100% Clean Energy Economy Is Much Closer Than You Think
Imagine: Your workday is done and when you walk to the parking lot, the first thing you do is unplug your vehicle from the office building where it's been soaking up electricity from rooftop solar panels all day. You hit the road and, as usual, there are no delays. With all the cars networked together, traffic moves seamlessly, like a flock of birds, using as little energy as possible. On the ride home, you switch to autopilot so you can check your phone to see how your house has been performing.
The rooftop panels there have also been cranking all day, but a lot of their power has gone to the grid, so the home battery isn't fully charged. No worries—the vehicle battery can top it off later. You activate your home air-conditioning, which has been in sleep mode while you were out and, with a swipe of a screen, begin preheating the oven. You look up as you round the bend: There are windmills spinning on the ridgeline.
Is this scenario science fiction? Not as much as you might think. "The future has already arrived," the writer William Gibson once said. "It's just not evenly distributed yet." The same is true of America's impending low-carbon future.
Rooftop solar panels on homes and businesses. Batteries that can power smart, energy-efficient homes. Electric cars and self-driving vehicles. These emerging technologies are with us now. But they're scattered and not yet at scale and they remain pricey in some cases, all of which can make them difficult to see.
The clean energy economy is poorly distributed, in part, because of the political stalemate in Washington, DC, where climate change remains a highly polarized issue. But outside of DC, local leaders from across the political spectrum are preparing for a low-carbon future. Businesses are also joining the effort. Hyper-efficient, clean energy technologies are attracting major investment—at least $310 billion globally in investor capital in 2014, a fivefold increase from a decade earlier—evidence that you don't have to be an environmentalist to believe that the greening of the U.S. is a profitable business opportunity.
"Local solutions are where the real opportunity lies and where the innovation is happening," said Tyler Nickerson of the Solutions Project, a nonprofit cofounded by Mark Jacobson, a Stanford University scientist whose work has helped guide state and local climate plans. "States can do a great deal and cities can do a lot," Jacobson said.
Jacobson has developed a blueprint that shows how the U.S. and the rest of the world can eliminate fossil fuels and transition to 100 percent renewable energy by 2050. His plan for the U.S. relies on solar, wind and water to generate all the electricity we need. Fully electrified systems for transportation, heating and cooling and industrial energy use will make other fuels obsolete.
Does that sound ambitious? It is. And—here's the beauty—it's also achievable. Already, a handful of small cities—Burlington, Vermont; Aspen, Colorado; and Greensburg, Kansas—get all their electricity from renewable energy. Another 12 communities—from Grand Rapids, Michigan, to Georgetown, Texas—have pledged to do so. Earlier this year, the Sierra Club launched its Ready for 100 campaign, which aims to enlist more cities to make a 100 percent clean energy commitment.
So far, the biggest city to set a 100 percent clean energy goal is San Diego. The move by the country's eighth most populous city is precedent setting. For starters, its climate action plan is legally binding, not just a vaguely worded proclamation. Also, the effort was bipartisan and gained the support of the Republican mayor, Kevin Faulconer and the Democratic city council. Even San Diego Gas & Electric, the local utility company, agreed—albeit reluctantly and at the last minute—not to oppose the plan.
In his 2016 State of the City address, Mayor Faulconer cited the climate action plan as one of his proudest accomplishments: "Business groups. Environmentalists. Democrats. Republicans. SDG&E, an industry leader on renewable energy. We brought them all to the table and united around a common-sense plan for a greener and more prosperous future." Faulconer said the plan will create new jobs in the renewable energy industry, improve public health and air quality, conserve water and save the government money.
San Diego is a potent symbol of the energy transition because it is emblematic of our automobile-centric landscapes. Thanks to their higher population densities, older cities such as New York and Chicago are much greener than newer cities in the South and West, suburbs and rural areas. The average carbon footprint of households living in big, dense cities is about 50 percent below the U.S. average.
In comparison, San Diego's 1.4 million people sprawl across some 370 square miles from the Pacific coast to the inland deserts. The place represents the challenges and the opportunities, of making the suburbs sustainable—a crucial goal, given that half of all Americans say they live in suburbia. Suburbs—or suburb-like cities such as San Diego, Phoenix and San Antonio—pose a tough task. Huge single-family homes, gas-guzzling sport-utility vehicles, long commutes, clogged thoroughfares, strip malls, parking lots and wide expanses of lawn that soak up water and fertilizer: The combination is awful for the planet. To reach the 100 percent clean energy goal, suburbs are going to have to change—and they already are.
