An international team of authors from 17 institutions in seven countries, including the Woods Hole Research Center, published a study in the journal Nature Climate Change on the 10 March 2013 (10.1038/NCLIMATE1836: http://www.nature.com/nclimate). The study shows that, as the cover of snow and ice in the northern latitudes has diminished in recent years, the temperature over the northern land mass has increased at different rates during the four seasons, causing a reduction in temperature and vegetation seasonality in this area. The temperature and vegetation at northern latitudes increasingly resemble those found several degrees of latitude farther south as recently as 30 years ago.
The NASA-funded study, based on newly improved ground and satellite data sets, examines critically the relationship between changes in temperature and vegetation productivity in northern latitudes. "The amplified warming in the circumpolar area roughly above the Canada-USA border is reducing temperature seasonality over time because the colder seasons are warming more rapidly than the summer," says Liang Xu, a Boston University doctoral student and lead co-author of the study. As a result of the enhanced warming over a longer ground-thaw season, the total amount of heat available for plant growth in these northern latitudes is increasingcreating large patches of vigorously productive vegetation totaling more than a third of the northern landscapeover 9 million km2, which is roughly about the area of the USA.
A key finding of this study is an accelerating greening rate in the Arctic and a decelerating rate in the boreal region, despite a nearly constant rate of temperature seasonality diminishment in these regions over the past 30 years. "Some areas of boreal forest will be negatively impacted by warming temperatures, from increased drought stress as well as insect and fire disturbance, but this w
|Contact: Ian Vorster|
Woods Hole Research Center