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Climate Change:A burning problem!

Presented by:

Surendra Bam

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Outline

• Introduction to climate change• What changes climate?• How do we know?• Why should we care?• What next—what can we do?

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Climate Change-Definition

• Any change in climate over timeAny change in climate over time, whether , whether due to natural variability or as a result of due to natural variability or as a result of human activity (IPCC)human activity (IPCC)

• Change of climate that is attributed directly Change of climate that is attributed directly or indirectly to human activity that alters or indirectly to human activity that alters the composition of the global atmosphere the composition of the global atmosphere and that is in addition to natural variability and that is in addition to natural variability observed over comparable time periods observed over comparable time periods (UNFCCC)(UNFCCC)

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What changes climate?

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

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What changes climate? Contd…

• Sun’s output Energy output increased about 0.1% from 1750 to 1950,

increasing temperatures by 0.1⁰C in the first part of 20th century. But since 1979, when we began taking measurements from space, the data show no long-term change in total solar energy, even though earth has been warming.

• Earth’s orbitRepetitive cycles in Earth’s orbit that occur over tens of

thousands of years can influence the angle and timing of sunlight.

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• Drifting continents In the distant past, drifting continents make a big difference

in climate over millions of years by changing ice caps at the poles and by altering oceans currents, which transport heat and cold throughout the ocean depths.

• Volcanic eruptions Huge volcanic eruptions can cool earth by injecting ash and

tiny particles into the stratosphere.

• Greenhouse gases Changes in the concentration of greenhouse gases, which

occur both naturally and as a result of human activities.

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“Greenhouse effect” Increasing greenhouse gases trap more heat

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Greenhouse gases

Nitrous oxide

Water

Carbon dioxideMethane

Sulfur hexafluoride

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How do we know?

Scientists learn about the past climate from such things as tree ring analysis, fossil evidence and analysis of patterns and chemical composition in coral skeletons and ice cores.

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Present day observations

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Computer models

Computer model used to forecast weather, climate models simulate the climate system with 3-dimensional gird. It performs trillions of calculations that describe changes in many climate factors in the grid.

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Why should we care?

Model correctly identify that the warming is due to man’s activities, and that projections of future warming are realistic.

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In Glacier National Park, there were 150 glaciers in 1850. Today, there are 26.

Effects: Snow and ice

Grinnell Glacier, Glacier National Park1900 and 2008

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Effects: Increment of glacial lake

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Effects on precipitation

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Effects on precipitation

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Effects on precipitation contd…• More water vapor held by a warmer atmosphere

also lead to heavier rains and more snowfall.

• But as storm tracks shift, it can also mean some areas get drier.

• A 2004 study by the National Center for Atmospheric Research found that the percentage of Earth’s land experiencing serious drought had more than doubled since the 1970’s.

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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

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Impacts AGRICULTURE

•Shift in food growing areasChanges in crop yieldsHigh irrigation demandIncreased pest, crop diseases & weeds in warm areas

WATER RESOURCES •Change in water supplyDecreases water qualityIncreased droughtIncreased flooding

FORESTS•Changes in forest composition and locationsDisappearance of some forestsIncreased fires from dryingLoss of wildlife habitat and species

BIODIVERSITY

•Extinction of some plant and animal speciesLoss of habitatDisruption of aquatic life

SEA LEVEL

•Rising sea levelsFlooding of low lying islands and coastal cities

WEATHER EXTREMES

•Prolonged heat waves and droughtIncreased floodingMore intense hurricanes, typhoons, tornadoes & violent storms

HUMAN POPULATION

•Increased deathsMore environmental refugeesIncreased migration

vHUMAN HEALTH•Increased death from heat and diseasesDisruption of food & water suppliesSpread of tropical disease to temperate areasIncreased respiratory diseasesIncreased water pollution from coastal flooding

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More CO₂ means a warmer atmosphere.

Global mean temperatures in some regions would be 8⁰C to 11⁰C warmer if CO₂ doubled (top), and 13⁰C if CO₂ quadrupled (bottom).

Future Scenario

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IPCC estimate sea level rise( High emission scenario)

Thermal expansion of seawater ........ 28 cm

Glaciers and ice caps ......................... 12 cm

Mass balance .................................... - 3 cm

Increased flow ................................... + 3 cm

Total: 40 cm

Range of Estimates: 18-59 cm

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Future Scenario contd…

• Global average temperature are expected to increase by about 1-7⁰C by the end of the century.

• Four major changes prior to sea level rise. They are: Thermal expansion, mountain glacier melting, Greenland ice and Antarctic ice sheet melting.

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What next—what can we do?

• Reducing our greenhouse gas emissions and our use of fuels will not be easy, but it double.

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Contd….

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8 technologies that could avoid 8 wedges•Produce more fuel-efficient vehicles•Reduce vehicle use•Improve energy-efficiency in buildings•Develop carbon capture and storage processes•Triple nuclear power•Increase solar power•Decrease deforestation/plant forests•Improve soil carbon management strategies

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Individual actions

Use mass transit, bicycle,

walk, roller skate

Plant trees Awareness

programs

Buy water-saving appliances and

toilets; installing low-flow shower

heads.

insulate, and replace old windows Buy products

with a U.S. EPA Energy Star

label

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Let us stop blaming each other

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Let us help each other

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Bibliography…

• NASA Earth observatory, 2011 “climate system”.

• IPCC Fourth Assessment Report• UNFCCC Report• Santra, S.C.2005, Environmental Science,

New central book agency, pg. 301-315• www. Google.com

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