Can we take droughts off the list as a sure sign of Climate Change?
- gale hawkLv 54 years agoBest Answer
Depends on what type of 'change' you are talking about.
UN Framework Convention on Climate Change
“Climate change” means a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.
Drought is a sign of a cold climate not a warm climate. Think about it. The sun heats the oceans and water evaporates and is transported by winds to land where it rains. Weaker sun, less evaporation less rain.
This is one of earth's feed back mechanisms that keeps the climate fairly even. Less evaporation less clouds reflecting sun more sunlight to warm the earth. To much sun more evaporation more sunlight reflecting clouds.
This page shows reconstructions of the earth climate. The earth was driest during the depths of the ice age and wettest during the Holocene Optimum.
The African maps show the expansion and contraction of the Sahara desert.
Stone-Age graveyard reveals life in a “green Sahara”
Multidecadal to multicentury scale collapses of Northern Hemisphere monsoons over the past millennium
...Late Holocene climate in western North America was punctuated by periods of extended aridity called megadroughts. These droughts have been linked to cool eastern tropical Pacific sea surface temperatures (SSTs)...Several megadroughts are evident, including a multicentury one, AD 1350–1650, herein referred to as Super Drought, which corresponds to the coldest period of the Little Ice Age. Synchronicity between southwestern North American, Chinese, and West African monsoon precipitation suggests the megadroughts were hemispheric in scale. ...The megadroughts are associated with cooler than average SST and Northern Hemisphere temperatures. Furthermore, the megadroughts, including the Super Drought, coincide with solar insolation minima, suggesting that solar forcing of sea surface and atmospheric temperatures may generate variations in the strength of Northern Hemisphere monsoons. Our findings seem to suggest stronger (wetter) Northern Hemisphere monsoons with increased warming.
Blocking phenomenon is what caused the Russian 2010 Heat wave and Pakistan floods
Top-Down Solar Modulation of Climate: evidence for centennial-scale change
The work presented here is consistent with the interpretation of a recently reported effect  of solar variability on the North Atlantic Oscillation (NAO) and European winter temperatures over the interval 1659–2010 in terms of top-down modulation of the blocking phenomenon...
New Insights into North European and North Atlantic Surface Pressure Variability, Storminess, and Related Climatic Change since 1830
The results show periods of relatively high dp(abs)24 and enhanced storminess around 1900 and the early to mid-1990s, and a relatively quiescent period from about 1930 to the early 1960s... there is no sign of a sustained enhanced storminess signal associated with global warming.....
The Holocene Asian Monsoon: Links to Solar Changes and North Atlantic Climate
A 5-year-resolution absolute-dated oxygen isotope record from Dongge Cave, southern China, provides a continuous history of the Asian monsoon over the past 9000 years. Although the record broadly follows summer insolation, it is punctuated by eight weak monsoon events lasting ∼1 to 5 centuries. One correlates with the “8200-year” event, another with the collapse of the Chinese Neolithic culture, and most with North Atlantic ice-rafting events. Cross-correlation of the decadal- to centennial-scale monsoon record with the atmospheric carbon-14 record shows that some, but not all, of the monsoon variability at these frequencies results from changes in solar output.
Paleotemperature variability in central China during the last 13 ka recorded by a novel microbial lipid proxy in the Dajiuhu peat deposit
The Asian summer monsoon is a very important climatic component affecting the land ecosystem on the eastern Asian continent.... Fluctuations in the continuous 13 ka BNA15-derived record of relative temperature change from the Dajiuhu peat core imply that solar activity is the dominant cause for most cold events at multicentennial to submillennial timescales.
- GringoLv 64 years ago
Cherry-picking a single graph out of a peer-reviewed paper while ignoring the rest of that paper is never a good basis for science.
Here's part of the 'Usage Notes" of the cherry-picked figure in question:
"The figure highlights a substantial increase in severe to exceptional drought in the late nineties as discussed in previous studies (e.g., see ref. 43). The figure indicates that in the peak time, around 20% of global land areas were in severe to exceptional drought, a record drought the likes of which has not been experienced since."
Ergo, the referenced paper actually contradicts the claim by the usual deniers, Roger Pielke Jr, WUWT, Marc Morano, Canada Free Press and Sagebrush, all of whom have looked at the graph but none have actually bothered to read the paper it is in.Source(s): http://www.nature.com/articles/sdata20141
- ChemFlunkyLv 74 years ago
The thing is, while the warming is global, the *effects* are local.
It is likely (not proven, of course, but likely) that the severe droughts in the western US are primarily due to AGW. Of course, the area has had droughts long before humans started changing anything, but I believe the records suggest that the current drought is unusual in depth and duration.
It may be that, overall, worldwide, there is very slightly less drought because of AGW. That actually doesn't surprise me a whole lot, since heat increases evaporation, and a lot of the planet is ocean. It likely depends in part on how you *measure* drought (since, while rainfall may be increasing slightly, evaporation from plants is *also* increasing, possibly by a larger amount). But I'd want a lot more than one study in order to be sure. Of anything, really, whether or not it fits with any preconceived narrative I may have on the subject.
- JamesLv 54 years ago
Droughts were never a "sure sign' of climate change, that was an erroneous conclusion of your "true scientists."
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- KanoLv 74 years ago
No not really, colder is usually drier, during the ice ages (to go to an extreme) deserts covered most of the earth (that not covered with ice) while during the warm Holocene Climate Optimum our Earth was much wetter, the Sahara had rivers and lakes, and China had forests where now is grassland or desert.
- ThornLv 74 years ago
only if you are scientifically illiterate
- SLv 74 years ago