Global warming has killed half a billion trees across the U.S.
Scientists tracking massive forest die-offs say a new study may help forest managers learn how to predict which trees will succumb to global warming — and what the implications are for the global carbon balance.
“There are some common threads that we might be able to use to predict which species are going to be more vulnerable in the future,” said University of Utah biologist William Anderegg, explaining that recent tree-killing droughts in the western U.S. were marked more by elevated temperature than by a lack of rainfall.
“These widespread tree die-offs are a really early and visible sign of climate change already affecting our landscapes,” Anderegg said.
NASA, Harvard scientists study wine harvest dates in cool-weather countries
Global warming is changing centuries-old climate patterns that are crucial for wine production in cool-weather regions, a new study from NASA and Harvard concludes. After analyzing climate records and grape harvesting dates from 1600 to 2007, the scientists found that harvests started happening much earlier during the second half of the 20th century.
These shifts were caused by changes in the connection between climate and harvest timing. Between 1600 and 1980, earlier harvests were linked to years with warmer and drier conditions during spring and summer. After that, global warming caused earliers harvests in years without droughts. Continue reading “Global warming is already affecting wine production”→
El Niño didn’t exactly go gangbusters in southwest Colorado last month, where the key river basins received only about 35 percent of average February precipitation. Statewide mountain precipitation was only slightly better, at 56 percent of normal.
“February in the mountains of Colorado is typically a slightly drier month than compared to say, April. But a dry February like this could have big ramifications should April and May not pan out” said Brian Domonkos, Snow Survey Supervisor with the Natural Resources Conservation Service. Continue reading “Climate: U.S. West very dry in February”→
Current regional dry spell appears to be the most severe in more than 900 years
The Mediterranean region may already be feeling the impacts of human-caused climate change, according to a new tree ring study that compared an ongoing drought in the region with historic climate conditions.
Although there are still a few months left in the rainy season, this year’s El Niño hasn’t exactly been the drought buster California was hoping for. Thus far, plentiful precipitation in the northern part of state will go a long way toward replenishing reservoirs, but central and southern California have remained relatively dry.
The “exceptional drought” footprint is now spread across about 38 percent of the state, as compared to 45 percent three months ago, and precipitation in the key snowpack areas of the Sierra Nevada has been about average. Farther south, especially in the L.A. Basin, precipitation is still well below average for the rainy season to date.
Meteorologists say the 2015-2016 El Niño has peaked, but it remains strong and will continue to influence global weather in the months ahead. With eastern and central tropical Pacific Ocean surface temperatures more than 2 degrees Celsius above average in late 2015, this El Niño will go down as one of the strongest on record, although it’s not clear if it was the strongest ever, according to the World Meteorological Organization.
For now, the outlook is that El Niño will fade during the next half year. As typically happens, El Niño reached its peak ocean surface temperature during November and December, but those temperatures have since declined by about half a degree.
“We have just witnessed one of the most powerful ever El Niño events which caused extreme weather in countries on all continents and helped fuel record global heat in 2015,” said WMO Secretary General Petteri Taalas. “In meteorological terms, this El Niño is now in decline. But we cannot lower our guard as it is still quite strong and in humanitarian and economic terms, its impacts will continue for many months to come,” Taalas said. Continue reading “Climate: This year’s El Niño has passed its peak, scientists say”→
‘A normal year in the Southwest is now drier than it once was’
A subtle long-term shift in atmospheric patterns driven by global warming could lead to longer and more intense droughts in the southwestern U.S. and other semi-arid regions. Most climate models suggest that that a belt of higher average pressure that now sits closer to the equator will move north. This high-pressure belt is created as air that rises over the equator moves poleward and then descends back toward the surface.