CLIMATE is what you expect

WEATHER is what you get,

weather is the exact state of the atmosphere at a specific time and place

weather elements: air temperature, air pressure, humidity, clouds, precipitation, visibility, wind

Infrared Satellite Image from 9 am

Climate is simply the statistics of weather: at right are 3 ways to view

Sea-Tac’s observed daily temperatures from

the past year

“Snow Water” as of January 4, 2011

http://www.wrcc.dri.edu/snotelanom/basinswe.html

Climate

The statistics of weather at a particular place for a specified window of time

• examples:– monthly averaged temperature and precipitation– average number of cloudy days per month– frequency of snow days (number per year)

weather and climate in our lives

• Weather dictates our activities, the clothes we wear, etc.

• Climate dictates the clothes we buy or what we pack for a vacation, and it dictates the infrastructure we build (hydropower dams, reservoirs for water supplies etc.)

Climate may vary over long time periods

Last glacialmaximum18,000 years ago

Climate Variability

Climate varies from season-to-season, year-to-year, decade-to-decade …

April-September

October-March

Climate Variations and this class

• This class focuses on the “unexpected” part of climate: climate variations in timeclimate variations in time– Natural climate variabilityNatural climate variability– Human caused (anthropogenic) climate Human caused (anthropogenic) climate

changechange

Issues Defining Decision Support Issues Defining Decision Support Needs in the Pacific NorthwestNeeds in the Pacific Northwest

• Water suppliesWater supplies– Heavy reliance on winter snowpack

– Limited reservoir storage capacity

– Multiple conflicting demands during summer low-flow season

– Vulnerability to droughts (region-wide) and winter flooding (west of the Cascades)

• Endangered speciesEndangered species– Important economically and culturally (tribal rights)

– Listed species in coastal, rural, and urban areas

– Fish compete with hydropower, irrigation, and M&I water needs

– Protection requires reshaping water, land management choices

Issues Defining Decision Support Issues Defining Decision Support Needs in the PNW (cont’d)Needs in the PNW (cont’d)

• ForestsForests– Important (but declining) part of PNW economy– Interior forests vulnerable to wild fire– High existence and ecosystem service values

• Coasts and EstuariesCoasts and Estuaries– Development pressures on coastal wetlands and

shorelines– Water pollution impacts on local estuaries (impacts on

endangered species and shellfish industry)

• PopulationPopulation – Rapid population growth (recent and forecasted) in

western WA and OR– Development pressures on sensitive areas

Equatorial Pacific SeaEquatorial Pacific SeaSurfaceTemperatureSurfaceTemperature

FF El NinoEl Nino

FF NormalNormal

FF La NinaLa Nina

Dec 97

Dec 90

Dec 88FF NOAA/PMELNOAA/PMEL

El Niño has big El Niño has big impacts!impacts!

But they are not the But they are not the same everywhere, or same everywhere, or

in every El Niño in every El Niño eventevent

From the Sacramento BeeAugust 1997

Sacramento Bee, August 1997

Californian’s were touched by El Niño in 1982-1983

• What will climate be like in the future?

• What might climate change mean for the Earth and its inhabitants?

What about the future?

Pop-culture perspectives

Perhaps this is a good read, but it is not good science

Likewise, the Day After Tomorrow scenario might

make for a fun movie, but it presents an extremely

unlikely impact of global warming at a ridiculous rate

of change