PT  - JOURNAL ARTICLE
AU  - Magnuson, John J.
AU  - Robertson, Dale M.
AU  - Benson, Barbara J.
AU  - Wynne, Randolph H.
AU  - Livingstone, David M.
AU  - Arai, Tadashi
AU  - Assel, Raymond A.
AU  - Barry, Roger G.
AU  - Card, Virginia
AU  - Kuusisto, Esko
AU  - Granin, Nick G.
AU  - Prowse, Terry D.
AU  - Stewart, Kenton M.
AU  - Vuglinski, Valery S.
TI  - Historical Trends in Lake and River Ice Cover in the Northern Hemisphere
AID  - 10.1126/science.289.5485.1743
DP  - 2000 Sep 08
TA  - Science
PG  - 1743--1746
VI  - 289
IP  - 5485
4099  - http://science.sciencemag.org/content/289/5485/1743.short
4100  - http://science.sciencemag.org/content/289/5485/1743.full
SO  - Science2000 Sep 08; 289
AB  - Freeze and breakup dates of ice on lakes and rivers provide consistent evidence of later freezing and earlier breakup around the Northern Hemisphere from 1846 to 1995. Over these 150 years, changes in freeze dates averaged 5.8 days per 100 years later, and changes in breakup dates averaged 6.5 days per 100 years earlier; these translate to increasing air temperatures of about 1.2°C per 100 years. Interannual variability in both freeze and breakup dates has increased since 1950. A few longer time series reveal reduced ice cover (a warming trend) beginning as early as the 16th century, with increasing rates of change after about 1850.