365 Days of Climate Awareness 135 – 2001 State of the World Climate

2001 Global Climate Data

• Atmospheric CO₂ conc.: 370.57 ppm, +1.61 ppm from 2000
• Surface (air & ocean) temp. anomaly: +0.51°C (0.92°F) over 1880-2000 ave
• Overland precipitation: -1.9% from 1961-1999 average
• ENSO: from La Niña to neutral

Departures (>10% difference) from 1961-1990 Average

• Warmth: southern Australia; New Zealand
• Cold: Siberia, eastern Russia, Mongolia—winter;
• Dryness: Brazil (austral summer); southern Africa; African horn; Cambodia; Vietnam; Iran; Pakistan; Afghanistan; Tajikistan; Uzbekistan; Turkmenistan; southern Australia; southwest Pacific
• Precipitation: South American Pampas (Uruguay, parts of Argentina and Brazil); northern
• Australia
  
  
  
  

At the time, 2001 ranked second behind 1998 as the second-warmest for global surface air temperature (from 1880 forwards). Now it ranks 20^th (1998 is tied for 17^th). As a look forward—every year from the 1998-2013 period, falsely labeled a global warming “pause” by deniers–appears in the top 20 all-time. Warmer overland temperatures occurred largely in the tropics and northern hemisphere, where positive anomalies were greater than in the southern extratropics (>23.5° S).

 

World climate events, 2001.  Larger version

Northern hemisphere snow cover was below average for the fifth consecutive year, despite extreme cold in northern and eastern Asia and extremely heavy snowfalls in Mongolia and northern China. Snow cover, like sea ice, precipitation, drought and other climate indicators, is highly variable from year to year, having many influencing factors. Snowmelt in areas such as Alaska’s north slope (between the Brooks range and the Arctic Ocean) is occurring earlier by the year.

Radiative forcing—the heating contribution per year in watts per meter squared (W/m²/year) of each individual greenhouse gas, increased 0.026 W/m² in 2001, almost entirely due to carbon dioxide. From the end of the last glaciation to the beginning of the industrial age (1750), radiative forcing has increased by roughly 2.8 W/m², of which CO₂ is responsible for about half. (2021’s CO₂ concentration of 370.57 ppm is roughly one-third higher than the interglacial average.) Though the Antarctic ozone hole continues to exist and affect temperatures in the stratosphere, it is not growing at the rate that it did before. Both that and the decline of CFCs in the radiative forcing budget are the result of successful regulation.

Tomorrow: 2002 state of the climate, North America.

Be brave, and be well.

Columbia University Annual Temperature Anomaly Rankings

Columbia University Global Temperature Monitoring Page

American Meteorological Society (AMS) Climate Assessment Report page