A new reconstruction by a large team of mainly European scientists (h/t NoTricksZone) of climate conditions in the European Alps spans nearly 9,000 years ending in 2014 and reveals, not a hockey stick, more like a ringette stick. Which for you non-rink-sports types is a hockey stick with the blade cut off so just kind of a pole stick thingy. Conditions were warmer and wetter 9,000 years ago during the early Holocene, then gradually got cooler and drier over time. The driest period of all was during the Little Ice Age that ended in the early 1800s. And current conditions are nothing unusual compared to what was observed throughout, except for being rather cooler and drier than most of the Holocene. Only the rhetoric is hot.

The authors used samples of 192 living and preserved trees found at high elevation sites in the European Alps to construct their record. They used a process called Tree Ring Stable Isotope (TRSI) analysis which, they argue, preserves accurate information about the climatic conditions the tree grew in. And while tree rings have serious limitations as proxies, as we’ve documented, the TRSI record is particularly good at mirroring the patterns in modern drought severity indexes, especially the so-called self-calibrating Palmer Drought Severity Index (scPDSI).

Their scPDSI reconstruction is as follows:

Although it’s called a Drought Severity Index the scale is upside down so really it’s a Drought Inseverity Chart where higher means wetter. The graph shows a steady downward slope from 9,000 years ago (about 7,000 BC), during the Holocene Climate Optimum, to the present and shows several important episodes in the past climate.

The period from 9,000 to 5,000 years is called the African Humid Period because even the Sahara was verdant and green (see our video on the Holocene Climate Optimum for more details). From 2,0000 to 1,500 years ago was the Roman Warm Period (RWP) followed by the - gasp! - Medieval Warm Period (MWP) around 1,000 years ago. In between those was the Late Antiquity Little Ice Age (LALIA – a new one for us) and more recently the Little Ice Age (LIA). So yes, confirming the traditional story and rebutting Michael Mann.

There’s more. The red line on the chart shows the long term decline in “orbital forcing”, meaning the amount of “summertime insolation”, solar energy striking the planet during Northern Hemisphere summer, which has declined gradually but steadily due to long-term changes in the Earth’s orbit. So again yes the sun affects the climate. And again yes the graph slopes down. Which means, as the authors state:

“Our data indicate significant long-term drying trend over much of the Holocene and that climate in Europe was not only warmer but also wetter during most of the preindustrial Holocene, with the presence of extremes.”

Something to keep in mind during this summer’s “hottest year ever” mania, or next time the climate dumps a lot of rainfall on the land.

It’s not the hottest year ever, nor is it the wettest, and since there have been carbon dioxide emissions of any importance only for the past several decades, CO2 is not the only thing that can cause warming, drying, etc. In fact from this study it looks like it’s far from being the most important thing.