A flood in California? You may be wondering what this is about. After all, California is in a drought that has wrecked considerable damage since 2012, with the recent wildfires being just one negative effect. However, a new study published by Science Advances suggests that climate change has made it more likely for a massive flood to occur within the next four decades.
Human-generated climate change has already been shown to have long-term detrimental effects, and flash floods are just one example. As global warming makes the atmosphere warmer, allowing more water to evaporate and be retained in the atmosphere, more precipitation will come down. Flash floods arise from atmospheric rivers-- long, narrow, areas of heavy moisture that can transport the evaporated water far-- and these atmospheric rivers usually bring rain to drier areas of California during the cooler seasons. However, because of the warmer atmosphere, this precipitation will come down as rain, running off and causing floods, instead of slowly melting snow. This phenomenon was seen recently in the Death Valley flash flood. As the state is next to the Pacific Ocean, there is an endless supply of water to evaporate and precipitate. Furthermore, California’s geography makes it more at risk for flooding. Wildfires create burn scars (smooth, slick surfaces easy for water to run down), and the current increase in wildfires has increased the number of burn scars.
California has endured megafloods from atmospheric rivers in the past, but scientists are warning the effects will be much worse than before. In the winter of 1861-1862, atmospheric rivers dumped water down mountains, transforming the San Joaquin and Sacramento valleys into inland seas. Great losses were accrued, including state-wide bankruptcy after a quarter of the economy was demolished. This was when the population of California was merely 50,000: now the state’s population is over 39 million.
Such a flood has impacts beyond the state of California and the US: it can affect the world. The most at-risk region of California is the Central Valley. The Central Valley is California’s most productive agricultural region, producing more than half of the produce grown in the US and a quarter of the US’s food supply. It is estimated that a flood in this region would result in over $1 trillion in losses, five times more than the current costliest US disaster, Hurricane Katrina. The loss of a productive, agricultural region creates a dramatic decrease in the food supply.
Climate change and its effects do not affect solely the region where disasters occur. Much of the modern world is interconnected, with people across the world relying on each other to live life as we know it today. To mitigate the impending consequences of climate change, society as a whole needs to take action to reverse the effects of climate change as much as possible.