global warming 2 Flashcards

1
Q

what GHG contributes most to CC?

A

Methane

its stored in hydrate deposits and in permafrost eg high arctic and siberia

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2
Q

positive feedback examples

A

temps warm > permafrost thaws> co2 and ch4 released

GHG increases> earth warms > increase in water vapour

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3
Q

negative feedback example

A

more clouds> more sunlight reflection> less radiation

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4
Q

define anomaly

A

amount of deviation from accepted normal value of that quantity

data - mean = anomaly

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5
Q

what year did we hit 1.5 degree warming

A

2016

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6
Q

what tells us cold and warm years

A

striped graphs

5 warmest years are recent

coldest years are in past

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7
Q

how is it hard to predict climate change?

A

as warming not evenly distributed

warming usually higher in high latitudes

earth climate is non linear dynamical system

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8
Q

what was the warming pause in 2000?

A

here there was no real trend in temp

it wasn;t predicted

don’t know why is happened

lots of energy stored in oceans and linked to el nino and la nina

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9
Q

name 2 ways we see climate change impact?

A

glacier recession -169 glaciers all show same trend - problem for water sources and tourism

arctic sea ice reduction - ice cover shrunk by 9% over 1976-2000 and thats increased to 13.5% decrease

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10
Q

if east antarctic ice sheet melted how much would sea evel rise?

A

65m

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11
Q

if west antarctic ice sheet melted how much would sea evel rise?

A

3.4 m

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12
Q

if greenland ice sheet melted how much would sea evel rise?

A

7.5m

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13
Q

if arctic sea ice melted how much would sea evel rise?

A

0m

sea ice doesn’t contribute to sea level change - only land ice does

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14
Q

name 2 ways sea level rises

A

ocean exppansion

melting glaciers

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15
Q

how much does ocean expansion contribute to sea level rise 2005 data?

A

2/3 from ocean expansion

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16
Q

how much does melting glaciers contribute to sea level rise 2005 data?

A

1/3

howevr melting glaicers contribute more to sea level rise than in the past

17
Q

why is sea level rise not globally unifrom?

A

eg isostatic rebound - removal of glacial weight from continent, the crust will rebound after losing the weight, land rises relative to the sea, other side of land subsides eg North of uk lifting and south is subsiding

18
Q

describe the impact of global warming on coral reef?

A

bleaching.

coral get nutrients from photosynthetic algae.

when water is too warm the coral expel algae living in their tissue.

bleaching can be reversible if water cools down

happens in warm waters and when ocean acidifies

19
Q

give examples of bleached coral reefs

A

great barrier reef worst bleaching in 2016

japans biggest reef - 75% of it has died from bleaching

20
Q

describe ocean acidification

A

1 half of co2 released over 200yrs has been absorbed by oceans.

co2 in sea water creates carbonic acid which lowers waters PH making it more acidic

this raises hydrogen ions in water and limits organisms acess to carbonate ions which are needed for shells

21
Q

how do we predict cc?

A

climate computer models - solve math equaltions and asses land/ocean/cryosphere interactions

however not all accurate
data takes a while to process

22
Q

what are the IPCC scenarios

A

RCP2/4.5/6/8.5

Possible climate futures - all possible depending on how much GHG emitted

23
Q

what is the prediction of global surface temp?

A

1.5 - 4 degrees

24
Q

what is radiative forcing?

A

difference of insolation absorbed by earth and energy radiated back to space

25
Q

what is the prospected seal level rise by end of 2100?

A

40-83 cm

increased recently by 20-60cm

26
Q

what is the prospected sea ice extent by 2100?

A

worse case scenario is ice free by 2070

27
Q

“All models are wrong. Some are useful”

A

attempt to stimulate reality

all have errors - comparable to proxy data

all tested, comapres and evaulated