From Nature volume 571, pages550–554
(2019):
No evidence for globally coherent warm and cold periods over the preindustrial Common Era
Earth’s climate history is often understood by breaking it down into constituent climatic epochs1. Over the Common Era (the past 2,000 years) these epochs, such as the Little Ice Age2,3,4, have been characterized as having occurred at the same time across extensive spatial scales5. Although the rapid global warming seen in observations over the past 150 years does show nearly global coherence6,
the spatiotemporal coherence of climate epochs earlier in the Common
Era has yet to be robustly tested. Here we use global palaeoclimate
reconstructions for the past 2,000 years, and find no evidence for
preindustrial globally coherent cold and warm epochs. In particular, we
find that the coldest epoch of the last millennium—the putative Little
Ice Age—is most likely to have experienced the coldest temperatures
during the fifteenth century in the central and eastern Pacific Ocean,
during the seventeenth century in northwestern Europe and southeastern
North America, and during the mid-nineteenth century over most of the
remaining regions. Furthermore, the spatial coherence that does exist
over the preindustrial Common Era is consistent with the spatial
coherence of stochastic climatic variability. This lack of
spatiotemporal coherence indicates that preindustrial forcing was not
sufficient to produce globally synchronous extreme temperatures at
multidecadal and centennial timescales. By contrast, we find that the
warmest period of the past two millennia occurred during the twentieth
century for more than 98 per cent of the globe. This provides strong
evidence that anthropogenic global warming is not only unparalleled in
terms of absolute temperatures5, but also unprecedented in spatial consistency within the context of the past 2,000 years.
Sunday, August 4, 2019
Friday, August 2, 2019
Leo 6.0 final released
Leo 6.0 final, http://leoeditor.com, is now available on GitHub.
Leo is an IDE, outliner and PIM, as described here.
The highlights of Leo 6.0
Leo is an IDE, outliner and PIM, as described here.
The highlights of Leo 6.0
- Leo now requires python 3.6 or above.
This greatly simplifies Leo's code. - Leo's default gui uses Qt Docks.
Use --no-dock to use Leo's legacy gui. - Several commands now generate clickable links in the Log pane.
This greatly speeds navigation. - The usual assortment of bug fixes and minor improvements.
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