What Do We Know About Climate Change?

Dr. Kyle ForinashProfessor of Physics

School of Natural SciencesIndiana University Southeast

New Albany, IN,USA

Climate is what you expect,

weather is what you get.

How Do We Get Climate Information?Instruments for last 200yr. Tree Rings for last 10,000yr.Ocean and Lake Sediment for last 125,000yr:– Tri- and di-saturated alkenones in plankton;– Micro fossils, pollen;– Oxygen isotopes;– Heavy metal uptake in coral;– Inorganic debris.

Ice Cores for last 800,000yr:– CO2 & Methane from air bubbles;– Temperature from deuterium, oxygen and nitrogen isotopes,

aerosols;– Volcanic activity from aerosols;– Solar activity from beryllium isotopes.

Where Do We Get Climate Data?

What Does the Data Tell Us?

What Causes the These Changes?

Forcing: – The sun (duh)! – Orbital parameters. – The atmosphere. – ENSO (El Niño), NAO, etc. – Volcanoes, meteors (aerosols, particulates).

Feedback: – Ocean and air circulation patterns.– Clouds.– Albedo.– Atmospheric Changes.

Energy Reaching the Earth’s Upper Atmosphere: S =1366W/m2

0 10 20 30 40 50 60 70 80 90 100

-3

-2

-1

0

1

2

3

Milankovitch Cycles.

EccentricityObliquityPrecessionTotal

Thousands of Years

Varia

tion

in O

rbit

Why Are Ice Age Transitions so Rapid?

Feedback:

•Pushes system away from equilibrium.

•Can work in both directions.

•But: Albedo feedback is NOT strong enough to produce ice ages.

All Objects Emit Infrared Radiation; (IR).

Energy from the Sun is Re-radiated as Infrared.

albedo

33C too Cold!

We’ve Known CO2, CH4 and H2O Absorb IR Since 1859! (O2 and N2 do not)

With an Atmosphere (CO2, H2O, CH4) We Get the Right Temperature.

emissivity (absorption)

15C – just right!

For Venus we get 480C.

CO2, CH4 (and H2O) Act as BIG Feedbacks.

Petroleum 39%

Natural Gas 24%

Coal 24%

Hydro-electric

6%

Renewable 1%

Nuclear 6%

World Energy Use (449 Quad, 2008)by Source: 86% Fossil Fuels.

Human Carbon Emission: 6.3Tkg/yr.

So Shouldn’t We Be Measuring Temperature Increases?

Temperatures Are Increasing.

Alaska: Face ofGlacier in 1951

Alaska: Face ofGlacier in 2001

The Arctic Icecap is Melting.

Temperature Does Not Go Up Uniformly.

Temperature Isn’t All That is Changing.

•Permafrost is melting.•Earlier springtime.•Changes in migration patterns.•Changes in plant growth patterns.•Ocean acidification.

Are We Missing Anything?

•El Niño (ENSO).•NAO.•Other Ocean Patterns.•Clouds.•Sea mixing.•Precipitation.

ENSO (El/La Niño/a)

Let’s Get a Computer to do the Calculations!

And Include:– More atmospheric layers;– Variations in sea and land surface temperature; – Stratosphere and troposphere temperature; – Temperature variations between daily extremes; – Sea level changes; – Average precipitation; – Ice coverage; ocean circulation; – Frequency and intensity of extreme weather events; – Deviations in atmospheric water vapor.

Should We Believe the Computers?

The Future?

What Do We Know for Sure?No doubts:• 35% increase in CO2 in 250yr due to human activities; • 0.6C temperature increase in last 100yr;• 20cm sea level rise in last 100yr; • 15% decrease in arctic sea ice in 40yr. Very High Confidence (90%):• Temperature increase in the past 30yr due to green

house gases; • Glaciers shrinking, permafrost melting; • Shifts in timing of peak river flow due to earlier spring

snow melting; • 28,000+ cases of changes in biological marine and land

systems.

What about the future?Very High Confidence (90%):• Continued emission will lead to an increase in

temperature of 1.4C to 5C in next 100 yr; • Sea levels will rise by 40cm in next 100yr; • Precipitation patterns will shift;• Hurricane and typhoon intensity will increase.

Likely (>66%):• Permanent submersion of some islands and coastal areas;• Food and water shortages;• More species extinctions;• Increased death during heat waves;• Migration of pests including infectious diseases;

What Can We Do?

• Energy Conservation.• Alternative Energy (solar, wind, nuclear,

biomass).• Capture Negative External Costs (the True Cost

of Fossil Fuels):– Carbon tax;– Carbon trading;– Tax incentives, rebates;– Subsidies.

Why the doubt about climate?• What do you read? Human caused climate change:– Scientific (peer reviewed) articles: 928 yes; 0 no.– Popular journals: 88% “balanced” (i.e. both positions

presented).• ~50 denying scientists, some not even climate scientists. • 2000+ climate experts on just the IPCC committees.

• IPCC: Very conservative process!• Follow the money: – Exxon-Mobil: $16 million to 43 organizations over 7 years

to confuse the public on climate.– IPCC scientists: not paid to write IPCC reports.

Kyle ForinashIndiana University

Southeasthttp://

homepages.ius.edu/kforinas/Forinash.html

Island Press, July 2010