Actual headline: Vikings grew barley in Greenland

Correction to the editorial addition: Climate was mild when and where they landed.

    The Medieval Warm Period (MWP), also known as the
    Medieval Climate Optimum or the Medieval Climatic Anomaly, 
    was a time of warm climate in the North Atlantic region
    that lasted from about 950 CE to about 1250 CE.

    Climate proxy records show peak warmth occurred 
    at different times for different regions, which 
    indicate that the MWP was not a globally uniform event.

    The MWP was followed by a regionally cooler period
    in the North Atlantic and elsewhere, which is sometimes
    called the Little Ice Age.

ref: https://en.wikipedia.org/wiki/Medieval_Warm_Period

xkcd global climate timeline: https://xkcd.com/1732/