Nature & Environment
Warming Temperatures May Cause More California Droughts
Catherine Griffin
First Posted: Mar 03, 2015 10:09 AM EST
The droughts in California have become more and more frequent during the last two decades. Now, scientists have found that this recent uptick in droughts may be the result of rising temperatures in the region, which are the result of climate change.
In this latest study, the researchers examined the role that temperature has played in California droughts over the past 120 years. They also looked at the effect that human emissions of carbon dioxide and other greenhouse gases are having on temperature and precipitation, focusing on the influence of global warming upon California's past, present and future drought risk.
In this case, the researchers found that the worst droughts in California have historically occurred when conditions were both dry and warm. Climate change actually increases the probability that dry and warm years will collide, which also ups the risk of drought. In fact, the findings suggest that California could be entering an era when nearly every year that has low precipitation also has high temperatures.
"Of course low precipitation is a prerequisite for drought, but less rain and snowfall alone doesn't ensure a drought will happen," said Noah Diffenbaugh, one of the researchers, in a news release. "It really matters if the lack of precipitation happens during a warm or cool year. We've seen the effects of record heat on snow and soil moisture this year in California, and we know from this new research that climate change is increasing the probability of those warm and dry conditions occurring together."
In fact, years that are both warm and dry are twice as likely to produce a severe drought as years that are cool and dry. In addition, in the past two decades nearly all of the years in California have been either warm or hot.
"Imagine having two coins-one controls temperature, and the other precipitation," said Diffenbaugh. "In the past, when you flipped the coins, they each came up tails half the time, meaning that a quarter of a time both coins came up tails, representing a warm and dry year. Now the temperature coin is coming up tails most years. So, even though the precipitation coin is coming up tails only half the time, it means that over the past two decades we have gotten two tails-warm and dry-in half the years, compared with only a quarter of years in the preceding century."
The findings reveal that California's droughts may be increasing due to climate change. Not only that, but the region may expect more dry years in the future.
The findings are published in the journal Proceedings of the National Academy of Sciences.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
See Now:
NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone
TagsDrought, California ©2024 ScienceWorldReport.com All rights reserved. Do not reproduce without permission. The window to the world of science news.
More on SCIENCEwr
First Posted: Mar 03, 2015 10:09 AM EST
The droughts in California have become more and more frequent during the last two decades. Now, scientists have found that this recent uptick in droughts may be the result of rising temperatures in the region, which are the result of climate change.
In this latest study, the researchers examined the role that temperature has played in California droughts over the past 120 years. They also looked at the effect that human emissions of carbon dioxide and other greenhouse gases are having on temperature and precipitation, focusing on the influence of global warming upon California's past, present and future drought risk.
In this case, the researchers found that the worst droughts in California have historically occurred when conditions were both dry and warm. Climate change actually increases the probability that dry and warm years will collide, which also ups the risk of drought. In fact, the findings suggest that California could be entering an era when nearly every year that has low precipitation also has high temperatures.
"Of course low precipitation is a prerequisite for drought, but less rain and snowfall alone doesn't ensure a drought will happen," said Noah Diffenbaugh, one of the researchers, in a news release. "It really matters if the lack of precipitation happens during a warm or cool year. We've seen the effects of record heat on snow and soil moisture this year in California, and we know from this new research that climate change is increasing the probability of those warm and dry conditions occurring together."
In fact, years that are both warm and dry are twice as likely to produce a severe drought as years that are cool and dry. In addition, in the past two decades nearly all of the years in California have been either warm or hot.
"Imagine having two coins-one controls temperature, and the other precipitation," said Diffenbaugh. "In the past, when you flipped the coins, they each came up tails half the time, meaning that a quarter of a time both coins came up tails, representing a warm and dry year. Now the temperature coin is coming up tails most years. So, even though the precipitation coin is coming up tails only half the time, it means that over the past two decades we have gotten two tails-warm and dry-in half the years, compared with only a quarter of years in the preceding century."
The findings reveal that California's droughts may be increasing due to climate change. Not only that, but the region may expect more dry years in the future.
The findings are published in the journal Proceedings of the National Academy of Sciences.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone