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April 1 Arlington Cafe Scientique - Changing Climate and Trends in Extreme Events

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Cafe sci

  1. 1. The Relationship Between Weather & Climate Dr. Emily Jones Becker Climate Prediction Center/NCEP/NWS/NOAA and Innovim April 1, 2014
  2. 2. Weather & Climate Thomas Cole - The Oxbow
  3. 3. 3 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
  4. 4. Climate: Long-term average Timescales: 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.” 4
  5. 5. What is the difference between a weather forecast and a climate forecast? 5 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 
  6. 6. Climate Change Maldives underwater cabinet meeting, 2009
  7. 7. Climate change Climate change is the long-term shift in the average. 7 • 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!
  8. 8. Is there global warming? 8 Sources: 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.
  9. 9. 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) 9 THE ENHANCED GREENHOUSE EFFECT Human activities have increased greenhouse gases, hence have artificially increased Earth’s temperature by another 1.4oF
  10. 10. Mark Stevenson –
  11. 11. How do we know human activities are the primary cause of the current warming? 11 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
  12. 12. Has global warming stopped?
  13. 13. Has global warming stopped?
  14. 14. 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. 14 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 1913 2005
  15. 15. Global Climate Change – Arctic sea ice 15
  16. 16. Global Climate Change – sea-level rise last house on Holland Island – image via baldeaglebluff/flickr
  17. 17. Global Climate Change – hardiness zones
  18. 18. Global climate change - fisheries 60% of major fisheries have shifted north Nye et al. 2009. MEPS 393: 111-139
  19. 19. 19 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.
  20. 20. 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
  21. 21. Extreme Weather and Climate Events
  22. 22. Billion Dollar Weather and Climate Disasters 22 • 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 Disasters 1980 – August 2011 NOAA/NESDIS/NCDC NOAA/NCDC
  23. 23. 23 Temperature Extremes
  24. 24. Temperature Extremes Different types of extremes: ― Daytime max temperature ― Nighttime min temperature ― Average temp. for the month ― Average temp. for the season ― Heat waves 24 Maps from NOAA NCDC
  25. 25. 25 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
  26. 26. Temperature Extremes – future projections 26 Extreme 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.
  27. 27. Hydrological Extremes 27
  28. 28. Precipitation Extremes – observed trends 28 Observed Trends in 1-day Very Heavy Precipitation (1958 to 2010) NOAA/NCDC NOAA/NCDC
  29. 29. 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 29 UMCES IAN (
  30. 30. Drought Droughts have increased in area and intensity over the last century over much of the world 30 IPCC
  31. 31. 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 31
  32. 32. Storms 32
  33. 33. 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 33 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.
  34. 34. 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) 34
  35. 35. 35 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)
  36. 36. Current weather and climate events
  37. 37. What the heck is going on with this winter??!? Globally, 4th warmest January since records began in 1880 Locally, the 12th coldest January!
  38. 38. 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
  39. 39. Ellen O via Flickr and Capital Weather Gang