W7

Question 1

What are the two main processes that govern the climate

Answer 1

Thermodynamic
Dynamic

Question 2

What is the thermodynamic system?

Answer 2

As the atmosphere warms by 1oc the moisture holding capacity increases by 7%

Question 3

What is the dynamic system?

Answer 3

Idea that there are different climate systems and weather patterns

different circulatory patterns around the globe- ie. hadley cells etc.

with warming there will be changes - exacerbate the expectations in the thermodynamic systems

Question 4

What is the impact of cc on the chances and strength and type of extreme events?

Answer 4

Normal distribution curve is shifting - more extreme events tail end events are happening with increasing probability

it is hotter it will be hotter

Question 5

What is the key attribution question when we look at the distribution of events?

Answer 5

has the likelihood and strength of events altered due to climate change

has it shifted to such an extent that X event would have been impossible without climate change

Question 6

What are the two methodolgoical approaches to understanding the influence of climate change on the two systems?

Answer 6

Storyline approach

probability-based approach

Question 7

What is the storyline approach?

Answer 7

Thermodynamic and dynamic processes that led to event

useful in understanding if we are prepared for the impacts of the future

look at the patterns in the variable that you are interested in and compare that pattern to several modelled scenarios

Question 8

How does the probability-based approach work to understand the influence of climate change?

Answer 8

Change in probability of event at leasts as extreme as the event

what are the chances that the same pattern will happen in the atmosphere and the same amount of extreme weather

Question 9

How does probabilistic attribution work?

Answer 9

look into the change in likelihood of an event occurring in an anthropogenically modified climate as compared to a naturally evolving climate

Question 10

What is the probability ratio?

Answer 10

PR= P1/P0

P1 = prob of occurrence in the actual world
P0= prob of occurrence in the world that would have been

if less than 0 - the probability of event in a world without cc was higher - cc made it less likely
If greater than 1- the probability of the event in a world without cc was lower - cc made it more likely

Question 11

How does observed data modeling work?

Answer 11

• take observed data and model simulations - historical long data
• Statistical distribution fitting ex.gev
• fit parameters are dependent on global mean temperature
  > scaled/shifted to past/future
  > scaled/shifted to the current year
• obtain the probability in each scenario
• calculate the probability ratio

Question 12

How does fixed model runs work?

Answer 12

Coupled or atmosphere only model runs
- factual or counterfactual

fit distribution to variable of interest

obtain the probability in each scenario - P1 or P0

calculate the probability ratio

see if the probability is the same in different counterfactual climate

Question 13

Can you explain what the probability of exceedance is?

Answer 13

Talking about the upper tail extremes - what is the probability of seeing an event as strong or stronger than X

Question 14

What is the probability of non-exceedence?

Answer 14

This would be any event in the middle of the distribution - like not exceeding x strength

Question 15

Why is calibrated language important?

Answer 15

Using words like very high confidende or virtually certain have the same understanding to everyone when it is used

= calibrates the amount of evidence supporting each claim or the probability of the same event happening multiple times (i.e. experimentally does it happen every time)

Question 16

How many regions of the globe are there that the IPCC uses to synthesis its assessment?

Answer 16

45 regions

Question 17

What is the expected pattern for warming?

Answer 17

medium to high temperature risks - hot events will become hotter and more frwuent

consistency across all regions

Question 18

What is the expectation for heavy preceitpitation?

Answer 18

high precipitation events are to become increasingly likely as the climate warms

dry areas are simultaneously going to get drier

there are hardly any regions with high evidence but all evidence points to a change

Question 19

What are the three key elements required in an attribution study?

Answer 19

1. event definition
2. hazard attribution
3. vulnerability and exposure

Question 20

What is an example of an attribution assessment

Answer 20

2022 heatwave study in wheat cultivation in India and Pakistan

looked into the one day max temperature

look into the probability ratio of the likelihood and strength happening in a counterfactual climate –> XX amount of cc is made more or less likely due to cc

qualitative assessment to understand what was missing and what would need to be addressed should the event happen again in the future

Question 21

What are the three main droughts?

