As the Arctic warms and its ice melts, growing numbers freight ships are reaping big savings from the 'Arctic short cut'. But this is creating a huge risk of invasive species spreading in ballast water and on hulls - disrupting both Arctic and temperate ecosystems.
It's not just people, animals and trees that suffer from radiation at Chernobyl, writes Rachel Nuwer, but also decomposer fungi and microbes. And with the buildup of dead wood comes the risk of catastrophic fire - which could spread radiation far and wide.
