



Last week I explored why drought periods may increase in the Southwest as a result of climate change. The 2011-2017 California Drought –the most severe in this part of the world in the last 1200 years - has had a widespread impact on local farming practices and water supply. The state withdraws a dangerously high amount of water from its rivers (over 75%), fundamentally threatening the local agricultural economy (Figure 1). This post will discuss the impacts of the 2011-2017 California Drought and ways in which future droughts can be mitigated.









Hydrological drought in the area led to agricultural drought , whereby farmers were lacking water to support their crops. Water shortages were not just due to the lack of water during times of drought; it was a result of a combination of changing agricultural patterns and extreme conditions accompanying the drought, both of which I will explore below.









In the past few decades, Californian farmers have replaced traditional field crops -such as wheat- with water t hirsty ones, including almonds and other tree crops. With increasing water demand due to drought conditions and changing agricultural patterns, the water deficit increased, thus reducing yields. More and more land was left fallow, leading to reduced demand for labour force. A study estimated that 18,600 local agricultural jobs were lost in 2015, with the drought playing a major role.









The lack of water from precipitation wasn’t the only issue; the drought was accompanied with abnormally high warm periods. Warming increased the rate of evapotranspiration, thus decreasing the amount of soil moisture. This led to a higher concentration of salts in the soil, reducing the soil fertility that the Californian agricultural industry has relied on for over 100 years.









The majority of local agricultural water demand is usually met by melting snowpacks in the spring. Changing weather patterns over the last few years has led to reduced precipitation over the winter, reducing the snowpacks of California’s Sierra Nevada; meteorologists have calculated that in February this year the size of snowpacks in the mountain range were a mere 30% of the average.





















Warming –a feature of climate change in this region- exacerbated the issue. It is becoming more and more common for precipitation to fall as rain instead of snow , meaning that snowpacks do not accumulate in the first place. This phenomenon has a harrowing impact on the agricultural industry; smaller snowpacks mean that the volume of spring melts is lower, red ucing the amount of water in the rivers and the reservoirs which the agricultural industry relies on. In addition to this, warming also leads to earlier and more rapid snowpack melt, causing flooding and disruption .









With the amount of water available from rainfall and snowpacks decreasing, farmers are looking elsewhere. Indeed, groundwater extraction to meet the needs of the state has increased from 40 to 60% in the last couple of years. Two vital aquifers for the agricultural economy - the High Plains and the Central Valley aquifers - have seen substantial decline. This not only leads to issues of subsidence , which may damage vital infrastructure such as pipes and pylons, but begs us to ask the question on how sustainable is this for the future? Groundwater extraction is occurring at a much faster rate than at which aquifers can recover. With the amount of precipitation reducing in the region, the replenishment rates are being reduced too. The Californian State has introduced legislation to limit groundwater use, but its implementation in some cases may not occur till 2042, which may be too little too late.









So what can California do? There have been numerous suggestions put forward to tackle drought in the area. For example, desalinating water was outlined as an option to meet agricultural needs in the future. However, the high costs accumulated already due to the drought may not make this scheme viable. It is an energy intensive process, meaning its implementation requires significant rises in crop prices, which may occur if the effects of climate change deteriorate conditions further.









Scientists are still debating whether this drought was a climate anomaly within the local climatic zone boundaries or was the first manifestation of climate change in the region. However, I believe for the local agricultural economy this debate doesn’t matter. Numerous studies show that the 2011-2017 drought conditions are more likely to occur, so California will have to adapt either way for future prosperity. It is difficult to gauge the costs of the drought on the economy. However, a detailed study suggested losses of $603m in 2016 alone. California needs to act now to maintain its agricultural industry and live up to its reputation as a state of wealth and prosperity.









In my opinion California needs to adapt its agriculture. In the face of climate change, it is near impossible to prevent such droughts from occurring again. However, by planting crops that are resistant or are adapted to these harsh conditions, the local agricultural economy may be able to successfully trump its effects.





@tomicserep





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