New Study: ‘Climate change’ made California drought ‘less likely’ – Published in Journal of Climate
Journal of Climate 2015
How Has Human-induced Climate Change Affected California Drought Risk?
Linyin Cheng,1,2,* Martin Hoerling,3 Amir AghaKouchak,4 Ben Livneh,2 Xiao-Wei Quan,2 and Jon Eischeid2
1 University of Colorado, Boulder, CO 80305, USA.
2 Cooperative Institute for Research in Environmental Sciences, Boulder, CO 80305, USA.
3 National Oceanic and Atmospheric Administration, Earth System Research Laboratory/PSD, Boulder, CO 80305, USA.
4 University of California Irvine, Irvine, CA 92697, USA.
Abstract The current California drought has cast a heavy burden on statewide agriculture and water resources, further exacerbated by concurrent extreme high temperatures. Furthermore, industrial-era global radiative forcing brings into question the role of long-term climate change on CA drought.
How has human-induced climate change affected California drought risk? Here, observations and model experimentation are applied to characterize this drought employing metrics that synthesize drought duration, cumulative precipitation deficit, and soil moisture depletion. The model simulations show that increases in radiative forcing since the late 19th Century induces both increased annual precipitation and increased surface temperature over California, consistent with prior model studies and with observed long-term change. As a result, there is no material difference in the frequency of droughts defined using bivariate indicators of precipitation and near-surface (10-cm) soil moisture, because shallow soil moisture responds most sensitively to increased evaporation driven by warming, which compensates the increase in the precipitation. However, when using soil moisture within a deep root zone layer (1-m) as co-variate, droughts become less frequent because deep soil moisture responds most sensitively to increased precipitation. The results illustrate the different land surface responses to anthropogenic forcing that are relevant for near-surface moisture exchange and for root zone moisture availability. The latter is especially relevant for agricultural impacts as the deep layer dictates moisture availability for plants, trees, and many crops. The results thus indicate the net effect of climate change has made agricultural drought less likely, and that the current severe impacts of drought on California’s agriculture has not been substantially caused by long-term climate changes.
AMS Journal study finds California drought is ‘not unprecedented’ over past 440 years:
Monckton: Harper defeat in Canada will allow ‘world government’ win at UN Paris climate meet
Monckton recounted a conversation when Sir David King, William Hague’s United Kingdom “climate change ambassador” was asked by the Environmentalist Committee of the House of Commons in May 2014 “whether all the nations of the world were in principle ready to sign their peoples rights away in such a treaty,” to which he replied “Oh yes, but there are two stand-outs. One is Canada, but don’t worry about Canada. They’ve got an election in the spring of 2015 and we and the U.N. will make sure that the present government is removed.” Monckton recalled his absolute bluntness about the matter.
The other holdout was Australia which was in an arguably stronger position as there was no election until after the 2015 Paris Climate Change Conference. With Tony Abbott as leader there was no chance that Australia would be signing the treaty. In 2014, Abbott had taken the unusual step of sending an additional minister to accompany foreign minister Julie Bishop to ensure that she did not vote for the treaty at the 2014 Climate Change Conference in Lima.…
Trudeau victory may not signal a U-turn in Canada’s climate policy
…Bernie Sanders To Feds: Investigate Exxon For ‘Climate Change Cover-Up’
…New paper explains the ~1,500 year climate cycle on basis of astronomic variables, not CO2 – Published in Climate of the Past
finds the well-known~1500 year climate cycle can be explained on the basis of astronomical variables that create a “high-frequency extension of the Milankovitch precessional cycle.”
“The existence of a ~ 1470 year cycle of abrupt climate change is well-established, manifesting in Bond ice-rafting debris (IRD) events, Dansgaard–Oeschger atmospheric temperature cycle, and cyclical climatic conditions precursory to increased El Niño/Southern Oscillation (ENSO) variability and intensity. This cycle is central to questions on Holocene climate stability and hence anthropogenic impacts on climate. To date no causal mechanism has been identified, although solar forcing has been previously suggested.”
“Here we show that interacting combination of astronomical variables related to Earth’s orbit may be causally related to this cycle and several associated key isotopic spectral signals. The ~ 1470 year climate cycle may thus be regarded as a high frequency extension of the Milankovitch precessional cycle, incorporating orbital, solar and lunar forcing through interaction with the tropical and anomalistic years and Earth’s rotation.”