GEOG 3900 Weeks 1 + 2

orbital variations

Historically, the climate has changed due to… (which are slight changes caused by small variations in the Earth’s orbit)

1.2-1.4 F

Bill Nye says temps have risen … in the last century

50%

Oceans provide__ of the Earth’s oxygen

0.3 F

Ocean temps have risen ___ since 1969 (Bill Nye)

1 billion

…People who rely on the ocean as their primary source of protein (BN)

400 billion tons

On avg, glaciers lose … of ice a year

140,000

Humans have been on earth for about … years (Prince Ea)

4.6 billion

Earth is about … years old

30 years

base period

Sun

The ultimate energy source

Global warming

Refers to human caused or anthropogenic alteration causing increased avg surface temps relatively abruptly in recent decades

Anomaly

Difference from the avg

Temp anamoly

Actual temp minus the avg, + or -

For climate avgs, multiple decades are used

Weather

The outfit

“What you get”

Climate

Statistical description over a long-term. Includes both avg ad variability

The wardrobe

“What you expect”

Why use anamolies?

Allows for rleative compariosn between dif stations w dif absolute local conditions

Climate change

Any systematic change in the long-term stats of climate elements sustained over several decades or longer

Climograph

Plot long term avg T and avg total P by month in a dual axes graph

More

Land heats/cools ___ than ocean

Why 30 years?

Consensus/convention, capture multi-decadal, allows for enough data

Lithosphere (rocks)

Biggest source of carbon

Some climate change effects

Shift in probabilities

Intensity tends to increase

C → F

5/9 (F - 32)

F → C

9/5C + 32

1.3, 2x

Last 50 yrs rate of warming __ per century (_ faster than entire century)

1978

Measuring temp independently rom satellites since ___

threshold system

ice is a…. — it changes phase at melting temp (0 C)

Retreat of mtn glaciers

Major contributor to sea level rise

Arctic sea ice decline

40% decrease since 1979 (avg -12.6% per decade)

sea level rise

3.63 mm/yr (1993-2025)

sea level rise causes

1) all that ice melting (adding mass to oceans;”barystatic” change)

2) thermal expansion (“thermostatic” change): warmer ocean exapnds, rise

zetta joule

10 to the 21st

93.4% to the ocean

where is global warming going?

warming

Lower/mid-troposphere is…

cooling

Stratosphere is…

CO2

… traps most IR near surface, raising temps, but radiates it efficiently in the upper atmosphere, leading to cooling

faster

minimum temps are rising….

paleoproxies

long-lived chemical or biological systems imprinted by climate, extracted from archives give indirect climate info of past

late cenozoic ice age

We live in the…

Has lasted for 2-3 million years

ice free

For most of earth’s history, Earth has been…

Large changes

Ice ages, hot houses

Certaceous

A hot house world

Temps ~14 C warmer than present

Paleocene-Eocene Thermal Maximum (PETM)

Temps rose steadily due to the slow release of GHG (~2 b tons per year). Today, we are emitting 30 b tons per year

45%

GHG increased by ___ in 2019 relative to 1990

>50%

Currently, atmospheric CO2 levels are up __ from pre-industrial levels

paleoclimate proxy factors

span and resolution