Climate of Columbus. Aaron Wilson. Byrd Polar & Climate Research Center State Climate Office of Ohio.

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1 Climate of Columbus Aaron Wilson Byrd Polar & Climate Research Center

2 Overview Historical Climatology Climate Change & Impacts Projected Changes Summary 2

3 Historical Climatology of Columbus 15th largest city in the US Greater Columbus home to over 2 million residents Topography is flat w/ravines Scioto & Olentangy NW of Downtown Hot and humid summers Mild winters - regular cold snaps Lake effects - increased cloudiness during the winter Subject to hot and cold extremes 3

4 Recent Climate Summary: Temperature and Precipitation Average Temperature Average Low Temperature Average High Temperature Historical Climatology of Columbus 53.1 F 43.6 F 62.6 F Days/Year that exceed 90 F 13.6 Days/Year that fall below 32 F 99.6 Lowest Average Temperature Highest Average Temperature 50.8 F 56.4 F Average Precipitation Total (in) 39.3 Lowest Annual Precipitation Total (in) 26.8 Highest Annual Precipitation Total (in) 53.2 Days/Year that exceed 1.25 of Precipitation 5.0 4

5 Historical Climatology of Columbus Average monthly temperatures during the period. Shaded bands represent the standard deviation in the 30-year monthly average. Average monthly total precipitation for the period. The shaded band represents the 25th to 75th percentile. 5

6 Climate Change & Impacts in Columbus Historical reference: Changes in Average Temperature Annual 2.3 Winter (Dec-Feb) 2.3 Spring (Mar-May) 3.1 Summer (Jun-Aug) 2.1 Fall (Sep-Nov) 1.8 Fell from warm periods (Dust Bowl of the 1930s) Rising steadily since the 1950s Faster than national and global rates Spring has warmed the fastest Winter temperatures have been highly variable 6

7 ( ) Climate Change & Impacts in Columbus Of 60 major US cities studied, Columbus had the 8 th most intense Urban Heat Island (4.4 F) and fastest growing (0.84 decade -1 ) 7

8 Climate Change & Impacts in Columbus Riverlea Waterman Farms Uptown District German Village 8

9 Climate Change & Impacts in Columbus Overnight low temperatures warmed four times as fast as mid-day high temperatures from 1951 through 2012 Departures from the average high and low temperatures. The red and blue lines are the 9-year moving averages. The shaded bands represent the standard deviations. Changes in Average Highs and Low Temperatures High Lows 0.9 F 3.6 F This may mean that temperatures have been cooling less overnight than they have warmed during mid-day 9

10 Number of days per year that exceed 90 F has declined slightly, even as average temperatures have warmed Climate Change & Impacts in Columbus Local factors and large-scale changes in land-use near the observing site can play a role Number of days falling below 32 F per year dropped by 25.9 between the and periods 10

11 Climate Change & Impacts in Columbus The freeze-free season 25.5 days longer ( ). March heat waves, followed by early budding of vegetation ( false spring ), followed by severe cold waves in April (years 2002, 2007, 2012). 11

12 Latitudinal shifts in agro-climatic zones Introduction of new agricultural pests, pathogens, fungi, and weeds 12

13 Changes in Total Precipitation inches % Annual Winter (Dec-Feb) Spring (Mar-May) Summer (Jun-Aug) Fall (Sep-Nov) Historical reference: Climate Change & Impacts in Columbus Annual precipitation totals rose 19.8% from All seasons have seen an increase in precipitation Fall seeing the greatest change both in actual volume and percentage change compared to the average 13

14 Climate Change & Impacts in Columbus Nuisance flooding and minor infrastructure impacts in some areas Columbus now sees approximately 5 such days per year, 2.8 more per year (increase of 78%), on average, than in the past 130% 14

15 Courtesy of Jeff Rogers Climate Change & Impacts in Columbus Extremes: Drought and Flooding May Both Increase Evaporation from Earth increases Soils dry up more readily leading to long dry spells. Everywhere! Drought more common. Planet Warms Up Does the humidity get lifted by fronts, weather systems??? Atmospheric Humidity is higher Yes! Beneficiaries get more rain returned to Earth, heavier rains, flooding (their soils may still dry out afterwards) No! Prolonged periods of drought due to lack of weather systems in some seasons 15

16 Climate Change & Impacts in Columbus Defined by the National Climate Assessment as an event in the top 1% of daily precipitation totals Disruptive and can cause infrastructure damage The number of daily precipitation totals for the and periods that exceeded the size of the heaviest 1% of storms as defined by the period. Columbus has seen a 31.7% increase in the number of these events 16

17 Climate Change & Impacts in Columbus Rainfall that closed I-70 east of Dayton equivalent to 1,000- year flood, ODOT says 21 May

18 Lake Erie s Toxic Algae Problem Toldeo Blade August

19 Lake Erie Algal Bloom Forecasts May 9 th Projection July 9 th Projection 19

20 Extreme Precipitation Strikes Ohio! 20

21 Projected Changes in Columbus, Ohio 21

22 Projected Changes in Columbus, Ohio 22

23 Summary of Observed Changes Byrd Polar & Climate Research Center Rising average temperatures: Annual average temperatures warmed by 2.3 F from , faster than national and global rates. Average low temperatures have warmed much faster than high temperatures. Longer freeze-free season: The length of the freeze-free season (growing season), increased 25.5 days from More precipitation: Total precipitation increased 19.8%, from 1951 through Fall precipitation increased dramatically, by 43.5% (3.2 inches). More heavy precipitation: From the period to the period, the amount of precipitation falling during the heaviest 1% of precipitation events increased by 36.2%. 23

24 Future Climate of Columbus Average Temperature: Continue to rise by 3-5 F through midcentury. More high temperature days: Expected to increase. Freeze-free season: Lengthen by an additional 1-2 months. Byrd Polar & Climate Research Center Total Precipitation: Most models project precipitation will increase overall, though the magnitude of projections vary widely. Many models project that summer precipitation will remain stable or decline. More Heavy Precipitation: Heavy precipitation events become more intense and more frequent as they have in the recent past. Changing winter precipitation: Less snow, more rain/freezing rain. 24

25 /ByrdPolar Aaron B. Wilson u.osu.edu/wilson