A 2003 marine heat wave in the waters around Greenland continues to impact North Atlantic ocean ecosystems decades on, with a sudden and strong increase in marine heat wave frequency persisting ever since. Marine biologists from Germany and Norway reviewed more than 100 scientific studies and found that marine heat waves (MHWs) in and after 2003 led to "widespread and abrupt ecological changes" across all levels of the ocean's ecosystems – from tiny, single-celled protists to commercially