There wasn’t any relief from a wave of worrisome global warming news in the spring of 2016, including a study from Harvard showing how rising temperatures will send ozone levels surging to dangerous highs across parts of the U.S.
Links to our climate and international news reporting …
By Bob Berwyn
Not as much content as usual on Summit Voice this week, but that’s because we were busy reporting elsewhere, with a few noteworthy stories. For example, Austria is holding a presidential election tomorrow (Sunday, Dec. 4) and the election of Donald Trump became an issue in the last few weeks of the campaign. I co-reported a story on the election with the European bureau chief of the Christian Science Monitor, including an interview with an American expat involved in the campaign.
Latest survey tallies more than 100 milion dead trees
California’s long-term drought has claimed another 36 million trees, the U.S. Forest Service said this week, announcing the results of a new aerial survey. Since 2010, more than 100 million trees have died across 7.7 million acres, the agency said.
The die-off intensified in 2016, after four years of drought, with mortality increasing 100 percent. Millions of additional trees are weakened and expected to die in the coming months and years. Forest Service leaders once again emphasized that their ability to address safety issues linked with dead trees has been severely hampered by climate change and limited resources.
Draft document highlights global warming threats to state
Colorado Governor John Hickenlooper says a “shifting climate” threatens many of the state’s vital industries, including skiing and agriculture, and he wants the state’s power plants to cut greenhouse gas emissions by 35 percent in the next 15 years from 2012 levels. The goals are outlined in a draft version of an executive order on mitigating and adapting to climate change, which spells out some specific threats of global warming that are already well-known, including:
Greater air pollution will lead to a more hospital admissions and increased cases of respiratory illness;
Changes in precipitation can adversely impact the amount and quality of Colorado’s water resources;
Changes in runoff patterns, intense precipitation, and rising temperatures can negatively affect food production and result in greater risk of food contamination and waterborne illness.
Some climate models project more rainfall in the West
While most recent research suggests that the Colorado River will be depleted well beyond current demands as global temperatures increase, there may be one small bright spot on the horizon. Even if runoff from snow declines, groundwater replenishment in the basin may hold stead under projected increases in precipitation, the U.S. Geological Survey and U.S. Bureau of Reclamation found in a new study.
“You can’t manage what you don’t measure,” said Fred Tillman, lead author and USGS scientist. “These results are the first step in understanding the quantity of groundwater we can expect in the Upper Colorado River Basin; however, further studies are needed to help more accurately forecast future groundwater availability.”
The Colorado River is a critically important source of water for more than 35 million people in the United States and 3 million people in Mexico. As much as half the water flowing in the rivers and streams in the Upper Colorado River Basin originates as groundwater. Understanding how much groundwater is available and how it’s replenished is important to sustainably manage both groundwater and surface water supplies in the Colorado River basin now and in the future.
In the new study, USGS and Reclamation scientists estimated projected changes in groundwater recharge for the Upper Colorado River Basin from recent historical (1950–2015) through future (2016–2099) time periods using climate projections and a groundwater-recharge model.
Simulated future groundwater recharge through 2099 is generally expected to be somewhat greater than the historical average in most decades due to an anticipated wetter future climate in the basin under the most advanced climate modeling projections. Groundwater resources are replenished through increases in precipitation, which may offset reductions from increased temperatures. The full report is available online in the journal Geophysical Research Letters.
But researchers urged caution interpreting the results because a few of the models suggested decreased future recharge relative to the historical climate period.
Deadly heatwaves and flooding part of emerging pattern of extremes
Blistering, record heat in the Southwest helped propel the lower 48 states to a new high-temperature record in June, with an average reading of 71.8 degrees Fahrenheit for the month. That included a new monthly temperature record set in Death Valley National Park, where the average temperature in June was 101.9 degrees Fahrenheit.
The warmest-ever June reading broke the record set during the Dust Bowl era, in 1933, according to NOAA’s National Centers for Environmental Information. The year-to-date is the third-warmest on record, the monthly state of the climate summary report said.
Climate change is wiping out forests on a staggering scale
California’s multiyear drought killed even more trees than previously thought, the U.S. Forest Service announced this week. Aerial and ground surveys show that 26 million trees across six counties in Southern California died, in addition to the 40 million trees that died statewide from 2010 to October 2015. Four years of drought, high temperatures and an outbreak of tree-killing bark beetles all contributed the historic levels of tree die-off, the agency said.
Around the same time, pine beetles started spreading across northern Colorado, parts of Wyoming and North Dakota, ultimately killing millions of acres of forest. And just as the pine beetle infestation waned, a spruce beetle outbreak in southern Colorado started to spread. Since 1996, spruce beetles have killed trees across about 1.5 million acres of forest.