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Tag: megadrought
Millions Of Trees Are Dying Because Of California Drought

Millions Of Trees Are Dying Because Of California Drought

By Veronica Rocha, Los Angeles Times (TNS)

LOS ANGELES — At least 12 million trees have died in California’s national forests because of four years of extreme drought, scientists say.

An aerial survey of select areas in Southern California and the south Sierra Nevada in early April showed that millions of trees have died and were “most severely drought impacted,” said biologist Jeffrey Moore, acting regional aerial survey program manager for the U.S. Forest Service.

Officials believed the trees will continue to die as summer approaches.

“It is almost certain that millions more trees will die over the course of the upcoming summer as the drought situation continues and becomes ever more long term and as bark beetle populations continue to expand,” he said.

William Patzert, climatologist for the Jet Propulsion Laboratory, has told the Los Angeles Times that California’s dwindling snowpack and warmer temperatures pose an extreme fire danger in the state’s forests.

Warmer temperatures are rapidly drying out the state, he said. Traditionally by spring, the forest is green and lush due to a substantial rainy season. But four years of drought and warm temperatures have taken their toll.

“The national forest is stressed out,” Patzert said. “The absence of snowpack has endangered the national forest.”

Bark beetles are tiny brown insects that chew away at the pines, making them brittle. As the beetles invade forests, the trees suffer a quick death and become the perfect fuel for fire.

Stressed trees competing for limited resources also become more susceptible to the beetles, which best survive in diseased, injured and drought-stressed trees.

During the aerial survey, Moore and fellow researchers looked to detect and map the severity of tree damage in Southern California’s forests.

Using a digital aerial sketch-mapping system, researchers flew in a fixed-wing aircraft about 1,000 feet above ground level and surveyed more than 4.2 million acres of forest.

The areas monitored were the Cleveland, San Bernardino, Angeles, and Los Padres national forests. Some private lands and Pinnacles National Park in Central California were also surveyed.

About two million recently killed trees were mapped in Southern California during the survey, he said. Higher-elevation trees were not mapped because it’s too early to properly assess the damage, Moore added.

“The most heavily impacted area right now is the southern Sierras,” he said.

Pine trees, including the precedence, Ponderosa, jeffrey, coulter, and pinyon species, suffered the most death, Moore said. Pinyon, for instance, is most common in lower elevations and drier, harsher environments.

Fir and oak trees were also harmed from the drought.

But it’s not all bad news for the forests. The drought means more competition for water.

“In all but the worst areas, many trees will survive and with less competition for the limited supply of water, may well survive long term,” Moore said.

A more complete picture of the statewide tree mortality will begin in June and may not be completed until the fall, Moore said.

Photo: Cyndy Sims Parr via Flickr

A Megadrought Could Be Coming Without Climate Action

A Megadrought Could Be Coming Without Climate Action

A new study published in the Journal of Climate warns that decade-long droughts are likely to occur in the U.S. Southwest within the coming century if no action is taken against climate change.

Megadroughts (or droughts that last for two decades or longer) are cyclical, and long periods of drought have plagued the Southwest in the past (such as the Dust Bowl). However, National Drought Mitigation Center climatologist Mark Svoboda points out, “We are simply much more vulnerable today than at any time in the past. People can’t just pick up and leave to the degree they did in the past.”

According to the study, “the risk of a decade-scale megadrought in the coming century [in the SW] is at least 80 percent, and may be higher than 90 percent in certain areas.”

As this map from USA Today shows, some of the most densely populated regions of the country are at very high risk of extended, civilization-threatening droughts.

Drought Map

Prolonged drought is no longer a far-off, abstract concept. The state of California is facing one of the most severe droughts on record. Governor Jerry Brown declared a drought State of Emergency in January, and as of August 28, 100 percent of the state of California was considered to be in a drought, according to the U.S. Drought Monitor. More than 58 percent is in “exceptional” drought, the highest level of intensity listed. Californians are in the midst of the worst three years for precipitation in 119 years of records. Reservoir storage levels have continued to drop, prompting comedian Conan O’Brien to launch a series of PSA videos urging Californians to conserve water.

O’Brien is right to be concerned about his state’s drought, but the recent study shows that California’s current situation is far from the worst of what we can expect to see if action against climate change is not taken.

Drought Map 2

This graphic from ThinkProgress reveals that for most parts of the Southwest, there is an over 40 percent chance of a megadrought lasting 35 years or longer during this century, if we do nothing (Figure i). As the scale shows, the percentages drop significantly in the other two scenarios (Figures g and h), where aggressive action is taken against carbon emissions. In Figure g, the nation and the world keep carbon pollution levels to 450 parts per million of total greenhouse gasses in the atmosphere, and in Figure h the levels are limited to 500 parts per million.

The study goes on to note that our action or inaction is more than just a national concern. After extending their analysis of megadrought risk, scientists found that “risks throughout the subtropics appear as high or higher than estimates for the U.S. Southwest.”

The prolonged drought that California has faced these past months would be a mere drop in the bucket, compared to a megadrought that lasts multiple decades. The most alarming aspect of the study is that scientists based their evaluations on conservative precipitation projections and did not take any possible increases in temperatures into account. These increases in temperature would make the risk of megadrought within the next century 100 percent, as ThinkProgress notes.

Photo via Wikimedia Commons

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Chance Of ‘Megadrought’ In U.S. Southwest Now 50 Percent, Study Concludes

Chance Of ‘Megadrought’ In U.S. Southwest Now 50 Percent, Study Concludes

By Veronica Rocha, Los Angeles Times

The chance of a “megadrought” gripping the Southwest for more than 30 years has increased to 50 percent, scientists say, which means bad news for California’s already parched landscape.

The odds of a 10-year drought afflicting the southwestern United States have increased to 80 percent, according to a new study by Cornell University, the University of Arizona, and the U.S. Geological Survey.

Whatever happens, California is likely to see prolonged drought and drier conditions, especially in the southern portion of the state, said Toby Ault, Cornell assistant professor of earth and atmospheric sciences and lead author of the study, which will be published next month in the American Meteorological Society’s Journal of Climate.

The current drought, he said, is a preview of what will “happen in the future in climate change.”

“I am not trying to say this is imminent,” he said, “but the risk is high.”

Nearly 82 percent of California is experiencing “extreme” drought — the fourth harshest on a five-level scale measured in weekly U.S. Drought Monitor reports. But roughly 58 percent of the state is facing worse, “exceptional” drought conditions.

Using climate model projections, researchers determined that prolonged drought would probably hit New Mexico and Arizona as well as California. On the other hand, the chances for the same conditions affecting parts of Idaho, Washington and Montana may actually decrease.

Megadrought conditions may also strike Australia, southern Africa, and the Amazon, the researchers said.

The risk for a decade-long drought like the 1930s Dust Bowl is even more alarming because researchers say such events occur “on average once or twice per century.”

According to researchers, the findings are important for governments to consider as they develop strategies for coping with the effects of climate change in densely populated areas where megadroughts — “worse than anything seen during the last 2,000 years” — would pose “unprecedented challenges” to water resources.

The severity of future droughts discussed in the report could also worsen as temperatures increase, which may be underestimated even with state-of-the-art global climate models, the scientists warned.

Photo via WikiCommons

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