climate change

Forcing Factors

• Forest fires

• Emission of greenhouse gases

• Draining of wetlands

• Deforestation

• Volcanic eruptions

• Aerosols Land use

• Ozone depletion

• Solar variation

Atmospheric carbon dioxide levels

• Changed throughout Earth’s history

• Scientists know this because of analyzing gas composition of bubbles formed in ice cores

dark ice

winter

human cause of deforestation

• mining

• agriculture

• road building

• settlement

• hydropower

• logging

Road Building

cut through forests or provide access deeper into forests

Mining

Clearance of forests to obtain precious minerals

Settlements

populations grows, space is needed for housing

Logging

Trees are cut for timber

Agriculture

areas cleared for crops and animals

hydropower

Building dams and reservoirs for electricity

deforestation

• Reduce interception/infiltration

• Monoculture

• Sedimentation

• Increased CO2

• Increased leaching of nutrients

• Increased overland flow

Increased CO2

• less trees removing it by photosynthesis

• carbon sinks removed

monoculture

reduce biodiversity

greenhouse gasses

• absorb infrared radiation emitted by the Earth

• atmosphere warms

• increase will increase effects

warming climates

• animals to move towards the poles/higher altitudes

• Competition with native species

• cannot adapt fast enough, extinction

Seasonal cycles

• changing (reproducing earlier)

• change in migration patterns

Weather events

• more extreme

• Changes to ocean currents, changing local climates

Water availability

• changing

• some species go extinct due to lack of rainfall

Polar ice and glaciers

• retreating

• loss: affect water supply

• Sea levels rise, risk flooding

ice cores

1. surface

2. FIRN

3. compacted ice

FIRN

porous areas where gasses diffuse in and out

compacted ice

dark/light ice layers showing winter vs summer

dark ice

winter

light ice

summer

20th century

recent polluntants

1960

plutonium - nuclear testing

1600

volcanic ash

17 BCE

ancient lead emissions

796 500 BCE

contains thousands of years of climate history

obtaining ice cores

1. preperation

2. drilling

3. logging and cutting

4. labelling sections

5. measure in field

6. storage

7. measure in lab

8. interpretation of results

core

taken through trunk

tree cores

1. tree bark

2. most recent growth

3. year growth in cold condition (short)

4. year growth in wam condition (long)

5. autumn/fall growth (short)

6. sprin and summer growth (long)

7. centre of trunk/first year growth