"San Diego is a big, spread-out city with a lot of residential neighborhoods and low buildings," said Jodie Van Horn, who directs the Sierra Club's Ready for 100 campaign. "It's got a lot of rooftops to fill. So the implementation of 100 percent clean energy with a big emphasis on solar has a lot of potential there and we hope San Diego will inspire other cities to follow suit."
If you look closely, you can glimpse the beginnings of tomorrow's low-carbon suburbs.
Nearly 40 years after President Jimmy Carter installed an array of bulky solar panels on the White House roof, solar technology is experiencing a breakthrough moment. Rooftop photovoltaic solar is booming and in the first three quarters of 2015, the solar industry represented about 30 percent of all new electricity-generating capacity in the U.S.
San Mateo, California-based SolarCity, the nation's leading rooftop installer, has operations in 27 states, employs more than 15,000 people and has 300,000 customers and it's just getting started, said Lyndon Rive, the CEO. "Homes are going to be providing energy to themselves and also to their neighbors and to their communities, perhaps even in the next zip code," Rive said.
As part of Jacobson's plan for a zero-carbon America, electricity will still be produced at big, centralized facilities—hydropower in the Pacific Northwest, concentrated solar in the Southwest and Florida, wind farms in Texas and the Great Plains, offshore wind in the Northeast. But a significant slice of energy generation (about 40 percent of the nation's needs) will shift to the rooftops of homes and businesses or to utility-scale photovoltaic solar installations.
This shift toward decentralization is already under way. Just as mainframe computers have given way to desktops and laptops and landlines are being replaced by mobile phones, distributed solar is poised to replace power plants that burn fossil fuels. Environmental advocates and some policy experts say that using existing buildings to generate electricity is more efficient and has fewer effects on open spaces (compared with utility-scale solar operations, some of which have proved controversial).
Lower prices are a significant factor driving the growth, along with the option to lease rather than buy panels, which eliminates up-front costs of $15,000 or more. A Deutsche Bank analysis of the solar industry predicted that rooftop solar will be the lowest-cost electricity option for most people in the U.S. by the end of 2016, particularly if utilities continue to raise electricity prices. Most homeowners say that saving money is a big reason why they go solar.
Shifts in public policy are helping to drive rooftop solar's success. For example, San Diego's 100 percent clean energy plan relies on a bold idea known as community choice aggregation or CCA. Under such a system, decision-making about electricity generation (which has always been left up to the utilities) is done by city officials, who set the electricity rates and decide where the power will come from, while the utility continues to operate the transmission lines and manage the electrical grid. The elected officials can be held accountable to voters—who, presumably, prefer clean energy to dirty fossil fuels.
CCAs already provide green power in Sonoma and Marin Counties in California as well as in Cleveland, Ohio and Lowell, Massachusetts. More than 2.4 million customers across the U.S. get their energy from CCAs. "We needed a mechanism to break away from the utility," said Nicole Capretz, an environmental advocate who helped write San Diego's plan and now leads the nonprofit Climate Action Campaign. Unlike an investor-owned utility, the CCA will be "mission driven and nonprofit," she said, meaning it will prioritize investments in renewable energy.
There is one obvious challenge to this bright future: A heavy reliance on solar power means that electricity has to be stored somewhere for cloudy days and for use at night. Building better batteries could transform how we produce energy. Cheaper and more powerful batteries will go a long way toward liberating homes from the need to use fossil fuel power from the grid. Homeowners will become energy producers and managers as well as consumers.
That, at least, is the vision of Enphase Energy, a California firm that has begun to sell what it calls a Home Energy Solution, which integrates solar panels, batteries, a smart thermostat and a software platform that enables homeowners to remotely monitor and manage their energy use. "In the long run, everything moves to a distributed architecture," said Raghu Belur, the company's cofounder and director of strategy. "More and more intelligence gets pushed to the periphery of the network."
