The Nicholas Institute for Environmental Policy Solutions at Duke University

The Nicholas Institute for Environmental Policy Solutions at Duke University

Scientists have warned that severe drought and precipitation are among the risks of greenhouse-gas-induced climate change, but a study published in the journal Nature finds that extremely warm temperatures do not always translate into record wet and dry extremes. Highlighting the complexities in predicting the effects of planetary warming on precipitation, lead author Fredrik Ljungqvist of Stockholm University said that more dramatic wet-dry weather extremes had occurred in centuries cooler than the 20th century.

“Several other centuries show stronger and more widespread extremes,” he said. “We can’t say it’s more extreme now.”

In this first hemispheric-scale, centuries-long water availability assessment, the researchers statistically analyzed evidence for changes in precipitation and drought, compiling hundreds of precipitation records across the Northern Hemisphere from historical accounts as well as archives on such things as tree-rings and lake sediments.

They detected a pattern of alternating moisture regimes throughout the last 12 centuries, suggesting that “the instrumental period is too short to capture the full range of natural hydroclimate variability.”

Their finding that the last century’s temperature rise may not have affected the hydroclimate as much as previously thought challenges the conclusions of the United Nations Intergovernmental Panel on Climate Change.

In a News and Views article published in Nature, Matthew Kirby of California State University at Fullerton suggested that current climate models should not be discarded because their results, which indicate that “dry gets dryer and wet gets wetter,” do not match the Ljungqvist team’s proxy results, which indicate no difference in the water dynamics of the 20th century and those of the pre-industrial era.

“Do their results invalidate current predictive models?” Kirby asked. “Certainly not. But they do highlight a big challenge for climate modellers, and present major research opportunities both for modellers and for climate scientists who work with proxy data.”

Study: Climate Change Causing Earth to Shift

A study published in the journal Science Advances reveals that climate change affects how Earth tilts on its axis. Although scientists have known that Earth’s spin axis has been drifting due to ice cap melt in Greenland and Antarctica, the new research suggests that changes in terrestrial water storage also play a role in the planet’s decadal axis swings. The finding is based on data collected from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite, which can detect changes in the mass of Earth’s ice sheets and oceans.

Before 2000, Earth’s spin axis was moving westward toward Canada, but since then, climate-change-driven ice loss has pulled the direction of drift eastward approximately seven inches a year—a shift that lead researcher Surendra Adhikari of NASA’s Jet Propulsion Laboratory described as “very dramatic” and that scientists say is meaningful.

“This is the first time we have solid evidence that changes in land water distribution on a global scale also shift which direction the axis moves to,” said Adhikari.

Although the study data doesn’t indicate whether the most recent shift in the pole is the result of human activities, the study authors think they will be able to use them to tease out man-made climate change later this year. Because polar motion and climate variability appear to be linked, scientists can examine historical records of the pole’s motion in relation to changes in Earth’s climate. If those changes are less dramatic than the ones evidenced today, scientists could assert that global warming has a controlling influence on Earth’s poles.

U.N. Climate Agreement Terms Studied, Launch Pegged Early

Next week on Earth Day (April 22), 130 countries are expected to sign the Paris Climate Agreement, which has a goal of limiting average surface temperatures to “well below” 2 degrees Celsius. But already the United Nations Intergovernmental Panel on Climate Change is looking into the feasibility of what U.N. Climate Chief Christiana Figueres describes as “a moonshot”: limiting global emissions to 1.5 degrees Celsius.

Figueres believes the Paris agreement will take effect in 2018—two years sooner than currently slated.

The agreement will come into force once 55 parties representing 55 percent of the world’s total emissions have both signed and ratified it.

The Climate Post offers a rundown of the week in climate and energy news. It is produced each Thursday by Duke University’s Nicholas Institute for Environmental Policy Solutions.

The Nicholas Institute for Environmental Policy Solutions at Duke University

The Nicholas Institute for Environmental Policy Solutions at Duke University

President Barack Obama announced a series of steps that aim to tackle the effects of climate change on the health of Americans. These 150 health-focused actions to boost climate change preparedness expand on the Climate Data Initiative launched a year.

“The sooner we act, the more we can do to protect the health of our communities, our kids, and those that are the most vulnerable,” the White House said in a statement. “As part of the administration’s overall effort to combat climate change and protect the American people, this week, the administration is announcing a series of actions that will allow us to better understand, communicate, and reduce the health impacts of climate change on our communities.”

Beyond the list of initiatives—including expanding access to climate and health data, improving air quality data and convening a climate change and health summit—the administration released a draft report on the observed and future impacts of climate change on our health. It focuses on risks such as weather extremes, air quality and water-and food-related issues that could affect Americans and is open for public comment. A final draft is expected for release in early 2016.

Another report by the Centers for Disease Control and Prevention, Adaptation in Action, highlights successful actions by state leaders in Arizona, California, Maine, Michigan, Minnesota and New York to reduce the health impacts of climate change.

Study Forecasts Canadian Glacier Loss; Could Have Wider Implications

A new study published in the journal Nature Geoscience predicts how much glaciers in western Canada will shrink—as much as 70 percent by 2100—depending on the rate of carbon dioxide added to the atmosphere between now and the end of the century.

“Over the next century, there is going to be a huge loss,” said lead author Garry Clarke of the University of British Columbia. “The glaciers are telling us that we’re changing the climate.”

The study—the first to model many glaciers in detail at one time—could have implications for predicting glacier loss around the world. New Scientist reports that unlike previous studies—including one by the Intergovernmental Panel on Climate Change—this Nature Geoscience study relies on detailed analysis of how glaciers are likely to move and change shape as they melt. The earlier studies relied on the difference between the amount of snow falling on the glacier at higher altitudes and the amount of thawing at lower ones.

Climate Change Triggers Rising Tide of Troubles for California

Last week the Risky Business Project released its third report on the economic impacts of climate change, a report calling on business leaders to push for policy reform and to factor climate change into their businesses’ risk models.

From Boom to Bust? Climate Risk in the Golden State describes how extreme heat and shifting precipitation patterns from escalating climate change will drain California’s water supply, worsen drought and wildfire, and undermine agriculture. Rising temperatures will also lead to decreased labor productivity, increased energy costs, and greater air pollution. Human health and property will be put at risk: a doubling or tripling of the number of days with temperatures exceeding 95 degrees Fahrenheit could contribute to nearly 7,700 additional heat-related deaths per year by century’s end, and rising sea levels along the California coast could submerge $10 billion in property by 2050. 

The report was published the same day that California Gov. Jerry Brown placed first-ever mandatory water restrictions on all Californians, a response to the state’s fourth year of drought, which has already challenged many of the state’s businesses. The executive order calls for a 25 percent slash in water use and comes as the Sierra Nevada snowpack, which Californians rely on heavily for summertime water needs, neared a record low.

The Climate Post offers a rundown of the week in climate and energy news. It is produced each Thursday by Duke University’s Nicholas Institute for Environmental Policy Solutions.