2004 was the fourth warmest year since recordings began in the XNUMXth century. James Hansen, of NASA's Goddard Institute for Space Studies, and his colleagues compiled data from ground weather stations and satellite measurements of ocean surface temperatures.
With 0,48 degrees Celsius higher than the 1951-1980 period, the overall average temperature of 2004 is just behind those of 1998, 2002 and 2003, confirming a softening trend observed over the last thirty years. For researchers, this increase
does not only originate from natural causes such as the El Nino climatic phenomenon or volcanic eruptions, likely to disrupt the climate for a few years (in
Generally, year-to-year fluctuations are larger than long-term variation, but this does not detract from the latter's value). The trend would come in part not
negligible human activities (including the burning of fossil fuels, which generates greenhouse gases).
Of course, fluctuations exist at the regional level. In Alaska and the regions of Europe and the Caspian Sea, annual average temperatures were particularly high in 2004, unlike the United States. According to projections by James Hansen,
2005 could also break records. Calculations long established by his team and others indeed suggest that the Earth is currently absorbing much more solar energy than it reflects, although the consequences may be masked by natural fluctuations.
NYT 10 / 02 / 05 (2004 Was Fourth-Warmest Year Ever Recorded)