Tesla, too, has entered the home energy storage market. The company says it will invest $2 billion by 2020 in what it calls a "Gigafactory" near Sparks, Nevada, to produce batteries for its electric cars and for homes. Last fall, the company began selling its seven-kilowatt-hour Powerwall home battery, a unit with enough capacity, the company says, to power homes during the night with energy collected by day. Some experts believe that suburban rooftops will eventually generate so much electricity that they will send the surplus to cities via the batteries of electric vehicles.
Putting solar panels on the roof of a home makes little sense if the electricity is wasted. Fortunately, American homes are becoming much more energy efficient. The average U.S. home today uses 31 percent less energy per square foot than it did in 1970. Unfortunately, homes have also grown 28 percent bigger since then, wiping out most of those gains. If we're going to reach the 100 percent goal, we'll have to break our appetite for super-size dwellings. Some home builders have already gotten the message. One example is Maple Lawn, a planned community midway between Washington, DC and Baltimore. In the last decade, developers have built about 900 homes in the community, which also includes offices, restaurants, retail stores and medical services. Big lawns are rare. Instead, people gather in shared playgrounds and pocket parks.
The newest homes in the development stand out for their efficiency. They rely on geothermal energy systems, which use steady underground temperatures to provide lower-cost heating and cooling and they are wired for solar. The homes score a rating of just 21 on the Home Energy Rating System index, a way of calculating energy performance. In comparison, a standard new home generally gets a rating of about 100, while older homes are rated as high as 150. The ultimate goal? Get homes to zero, which means the buildings produce as much energy as they use.
Ensuring that these pockets of innovation are evenly distributed among all communities won't be easy. For now, many clean energy technologies remain prohibitively expensive for too many U.S. residents. But on this front, too, there are signs of progress. One residential rooftop solar company that operates in the Northeast and Louisiana, PosiGen, has cracked the code on leasing panels to lower-income families while still turning a profit. In Minnesota, where many utilities are organized as local cooperatives, community solar gardens offer residents a chance to buy a green energy "subscription" and tap into clean energy produced by medium-scale plants located in their area. As these and similar companies grow in size, they will be generating local jobs along with clean energy.
Engineers and entrepreneurs can do their part to ensure that the clean energy economy benefits everyone. But ultimately, political organizing and policy reform will be needed to drive change. Near the top of the list is ensuring that polluters have to pay for dumping carbon into the atmosphere. The rooftop solar panels, the smart homes, the highly efficient batteries and the electric vehicles—all of them will spread more rapidly to the mainstream once there's a price to be paid for emitting greenhouse gases.
"The most important thing we need is a price on carbon," SolarCity's Rive said. "Right now, fossil fuels get to pollute for free." But the Republicans who control Congress are loath to tax or regulate greenhouse gases—which is exactly why the local leadership and homegrown solutions are so important. They are laying the foundation for a future that remains in the near distance, at least for now.
But history offers a consolation of sorts. More often than not, social change comes with unlikely speed and from unexpected directions. If people can be persuaded that a clean energy economy means more jobs, less pollution, better health and, ultimately, a more attractive way of life, the transition could happen more quickly than expected. And the unglamorous work of, say, reforming utility regulations will, in hindsight, look like a no-brainer.
"True leadership means setting an ambitious goal and then working toward it, even if you don't know today how exactly you're going to get there," Van Horn said. "The technology's here. The economics are here. The only thing missing is the political will."
This article was funded by the Ready for 100 campaign.
On Thursday, April 22, the world will celebrate Earth Day, the largest non-religious holiday on the globe.
This Earth Day falls at a critical turning point. It is the second Earth Day since the start of the coronavirus pandemic and follows a year of devastating climate disasters, such as the wildfires that scorched California and the hurricanes that battered Central America. But the day's organizers still have hope, and they have chosen a theme to match.
"At the heart of Earth Day's 2021 theme, Restore Our Earth, is optimism, a critically needed sentiment in a world ravaged by both climate change and the pandemic," EarthDay.org president Kathleen Rogers told USA TODAY.
Last Earth Day marked the first time that the holiday was celebrated digitally to prevent the spread of COVID-19. This will largely be the case this year as well.
"Most of our Earth Day events will be virtual with the exception of individual and small group cleanups through our 'Great Global Cleanup' program," EarthDay.org's Olivia Altman told USA TODAY.
