by Don J. Easterbrook, 2011 in ScienceDirect
The Medieval Warm Period (MWP) was a time of warm climate from about 900 A.D. to 1300 A.D. when global temperatures were apparently somewhat warmer than at present. Its effects were evident in Europe where grain crops flourished, alpine tree lines rose, many new cities arose, and the population more than doubled. The Vikings took advantage of the climatic amelioration to colonize Greenland, and wine grapes were grown as far north as England where growing grapes is now not feasible and about 500 km north of present vineyards in France and Germany. Grapes are presently grown in Germany up to elevations of about 560 m, but from about 1100 A.D. to 1300 A.D., vineyards extended up to 780 m, implying temperatures warmer by about 1.0–1.4 °C (Oliver, 1973).
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by P. Gosselin , February 19, 2019 in NoTricksZone
Readers should note that among climate modelers volcanoes and atmospheric aerosols have been a favorite way of fudging climate models to explain away inconvenient cooling periods that weren’t supposed to happen in a system that is supposed to be dominated by trace gas CO2.
Extratropical volcanoes influence climate more than assumed
Study shows surprisingly strong cooling after volcanic eruptions in mid and high latitudes
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by P. Homewood, February 18, 2019 i
Here’s the text from the original page (my bolding).
The Sun is the primary forcing of Earth’s climate system. Sunlight warms our world. Sunlight drives atmospheric and oceanic circulation patterns. Sunlight powers the process of photosynthesis that plants need to grow. Sunlight causes convection which carries warmth and water vapor up into the sky where clouds form and bring rain. In short, the Sun drives almost every aspect of our world’s climate system and makes possible life as we know it.
Earth’s orbit around and orientation toward the Sun change over spans of many thousands of years. In turn, these changing “orbital mechanics” force climate to change because they change where and how much sunlight reaches Earth. (Please see for more details.) Thus, changing Earth’s exposure to sunlight forces climate to change. According to scientists’ models of Earth’s orbit and orientation toward the Sun indicate that our world should be just beginning to enter a new period of cooling — perhaps the next ice age.
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Repost from JoNova
La géologie, une science plus que passionnante … et diverse