365 Days of Climate Awareness 155 – 2011 State of the Climate, North America

2011 US Climate Data

• Global atmospheric CO2 concentration: 390.63 ppm, +1.87 ppm from 2010
• Average air temperature: 54.8°F, 28^th all-time 1895-2021
• Average precipitation: 27.84”, 57^th wettest (61^st driest) 1895-2021
• Tornadoes: 1625, 355 (28%) above the ten-year average 1270
• 19 named tropical cyclones: 7 hurricanes, 3 major (winds > 111 mph, 3-5 Saffir-Simpson)
• Atlantic ACE: 136.22 x 10⁴ kts²
• ENSO: Strong La Niña early in the year; neutral through boreal summer; strong La Niña through the end of the year (boreal summer neutral is common to La Niña phases)

Larger Version

North American Conditions

• Warmer than average: Canada (esp. winter); northeastern & southern US (record-setting); Midwestern & southeastern US; Mexico
• Cooler than average: Washington; Oregon
• Drier than average: Canada; southern US; Mexico
• Above-average precipitation: Northeastern US (record-setting); upper Midwestern US;
• Wildfires: Record area (956,000 ha/2.4 million acres) in Mexico; 3.5 million ha/8.6 million acres in the US

2011 was an historically destructive tornado season in the US, totaling more than $28B in damages and 511 deaths. Central Canada experienced record flooding, following an extraordinarily cold winter which deepened the frost and prevented meltwater from soaking into the ground in spring. Heavy springtime rains worsened the problem. In some areas of Manitoba flooding lasted more than 120 days. At the same time, La Niña led to dry conditions across the entire southern US (particularly in summer, as air temperature effects tend to lag the ENSO cycle by several months).

2011 US Area Percentage Very Warm vs Very Cold (10th percentile)

2011 US Area Percentage Very Wet vs Very Dry (10th percentile)

The Arctic Ocean has seen a large (~20% as of 2011, and more by now) increase in primary production—i.e. phytoplankton activity—since the late 80’s. This is measured by satellite through changes in color of the ocean water. The increasing efficiency of global heat distribution from equator to poles has led to a consistent year-round drop in Arctic sea ice, including annual maxima (February) and minima (August). More open water absorbs more solar heat, increasing water temperatures and increasingly stratifying the ocean, making it more suitable for phytoplankton and other species. This is part of the thorough ecosystem change happening throughout the Arctic.

Northern Hemisphere February Sea Ice Extent, 1979-2021

Tomorrow: 2011 State of the World Climate.

Be brave—these times require it—and be well. The people who love you want that for you.