'Global Warming' - Another paper refutes the Mann made hockey stick – MWP was ≈1°C warmer than current temperatures.

'Global Warming' - Another paper refutes the Mann made hockey stick – MWP (Medieval Warm Period Project) was ≈1°C warmer than current temperatures.(WUWT).This new paper uses a rather unique proxy; high-resolution samples micromilled from archaeological shells of the European limpet, Patella vulgata. Mr. Limpet would be proud.
A paper published this week in the journal Palaeogeography, Palaeoclimatology, Palaeoecology finds that the Medieval Warming Period “was warmer than the late 20th century by ~1°C.” The paper adds to the peer-reviewed publications of over 1000 scientists in the Medieval Warm Period Project showing that the global Medieval Warming Period was warmer than the current warming period.
Highlights:
► We investigated oxygen isotope ratios of Viking Age limpet shells.
► Seasonal SST was reconstructed for the early MCA (10th-12th centuries).
► Early MCA winters were cooler and summers were warmer than late 20th century.
► MCA seasonality was almost twice that of the late 20th century.
The paper is titled:
Marine climatic seasonality during early medieval times (10th to 12th centuries) based on isotopic records in Viking Age shells from Orkney, Scotland.
During the 10th to 12th centuries winters were colder and summers were warmer by ~ 2 °C and seasonality was higher relative to the late 20th century. Without the benefit of seasonal resolution, SST averaged from shell time series would be weighted toward the fast-growing summer season, resulting in the conclusion that the early MCA was warmer than the late 20th century by ~ 1 °C. This conclusion is broadly true for the summer season, but not true for the winter season. Higher seasonality and cooler winters during early medieval times may result from a weakened North Atlantic Oscillation index.Read the full story here.