Climate Change prt 2

how do humans put methane in atmosphere

agriculture via livestock, land use changes via fires/ turning over of soil, production and use of natural gas, generates in landfills during decomposition

Why would temperatures still increase if we stabilize the carbon cycle

• because carbon cycle takes so much time the results of stabilizing the carbon cycle would take some time to be felt

• oceans thermal inertia would cause the temperature to continue to rise as it takes time to cool down. It would take at least a couple decades as oceans release stored heat and reach equilibrium.

Warming is Uneven

• continents more than oceans

• high latitudes more than tropics

• smaller temperature contrasts summer vs winter day vs nights

• extremes extremer

What is not responsible for modern warming

continental drift, solar cycles, earth’s orbit, internal variabilty

b/c too slow to be responsible for changes in last hundreds of years

Cause of recent warming and how do we know

greenhouse gases

known: can be documented in lab, climate behavior can be reproduced by models, correlations in past climate

PETM

• most similar to us today

• gain of 5 degrees Celsius over few thousand years

• took 100k to return to previous Co2 levels

• largest mass extinction event in 93 million years

What determines planet temperature

energy in vs energy out, forcings then feedbacks, greenhouse gases, human emissions

What does the greenhouse gasses released determined by

1. The number of people

2. How much they are engaging in activities that release greenhouse gases.

I in IPAT

number of people) x (how much greenhouse gas they contribute)

P

population

why does population matter

• people need clean water and food

• folks want to live indoors

• no naked

• tanspo

• electricity

• security

A

• affluence (how much greenhouse gas each person contributes)

• measured through GDP

T

• combines energy intensity and carbon intensity (T=EI*CI)

• technology’s impact on emissions

• impact is going down

EI

• Industrial or service industries?

• energy efficiency?

• requires transpo?

CI

• which fuel?

  energy production process?

  emissons?

Why do we think emissions will increase

pop growth, affluence growth, energy and carbon intensity decreased but not enough to offset the other factors

growth= 15 to 40 GtCO2 from 1960

representative concentration pathways

named based on forcing level achieved by 2100 caused by carbon dioxide emissions

ex: RCP 8.5, RCP 6.0, RCP 4.5

Shared Socioeconomic Pathways

based on the decisions we make and actions we choose as a global community

• storylines regarding GDP, population, economic collaboration +RCPs

• possible future worlds

SSP1

sustainability- take the green road 1.9 forcing

SSP2

middle of the road same as it ever was 4.5 forcing

SSP3

regional rivalry taking care of own

SSP4

Inequality a road divided- high unequal investments in human capital

SSP5

fossil dueled development

SSP vs RCP

ssp= social and economic development patterns

rcp= changes in greenhouse gas emissions, land use patterns, other climate drivers

Why would temps rise with decreased carbon

• because there is already too much carbon in the atmo to be abosrbed by carbon sinks

• slow feedback loops will continue to amplify temperature increases even with decreased carbon ex: destruction of ice sheets

What has modern climate change caused

precipitation: global increase, shift to higher latitudes, drought, less rain events but heavy when they come, flood

loss of freshwater via saltwater intrusion

sea level rise: issues for infrastructure, we are at center

changes in growing seasons

longer pollen season

How does CC impact us financially?

issues tied to climate change will result in citizens having to pay for expensive infrastructure to combat effects via taxes and insurance

change of ag zones will raise prices of food

ex: People living in Florida have to pay high house insurance due to the increasing risk of flooding and hurricane damage

why is ocean acidification a result of climate change

• oceans act as sponge absorbing increasing amounts of carbon dioxide from atmo as they do this, they create bicarbonate ions and calcification is impeded

• breaks down hard shell animals that are vital to marine ecosystem

Why do I care icesheets are melting

• I am going to have to pay for infrastructure needed to combat higher sea levels and higher insurance rates because of increased damage from storms

• security issue as new pathways in ocean will be made

exponential growth

• growth rate depends on current size

• anything that grows a percent

• becomes powerful over time

how long will it take for the original quantity to double

72/ growth rate

exponential growth formula

F= P * (1+r/100)^n

discounting

how much is a future thing worth now

P= F/(1+r/100)^n

Why does exponential growth make curved line not straight line

• b/c the next point on the graph is based on the current value and that value is compounding with itself

• it is reflecting an increasing rate of change

Why does exponential growth make curved line not straight-line climate example

• concentration of carbon in the atmo is an example of exponential growth as there is a positive feedback loop

Why so hard to put social cost on carbon

uncertainty in the discount rate and assessing the monetary value of climate change impacts

ex: Obama (worldwide) vs Trump (US only) put different use different discount rates when calculating and end up with drastically different numbers

social cost of carbon

loss of goods and services, defense against sea level rise, rebuilding infrastructure