Water Cycle is Speeding Up Over Much of the U.S.

Regions with weakening water cycles and low soil moisture should be carefully tracked over the next few decades because they could become increasingly dry. That would make agriculture more difficult or require more irrigation.

Read more here. NASA Earth Observatory image by Lauren Dauphin, using data from Huntington, Thomas, et al. (2018). Story by Kasha Patel. Image shows difference in water intensity from January 1, 1945 – December 31, 2014.

In new research, scientists from the U.S. Geological Survey (USGS) showed that there has been an increase in the flow between the various stages of the water cycle over most the U.S. in the past seven decades. The rates of ocean evaporation, terrestrial evapotranspiration, and precipitation have been increasing. In other words, water has been moving more quickly and intensely through the various stages.

“As the planet warms we anticipate that the warmer air, which holds more moisture, will lead to more evaporation and precipitation,” said Tom Huntington, the study’s first author and a research hydrologist at USGS. “If those processes are increasing, it is evidence for an intensifying water cycle. But no one had really shown that trend quantitively.” Until now….

Huntington said these regions with weakening water cycles and low soil moisture should be carefully tracked over the next few decades because they could become increasingly dry. That would make agriculture more difficult or require more irrigation. On the other hand, too much rain or soil moisture storage, such as in the northeast U.S. or Texas, could lead to increased flooding. ..

Megadroughts Are Likely Coming to the US Southwest Within Decades, Scientists Say

Climate change is ‘almost assured’ to cause decades-long droughts in the American Southwest not seen since medieval times, scientists warn in a new study.

by Madeleine Gregory See full Vice article here

In medieval times, the US Southwest was routinely struck by decades-long droughts. Those megadroughts stopped around 1600, but climate change could bring them back.

In a study published on Wednesday in Science Advances, researchers from Columbia’s Earth Institute used climate models to study what caused the megadroughts. Using historical climate data, they determined that two things were to blame: changing ocean temperatures and excess energy trapped inside the Earth’s atmosphere (called radiative forcing)….

“Having paleoclimatic evidence shows you what happened in the past,” lead author Nathan Steiger said over the phone. “It helps verify projections that say the American Southwest is almost assured to have a megadrought in the next few decades.” …

According to the study, the biggest driver of these historical megadroughts were La Niña events, which made the Pacific Ocean unseasonably cold, pushing the storm path north towards Washington and British Columbia. A warmer Atlantic played a smaller role, shifting a high pressure system that blocked storms from rolling over the continental US. “Both a warm Atlantic and a cold Pacific change where storms go,” Steiger said. “They both result in fewer storms going to the Southwest.”

Four years after California’s largest dam removal project, Steelhead trout numbers are growing, a model for other projects nationwide

by Paul Roger Read full Mercury News article here

The destruction of the [10-story] San Clemente Dam [along the Carmel River near Monterey], which had blocked the river since 1921, remains the largest dam removal project in California history. It’s still early, but one of the main goals of the project seems to be on track: The river is becoming wilder, and struggling fish populations are rebounding.

…. The 106 foot-tall dam had been located 18 miles up river from Monterey Bay. In 2016, the first year after it was removed, researchers found that no steelhead trout, an iconic type of rainbow trout listed as threatened under the Endangered Species Act, swam past its former site to a tagging location seven miles upriver. By 2017, seven steelhead had made the trip. Last year, the count was 29. So far this year, 123 steelhead have traveled upriver.

… The broader lesson, scientists say, is one of hope. Despite declines in other species, some wildlife species — from the Great Plains bison to Pacific gray whales to bald eagles — have rebounded significantly, despite plummeting close to extinction, after humans recognized what was killing them and corrected it. For bison and whales, it was hunting. For bald eagles, it was the now-banned chemical DDT. For steelhead trout, dams built across the West over the past century blocked their ability to swim to the ocean and return upriver to spawn, crashing their populations….

… Crews recycled the dam’s steel. They broke the concrete pieces ranging in size from softballs to boulders. They buried the debris in the sediment pile and covered it with willows, sycamores and other native plants. They built rocky step-pools, each one foot higher than the previous one so the fish could migrate upriver more easily. ,,

Dangerous decline of nature and increase in species extinctions unprecedented in human history- New UN report

“The health of ecosystems on which we and all other species depend is deteriorating more rapidly than ever. We are eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide.” The five direct drivers of change in nature with the largest relative global impacts so far are, in descending order: (1) changes in land and sea use; (2) direct exploitation of organisms; (3) climate change; (4) pollution and (5) invasive alien species.

Read Policymakers Summary here (Pdf), press release here and ScienceDaily coverage here.

Nature is declining globally at rates unprecedented in human history — and the rate of species extinctions is accelerating, with grave impacts on people around the world now likely, per a new report from the UN’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES)… More than 1,000,000 species- or ~25% of all species- are threatened with extinction. Transformative changes are needed to restore and protect nature for our well-being.

