by John Lawrence from the San Diego Free Press
Three new studies do not bode well for the future of the American southwest. California is in the midst of the worst drought in recorded history. However, this may be just the beginning. There have been megadroughts before. And scientists are now 99.99% certain that climactic changes responsible for this extreme weather condition are caused by human activity which spews greenhouse gasses into the atmosphere.
And as the drought continues in California, record amounts of groundwater are being pumped by corporations which are bottling and selling it in other states. Due to crippling drought in California, there’s been a crackdown on watering lawns and washing cars. Yet Nestle has continued its bottling operations, adding to the national debate over corporate right and common good.
Farmers in the Central Valley are also pumping record amounts to make up for the lack of water from above ground sources. Recently a bill was passed which Governor Jerry Brown is expected to pass regulating groundwater for the first time.
California's groundwater provides approximately 30 to 46 percent of the State's total water supply, depending on wet or dry years, and serves as a critical buffer against drought and climate change. Some communities in California are 100 percent reliant upon groundwater for urban and agricultural use. So much water is being pumped from the ground in parched California that the land is sinking, according to scientists.
From Science Daily:
Due to global warming, scientists say, the chances of the southwestern United States experiencing a decade long drought is at least 50 percent, and the chances of a “megadrought” – one that lasts over 30 years – ranges from 20 to 50 percent over the next century.
The study by Cornell University, University of Arizona and U.S. Geological Survey researchers will be published in a forthcoming issue of the American Meteorological Society’s Journal of Climate.
“For the southwestern U.S., I’m not optimistic about avoiding real megadroughts,” said Toby Ault, Cornell assistant professor of earth and atmospheric sciences and lead author of the paper. “As we add greenhouse gases into the atmosphere – and we haven’t put the brakes on stopping this – we are weighting the dice for megadrought conditions.”
As of mid-August, most of California sits in a D4 “exceptional drought,” which is in the most severe category. Oregon, Arizona, New Mexico, Oklahoma and Texas also loiter between moderate and exceptional drought. Ault says climatologists don’t know whether the severe western and southwestern drought will continue, but he said, “With ongoing climate change, this is a glimpse of things to come. It’s a preview of our future.”
Ault said that the West and Southwest must look for mitigation strategies to cope with looming long-drought scenarios. “This will be worse than anything seen during the last 2,000 years and would pose unprecedented challenges to water resources in the region,” he said.
In computer models, while California, Arizona and New Mexico will likely face drought, the researchers show the chances for drought in parts of Washington, Montana and Idaho may decrease.
Beyond the United States, southern Africa, Australia and the Amazon basin are also vulnerable to the possibility of a megadrought. With increases in temperatures, drought severity will likely worsen, “implying that our results should be viewed as conservative,” the study reports.
“These results help us take the long view of future drought risk in the Southwest – and the picture is not pretty. We hope this opens up new discussions about how to best use and conserve the precious water that we have,” said Julia Cole, UA professor of geosciences and of atmospheric sciences.
The study, “Assessing the Risk of Persistent Drought Using Climate Model Simulations and Paleoclimate Data,” was also co-authored by Julia E. Cole, David M. Meko and Jonathan T. Overpeck of University of Arizona; and Gregory T. Pederson of the U.S. Geological Survey.
From the University of Arizona:
A new study has revealed a previously unknown multi-decade drought period in the second century A.D. The findings give evidence that extended periods of aridity have occurred at intervals throughout our past. Almost 900 years ago, in the mid-12th century, the southwestern U.S. was in the middle of a multi-decade megadrought. It was the most recent extended period of severe drought known for this region. But it was not the first. The second century A.D. saw an extended dry period of more than 100 years characterized by a multi-decade drought lasting nearly 50 years, according to the study.
And from Daily Kos:
A new study has calculated that the chances that humans are causing global warming is 99.999%.
New study finds 99.999 percent certainty humans are causing global warming
By Philip Kokic, Mark Howden, and Steven Crimp
There is less than 1 chance in 100,000 that global average temperature over the past 60 years would have been as high without human-caused greenhouse gas emissions, our new research shows.
Published in the journal Climate Risk Management today, our research is the first to quantify the probability of historical changes in global temperatures and examines the links to greenhouse gas emissions using rigorous statistical techniques.
Our new CSIRO work provides an objective assessment linking global temperature increases to human activity, which points to a close to certain probability exceeding 99.999%.
Also check out ThinkProgress: Global Warming Boosts Chances of Civilization-Threatening Megadroughts Here And Abroad