9.4 climate change

9.4 Climate Change

Global warming or climate changeGreenhouse effect

Impacts

Weather

• Day to day temperatures• Changes with the seasons

Climate

• Long-term patterns of weather in a region• Climate should not change much over the

years

Patterns

• World has warmed and cooled for years• Several ice ages in the last million years• Scientists can look at ice cores in glaciers to

find out what the climate was like• Or muck at the bottom of lakes• Or rings inside a tree

Last 100 years

• The global temperature is rising• It has increased almost 1 degree C

Climate Change

• Many changes are occurring besides temperature..some places experience….

• More rain• More drought• Colder temperatures• More cloud cover• Natural disasters – flooding, hurricanes

Extreme Weather

• Floods• Hurricanes• Droughts• Damage buildings, kill people, wildlife, destroy

crops

A Few Degrees

• The last ice age the world was only about 4-6 degrees cooler than it is today

• By 2080 winter temperatures in the Arctic could rise up to 14 degrees

• Summer temperatures could increase 4-7 degrees

Our Atmosphere

• The sun’s energy is absorbed by land and water

• Absorbed heat is slowly released into the atmosphere

• The atmosphere traps the heat in, like a greenhouse

Greenhouse Gases

• Green house gases• Carbon dioxide, methane and nitrous oxide

Greenhouse gases

Nitrous oxide

Water

Carbon dioxideMethane

Sulfur hexafluoride

“Greenhouse effect” Increasing greenhouse gases trap more heat

Greenhouse Effect

• The rise in Earth’s average temperature over time

• Due to gases that trap heat• Without these gases, heat would escape back

into space and Earth’s average temperature would be about 60ºF colder.

What do climate scientists really think?

Human Activities

That emitt green house gases• Burning fossil fuels• Fuel for vehicles-gas, diesel• Heat - propane, natural gas• Electricity – coal• Cutting down trees and plants

Impacts

• Crazy weather• Melting permafrost (landslides)• Break up of sea ice (homes for wildlife)• Rising sea levels (flooding of coastal cities)• Forest fires (too dry)• Southern species are moving North

Carbon Sink

• Absorb and store carbon• Forests, soil oceans, plants, animals

Carbon Sequestration

• Store excess carbon emitted by humans• Carbon sinks naturally • Plant trees• Protect forests

Artificial Trees

• Built to absorb carbon