GHG Lecture 1- Marc

Question 1

what are the major GHGs and their relationship with Earth Climate

Answer 1

Carbon dioxide 9-26%
methane 4-9%
nitrous oxide
water vapour 36-70%
percentages are contirbution to GH effect
CFC- 12
CFC-11

Question 2

what have Dansgaard–Oeschger cycles caused?

Answer 2

rapid climate change during the last glaciation

Question 3

explain the GHG effect

Answer 3

sunlight passes the atmosphere, warms the surface of the Earth
infrared radiation given off by Earth
most escapes to outer Space and cools the Earth
but some IR is trapped by gases in the air, thus reducing the cooling

Question 4

is the gh effect good?

Answer 4

yes, it is critical to our survival. Without it, the planet would be uninhabitable: 30oC colder than today.

Question 5

if the effect of CO2 on GH effect is 1, which gases are worst?

Answer 5

ch4 34
n2o 298
Ozone 2000
CF4 7350
CFC-12 12000

Question 6

The impact of each particular greenhouse gas on global warming results from a combination of:

Answer 6

The compound’s infrared absorption spectrum at wavelengths not absorbed by water and CO2
The atmospheric lifetime of the gas

Question 7

What is the equation of relative contributions to GH effect

Answer 7

Incoming Energy- Outgoing Energy= Radiative Forcing.
RF is expressed relative to the year 1750

Question 8

what is the IPCC?

Answer 8

“IPCC is an intergovernmental body of the United Nations providing the world with objective, scientific information relevant to understanding the scientific basis of the risk of human-induced climate change, its natural, political, and economic impacts and risks, and possible response options

Question 9

What does UNFCCC stand for?

Answer 9

The United Nations Framework Convention on Climate Change (UNFCCC)

Question 10

what is the aim of the UNFCCC?

Answer 10

Seeks for the stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic human-induced interference with the earth’s climate system”

Question 11

it is predicted that global warming from fossil fuel burning may delay the next glaciation by

Answer 11

500,000 years

Question 12

when looking at climate change, what two factors most correlate?

Answer 12

temp, atmospheric co2

Question 13

what are alternative contributors to climate change (NOT GHG)

Answer 13

warming, cooling

Question 14

name the 3 major soil-borne GHG

Answer 14

CO2,
CH4, methane
N2O nitrous oxide

Question 15

Global warming potential (GWP) is..

Answer 15

A comparison of how much heat is trapped in the atmosphere of a gas relative to that of CO2.

Question 16

Global temperature change potential (GTP): is..

Answer 16

how much surface temperature change relative to CO2 = Marc’s definition

is a measure of how much infrared thermal radiation a greenhouse gas added to the atmosphere would absorb over a given time frame, as a multiple of the radiation that would be absorbed by the same mass of added carbon dioxide (CO2). GWP is 1 for CO2.

Question 17

CH4 has a lifetime in the atmosphere of 12.4 years, but we compute GWP20 or GWP100

Which is lower for CH4, GWP20 or GWP100 ?

Answer 17

GWP100

Because all GWPs are calculated relative to CO2, GWPs based on a shorter timeframe will be larger for gases with lifetimes shorter than that of CO2, and smaller for gases with lifetimes longer than CO2. For example, for CH4, which has a short lifetime, the 100-year GWP of 27–30 is much less than the 20-year GWP of 81–83.

Question 18

what was the COP26 Global Methane Pledge

Answer 18

COP26 Global Methane Pledge: “cutting anthropogenic methane emissions at least 30 percent by 2030 from 2020 levels is the fastest way to reduce near-term warming”

Question 19

give examples of climate geoengineering

Answer 19

(a) using satellites in space
(b) injecting aerosols into the stratosphere
(c) brightening marine clouds
(d) making the ocean surface more reflective
(e) growing more reflective plants
(f) whitening roofs and other built structures

Question 20

why is climate geoengineering highly controversial?

Answer 20

Much better to address the cause rather the effect
Inherent risks
Risks of unintended consequences
Efficacy is difficult to determine
Who would regulate their deployment?

Question 21

what is negative emission technology? NETs

Answer 21

Negative emissions technologies are mechanisms for the absorption and storage of carbon and other atmospheric greenhouse gases - try to reverse emissions

Question 22

give examples of the types negative emission technology

Answer 22

1afforestation+ reforestation AR
2soil carbon sequestration SCS
3biochar BC
4Bioenergy with carbon capture + storage BECCS
5Direct air capture DACCS
6enhanced weathering + ocean alkalinization EW
7Ocean fertilization OF

Question 23

what does geoengineering try to achieve?

Answer 23

lock in emissions

Question 24

examples of NETs?

Answer 24

1+2 agro-forestry- boreal, temperate, tropical, agricultural practices, livestock practices
3+ 4 crop residues, dedicated crops or marginal dedicated crops
5 suspended amines, wet calcination
6 silicate rocks, carbonate rocks
7 iron fertilisation, N+P fertilisation, enhanced upwelling