Cafe sci

The Relationship BetweenWeather & Climate

Dr. Emily Jones BeckerClimate Prediction Center/NCEP/NWS/NOAA and Innovim

April 1, 2014

Weather & Climate

Thomas Cole - The Oxbow

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Weather: current conditions• Timescale: minutes – hours – days; changes quickly• Storms, including hurricanes, are weather• Weather forecasts are specific• Can vary wildly and

still be “normal”• “It’s very cold

today”• “It’s going to rain

tomorrow”• “A hurricane is

forecast to come ashore this weekend”

Edward Hopper – Ground Swell

Climate: Long-term averageTimescales: Months – years – decades etc.• “It’s too hot here, I’m moving to Antarctica.”• “This area gets a lot of rain during the summer.”• “Last winter was so warm.”

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What is the difference between a weather forecast and a climate forecast?

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Weather Forecasts:

•Event, location and time specific

•How warm, how much rainfall, probability of rain

•Maximum of ten days into future

Climate Forecasts:

•“Average of weather” for a week, month, season, …

•Likelihood of warmer/cooler wetter/drier than average

•Month, season, year, multi-year, decade

www.cpc.noaa.gov

Climate Change

Maldives underwater cabinet meeting, 2009

Climate changeClimate change is the long-term shift in the average.

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• Can take place over millions of years, or decades

• Caused by changes in incoming solar radiation, volcanoes, plate tectonics, ocean circulation, human activities

• Earth’s climate is always changing!

Is there global warming?

8Sources: NOAA, NASA

•Global surface temps have increased ~ 1.5°F since the late-19th century.

•The trend is +0.23°F per decade for the past 50 years.

•The warming has not been uniform. Some areas have cooled slightly.

•The recent warmth has been greatest over high latitudes.

What is the Greenhouse Effect?How is it related to Climate Change?

THE NATURAL GREENHOUSE EFFECT

Heat absorption by carbon dioxide, water vapor and other trace gases in the atmosphere warms the earth to ~55°F (like a greenhouse)

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THE ENHANCED GREENHOUSE EFFECT

Human activities have increased greenhouse gases, hence have artificially increased Earth’s temperature by another 1.4oF

Mark Stevenson – fineartamerica.com

How do we know human activities are the primary cause of the current warming?

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Both natural and human factors can lead to climate change. Even if people burn no fossil fuels, we would still see changes in Earth’s climate due to natural forces (e.g. solar cycles, volcanoes).

The observed warming over the last half-century is primarily due to human factors. IPCC 2007

Has global warming stopped?

Has global warming stopped?

Effects of Global Climate Change

• Rapid change in glaciers, ice sheets, and sea level

• Changes to the water cycle, including droughts; desertification

• Rapid release of methane • Marine and land animal species are

moving north• Northern Hemisphere Spring snow

cover has decreased by about 10% since 1966.

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Climate Change that occurs quickly (a few decades or less) and persists for decades to millennia poses a major challenge to humans, animals, and plants

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2005

Global Climate Change – Arctic sea ice

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Global Climate Change – sea-level rise

last house on Holland Island – image via baldeaglebluff/flickr

Global Climate Change – hardiness zones

Global climate change - fisheries60% of major fisheries have shifted north

Nye et al. 2009. MEPS 393: 111-139

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Increased atmospheric carbon: ocean acidification

Atmospheric carbon dioxide dissolves in ocean water and creates carbonic acid. Shells and skeletons of corals and oysters can dissolve.

Acidification has been detected in the Chesapeake, due to atmospheric CO2 and from other sources; the Chesapeake is a very complex system.

How can we predict climate if we can’t predict the weather?

The same way we can predict the tide, but not the individual waves

Extreme Weather and Climate Events

Billion Dollar Weather and Climate Disasters

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• Since 1980, the U.S. has seen a total of 151 weather-related disasters each totaling over $1 billion dollars in damage.

• Total standardized losses since 1980 of billion-dollar disasters exceeds $800 billion.

• The nation is becoming more vulnerable to extreme events.

Number of Billion Dollar Weather/Climate Disasters1980 – August 2011NOAA/NESDIS/NCDC

NOAA/NCDC

23Temperature Extremes

Temperature Extremes

Different types of extremes:― Daytime max

temperature― Nighttime min

temperature― Average temp. for the

month― Average temp. for the

season― Heat waves

24Maps from NOAA NCDC

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Temperature Extremes – observed changes

In the United States, record high temperatures are now occurring more than

twice as often as record lows

• Daily minimum temperatures are warmer

• More unusually warm days and nights in recent decades.

• Increasing number of heat waves, but 1930s still most severe

Temperature Extremes – future projections

26Extreme Weather and Climate Events in a Changing Climate

• More frequent warm days and nights, and heat waves

• Much less frequent cold days and cold nights

• Decrease in days with frost

• Hot days currently experienced once every 20 years would occur every other year or more by the end of the century.

Hydrological Extremes 27

Precipitation Extremes – observed trends

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Observed Trends in 1-dayVery Heavy Precipitation

(1958 to 2010)

NOAA/NCDC

NOAA/NCDC

Extreme precip. and flooding

• Flooding can result from rapid snowmelt, heavy thunderstorm rain, tropical storm remnants

• Low-lying Eastern Shore can flood from just a full- moon high tide

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UMCES IAN (ian.umces.edu)

Drought

Droughts have increased in area and intensity over the last century over much of the world

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IPCC

Hydrological Extremes – future projections

• An increase in precipitation intensity is expected

• Heaviest precipitation is projected to increase strongly.

• Lightest precipitation is projected to decrease.

• Drought is forecast to increase, but many questions remain

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Storms

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But their names make them sound so friendly…

Atlantic Hurricanes in the last decade

Local effects:• Isabel (2003): 6-8’ storm surge• Ivan (2004): 32 tornadoes in MD-VA area• Ernesto (2006): 5-10” rain, ~4’ storm surge• Nicole (2010): 7” rain• Irene (2011): millions without power for days• Lee (2011): intense rainfall and flooding• Sandy (2012), East Coast: 285 deaths,

widespread & prolonged power outages, coastal destruction

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We haven’t detected a long-term trend in the number of hurricanes. It’s likely we’ll see an increase in intensity of hurricanes.

Tornadoes • Record month – April

2011: 751 confirmed tornadoes in US

• However, there’s no detectable long-term trend in tornadoes

• Maryland has 3rd-highest concentration of tornadoes in US (number per 10,000 sq miles per year)

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Should we really attribute every extreme event(heat wave, flood, hurricane) to climate change?

No individual weather event can be attributed to climate change.

• Changes in the number and intensity of some events (e.g. more intense rainfall; warmer winter nights) have strong links to climate change.

• Changes in observing systems (e.g. introduction of satellites) have complicated attempts to document trends (e.g. hurricanes over the Atlantic).

• Damage resulting from extremes can be exacerbated by climate change (e.g. sea-level rise and coastal flooding)

Current weather and climate events

What the heck is going on with this winter??!?

Globally, 4th warmest January since records began in 1880

Locally, the 12th coldest January!

California drought

oThis may be the driest year in 500 years (from tree-ring data)

o 90% of US tomatoes, 95% of broccoli, 99% of almonds and walnuts are grown in CA

o20th Century overall was wettest in last 500 years

U.S. Drought Monitor

Ellen O via Flickr and Capital Weather Gang