The public tends to blame habitat loss and pesticides for the declining butterfly populations in...
Edith’s checkerspot (Euphydryas editha) is one of the species declining in at least two datasets quoted in the Science publication. (Photo courtesy of Walter Siegmund, Wikipedia)
Edith’s checkerspot (Euphydryas editha) is one of the species declining in at least two datasets quoted in the Science publication. (Photo courtesy of Walter Siegmund, Wikipedia)
UC Davis distinguished professor Art Shapiro monitoring butterfly populations along Gates Canyon Road, Vacaville. This image was taken Jan. 25, 2014. (Photo by Kathy Keatley Garvey)
UC Davis distinguished professor Art Shapiro monitoring butterfly populations along Gates Canyon Road, Vacaville. This image was taken Jan. 25, 2014. (Photo by Kathy Keatley Garvey)
Posted on
Friday, March 5, 2021 at
1:45 PM
Focus Area Tags: Environment, Health, Yard & Garden
From their website:
"The Global Earth Repair Conference will bring 500 or more people...
Posted on
Monday, March 11, 2019 at
10:57 AM
Focus Area Tags: Environment
Reposted from UC Davis News
Scientists at the University of California, Davis, are taking the temperature — and other measurements — of lakes of all sizes and shapes throughout the mountains of California to see how climate change is affecting them and what, perhaps, can be done about it.
A study published this month in the journal Limnology and Oceanography Letters shows that, despite rapidly warming air temperatures, spring snowpack is the biggest predictor of summer warming in small Sierra Nevada lakes.
The study examined more than 30 years of climate and lake temperature data at Emerald Lake, a long-term study site in Sequoia National Park. It was led by UC Davis with colleagues at UC Santa Barbara and UC Riverside.
Benthic chambers measure sediment metabolism at a small Sierra Nevada lake in August 2018. (E. Suenaga)
High rates of warming air
The researchers found that summer air temperatures at Emerald Lake are warming at a rate of 1.0 degree Celsius, or 1.5 degrees Fahrenheit, per decade.
“That's huge,” said lead author Steven Sadro, a UC Davis assistant professor in the Department of Environmental Science and Policy and a member of the Tahoe Environmental Research Center. “That's as high a rate of warming as nearly anywhere on the planet. It's also consistent with what you'd find in a lot of mountain regions, which are warming at rates as high as those seen in the Arctic, in many cases.”
Yet these small alpine lakes are somewhat buffered from the higher air temperatures because they respond primarily to variation in the snow. The amount of snow controls when the lake becomes free of ice and can absorb radiation from the sun, which heats the water.
“That's not to say that there is no climate warming signal,” said Sadro. “In drought years, when the role of snow is small, we find a warming trend consistent with the rate of warming found in other lakes throughout the world.”
Climate affects phytoplankton, too
A companion study conducted at Emerald Lake and published in June in the journal Water Resources Research found that changes in snowpack also increased the abundance of phytoplankton in Emerald Lake. If droughts continue to be more frequent, high-elevation lakes in the Sierra are expected to become more productive. Researchers are not yet certain how that might affect the lakes. More phytoplankton could mean more food for lake organisms, but it could also impact lake clarity, which is often an indicator of ecosystem health.
Together, the papers show that yes, climate change is impacting these lakes and that its effects are somewhat buffered by snowpack. But what that means for the greater ecology of the area is still unclear.
A current project may provide additional answers.
Adrianne Smits, a NSF postdoctoral fellow at UC Davis, deploys a mooring in a Yosemite lake. (E. Suenaga)
There are upwards of 14,000 small lakes in the Sierra Nevada. This past summer, UC Davis limnologists and colleagues began installing high-frequency instruments in nearly 20 of these lakes, which stretch from Castle Lake in Northern California to Emerald Lake in the southern Sierra.
The project is called the California Mountain Lake Observatory Network, and it's being conducted through Sadro's lab by Adrianne Smits, a National Science Foundation Postdoctoral Fellow at UC Davis.
As weather events occur, be they storm, drought, wildfire or clear skies, the instruments capture data about water temperature, dissolved oxygen, light levels and other factors. Data from these lakes will be used to develop models to help predict how all the other lakes in the Sierra are responding to changes in climate.
“Castle and Emerald lakes are both long-term study sites, and together they provide unique bookends to the entire Sierra Nevada mountain range,” Sadro said. “We're trying to fill in everything in between to better predict how lakes across the Sierra are expected to change.”
This ongoing research could help resource managers identify which lakes are most sensitive to climate impacts and target them for mediation.
The analysis for the two published studies was made possible because of long-term research support for Emerald Lake and the Tokopah watershed since the early 1980s from the National Science Foundation, National Oceanic and Atmospheric Association, National Aeronautics and Space Administration, and the California Air Resource Board.
Co-authors for both studies include John Melack of UC Santa Barbara and James Sickman and Kevin Skeen of UC Riverside.
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Posted on
Wednesday, December 19, 2018 at
2:08 PM
Reposted from UC Berkeley News
A controversial paper published two years ago that concluded there was no detectable slowdown in ocean warming over the previous 15 years — widely known as the “global warming hiatus” — has now been confirmed using independent data in research led by researchers from UC Berkeley and Berkeley Earth, a non-profit research institute focused on climate change.
A NEMO float, part of the global Argo array of ocean sensing stations, deployed in the Arctic from the German icebreaker Polarstern Bremerhaven. (Photo courtesy of Argo)
The 2015 analysis showed that the modern buoys now used to measure ocean temperatures tend to report slightly cooler temperatures than older ship-based systems, even when measuring the same part of the ocean at the same time. As buoy measurements have replaced ship measurements, this had hidden some of the real-world warming.
After correcting for this “cold bias,” researchers with the National Oceanic and Atmospheric Administration concluded in the journal Science that the oceans have actually warmed 0.12 degrees Celsius (0.22 degrees Fahrenheit) per decade since 2000, nearly twice as fast as earlier estimates of 0.07 degrees Celsius per decade. This brought the rate of ocean temperature rise in line with estimates for the previous 30 years, between 1970 and 1999.
This eliminated much of the global warming hiatus, an apparent slowdown in rising surface temperatures between 1998 and 2012. Many scientists, including the International Panel on Climate Change, acknowledged the puzzling hiatus, while those dubious about global warming pointed to it as evidence that climate change is a hoax.
Climate change skeptics attacked the NOAA researchers and a House of Representatives committee subpoenaed the scientists' emails. NOAA agreed to provide data and respond to any scientific questions but refused to comply with the subpoena, a decision supported by scientists who feared the “chilling effect” of political inquisitions.
The new study, which uses independent data from satellites and robotic floats as well as buoys, concludes that the NOAA results were correct. The paper will be published Jan. 4 in the online, open-access journal Science Advances.
“Our results mean that essentially NOAA got it right, that they were not cooking the books,” said lead author Zeke Hausfather, a graduate student in UC Berkeley's Energy and Resources Group.
Long-term climate records
Hausfather said that years ago, mariners measured the ocean temperature by scooping up a bucket of water from the ocean and sticking a thermometer in it. In the 1950s, however, ships began to automatically measure water piped through the engine room, which typically is warm. Nowadays, buoys cover much of the ocean and that data is beginning to supplant ship data. But the buoys report slightly cooler temperatures because they measure water directly from the ocean instead of after a trip through a warm engine room.
A new UC Berkeley analysis of ocean buoy (green) and satellite data (orange) show that ocean temperatures have increased steadily since 1999, as NOAA concluded in 2015 (red) after adjusting for a cold bias in buoy temperature measurements. NOAA's earlier assessment (blue) underestimated sea surface temperature changes, falsely suggesting a hiatus in global warming. The lines show the general upward trend in ocean temperatures. (Zeke Hausfather graphic)
NOAA is one of three organizations that keep historical records of ocean temperatures – some going back to the 1850s – widely used by climate modelers. The agency's paper was an attempt to accurately combine the old ship measurements and the newer buoy data.
Hausfather and colleague Kevin Cowtan of the University of York in the UK extended that study to include the newer satellite and Argo float data in addition to the buoy data.
“Only a small fraction of the ocean measurement data is being used by climate monitoring groups, and they are trying to smush together data from different instruments, which leads to a lot of judgment calls about how you weight one versus the other, and how you adjust for the transition from one to another,” Hausfather said. “So we said, ‘What if we create a temperature record just from the buoys, or just from the satellites, or just from the Argo floats, so there is no mixing and matching of instruments?'”
In each case, using data from only one instrument type – either satellites, buoys or Argo floats – the results matched those of the NOAA group, supporting the case that the oceans warmed 0.12 degrees Celsius per decade over the past two decades, nearly twice the previous estimate. In other words, the upward trend seen in the last half of the 20th century continued through the first 15 years of the 21st: there was no hiatus.
“In the grand scheme of things, the main implication of our study is on the hiatus, which many people have focused on, claiming that global warming has slowed greatly or even stopped,” Hausfather said. “Based on our analysis, a good portion of that apparent slowdown in warming was due to biases in the ship records.”
Correcting other biases in ship records
In the same publication last year, NOAA scientists also accounted for changing shipping routes and measurement techniques. Their correction – giving greater weight to buoy measurements than to ship measurements in warming calculations – is also valid, Hausfather said, and a good way to correct for this second bias, short of throwing out the ship data altogether and relying only on buoys.
Berkeley's analysis of ocean buoy (green) and satellite data (orange) and NOAA's 2015 adjustment (red) are compared to the Hadley data (purple), which have not been adjusted to account for some sources of cold bias. The Hadley data still underestimate sea surface temperature changes. (Zeke Hausfather graphic)
Another repository of ocean temperature data, the Hadley Climatic Research Unit in the United Kingdom, corrected their data for the switch from ships to buoys, but not for this second factor, which means that the Hadley data produce a slightly lower rate of warming than do the NOAA data or the new UC Berkeley study.
“In the last seven years or so, you have buoys warming faster than ships are, independently of the ship offset, which produces a significant cool bias in the Hadley record,” Hausfather said. The new study, he said, argues that the Hadley center should introduce another correction to its data.
“People don't get much credit for doing studies that replicate or independently validate other people's work. But, particularly when things become so political, we feel it is really important to show that, if you look at all these other records, it seems these researchers did a good job with their corrections,” Hausfather said.
Co-author Mark Richardson of NASA‘s Jet Propulsion Laboratory and the California Institute of Technology in Pasadena added, “Satellites and automated floats are completely independent witnesses of recent ocean warming, and their testimony matches the NOAA results. It looks like the NOAA researchers were right all along.“
Other co-authors of the paper are David C. Clarke, an independent researcher from Montreal, Canada, Peter Jacobs of George Mason University in Fairfax, Virginia, and Robert Rohde of Berkeley Earth. The research was funded by Berkeley Earth.
Posted on
Tuesday, January 24, 2017 at
9:50 AM
For Immediate Release
July 7, 2014
BLUESKY BIOCHAR HELPS SOUTHERN CALIFORNIA CITY...
Posted on
Friday, February 5, 2016 at
8:56 PM