The tendency to a warmer Earth continues

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  • NASA and NOAA: Relative to a common 1951-80 base period. Credit: NOAA/NASA

    Ongoing trend: No significant change from 1998. Credit: NASA GISS

  • The tendency to a warmer Earth continues
    21.02.2015 15:13

     

    In January, the main meteorological agencies that compile the dataset about global surface temperatures released the results for 2014. Due to the fact that early indications suggested that 2014 could be one of the warmest years on record, the issue had much more press attention than previous year. Let’s try to summarise the main conclusions.

    The first agency to release its dataset was the Japanese Meteorological Agency. They showed that 2014 was the warmest year since 1891 with a mean temperature +0.27ºC above the 1981-2010 average (+0.63°C above the 20th century average). On a longer time scale, global average surface temperatures have risen at a rate of about 0.70°C per century. (1)

    A few days later, NASA GISS and NOAA NCDC had a press conference and jointly announced that 2014 was a record year by a small margin, bearing in mind that no El Niño occurred. This phenomenon contributed significantly to the last record in 1998. G.A. Schmidt, head of the NASA GISS, and Thomas R. Larks, head of the NOAA NCDC, confirmed that 2014 was the warmest with a temperature 0.69ºC higher than this century's average. In addition, they stated that the oceanic surface temperature was also a record and that the sea ice loss in the Arctic does not offset the enhancement in Antarctica, even during 2014 it reached its highest extension ever. (2)

    By mid-month, ECMWF confirmed that "2014 was within the top 10% of the warmest years, demonstrating the consistency of these various estimates.”  ECMWF stated that slight differences among the results arise from incomplete global coverage, particularly a lack of observations from the Polar regions and limitations of the measurements used to produce the data sets. (3)

    By the end of January, the Met Office and the University of East Anglia stated that last year was 0.56ºC higher that the long-term average (1961-1992) with 0.01ºC uncertainty range. Phil Jones, from the University of East Anglia said: “2014 was an exceptionally warm year which saw warm tropical Pacific temperatures, despite not being officially regarded as an El Niño year." (4)

    Confirming all of this, the World Meteorological Organisation (WMO) released its dataset at the beginning of February showing that 2014 was “the hottest year on record as part of a continuing trend”, although “the difference in temperature in the warmest years is only a few hundredths of a degree”. (5)

    As was mentioned by all the agencies, the human influence factor is important to understand this record. However, the ongoing trend is more significant than just a single year. As G.A. Schmidt said: “The long-term trends or the expected sequence of records are far more important than whether any single year is a record or not”. (6) With carbon dioxide mixing ratios close to 400 ppm, new record years are likely to happen over the coming decade with a further decrease of Arctic sea ice, land ice and an increase in sea level. However, Antarctica looks like being colder with increasing sea ice.

    References

    (1)    ds.data.jma.go.jp/tcc/tcc/products/gwp/temp/ann_wld.html

    (2)    www.ncdc.noaa.gov/sotc/briefings/201501.pdf

    (3)    www.metoffice.gov.uk/news/release/archive/2015/2014-global-temperature

    (4)    www.ecmwf.int/en/about/media-centre/news/2015/ecmwf-releases-global-reanalysis-data-2014-0

    (5)    https://www.wmo.int/media/?q=content/warming-trend-continues-201

    (6)    www.realclimate.org/index.php/archives/2015/01/thoughts-on-2014-and-ongoing-temperature-trends/

    By: Mario Cuellar