Answer 21

Meteorological
- reduced rainfall

Hydrological
- impact on stream flow and soil moisture

Agricultural and Ecological
- rainfall not percolating from the soil, roots draw the rainfall from the soil - not infiltrate itself
- important requirements for rain at certain points of the agricultural growing period vs requirements for it to be dry

Question 22

Why are droughts more interesting than heatwaves?

Answer 22

droughts are a creeping phenomena - dont necessarily see the impacts of droughts in the immediate future

irrigated resions and crop yields delayed response - doesn’t necessarily impact this season but would have an impact in future seasons

Droughts are often exacerbated by accompanying temperatures - impacts due to heat, water and concurrent impacts - combined effects due to temperature and droughts

Question 23

How do you quantify droughts?

Answer 23

Look at a hydrological variable - rainfall, runoff, groundwater level or soil moisture

standardised indicators like SPI

rainfall deficit - below expected threshold consistently then will have a long drought

Question 24

Why is it important to consider regional warming?

Answer 24

There were anomolously high rainfall deficits accompanied by high temperature - issues of evapotranspiration

the impact of low rainfall are exacerbated by high temperatures

Question 25

What are some of the direct and indirect impacts of drought on the environment

Answer 25

Direct
- soil moisture
- groundwater level
- runoff
-spring yields
-surface runoff
- water level in lakes
- available exploitable amounts of drinking water

Indirect
- water quality
-biomass development
-biodiveristy
- dust storms
-desertification
- forest fires

Question 26

What are the direct and indirect impacts of drought on the economy?

Answer 26

Direct
- exploitation of surface water
- exploitation of groundwater
- diminishing of drinking water sources

Indirect
- irrigation water
-water for farming
-failure of irrigation
- loss of animals on farms
- reduction of navigable rivers
- reduce of hydroelectric power production
- food price increasing
-reduction of economic growth

Question 27

What are the direct and indirect impacts of droughts on social

Answer 27

Direct
- drinking water

Indirect
- conflicts and conflicts of interest

Question 28

What is the patter of literature around droughts?

Answer 28

Increasingly prominent - more frameowkrs being developed
Concentration of studies in certain parts of world

Question 29

Can you speak to the study done for the spring heatwave in India and Pakistan in 2022

Answer 29

the heatwave was made 30x more likely and 1o hotter by cc

expected to become 2-20 x more likely and 0.5-1/5oc hotter at +2o warming

blocking of the rainfall patterns that usually bring moisture in from the himilayas - short spell of rain but system failed therefore soil was already dry when the heatwave happened

Wheat yields suffered the most but region was irrigated which mediated the loss - ukraine what - export ban

high temperatures due to cc caused the crops to reduce and as a result the vulnerabilities cascaded into agricultural vulnerabilities

Question 30

What was the impact of cc on the droghts in the northern-hemisphere 2022

Answer 30

made at least 20x more likely and 2% drier due to cc

looked at soil moisture content as the variable - available for most the region

Question 31

What were some of the imapcts of the northern-hemosphere drought?

Answer 31

• power generation due to heat and drought coincided with energy price increases ukraine conflict
• impacted agricultural yeilds in Europe coincided with reduced exports from Russia and Ukraine
• low reservoir levels impacted agri
• Po basin drying up affected rice in Italy

Question 32

What are the three methods of disaggregating sensitivity of crop yields to climate variables?

Answer 32

Regression model - understand the relationships –> but need long records or could use a crop model

probabilisitic model - understand the dependency - can provide probabilistic estimates

process-based model

Question 33

How do you disentangle climate and socioeconomic factors for agriculture?

Answer 33

India - high agricultural region - 90% live there rely on agriculture for their livelihood but also drought prone region

impacts mediated due to human based errors rather than cc but there can be a signal loss due to cc

look at crop databases to understand crops sensitivity/resiilence to rainfall, nutritional content, and profitability - see what the patterns and benefits are of these crops

Question 34

Why is it important to loook at vulnerabilities?

Answer 34

V is mediated by cc in how the hazards can increase vulnerability to cc agriculture but also compounded by cc
conflicts due to land use change and how emissions are being managed

important to also consider our current practices to ensure that we can mitigate any future impacts