365 Days of Climate Awareness 142 – 2004 State of the World Climate

2004 World Climate Data

• Atmospheric CO₂ concentration: 376.95ppm, +1.80 ppm from 2003
• Surface air temperature anomaly: +0.58°C/1.04°F, 18^th all-time 1880-2021
• Precipitation 10.7 mm, ~1% above 1961-1990 global average
• Global mean sea level: 1.75 mm below 1993-2008 average, +1.96 mm from 2003
• ENSO: Neutral through June, weak El Niño from then till year’s end
• Antarctic ozone: annual minimum 138 Dobson units (DU)*, South Pole station

Global Conditions

• Above-average temperatures: South America; European Russia; China; southwest Asia; central Asia; Australia
• Below-average temperatures: Asian Russia
• Drought: southern and norther horn, and southern Africa; Central America; eastern Cuba; northeast, northwest and central east coast China; central Asia; India; eastern and southwestern Australia
• Extreme rain: southwest Asia; Colombia; Brazil; Algeria; equatorial horn of Africa

Larger version

* The Dobson unit (DU) is a measure of trace gases in the atmosphere. It is estimated from concentration measurements (satellite and in-situ). The DU represents the number of 10 um (micrometer, one millionth of a meter: one one-thousandth of a millimeter) pure layers in the atmosphere the observed amount of trace gas would form, at standard temperature and pressure (STP: 1 bar, 0°C/32°F). For example, a typical average value for ozone (O₃) is 300 DU, meaning, ozone, if isolated, ozone would form a pure layer of 3000 um (3 mm) at STP around much of the world. 2004’s South Pole station value of 138 DU (1.38 mm) is 46% of this average value. The Antarctic ozone hole is tracked year-round via measurements across the continent.

The weak late-year El Niño did not prevent an extremely active North Atlantic hurricane season. Meanwhile the South Atlantic experienced its first hurricane (named Catarina) which struck southern Brazil in March. North Pacific cyclone activity fell into two halves: below average in the northeast, above average in the northwest, with 10 cyclones impacting Japan. Australia and the South Pacific also had light hurricane seasons, while the Indian Ocean was average. Madagascar was badly damaged by category 5 supercyclone Gafilo.

Despite an overall warm year, South America experienced a very cold May. India’s monsoonal rainfall was 30% below average. Above-average rainfall in the Sahel and across western and northern Africa led to the worst desert locust outbreak since 1987-89. Due to warm temperatures in Afghanistan, snowpack was well below average there, leading to decreased snowmelt and dry conditions throughout the region.

Global Mean Sea Level (GMSL), 1900-2018, relative to 1900

Tomorrow: 2005 State of the Climate, North America and Europe.

Be brave, and be well.