365 Days of Climate Awareness 153 – 2010 State of the Climate, North America

2010 US Climate Data

• Global atmospheric CO2 concentration: 388.76 ppm, +2.26 ppm from 2009
• Average air temperature: 54.9°F, 27^th all-time 1895-2021
• Average precipitation: 28.92”, 31^st wettest (97^th driest) 1895-2021
• Tornadoes: 1282, 12 (1%) below the ten-year average 1270
• 19 named tropical cyclones: 12 hurricanes, 5 major (winds > 111 mph, 3-5 Saffir-Simpson)
• Atlantic ACE: 169 x 10⁴ kts²
• ENSO: Strong El Niño early in the year; La Niña by early summer through year’s end

North American Conditions

• Warmer than average: Canada (record at the time, +3.1°C/5.6°F above 1961-1990 mean); Alaska; northeastern US
• Cooler than average: southeastern US
• Drier than average: British Columbia; Alberta; Northwest Territories; Southeast US; upper Midwestern US; Hawaii
• Above-average precipitation: US east coast; Saskatchewan; Manitoba; Mexico
• Wildfires: US below average (1.4 million ha/3.5 million acres)

In 2001-2010 the United States spent $350B on natural disaster recovery (almost half of what was spent on education during the same period), with nearly half spent in 2005, the historically active year featuring hurricanes Katrina, Rita and Wilma. This number includes events from all seasons including thunderstorms, blizzards, extreme rainfall and flooding, droughts, wildfires and tornadoes. Economic losses such as crops are harder to quantify and might well be undercounted.

The 2009-10 winter was quite severe and cold throughout much of the eastern United States (though not Canada), with record precipitation (snow and later rain) in the Northeast. The large-scale backdrop to this was the early El Niño followed by a late-year La Niña, at the same time that the North Atlantic Oscillation (NAO) was historically negative, meaning high air pressures at high latitudes (Iceland) and low pressure at low latitudes (the Azores). The negative phase—and this was a historically low negative phase—tends to bring cold temperatures to the eastern United States and Europe. The combination of negative NAO and El Niño produced the extreme cold and wetness in that region. The subsequent La Niña event greatly moderated both temperature and precipitation.

Western Canadian farmers experienced a year of intense contrasts, lurching from extreme drought early in the year to spring and summer flooding. Despite the season’s unevenness they were able to recover 70% of the region’s average crop yield, though 40 different towns declared themselves agricultural disaster zones. The 2010 Winter Olympics in Vancouver occurred during a warm, snowless winter (part of Canada’s consistently warm year). Snow was manufactured for outdoor venues such as snowboarding.

2010 US Percentage Area Very Warm vs Very Cold (top 10th percentile for each)

2010 US Percentage Area Very Wet vs Very Dry (top 10th percentile for each)

Tomorrow: 2010 State of the World Climate.

Be brave, and be well.