Radiative forcing

Question 1

What does the global warming potentially (GWP) account for?

Answer 1

• radiative forcing for a known amount of gas
• emission rate of gas
• lifetime of the gas in the atmosphere
• indirect effects of the gas on radiative forcing

Question 2

What is the global warming potential (GWP)?

Answer 2

The estimated forcing at some future time based on emissions now. It accounts for the radiate forcing for a known amount of gas, the emission rate of the gas, the lifetime of the gas in the atmosphere and any indirect effect of the gas on radiative forcing.

Question 3

What is a well mixed greenhouse gas?

Answer 3

Gases for which the timescale of removal is much longer than the mixing time of the atmosphere

Question 4

How long is the lifetime of methane?

Answer 4

12 years

Question 5

What are some examples of well-mixed greenhouse gases?

Answer 5

Carbon dioxide, Methane, Nitrous oxide, Chlorocarbons

Question 6

How much of total radiative forcing does CO2 contribute to?

Answer 6

60%

Question 7

How much has atmospheric concentration of CO2 increased since 1750-2005?

Answer 7

From 280ppm to 380ppm (36%)

Question 8

How much have CO2 emissions increased annually from 1999-2005?

Answer 8

3% annual increase

Question 9

How much of methane emissions are anthropogenic?

Answer 9

50%

Question 10

What contribution does methane have to radiative forcing?

Answer 10

20%

Question 11

What are some natural sources of methane?

Answer 11

Ocean, Termites, Wetlands,

Question 12

What are some anthropogenic sources of methane?

Answer 12

Biomass burning, landfill, domestic sewage, animals waste, fossil fuels, animal husbandry, paddy fields

Question 13

What is the lifetime of CO2?

Answer 13

Variable (>100)

Question 14

What is the GWP of CO2 on a 20 year time scale?

Answer 14

1

Question 15

What is the GWP of methane on a 20 year time scale?

Answer 15

62

Question 16

What is nitrous oxide?

Answer 16

Byproduct of natural and agricultural ecosystems (biotic processes in soil)

Question 17

What are some sources of nitrous oxide?

Answer 17

• increased fertiliser use
• nylon production
• nitric acid production
• vehicular emissions

Question 18

How long is the lifetime of nitrous oxide?

Answer 18

114 years

Question 19

How much stronger is nitrous oxide compared to CO2?

Answer 19

x300 stronger per kg

Question 20

What is the GWP of nitrous oxide on a 20 year time scale?

Answer 20

275

Question 21

What is a halocarbon?

Answer 21

A man-made compound containing carbon and either chlorine, bromine or fluorine

Question 22

What are some example of halocarbons?

Answer 22

CFCs, Halons, HCFCs (hydrochlorofluorocarbons), HFCs (hydrofluorocarbons)

Question 23

What is the lifetime of halocarbons?

Answer 23

11.9 years (HCFC-22) up to 260 years (HFC-23)

Question 24

What is the radiative forcing of all well-mixed greenhouse gases since pre-industrial times?

Answer 24

2.64 +- 10% (IPCC AR4)

Question 25

What was the abundance of methane in 2005?

Answer 25

1774 ppb

Question 26

What is tropospheric ozone?

Answer 26

A pollutant produced by photochemical reactions involving hydrocarbons and nitrogen oxides typical of biomass burning and urban pollution

Question 27

How much of total ozone is found in the troposphere?

Answer 27

1/6

Question 28

Why is ozone not retrievable from ice core?

Answer 28

It is too short lived

Question 29

What is the relationship between solar forcing since 1750 and anthropogenic forcing?

Answer 29

Solar forcing has likely been 5 times smaller than total anthropogenic forcing

Question 30

What is the GWP of methane in 20 years compared to CO2?

Answer 30

60