Climatologist Dr. Judith Curry: ‘Until we can explain early 20th century warming, I have little confidence UN IPCC & NCA4 attribution statements regarding the cause of the recent warming’

Climate Depot | 1/23/2019 | Admin
penaert (Posted by) Level 3
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A careful look at the early 20th century global warming, which is almost as large as the warming since 1950. Until we can explain the early 20th century warming, I have little confidence IPCC and NCA4 attribution statements regarding the cause of the recent warming.

This is an issue that has long interested me. Peter Webster wrote a previous post Mid 20th Century Global(?) Warming, which focused on the warm bump that culminated in the 1940’s. My interest in this period was reignited while working on my report Sea Level and Climate Change. Then, the recent paper by Zanna et al. discussed in Ocean Heat Content Surprises further made the wheels turn.

Response - Ocean - Heat - Content - Thread

In response to the Ocean Heat Content thread, David Appell posted a link to this paper on twitter:

Abstract: “The most pronounced warming in the historical global climate record prior to the recent warming occurred over the first half of the 20th century and is known as the Early Twentieth Century Warming (ETCW). Understanding this period and the subsequent slowdown of warming is key to disentangling the relationship between decadal variability and the response to human influences in the present and future climate. This review discusses the observed changes during the ETCW and hypotheses for the underlying causes and mechanisms. Attribution studies estimate that about a half (40–54%; p > .8) of the global warming from 1901 to 1950 was forced by a combination of increasing greenhouse gases and natural forcing, offset to some extent by aerosols. Natural variability also made a large contribution, particularly to regional anomalies like the Arctic warming in the 1920s and 1930s. The ETCW period also encompassed exceptional events, several of which are touched upon: Indian monsoon failures during the turn of the century, the “Dust Bowl” droughts and extreme heat waves in North America in...
(Excerpt) Read more at: Climate Depot
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