmest year on record.  Nine of the ten warmest years on record have occurred since 2000.

Global temperatures have increased approximately 1.0 °F (0.6 ºC) over the last hundred years.

As Earth has become trapped in its own greenhouse gases, other phenomena attributed to global warming include drought, wildfires, melting arctic ice, melting land ice, and rising sea levels.


Arctic Ice
arcticseaicemelt
In 2012, arctic sea ice shrank to the lowest level on record.  Ice in both the North and South Poles has been melting.


Land Ice
glacialretreat
Land ice, in the form of sheets, glaciers, and snow cover, has diminished.  Land ice loss in the near-polar country of Greenland doubled between 1996 and 2005.


Sea Level
risingsealevelGlobal sea level has risen seven inches over the past hundred years.  Certainly, the melting of arctic and land ice has contributed to this rise.  But the ocean itself has warmed a
not-insignificant 0.18 °F (0.10 ºC) over the last hundred years.


Practice – Questions

The following line graphs from the National Oceanic & Atmospheric Administration show the trend in carbon dioxide (CO2) levels over the ocean over time.  The black line represents average CO2 levels and the red line represents monthly CO2 levels.co2
1.  Based on the black line graph, how did average CO2 levels change (in parts per million) from the beginning of 2010 to the beginning of 2015?
A.  from 397 to 399
B.  from 377 to 399
C.  from 400 to 399
D.  from 387 to 399

2.  What might account for the periodic upward rises in the red line graph?
A.  Increased CO2 from increased solar panel emissions.
B.  Decreased CO2 from increased solar panel emissions.
C.  Increased CO2 from increased winter power plant emissions.
D.  Decreased CO2 from increased winter power plant emissions.

The following line graph from NASA shows the trend in global temperature over time.temperature
3.  Based on the line graph, in which year was the 5-year mean temperature the lowest?
A.  2010
B.  1880
C.  2000
D.  1910

4.  Based on the line graph, what theoretically could have accounted for the temporary spike in 5-year mean temperature around 1942?
A.  Increased consumer purchases of silk stockings.
B.  Decreased sales of war bonds.
C.  Increased worldwide armament factory CO2 emissions during World War II.
D.  Decreased worldwide armament factory CO2 emissions during World War II.

The following graph from NASA shows the trend in arctic sea ice coverage over time.arcticseaice
5.  Based on the graph, in what year was arctic sea ice at its most expansive?
A.  1996
B.  2012
C.  2004
D.  2000

6.  Based on the graph, in what year was arctic sea ice at its least expansive?
A.  1996
B.  2012
C.  2004
D.  2000

The following side-by-side histograms from NASA show trends in deforestation in Indonesia and Brazil.deforestation
7. Based on the histogram, in which country has deforestation increased?
A.  Lilliput
B.  Oz
C.  Brazil
D.  Indonesia

7. Based on the histogram, in which country has deforestation decreased?
A.  Lilliput
B.  Oz
C.  Brazil
D.  Indonesia

The following line graph from NASA shows the trend in coastal sea levels over time.sealevel
9.  Based on the line graph, how did the coast sea level change (in mm) from the beginning of 1870 to the beginning of 1990?
A.  from 2 to 175
B.  from 50 to 175
C.  from -2 to 175
D.  from -50 to 175

10.  Based on the line graph, which of the following years would have been best for an astronaut orbiting in a space capsule to return to Earth by plopping into the sea?
A.  1950
B.  1952
C.  1961
D.  1951


Practice – Answers

1.  D.  from 387 to 399

2.  C.  Increased CO2 from increased winter power plant emissions.

3.  D.  1910

4.  C.  Increased worldwide armament factory CO2 emissions during World War II.

5.  A.  1996

6.  B.  2012

7.  D.  Indonesia

8.  C.  Brazil

9.  C.  from -2 to 175

10.  C.  1961

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