Arctic

The Arctic is warming twice as fast as the rest of the planet, and scientists are seeing the effects across ice and ecosystems. The average annual air temperature over Arctic land is now 3.5°C (6.5°F) warmer than it was 1900, Greenland is experiencing longer melting seasons, and this year’s spring snow cover extent set a record low in the North American Arctic, according to the National Oceanic and Atmospheric Administration’s newly released 2016 Arctic Report Card.

The Arctic’s frozen ground contains large stores of organic carbon that have been locked in the permafrost for thousands of years. As global temperatures rise, that permafrost is starting to melt, raising concerns about the impact on the climate as organic carbon becomes exposed. A new study is shedding light on what that could mean for the future by providing the first direct physical evidence of a massive release of carbon from permafrost during a warming spike at the end of the last glacial period.

Tiny one-celled organisms called radiolaria are ubiquitous in the oceans, but various species prefer distinct habitats. Thus it aroused considerable intrigue in 2012 when protozoa specialist O. Roger Anderson and colleagues published a study showing that radiolaria normally found near the equator were suddenly floating around in arctic waters above Norway. Was this a sign that global climate change was bringing an invasion of warm-weather plankton?

Summers on the Norwegian archipelago of Svalbard are now warmer than at any other time in the last 1,800 years, including during medieval times when parts of the northern hemisphere were as hot as, or hotter, than today, according to a new study in the journal Geology.