The graphs shown here illustrate four changes that are ongoing in the Arctic. They show these changes over a period of 30 years, from 1982-2011. The top-left graph shows reduction in coastal sea ice of many major Arctic seas. The top-right chart shows the change in mean temperatures on coastal lands over that same period based on the Summer Warmth Index, calculated as the sum of monthly mean temperatures on land exceeding 0°C. The two lower graphs show how plant density in the Arctic increased on coastal lands, as represented by the Normalized Difference Vegetation Index (NDVI). The NDVI uses satellite data to assess (among other things) the extent to which the ground is covered by vegetation. These changes are evident not just from satellite data, but also from comparing equivalent aerial photos taken in different years.
There are other indicators of change as well. For example, about one third of Arctic land became substantially “greener” between 1982 and 2012, while plant biomass in wetlands on Bylot Island, in Canada’s High Arctic, increased by 123% (as measured at the peak of summer production) over the past 23 years.
Click here to read more from the “Terrestrial Ecosystems” chapter in the ABA.
Click here to learn more about sea ice dynamics and the effects on biodiversity with the Life Linked to Ice Report.