The end

Time is flying, I still remember the first day I start this blog. I have been enjoying this process, because I learn a lot of totally new things through this blog. It seems I chose a broad topic, natural disasters. Through limited posts, I just picked several items I am interested in to have my exploration.  Too frequent to change another type of natural disasters take me lots of time, but I am really glad I gradually get hold of it. Hope all you read this blog have a nice enjoy.

More about U.S. droughts

In regard to palaeoclimatic data tree rings, there was a drought history with some multidecadal aridity periods of California in the past 500 years and since 1900, there have been at least eight multiyear periods of low precipitation (Larsen et al. 2014). Woodhouse et al. 2009 argued that increasing dryness accompany with increasing temperatures relative to both instrumental records and palaeoclimatic records.

Long period droughts bring a large amount of losses to California. There is an economic impacts assessment of the year 2014 has been taken under the third driest year circumstance to estimate losses from dairies, crop production and livestock by using a set of models (Howitt et al. 2014). The summary table show as follow:

Table1  2014 Drought and California Agriculture Summary 

In the context of worse drought situation, some effective measures should be taken into implement to relief the drought stress. Groundwater is really important in U.S., on which 60% of irrigation relies (Scanlon et al. 2012), however the situation of groundwater seems not very well (Figure1). While increasing water storage through managing extra surface water return to aquifers by up to 3 km3  exhibits hope for dealing with droughts and improving sustainability of groundwater resources in the Central Valley (Scanlon et al. 2012).

Figure1  Measured groundwater level changes from predevelopment (~1950) to 2007 in the high plain aquifer 

In conclusion, recent droughts in California are not unparalleled and they might occur as warm-drought type. Droughts will cause a range of money losses, therefore some effective steps should be exerted to mitigate this worse situation.