365 Days of Climate Awareness 152 – 2009 State of the World Climate

2009 World Climate Data

• Global atmospheric CO₂ concentration: 386.5ppm, +1.48 ppm from 2008
• Surface air temperature anomaly: +0.44°C/1.15°F, 12^th all-time 1880-2021
• Precipitation 3.5 mm (0.3%) above 1961-1990 global average
• Global mean sea level 12.56  mm above 1993-2008 average, +5.21 mm from 2008
• Antarctic ozone hole: max. area 24.4 million km²; minimum O₃ 97 DU (Dobson Units)
• ENSO: Neutral through May; moderate El Niño through year’s end

Global Conditions

• Above-average temperatures: Central Europe; Scandinavia; Iberian peninsula; southern Europe; eastern Europe; Middle East; western Russia; northeastern China; India; Pakistan; Australia; southern South America; Africa
• Below-average temperatures: Siberia
• Above-average precipitation: Northern central Europe; the Balkans; southern Italy; Japan; southern South America
• Below-average precipitation: Middle East; China; India; Pakistan; Australia; Venezuela; western & eastern Africa

Larger Version

The decade from 2000-2009 was then the warmest on record, and now ranks second relative to the 20^th century average:

1. 2010-19: +0.82°C/1.48° F
2. 2000-09: +0.54°C/0.96° F
3. 1990-99: +0.36°C/0.65° F

In March—late winter--Arctic sea ice was 15.2 million km², very close to 2008 and 4% below the 1979-2000 average. In August—late summer, the annual minimum—Arctic sea ice extent was 5.1 million km2, third least since 1979 behind 2007 (4.1 million km²) and 2008 (4.5 million). Measurements of the cryosphere—annual ice and snow extents—are one of the many areas opened to research and interpretation because of satellite observations, like sea surface temperature, elevation, chlorophyll content and global albedo, among many other parameters. These include the age (based on albedo) and thickness (based on altitude of the ice surface). From 2000-2009 the Arctic has lost 1.5 million km² of multiyear ice, indicating progressive losses where continuous ice cover had once existed. Older ice also tends to be thicker ice, and satellites show sea ice thinning of roughly 0.6 m across the Arctic basin from 2004-2008.

Though the ozone hole over Antarctica persists, globally, O₃ measurements have been slowly trending toward pre-1980 levels, reflecting the vast global reduction in ozone-destroying chemicals. Meanwhile, global trends in salinity continued, with less-salty areas (especially the western Pacific) continuing to become fresher, and saltier areas (such as the Red Sea) becoming still more salty, reflecting an increasingly active global water cycle. The developing El Niño also had an effect on global sea level measurements. Increased sea surface temperatures increase sea level due to thermal expansion of the water. 2009 being a largely El Niño year saw a large jump in measured sea level. La Niña has the opposite effect. ENSO is therefore one of the main factors contributing to the noisiness of global mean sea level (GMSL).

Tomorrow: 2010 State of the Climate, North America.

Be brave, and be well.