Archives par mot-clé : Precipitation

climate-debate

More New Studies Indicate There Has Been No Climate-Induced Precipitation Trend Since The 1800s

by K. Richard, Mar 11, 2024 in NoTricksZone

CO2-induced global warming was supposed to intensify the hydrological cycle and extreme precipitation. It hasn’t.

New research (Mitchell and Knapp, 2024) at a southeastern United States study site indicates there has been no significant trend in either total precipitation or intense rainfall events (IRE) over the last 250 years (1770-2020).

However, there was more IRE precipitation from 1936-1959 than from 1960-2020. In fact, the most recent 60 years has the lowest record of extreme precipitation during the study, with averages of 81.20 mm for 1770–1935, 230.45 mm for 1936–1959, but just 168.27 mm during 1960–2020.

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climate-debate

LONG-TERM US DROUGHT AND PRECIPITATION TRENDS

by R. McKitrick & J. Christy, Sep. 14, 2019 in WUWT

Ross McKitrick and John Christy have published a new paper in the Journal of Hydrology.

Abstract : We estimate trends in US regional precipitation on multiple time spans and scales relevant to the detection of changes in climatic regimes. A large literature has shown that trend estimation in hydrological series may be affected by long-term persistence (LTP) and selection of sample length. We show that 2000-year proxy-based reconstructions of the Palmer Modified Drought Index for the US Southeast (SE) and Pacific Coast (PC) regions exhibit LTP and reveal post- 1900 changes to be within the range of longer-term natural fluctuations. We also use a new data base of daily precipitation records for 20 locations (10 PC and 10 SE) extending back in many cases to the 1870s. Over the 1901–2017 interval upward trends in some measures of average and extreme precipitation appear, but they are not consistently significant and in the full records back to 1872 they largely disappear. They also disappear or reverse in the post-1978 portion of the data set, which is inconsistent with them being responses to enhanced greenhouse gas forcing. We conclude that natural variability is likely the dominant driver of historical changes in precipitation and hence drought dynamics in the US SE and PC.

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