55: Changes in the Atmosphere

Question 1

How can temperature be measured?

Answer 1

through thermometers and satellites

Question 2

How do thermometers measure temperature?

Answer 2

invented in the 17th century
- measurements are often taken close to the ocean surface and not so close to the land surface

Question 3

How do satellites measure temperature?

Answer 3

measure infrared radiation emitted from the sea surface

Question 4

Why is land surface not the best measure?

Answer 4

land surface could have an effect on the temperature, land has a smaller heat capacity

Question 5

What is a proxy?

Answer 5

a figure that can be used to represent the value of something in a calculation
- indirect way of estimating the temperature

Question 6

What are examples of proxys?

Answer 6

O2 Isotopes in water and density of tree rings

Question 7

What is O2 isotopes in water used for?

Answer 7

oxygen dating of water

Question 8

What can the density of tree rings show?

Answer 8

gives information on temperature and precipitation
- less packed = more rain/high temp
- closely packed = low precipitation/temp

Question 9

What are ice cores?

Answer 9

frozen time capsules

Question 10

How old are the oldest ice core records?

Answer 10

extend to 130,000 years in Greenland, and 800,000 years in Antarctica

Question 11

What do ice layers contain?

Answer 11

they hold particles and contain tiny bubbles of atmospheric air (fossil air pockets)

Question 12

What is ice core analysis?

Answer 12

extract air from ice layers and look at the concentrations of different gases
- particles can be used to look for pollen grains and see what year there was a lot of pollen or not much pollen
- isotopes: forming layers, look at how many, their tightness

Question 13

What are other indirect ways to look at temperature?

Answer 13

paleoclimatology datasets
- caves, holes in the ground, corals, fauna, fire history

Question 14

What are CO2 levels in history?

Answer 14

cycling up and down but now it is rising (hockey stick)

Question 15

What is the relationship between temperature and CO2 in history?

Answer 15

go hand in hand in history
- more CO2 = higher temperature
- less CO2 = lower temperature
CORRELATION IS NOT CAUSATION

Question 16

Could the CO2 increase be natural?

Answer 16

no, CO2 levels vary naturally but natural variations cannot explain the spike in CO2 concentration we have seen in the last years

Question 17

Could higher temperatures be explained by changes in the earth’s rotational axis?

Answer 17

NO

Question 18

Could higher temperatures be explained by increase solar radiation?

Answer 18

NO

Question 19

What is the conclusion so far about temperature and CO2 levels?

Answer 19

warming of the last century is unusual by the standards of the last few thousand years and almost certainly caused by increasing atmospheric CO2 concentrations

Question 20

Is global climate change happening?

Answer 20

yes
- ice is melting
- global temperatures are increasing
- sea levels are going up
- more extreme weather events are occurring

Question 21

What do scientists agree on?

Answer 21

• the greenhouse effect is a natural phenomenon that keeps the Earth warm
• human activities (anthropogenic) are responsible for the increased release of greenhouse gases
• because of higher concentrations of greenhouse gases, the global temperatures are increasing
• higher global temperatures are affecting the climate