A study published in the latest issue of Nature Climate Change reveals that snow cover in the northern latitudes has been significantly reduced. In addition, due to the increase in temperatures, the seasonal variation of vegetation cover has changed and it is now similar to the typical flora found in the regions several degrees further south 30 years ago.
The study conducted by an international team of scientists from seventeen different institutions is fully funded by NASA. Using new ground-based and satellite data, the scientists were able to evaluate the influence of temperature on vegetation patterns in the northern latitudes.
According to Liang Xu, a Boston University doctoral student and lead co-author of the study, we are now observing an amplified warming in the area. Due to the increased temperatures during the winter season, the seasonality of temperature is reducing. Consequently, this affects the type of vegetation found in the region. The scientists observed that large areas, almost the size of the US, are now covered with productive vegetation because of the increased availability of heat.
Another one of the co-authors, Scott Goetz, a senior scientist at the Woods Hole Research Center, added that warming will have a negative effect on large regions of the boreal forest. He explained that this will be caused by increased flood rates, drought stress and fire disturbance. However, when it comes to northern latitudes, the reduced seasonal temperature variability will result in higher vegetation productivity.
Latitude was the main variable the scientists used in their study. They related vegetation change and shift in patterns with established latitudinal profiles. Prof. Terry Chapin, Professor Emeritus, University of Alaska, Fairbanks indicates that arctic plant growth has shifted in characteristics over the past 30 years with around 7 degrees in latitude, which in distance equals around 480 miles south.
The scientists assessed the results from 17 different climate models. The simulations indicated that if the period is extended further back to the 1950s, then the shift might have been as much as 20 degrees. These changes will not only have a severe impact on local food production, but they can also influence the greenhouse emission regulations.