Findings include:

  • Three-quarters of the land-based environment and about 66% of the marine environment have been significantly altered by human actions. On average these trends have been less severe or avoided in areas held or managed by Indigenous Peoples and Local Communities.
  • More than a third of the world’s land surface and nearly 75% of freshwater resources are now devoted to crop or livestock production…

….Compiled by 145 expert authors from 50 countries over the past three years, with inputs from another 310 contributing authors, the Report assesses changes over the past five decades, providing a comprehensive picture of the relationship between economic development pathways and their impacts on nature. It also offers a range of possible scenarios for the coming decades.

Based on the systematic review of about 15,000 scientific and government sources, the Report also draws (for the first time ever at this scale) on indigenous and local knowledge, particularly addressing issues relevant to Indigenous Peoples and Local Communities.

“Biodiversity and nature’s contributions to people are our common heritage and humanity’s most important life-supporting ‘safety net’. But our safety net is stretched almost to breaking point…”

For ease of reference, a number of issues highlighted in the Report are summarized in the ‘Further Information’ section that follows below, specifically on:

…Societal goals – including those for food, water, energy, health and the achievement of human well-being for all, mitigating and adapting to climate change and conserving and sustainably using nature – can be achieved in sustainable pathways through the rapid and improved deployment of existing policy instruments and new initiatives that more effectively enlist individual and collective action for transformative change. Since current structures often inhibit sustainable development and actually represent the indirect drivers of biodiversity loss, such fundamental, structural change is called for. By its very nature, transformative change can expect opposition from those with interests vested in the status quo, but such opposition can be overcome for the broader public good. If obstacles are overcome, commitment to mutually supportive international goals and targets, supporting actions by indigenous peoples and local communities at the local level, new frameworks for private sector investment and innovation, inclusive and adaptive governance approaches and arrangements, multi-sectoral planning and strategic policy mixes can help to transform the public and private sectors to achieve sustainability at the local, national and global levels…

Nitrogen pollution’s path to streams weaves through more forests (and faster) than suspected

Read full ScienceDaily coverage here

Sebestyen et al. Unprocessed atmospheric nitrate in waters of the Northern Forest Region in the USA and CanadaEnvironmental Science & Technology, 2019; DOI: 10.1021/acs.est.9b01276

Scientists have completed one of the largest and longest examinations to trace unprocessed nitrate movement in forests. The team found that some nitrate occasionally moves too fast for biological uptake, resulting in ‘unprocessed’ nitrate bypassing the otherwise effective filter of forest biology.

The study links pollutant emissions from various and sometimes distant sources including industry, energy production, the transportation sector and agriculture to forest health and stream water quality.

“Nitrogen is critical to the biological productivity of the planet, but it becomes an ecological and aquatic pollutant when too much is present,” said Stephen Sebestyen, a research hydrologist with the USDA Forest Service’s Northern Research Station based in Grand Rapids, Minn., and the study’s lead author….

“From public land managers to woodlot owners, there is a great deal of interest in forest health and water quality. Our research identifies widespread pollutant effects, which undermines efforts to manage nitrogen pollution.”

Climate change + population growth set stage for water shortages including in CA, the Southwest; reductions in ag water use will be key to limiting future shortages

Read ScienceDaily article here

Even efforts to use water more efficiently in municipal and industrial sectors won’t be enough to stave off shortages, say the authors of the new study. The results suggest that reductions in agricultural water use will probably play the biggest role in limiting future water shortages.

The new study is part of a larger 10-year U.S. Forest Service assessment of renewable resources including timber, rangeland forage, wildlife and water. …The new study finds climate change and population growth are likely to present serious challenges in some regions of the U.S., notably the central and southern Great Plains, the Southwest and central Rocky Mountain States, and California, and also some areas in the South and the Midwest.

The heart of the new analysis is a comparison of future water supply versus estimated water demand in different water-using sectors, like industry and agriculture….

  1. Thomas C. Brown, Vinod Mahat, Jorge A. Ramirez. Adaptation to Future Water Shortages in the United States Caused by Population Growth and Climate ChangeEarth’s Future, 2019; DOI: 10.1029/2018EF001091

Healthy Soils to Cool the Planet – A Philanthropic Action Guide

See more here about Breakthrough Strategies and read their excellent new guide here (Pdf)

Background from Ellie: Conservatively, managing agricultural soils for soil organic matter can sequester 5 billion tons (Gt) of CO2e out of the atmosphere globally every year, drawing down 50% of what is needed to return to a safe climate by 2050.

The UN IPCC’s recent 1.5C report called soil carbon sequestration as among the cheapest methods with the greatest potential (http://www.ipcc.ch/report/sr15/). Healthy soils are foundational to human well-being, climate stabilization and vibrant ecosystems. The sustainable management and restoration of soils enhance agricultural productivity, fresh water availability, biodiversity, and climate change preparedness with enormous potential to slow and reverse negative impacts such as droughts, floods and more (von Unger, M. & Emmer, I. 2018. Carbon Market Incentives to Conserve, Restore and Enhance Soil Carbon. Silvestrum & TNC).  

