Presented by:Daniela Visinica

Global Climate Change

• Identifiable change in the climate of Earth as a whole that lasts for an extended period of time (decades or longer) – When due to natural processes, it is

usually referred to as global climate variability

– Usually refers to changes forced by human activities that change the atmosphere

What causes Earth’s climate to change?

• Changes in the atmosphereChanges in the atmosphere• Natural processesNatural processes

– Volcanoes Volcanoes – Tectonic plate movementTectonic plate movement– Changes in the sunChanges in the sun

• Human activities – any activity that releases Human activities – any activity that releases “greenhouse gases” into the atmosphere“greenhouse gases” into the atmosphere

What causes Earth’s What causes Earth’s climate to change?climate to change?

What are What are greenhouse gases?greenhouse gases?

Any gases that cause the “greenhouse Any gases that cause the “greenhouse effect!”effect!”

Imagine… a car on a cool but sunny day…

Climate Change:Fitting the pieces together

Outline

• What changes climate?• Is it real?• How do we know?• Why should we care?• How sure are scientists?• What next—what can we do?

What changes climate?

• Changes in:– Sun’s output– Earth’s orbit– Drifting continents– Volcanic eruptions– Greenhouse gases

“Greenhouse effect” Increasing greenhouse gases trap more heat

Greenhouse gases

Nitrous oxide

Water

Carbon dioxideMethane

Sulfur hexafluoride

Could the warming be natural?

Is it real?

Effects: Snow and ice

Grinnell Glacier, Glacier National Park1900 and 2008

Effects on precipitation

Europe’s Climate is AnormalEurope’s Climate is Anormal

Rahmstorf & Ganopolski, Climatic Change, 1999. 43: p. 353-367

European temperatures are 5-10 °C higher than normal

1976–1999:• Number of cold and frost days decreased• Number of summer days increased

Temperature ExtremesTemperature Extremes

Summer days (Tmax >= 25 °C)Changes in 1976–1999

Data-sources: ECA, IPCC, ACACIA, KMNI

Projections:• Cold winters disappear almost entirely by 2080 • Hot summers much more frequent

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1976–1999:• Southern Europe: decrease • Mid and northern Europe: increase

Precipitation ExtremesPrecipitation Extremes

Very heavy precipitation days (p >= 20mm)Changes in 1976–1999

Data-source: ECA, IPCC, ACACIA, KMNI

Projections:• Likely more frequent droughts and intense precipitation events

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Effects on ecosystems

How do we know?

Computer models

Why should we care?

2003 European Heat Wave

Germany: Lowest river levels this century

Switzerland: Melting glaciers, avalanches

France: >14,000 deaths

Portugal: Forest fires

U.K.: Train rails buckle

Sea-level rise projections : a few inches to a few feet

•2 ft: U.S. would lose 10,000 square miles•3 ft: Would inundate Miami•Affects erosion, loss of wetlands, freshwater supplies•Half of the world’s population lives along coasts•Big question: Ice sheets

What do climate scientists really think?

What next—what can we do?

What next—what can we do?

Produce more fuel-efficient vehiclesReduce vehicle useImprove energy-efficiency in buildingsDevelop carbon capture and storage processesTriple nuclear powerIncrease solar powerDecrease deforestation/plant forestsImprove soil carbon management strategies

Individual actions

Use mass transit, bike, walk, roller

skate

Tune up your

furnaceUnplug

appliances or plug into a

power strip and switch it off

Buy water-saving appliances and

toilets; installing low-flow shower

heads.

Caulk, weatherstrip, insulate, and replace old windows

Buy products with a EPA Energy Star

label