Global WarmingWinter Storming

Ellen E. MartinDept of Geological Sciences

Snow angelOcala , Florida, Jan. 8,

2010

• If global warming is really happening…

• Why was this winter so cold and wet?

• Winter 2010 -second coldest winter on record in Florida

• Need to understand:• the difference between climate

and weather• what :global warming” means

Snowstorm in Washington DC, Feb. 2010

Climate vs. Weather• Weather

– The state of the atmosphere at a given time and place with respect to temperature, cloudiness, moisture, wind, pressure

• Climate– 30 year average of atmospheric state

(World Meteorological Organization)

– “expected weather”

Global Warming

• A tendency for the global mean surface temperature to increase

Average:• Land and ocean• All latitudes• All seasons

Global Mean Temperature

Mean Temperature-

Gainesville

58°F

72°F

Measured temperature record for past ~150 yrs

MedievalWarmth

Little Ice Age

Northern Hemisphere Temperatures for the past 1000 yrs

Time series, Alaska

Kilimanjaro, Africa

19791979

20002000

NASA Goddard Space Flight Center

Arctic Sea Ice- summer

http://www.youtube.com/watch?v=JMQ21p93JZc

• Whether the world is getting warmer isn’t controversial

Political debate focused on whether the world is getting warmer due to:

- natural causesor- man-made greenhouse gases (the greenhouse effect)

Centuries

Millennia

Millions of years

Zachos et al., 2001

ColderMore ice

So, why was this winter so

cold?•El Niño

Conditions in US during El Niño

winters

Vancouver

Vancouver

• Global warming = climate= global

• Cold winter in southeast US = weather= local

El Nino

La Nina

Strong evidence that the global mean surface temperature of earth is increasing

Related to El Niño conditions

http://data.giss.nasa.gov/gistemp/From Goddard Space Institute

Record of atmospheric CO2 from ice cores

Record of atmospheric CO2

from direct measurements

(Hawaii)

Greenhouse Gases

IPCC 2007

Ice core data

Ice Core CO2 RecordModern rate of increased compared to past

400 ky

Atmosphere

Earth’s Greenhouse

(S/4)(1-)

Earth

T4

Ts = 58°F

IncomingShort wave

energy

OutgoingLong wave

energy

Global Carbon Cycle

NASA- earthobservatory (~1990)

+3/yr

+0.5/yr

+1.5/yr

Reforestation

Deforestation

40,000,000

826

7

CO2 by Country

Per capita2002

Fate of Anthropogenic CO2

Kump, Kasting and Crane

Consume all fossil fuels (2300) 2100 ppmV CO2

(CCD)

Temperature- Greenhouse Gas Correlation

NOAA/NCDC

Correlation between temperature and CO2 concentration

Anthropogenic Greenhouse Gases

IPCC 2007

Gases

Processes

Climate System

Atmosphere

Geosphere- land

Cryosphere-ice

Hydrosphere-ocean

Biosphere- vegetation