Almost all IPCC scenarios that keep us below 2°C of warming include CO2 removal – typically about 10 billion tons CO2 yr-1. Based on the latest estimates from the IPCC, soils management could conservatively pull 5 billion tons of CO2 out of the atmosphere annually on croplands and rangelands by 2050, offering 50% of the needed carbon removal, with zero additional land and water use (D. Bossio, TNC; and, Zomer et al. Global Sequestration Potential of Increased Organic Carbon in Cropland Soils. Scientific Reports 7.; Vermeulen et al, A Global Agenda for Action on Soil Carbon. Nature Sustainability, Jan 2019). Equally important is avoiding future emissions from soil by protecting existing soil carbon stocks in grasslands and wetlands. 

Currently, only 8 governments include soil health in their efforts to achieve the Paris Climate goals (UNFCCC 2015). Yet boosting soil health at scale should be relatively easy to achieve through low-tech sustainable agricultural practices with policy, funding and technical support. There are other natural climate solutions as well such as climate-smart habitat restoration (https://www.sciencebase.gov/catalog/item/59fb62cbe4b0531197b165f8 and Dybala et al. (2018) Carbon sequestration in riparian forests: a global synthesis and meta-analysisGlobal Change Biology. ) and silviculture (https://www.fs.usda.gov/ccrc/topics/silviculture-climate-change).  

Climate change tipping point could be coming sooner — Vegetation and soil may not be able to sequester as much carbon due to variability in soil moisture

A net gain of carbon on the land surface, would actually be almost twice as high if it weren’t for the variability in soil moisture

Columbia University School of Engineering and Applied Science Read full ScienceDaily article here

  • Julia K. Green, Sonia I. Seneviratne, Alexis M. Berg, Kirsten L. Findell, Stefan Hagemann, David M. Lawrence & Pierre Gentine. Large influence of soil moisture on long-term terrestrial carbon uptakeNature, 2019 DOI: 10.1038/s41586-018-0848-x

A new study confirms the urgency to tackle climate change. While it’s known that extreme weather events can affect the year-to-year variability in carbon uptake, and some researchers have suggested that there may be longer-term effects, this study is the first to actually quantify the effects through the 21st century and demonstrates that wetter-than-normal years do not compensate for losses in carbon uptake during dryer-than-normal years, caused by events such as droughts or heatwaves.

…Anthropogenic emissions of CO2 — emissions caused by human activities — are increasing the concentration of CO2 in the Earth’s atmosphere and producing unnatural changes to the planet’s climate system. The effects of these emissions on global warming are only being partially abated by the land and ocean. Currently, the ocean and terrestrial biosphere (forests, savannas, etc.) are absorbing about 50% of these releases — explaining the bleaching of coral reefs and acidification of the ocean, as well as the increase of carbon storage in our forests.

“It is unclear, however, whether the land can continue to uptake anthropogenic emissions at the current rates,” says Pierre Gentine…

Desalination plants produce more waste brine than than previously thought

There’s enough wastewater from the world’s facilities to cover Florida a foot deep—here’s why that’s a potential problem.

By Tik Root Read full National Geographic article here

As clean freshwater has become scarcer around the world—especially in arid regions such as the Middle East and North Africa—those countries that can afford it have increasingly turned to desalination. That energy-intensive process extracts salt from sea (or other saline) water, transforming it into water that’s fit for human consumption. There are now nearly 16,000 desalination plants either active or under construction across the globe.

“[But] they don’t just produce desalinated water,” explains Manzoor Qadir, a researcher at the United Nations University in Canada. “They also produce brine.” Brine is the concentrated salt water that’s left after desalination. But Qadir says, “there is no comprehensive assessment” of how much is being produced. …Qadir’s team analyzed available literature as well as a database of roughly 20,000 desalination plants (including some that are no longer active)….

The literature had long assumed a one-to-one ratio. But Qadir’s study found that the average desalination plant actually produced 1.5 times more brine than desalinated water—fifty percent more than previously thought. That translates to 51.8 billion cubic meters of brine each year, which Qadir says is enough to cover all of Florida, a foot deep.

….Arguably best known [deleterious impact of desalination] is the copious amount of fossil fuels that are often used to power the plants, resulting in a significant amount of emissions. Most desalination plants work by reverse osmosis, meaning energy is needed to push water past a membrane at high pressure in order to separate the salt (learn more how it works). A typical plant takes an average of 10 to 13 kilowatt hours of energy per every thousand gallons processed. That energy use adds to the cost of the process. A recent desalination plant in California cost a billion dollars, and now provides about ten percent of the drinking water of the county of San Diego. The cost, and environmental impacts, of this overall industry have spurred researchers to look for alternatives, including developing more efficient separation membranes and desalination units that can be powered by solar energy. (Learn more about these emerging efforts.)

On the intake side, Burt says that small organisms such as fish larvae and coral can get sucked into a plant. But the greater risk comes at the other end of the process, when the brine is put back into the ocean (where the majority of desalination is done)…..

“Brine will be substantially higher in salinity than normal oceanic water,” he said. “The brine discharge is also warm.” Those conditions, he says, can make it more difficult for marine life in the immediate vicinity of the discharge to survive or thrive.

What Burt is more concerned about, however, are the chemicals that are often in the brine. Qadir’s study points to copper and chlorine as particularly troublesome compounds. …