365 Days of Climate Awareness 129 – 1998 State of the World Climate

1998 Global climate data

Atmospheric CO₂ concentration: 365.70 ppm, +2.65 over 1997

Mean temperature anomaly: 1.17°F above 20^th c. mean (11^th warmest year 1900-2021)

1998 began with a very strong El Niño and ended with a very strong La Niña, and both phases were joined by global temperature trends. The warm, El Niño phase of the year brought elevated temperatures globally. Record high temperatures at the time were set in both hemispheres. Further, both north and south tropics experienced record high temperatures, as well as the northern extratropics (>23.5° N latitude). Late in the year, with the Pacific Ocean in its cold La Niña phase, dry, cold air dominated the eastern Pacific, and global monsoons and the North Atlantic hurricane season picked up.

Northern hemisphere snow cover was the lowest in every single month except October for the period of 1972-1998 (due to varying length and spatial coverage of datasets, different measurable like temperature, CO₂, precipitation and snow cover among others, seldom have similar baselines. Uneven, at times highly uneven, coverage is one of the limitations of global climate science).

Mexico experienced a severe drought during the El Niño event. Likewise northern South America, except for coastal Ecuador Peru, was drier than normal at this time, and southern South America somewhat wetter. In late October and early November Hurricane Mitch, today considered the 7^th most powerful hurricane in history, formed in the Caribbean and devastated Honduras and Nicaragua, causing more than 11,000 deaths and, according to the president of Honduras, setting the country back economically 50 years.

India’s monsoon season went from average in the first (El Niño) part of the year to substantially wetter in the second (La Niña) half, though catastrophic rains killed thousands in Nepal and Bangladesh. The August rains also caused flooding in the Yangtze (one of the many rivers which drains the Himalaya, along with the Indus, Ganges, Brahmaputra, and Yellow).

Northern Africa’s weather is more closely related to the equatorial region known as the Intertropical Convergence Zone, the region between the northern and southern Hadley Cells (discussed in posts 36 and 125). A dry early phase of the year was followed by severe floods in Mali and Niger. South African weather is closely correlated to ENSO, and the same pattern held of a dry early and wet late year.

Tomorrow: 1999 State of the Climate, North America and Europe.

Be brave, and be well.