Phoenix tries to tackle urban heat with trees, for increased shade. Lake Tahoe and other western lakes face impacts.

In Phoenix, an ambitious plan aims to cover 25% of the metropolis with tree shade, Los Angeles Times, July 25, 2016. With a new emphasis on downtown development and walkable neighborhoods, as well as on increasing climate-change-driven concerns about heat on human health, the city is planning to double its tree canopy.

Warming at alarming rate, Lake Tahoe reflects rapid Sierra climate change, KQED Science, July 28, 2016. The University of California-Davis Tahoe Environmental Research Center reports that the lake has been warming faster than ever recorded – the rise was 15 times faster than the lake’s historic warming rate over the last four years – and that last year the depth at which oxygen-rich surface waters and deeper waters mix was the most shallow ever recorded. The report’s authors noted that during the winter of 2014-2015, just 6.5 percent of precipitation at the lake level fell in the form of snow. Decades ago it was more like a 50-50 mix.

‘We’ve primed the system’: Why disgusting toxic blue-green algae blooms seem increasingly common, Washington Post, July 25, 2016. A summer with unusually widespread blooms of harmful blue-green algae nationwide, including lakes in Utah and Idaho, spotlights recent reports in which scientists say climate change increases the risks of elevated cyanobacterial blooms in waters (see abstracts in Science Direct and Water Research).

Warm water prompts ‘hoot-owl’ fishing restrictions on western Montana rivers, Missoulian, July 28, 2016. Montana Fish, Wildlife and Parks places mandatory fishing closures on many river reaches to reduce stress on cold water species approaching the limits of survivable water temperatures. Most of the closures are from 2 p.m. – midnight, but several are for 24 hours. See also What does climate change mean for America’s $73 billion angling industry?, Ensia, July 15, 2016 and a special issue of Fisheries magazine devoted to climate change.

New report shows how global warming will affect birds and reptiles in the Southwest, Summit County Citizens Voice, July 15, 2016. In a new U.S. Geological Survey report, scientists use a mid-range future emissions scenario (A1B) to project impacts on 31 species, some of which could lose up to 75 percent of their ranges. Species already in fragmented habitats are shown to be particularly at risk.

Blazing hot first half of 2016 sends climate records tumbling, Inside Climate News, July 21, 2016. Scientists at NASA release their first-ever mid-year analysis of climate trends, which reveals that every month between January and June had the warmest average temperature on record for that month.

For the first time, forecast predicts hotter-than-normal in every square inch of the USA, USA Today, July 26, 2016. For the first time on record, every square inch of all 50 states is forecast to see above-average temperatures for the next three months, according to a forecast map from the National Weather Service’s Climate Prediction Center.

U.S. faces dramatic rise in extreme heat, humidity, Climate Central, July 13, 2016. Climate Central’s States at Risk project analyzes historic trends in summer temperatures since 1970 as well as projections for future extreme heat for hundreds of metro areas across the lower 48 states. Using several measures, the findings show that most U.S. cities have already experienced large increases in extreme summer heat and absolute humidity, which together can cause serious heat-related health problems.

The Western Water Assessment, one of ten regional Integrated Sciences and Assessments (RISAs) sponsored by the National Oceanic and Atmospheric Administration, last year began a new research focus designed to assess the risk of extreme events for its region, which covers Colorado, Utah, and Wyoming. Based on the recognition that events like the 2013 Colorado Front Range floods cause the lion’s share of total societal costs related to weather and climate, WWA is exploring how such risks might change in the future, and is examining the performance of adaptation strategies for extreme events. WWA has recently developed the following resources: