- Urbanization and climate change combine to heighten danger
- Cloud cover is decreasing in Southern CA and as clouds decrease, that increases the chance of bigger and more intense fires.
- Scientists found that periods of less cloud cover during the summer are correlated neatly with lower vegetation moisture, and thus more danger of fire.
- May 30, 2018 Lamont-Doherty Earth Observatory, Columbia University Read full ScienceDaily article here
- “Cloud cover is plummeting in southern coastal California,” said Park Williams, a bioclimatologist at Columbia University’s Lamont-Doherty Earth Observatory and lead author of the research. “And as clouds decrease, that increases the chance of bigger and more intense fires.” Williams said the decrease is driven mainly by urban sprawl, which increases near-surface temperatures, but that overall warming climate is contributing, too. Increasing heat drives away clouds, which admits more sunlight, which heats the ground further, leading to dryer vegetation, and higher fire risk, said Williams. The study appears this week in the journal Geophysical Research Letters…
…The catastrophic California-wide fires that consumed over 550,000 acres in fall of 2017 were probably not strongly affected by the reductions in summer cloud cover, said Williams. Although he did find that vegetation is drier in fall seasons that follow summers with few clouds, the fall 2017 fires were driven mainly by extreme winds and a late onset of the fall rainy season. And ironically, part of this record wildfire wave resulted not from a recent record four-year drought driven in part by climate change, but rather from record rains that followed the drought, which produced a surfeit of flammable vegetation…
A. Park Williams, Pierre Gentine, Max A. Moritz, Dar A. Roberts, John T. Abatzoglou. Effect of reduced summer cloud shading on evaporative demand and wildfire in coastal southern California. Geophysical Research Letters, 2018; DOI: 10.1029/2018GL077319
May 29 2018 Read full Reuters article here
(Reuters Health) – Hurricane Maria claimed the lives of 4,645 people in Puerto Rico last year and not the 64 long pegged by the island’s government as the official death toll, according to a survey of thousands of residents by a research team led by Harvard University.
The researchers estimated that most victims of the storm died between Sept. 20 and Dec. 31, 2017, as a direct or indirect result of Puerto Rico’s worst natural disaster in 90 years. One-third perished because of delayed or interrupted medical care.
While cautioning that the estimate of 4,645 victims may be too low, the researchers said the numbers “underscore the inattention of the U.S. government to the frail infrastructure of Puerto Rico.”
The tally, reported online on Tuesday in the New England Journal of Medicine, is likely to be controversial because it is far higher than previous independent estimates….
- The warmer the ocean surface gets, the more surfactants we can expect, and an even greater reduction in gas exchange
- Findings have major implications for predicting our future climate.
Researchers from Heriot-Watt, Newcastle and Exeter universities say the findings, published in the journal Nature Geoscience on Monday, have major implications for predicting our future climate.
The world’s oceans absorb around a quarter of all man-made carbon dioxide emissions, making them the largest long-term sink of carbon on Earth. Greater sea turbulence increases gas exchange between the atmosphere and oceans and until now it was difficult to calculate the effect of “biological surfactants.”
….They found surfactants can reduce carbon dioxide exchange by up to 50%. Dr Ryan Pereira, a Lyell research fellow at Heriot-Watt University in Edinburgh, said: “As surface temperatures rise, so too do surfactants, which is why this is such a critical finding. The warmer the ocean surface gets, the more surfactants we can expect, and an even greater reduction in gas exchange.”…
….Scientists say the surfactants are not necessarily visible like an oil slick or foam and are difficult to identify from satellites monitoring our ocean’s surface. They say they need to be able to identify organic matter on the surface microlayer of the ocean so they can reliably estimate gas exchange rates such as carbon dioxide and methane….
Ryan Pereira, Ian Ashton, Bita Sabbaghzadeh, Jamie D. Shutler & Robert C. Upstill-Goddard. Reduced air–sea CO2 exchange in the Atlantic Ocean due to biological surfactants. Nature Geoscience (May 28, 2018)
- Beaver ponds were shown to hold large volumes of sediment and associated nutrients.
- The beavers’ enclosure, roughly the size of three (American) football fields and situated on a stream below a farm, originally contained one small pond… and is now a wetland mosaic regulated by dams and canals, and the ponds are slowly filling with sediment — 101 tons of it to date, estimate Brazier’s team.
- Some of that sediment was generated by the beavers’ own digging. The vast majority, though, is eroded soil from the adjacent farmland. Altogether the sediments contain 16 tons of carbon — representing, were every last ounce of it sequestered permanently, the average yearly carbon emissions of six British citizens.
Puttock et al. “Sediment and Nutrient Storage in a Beaver Engineered Wetland. Earth Surface Processes and Landforms.” Earth Surface Processes and Landforms, 2018.
AND see this article about this study: The tremendous benefits provided by just one beaver family Anthropocene Magazine May 30 2018
Beavers, primarily through the building of dams, can deliver significant geomorphic modifications and result in changes to nutrient and sediment fluxes. Research is required to understand the implications and possible benefits of widespread beaver reintroduction across Europe. This study surveyed sediment depth, extent and carbon/nitrogen content in a sequence of beaver pond and dam structures in South West England, where a pair of Eurasian beavers (Castor fiber) were introduced to a controlled 1.8 ha site in 2011. Results showed that the 13 beaver ponds subsequently created hold a total of 101.53 ± 16.24 t of sediment, equating to a normalised average of 71.40 ± 39.65 kg m2. The ponds also hold 15.90 ± 2.50 t of carbon and 0.91 ± 0.15 t of nitrogen within the accumulated pond sediment.
The size of beaver pond appeared to be the main control over sediment storage, with larger ponds holding a greater mass of sediment per unit area. Furthermore, position within the site appeared to play a role with the upper‐middle ponds, nearest to the intensively‐farmed headwaters of the catchment, holding a greater amount of sediment. Carbon and nitrogen concentrations in ponds showed no clear trends, but were significantly higher than in stream bed sediment upstream of the site.
We estimate that >70% of sediment in the ponds is sourced from the intensively managed grassland catchment upstream, with the remainder from in situ redistribution by beaver activity. While further research is required into the long‐term storage and nutrient cycling within beaver ponds, results indicate that beaver ponds may help to mitigate the negative off‐site impacts of accelerated soil erosion and diffuse pollution from agriculturally dominated landscapes such as the intensively managed grassland in this study.
Results presented in this paper illustrate that beavers can exert a significant impact upon sediment and nutrient storage. Beaver ponds were shown to hold large volumes of sediment and associated nutrients. Results also suggest that, whilst pond age and deposition in a dam–pond sequence may play a role in sediment and nutrient storage, the clearest control was pond size, with larger ponds holding more sediment per unit area.
Unlike most previous work, this study focused on a site located within an intensively managed grassland landscape. It was inferred that the majority of sediment trapped in the ponds originated from erosion in the upstream intensively managed grassland catchment, therefore, beaver dams mitigated the loss of this sediment downstream. While further understanding of the long‐term stability of sediment and nutrient storage in beaver ponds is now required, findings presented in this study have important implications for understanding the role beavers may play as part of catchment management strategies.
- Automated rain gauges in and around Catonsville, at ground zero, recorded nearly 13 to 15 inches of rain over ~3 hours. The National Weather Service received a gauge report of 8.4 inches in Ellicott City.
- These types of extreme floods are probably becoming more common, in areas that are normally rainy as a result of global warming
By Jeff Halverson May 28 2018 Read full WashPost article here
Ruined once more, Ellicott City endured an hours-long cloudburst that drowned the town Sunday. To witness this disaster unfold again, less than two years after the previous flood catastrophe, is nearly unthinkable. Call it Flood City, USA, for a location that has flooded 15 times, at the hand of storms, since 1768.
A waterlogged weather pattern, Ellicott City’s flood-prone geography and climate change all conspired to make this latest flash-flood horror show….
…climate change has probably altered the larger environment in which these small thunderstorms are embedded. Notably, the water vapor content of the atmosphere, as a whole, has increased and scientific studies have shown a statistically meaningful uptick in the frequency of extreme rain events over the eastern United States. Statistically, over the long term, these types of extreme floods are probably becoming more common, in areas that are normally rainy as a result of global warming….
- Findings project that the atmospheric rivers will be, on average, about 25 percent wider and longer, the global frequency of atmospheric river conditions — like heavy rain and strong winds — will increase by about 50 percent.
- The frequency of the most intense atmospheric river storms is projected to nearly double.
By Esprit Smith,NASA’s Jet Propulsion Laboratory May 24, 2018 Read the full article here at NASA’s Vital Signs of the Planet Blog (with thanks to Maven’s Notebook)
A new NASA-led study shows that climate change is likely to intensify extreme weather events known as atmospheric rivers across most of the globe by the end of this century, while slightly reducing their number.
The new study projects atmospheric rivers will be significantly longer and wider than the ones we observe today, leading to more frequent atmospheric river conditions in affected areas.
“The results project that in a scenario where greenhouse gas emissions continue at the current rate, there will be about 10 percent fewer atmospheric rivers globally by the end of the 21st century,” said the study’s lead author, Duane Waliser, of NASA’s Jet Propulsion Laboratory in Pasadena, California. “However, because the findings project that the atmospheric rivers will be, on average, about 25 percent wider and longer, the global frequency of atmospheric river conditions — like heavy rain and strong winds — will actually increase by about 50 percent.”
The results also show that the frequency of the most intense atmospheric river storms is projected to nearly double….
- A new analysis compares 22 named storms with possible hurricanes of the future.
- The number of hurricanes and amount of rainfall are expected to increase– increasing concerns regarding coastal development.
- The rainfall rate of simulated future storms would increase by an average of 24 percent.
- Hurricane Harvey produced more than 4 feet of rain in some locations, breaking records and causing devastating flooding across the Houston area.
- May 21, 2018 National Science Foundation Read full ScienceDaily article here
- Scientists have developed a detailed analysis of how 22 recent hurricanes would be different if they formed under the conditions predicted for the late 21st century.
- …Hurricane Ike — which killed more than 100 people and devastated parts of the U.S. Gulf Coast in 2008 — could have 13 percent stronger winds, move 17 percent slower, and be 34 percent wetter if it formed in a future, warmer climate.
….”Our research suggests that future hurricanes could drop significantly more rain,” said NCAR scientist Ethan Gutmann, who led the study. “Hurricane Harvey demonstrated last year just how dangerous that can be.”
Harvey produced more than 4 feet of rain in some locations, breaking records and causing devastating flooding across the Houston area.
…”This study shows that the number of strong hurricanes, as a percent of total hurricanes each year, may increase,” said Ed Bensman, a program director in NSF’s Division of Atmospheric and Geospace Sciences, which supported the study. “With increasing development along coastlines, that has important implications for future storm damage.”….
Ethan D. Gutmann, Roy M. Rasmussen, Changhai Liu, Kyoko Ikeda, Cindy L. Bruyere, James M. Done, Luca Garrè, Peter Friis-Hansen, Vidyunmala Veldore. Changes in Hurricanes from a 13-Yr Convection-Permitting Pseudo–Global Warming Simulation. Journal of Climate, 2018; 31 (9): 3643 DOI: 10.1175/JCLI-D-17-0391.1
- Seagrass meadows help to support world fisheries productivity
- “The chasm that exists between coastal habitat conservation and fisheries management needs to be filled to maximise the chances of seagrass meadows supporting fisheries, so that they can continue to support human wellbeing”
- May 21, 2018 Swansea University Read full ScienceDaily article here
- “Scientific research has provided the first quantitative global evidence of the significant role that seagrass meadows play in supporting world fisheries productivity… The study provides evidence that a fifth of the world’s biggest fisheries, such as Atlantic Cod and Walleye Pollock are reliant on healthy seagrass meadows. The study also demonstrates the prevalence of seagrass associated fishing globally….
….Dr Unsworth said: “The coastal distribution of seagrass means it is vulnerable to a multitude of both land and sea based threats, such as land runoff, coastal development, boat damage and trawling. There is a global rapid decline of seagrass and when seagrass is lost there is strong evidence globally that fisheries and their stocks often become compromised with profound negative economic consequences. To make a change, awareness of seagrasses role in global fisheries production must pervade the policy sphere. We urge that seagrass requires targeted management to maintain and maximise their role in global fisheries production.”
Richard K.F. Unsworth, Lina Mtwana Nordlund, Leanne C. Cullen-Unsworth. Seagrass meadows support global fisheries production. Conservation Letters, 2018; e12566 DOI: 10.1111/conl.12566
- Just 5 percent of California farmers use cover cropping, but that’s likely to increase as researchers work to quantify the amount of water that can be saved by the practice and its benefit for river ecosystems.
- Funded by a $779,000 grant through the Natural Resources Conservation Service, the Freshwater Trust is developing a data-driven system to demonstrate the on-the-ground benefits of cover cropping – and those below the ground, too- water and carbon.
Jane Braxton Little May 15 2018 Read full NewsDeeply article here
….Cover cropping, an agricultural technique as old as dirt, is taking root in California. Used to enhance soil nutrition and improve the growth of plants, it fell out of favor after World War II when the practice was replaced by the use of chemical fertilizers.
Today just 5 percent of California growers are using cover crops – and 3 percent nationwide – but that’s likely to change.
Farmers have used off-season plantings for millennia to build soil and keep it from blowing or washing away. Like their predecessors, walnut and almond growers are using these seasonal noncash crops to hold in moisture and provide habitat.
Farmers are also returning to the practice to curb the effects of a changing climate. As hotter and drier conditions hit most of the state, Central Valley growers are planting grasses and legumes under their trees to increase the carbon and nitrogen in their soils….
….The use of cover crops is definitely on the rise in the northern Sacramento Valley, said Sara Tiffany. As a specialist with the Community Alliance of Family Farmers Climate-Smart Farming program, she works with growers not represented by larger agricultural organizations. …