A Snapshot of Our Changing Climatology

Size: px

Start display at page:

Download "A Snapshot of Our Changing Climatology"

Blaze Potter
5 years ago
Views:

1 A Snapshot of Our Changing Climatology Dr. Kenneth ( Kenny ) Blumenfeld Sr. Climatologist DNR State Climatology Office 11/17/2018 1

2 Items to bear in mind 1. Climate news elsewhere may not apply here 2. Observations & Projections are different 3. We can (and do have) Variability and Trends simultaneously they do not disprove each other! 4. Not all hazards are changing but they re still hazardous! 5. Seek more info and refresh frequently! 11/17/2018 2

3 Minnesota s pronounced OBSERVED trends 1. Minnesota is becoming wetter and warmer Major shift observed, projected to continue 2. Lowest temperatures are increasing fastest Rapid loss in cold extremes, projected to continue 3. Extreme rainfall increasing More and larger big events, projected to continue

4 These important hazards affect us but are not worsening YET 1. Hot days, warm nights, heat waves not yet increasing But PROJECTIONS indicate future increases likely 2. Drought Future increases possible 3. Tornadoes, severe convective storms Future unclear; scientific uncertainty

5 Confidence that climate change has already impacted Minnesota s weather and climate hazards Confidence Attribute Impacts Highest Low Winter, extreme cold Becoming less severe Rainfall extremes Larger, more frequent Severe convective storms Data quality issues Heat No increases or worsening Indirect (expanded species ranges) Direct (floods, damage, life/safety) Direct (Structural damage, power outages) Direct (heat sickness, power failure) Lowest Drought No increases or worsening Indirect (water shortages, crop failure)

6 Confidence that climate change will impact Minnesota s weather hazards by mid-century Confidence Attribute Expectations by mid-century Highest Winter, extreme cold Continued rapid decline Extreme rainfall Unprecedented events expected High Heat Increases in severity, coverage, and duration Moderately High Moderately Low Drought Severe convective storms Increases in severity, coverage, and duration possible More super events possible, even if frequency decreases

7 MN Getting Warmer and Wetter 11/17/2018 7

8 Annual Precipitation (in.) Minnesota Average Temperature and Precipitation Annual Temperature (F)

9 Annual Precipitation (in.) Minnesota Average Temperature and Precipitation Annual Temperature (F)

10 (Precip. Inches) Precipitation, Cottonwood River Watershed yr avg (thru Jun), watershed 5-yr avg (thru Jun), watershed Jul-Jun precip, watershed /17/

11 (Precip. Inches) Precipitation, Cottonwood River Watershed Jul-Jun precip, watershed /17/

12 (Precip. Inches) Precipitation, Cottonwood River Watershed Jul-Jun precip, watershed Lambtn, Jul-Jun, /17/

13 (Precip. Inches) Precipitation, Cottonwood River Watershed Jul-Jun precip, watershed Lambtn, Jul-Jun, Lambtn, Jul-Jun, /17/

14 (Precip. Inches) A new precipitation regime? Precipitation, Cottonwood River Watershed Lambtn, Jul-Jun, Lambtn, Jul-Jun, mean precip diff = inches annually Precip diff per square mile =8.08 million ft 3 p (60 mil gallons) per year 11/17/

15 2010s wettest decade on record (almost certainly) 11/17/

16 How We re Getting Wetter and Warmer Increases in frequency of heavy rainfall and magnitude of heaviest rainfall Winter warming + loss of cold extremes This warming sets us up for eventual extreme heat increases 11/17/

17 More 1 rains, and more rainfall produced by them inch rainfalls by year /17/

18 and 3 rains increasing 80 2-inch rainfalls by year 35 3-inch Rainfalls by Year /17/

19 Even 4 rains increasing 18 4-in rainfalls by year /17/

20 Max Rainfall size (inches) Heaviest rain in state larger and more variable station max rainfall by year /17/

21 Projections: Continued increase in upper 2 percentile rainfall Source: 2014 National Climate Assessment, Midwest Chapter

22 Winter warming 13x faster than summer Season Winter (Dec - Feb) Summer (Jun - Aug) Temperature Metric Avg. change per decade since 1895 Avg. change per decade since 1970 Seasonal Avg F F Seasonal Avg F F

1896 1906 1916 1926 1936 1946 1956 1966 1976 1986 1996 2006 2016 Temperature (F) 16 Minnesota Average Winter Minimum

23 Temperature (F) 16 Minnesota Average Winter Minimum Temperatures Season Beginning Avg Min Temp 7-yr moving avg Trend: F/decade

24 # Days between spring and fall freezes Days entirely above freezing increasing dramatically Annual above-freezing days 160 Freeze-Free Characteristics at Milan, MN s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s Average number of above freezing days per year (right axis) Days between last freeze of spring and first freeze of fall (left axis) /17/

25 Degrees F Highest Highs of Winter, Milan (MN), Additional warm winter days a MINOR contributor to recent winter warming warmest of winter 10-yr avg (warmest) Avg of 15 warmest 10-yr avg (15 warmest) Year

26 Degrees F Lowest Lows of Winter, Milan (MN), Loss of cold extremes is a MAJOR contributor to winter warming Avg of 15 coldest 10-yr avg (15 coldest) Coldest of winter 10-yr avg (coldest)

27 Count Dramatic Loss of Cold Extremes Across MN Count of Minimum Temps -35F or Lower, by Decade Grand Rapids Forest Research Station 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s* * Prorated

28 Daily Average T Degrees Below 10F Length and Magnitude of 10 F Temperature Season, Duluth MN

29 Daily Average T Degrees Below 10F Length and Magnitude of 10 F Temperature Season, Duluth MN

30 Daily Average T Degrees Below 10F Length and Magnitude of 10 F Temperature Season, Duluth MN Where did the 10-degree season go???

Daily Average T Degrees Below 10F Length and Magnitude of 10 F Temperature Season, Duluth MN 6 5 4 3

31 Daily Average T Degrees Below 10F Length and Magnitude of 10 F Temperature Season, Duluth MN Because Hiding There below it doesn t it zero is! exist anymore

32 Temperature (F) 84 Minnesota Average Summer Maximum Temperatures Avg Max Temp Year 7-yr moving avg

33 Degrees F Extreme heat not increasing--yet Highest Highs of Summer Milan (MN), Hottest of summer 10-yr avg (hottest) Avg of 15 hottest 10-yr avg (15 hottest) Year

34 Extreme heat not increasing--yet 6 Average # 90-degree days per year, Duluth

35 However, additional days above 95 F projected by mid-century Source: 2014 National Climate Assessment, Midwest Chapter

36 In Summary 1. Minnesota has gotten much wetter and warmer, and is projected to continue doing so. 2. Increased wetness has been driven in part by more frequent and larger heavy rains, with further increases expected. 3. The coldest conditions have eroded the fastest. 4. Hot weather has not worsened, but erosion of winter cold will set us up for hotter summers in years/decades ahead Remember, we don t know exactly when this will begin (2040?)

37 Thank You! Kenny Blumenfeld /17/

Image courtesy of NASA/GSFC

Image courtesy of NASA/GSFC Impact of Weather Extremes and Climate Change on Midwest Agriculture Eugene S. Takle Professor Department of Agronomy Department of Geological and Atmospheric Science Director,