Climate change and global warming

Aiming Wu

Department of Earth and Ocean SciencesUniversity of British Columbia

Vancouver, BC, CanadaDecember 2004

• What is climate and climate change?

• What is global warming and its effects?

• Why the earth is getting warmer?

• What climate will be in the future?

• What shall we do to protect our Earth?

Outline

What is climate ?

Weather

sunny cloudy

rainy snowy

fogy rain or snow

snow (daytime)

snow (overnigh

t)

Weather: what is happening outdoors in a given place at a given time. Weather changes from minute to minute, and place to place.

• Temperature • Precipitation • Wind • Humidity • Visibility

How to describe weather?

Weather forecast

• TV, radio

• newspaper

(cold, cool, warm, hot)(rainy, snowy, sunny)(light, strong)

(dry or wet)

(fogy, dusty)

• 2 hours later• this evening

• tomorrow ……

Climate

Weather

Climate: An average of all weather occurring over a period of time in a given place

* Monthly, seasonal (or annual) mean temperature or precipitation (don’t look at the weather on a specific day)

* tells us what it's generally or usually like

* May talks about 10 millions years ago, 10 years ago, this season, this year, next year or 100 years later ……

* Climate also depends on time and place

Different places have different climate…

Victoria, Canada summer 21oC winter 8oC

annual precipitation 1250cm

Sahara, Africa Max. summer 58oC annual precipitation

76mm

mild Dry, hot

Tropical forests

Warm & wet

Europe

Cold

In winter

Climate also changes with time ……

Temperature precipitation

Changes with season ……

Global warming

G * Global mean surface temperatures have increased about 1oF since the late 1800s

* The Earth is getting warmer !

The warming is GLOBAL !

Temperature changes 1895-1995

British Columbia (Canada)

What are the effects of global warming?

Good or bad to us ?

Human Health• Extreme hot weather can directly cause death (over 40oC) [normal human body temperature ?]

• Several serious diseases only appear in warm areas [virus or bacteria like warm place to live]

• Warm temperatures can increase air and water pollution

Severe drought or flood

• more water evaporates, soil will become drier; desert will expand; lake or river levels will drop or even get dried,

• flood in some other places

Sea level rise

• Seas, oceans expand

• Antarctic, Greenland ice melt

• low-lying coastal lands drown

(many people lose their homes)

• large area of farmland be ruined

Farming

• Some plants and crop cannot grow under higher temperatures

• Drought makes plants & crop die (need water)

• people have no enough food, die because of starvation

Animal, forest-fire

• Some animal will die when the temperature changes

• More and more forest fires

So, global warming is causing serious

problems to our environment

and our lives . . .

Why is the climate getting warmer?

Earth

Atmosphere

Other includes:

Argon (Ar, 0.9%)

Water vapor (H2O)

Carbon Dioxide (CO2, 0.03% )

Ozone (O3), CFCs

Methane (CH4)

Also called “greenhouse gas”

How to grow plants in winter?

greenhouse

(a) Let sunlight come in (b) keep heat from going out

The greenhouse effect

Greenhouse gas molecules absorb infrared radiation and emit it again

Greenhouse gases

* let the sun rays come in

* absorb infrared radiation and emit it back to the Earth

Make the earth warmer

Atmospheric CO2 is increased rapidly in the recent 100 years !

Global warming happened only in the

recent 100 years

So the global warming is mainly caused by the increase of CO2 in the atmosphere

Who causes CO2 increase ?

Industrial pollution

Forest cut

Vehicle pollution

Human

Natural pollutions

Volcanic ash (works like the greenhouse gases)

What is in the future ?

It is estimated that CO2 will double from pre-industrial levels in 50-100 years ……

Global temperature

Sea level

By 2050: 0.6-2.5ºC

By 2100: 1.4-5.8ºC

By 2050: 5-30 cm

By 2100: 10-90 cm

What can we do to protect our Earth ?

• Read and learn about the environment science• Save energy (turn off lights, TV, computer…)

• Use bike, bus, walk or car pool

• Plant trees (plants absorb CO2, vapor …)

• Recycle (papers, cans, plastic bags, bottles)

• Use solar energy

• Talking to your family and friends (let them know)

Summary

• The global climate is getting warmer since the late 1800s

• The global warming is making our environment worse and threatening out lives

• Global warming is mainly caused by human activities (industry, transportations etc)

• However, everyone can do something to protect our Earth

The end, thank you.

Questions & comments ?