Tuesday, April 20: A Global Youth Summit begins at 2:30 p.m. ET featuring young climate activists like Greta Thunberg and Alexandria Villaseñor. This will be followed at 7 p.m. ET by "We Shall Breathe," a virtual summit organized by the Hip Hop Caucus to look at issues like the climate crisis, pollution and the pandemic through an environmental justice lens.
Wednesday, April 22: Beginning at 7 a.m. ET, Education International will lead the "Teach for the Planet: Global Education Summit." Talks will be offered in multiple languages and across multiple time zones to emphasize the importance of education in fighting the climate crisis.
Thursday, April 22: On the day itself, EarthDay.org will host its second ever Earth Day Live digital event beginning at 12 p.m. ET. This event will feature discussions, performances and workshops focusing on the day's theme of restoring our Earth through natural solutions, technological innovations and new ideas.
"EARTHDAY.ORG looks forward to contributing to the success of this historic climate summit and making active progress to Restore Our Earth," Rogers said in a press release. "We must see every country rapidly raise their ambition across all climate issues — and that must include climate education which would lead to a green jobs-ready workforce, a green consumer movement, and an educated and civically engaged citizenry around the world."
EarthDay.org grew out of the first Earth Day in 1970, which drew 20 million U.S. residents to call for greater environmental protections. The movement has been credited with helping to establish the U.S. Environmental Protection Agency and to pass landmark environmental legislation like the Clean Air and Water Acts. It has since gone on to be a banner day for environmental action, such as the signing of the Paris agreement in 2016. More than one billion people in more than 192 countries celebrate Earth Day each year.
This legacy continues. The organization called the scheduling of Biden's summit a "clear acknowledgement of the power of Earth Day."
"This is a critical stepping stone for the U.S. to rejoin the world in combating the climate crisis. In concert with several planned parallel EARTHDAY.ORG events worldwide, Earth Day 2021 will accelerate global action on climate change," EarthDay.org wrote.
Super-emitters are individual sources such as leaking pipelines, landfills or dairy farms that produce a disproportionate amount of planet-warming emissions, especially methane and carbon dioxide. Carbon Mapper, the non-profit leading the effort, hopes to provide a more targeted guide to reducing emissions by launching special satellites that hunt for sources of climate pollution.
"What we've learned is that decision support systems that focus just at the level of nation states, or countries, are necessary but not sufficient. We really need to get down to the scale of individual facilities, and even individual pieces of equipment, if we're going to have an impact across civil society," Riley Duren, Carbon Mapper CEO and University of Arizona researcher, told BBC News. "Super-emitters are often intermittent but they are also disproportionately responsible for the total emissions. That suggests low-hanging fruit, because if you can identify and fix them you can get a big bang for your buck."
The new project, announced Thursday, is a partnership between multiple entities, including Carbon Mapper, the state of California, NASA's Jet Propulsion Laboratory (JPL) and Planet, a company that designs, builds and launches satellites, according to a press release. The project is being implemented in three stages.
The initial stage, which is already complete, involved the initial engineering development. NASA and Planet will work together in the second stage to build two satellites for a 2023 launch. The third phase will launch an entire constellation of satellites starting in 2025.
The satellites will include an imaging spectrometer built by NASA's JPL, NASA explained in a press release. This is a device that can break down visible light into hundreds of colors, providing a unique signature for chemicals such as methane and carbon dioxide. Most imaging spectrometers currently in orbit have larger pixel sizes, making it difficult to locate emission sources that are not always visible from the ground. However, Carbon Mapper spectrometers will have pixels of around 98 square feet, facilitating more detailed pin-pointing.
"This technology enables researchers to identify, study and quantify the strong gas emission sources," JPL Scientist Charles Miller said in the press release.
Once the data is collected, Carbon Mapper will make it available to industry and government actors via an open data portal to help repair leaks.
"These home-grown satellites are a game-changer," California Governor Gavin Newsom said of the project. "They provide California with a powerful, state-of-the-art tool to help us slash emissions of the super-pollutant methane — within our own borders and around the world. That's exactly the kind of dynamic, forward-thinking solution we need now to address the existential crisis of climate change."
By Jenna McGuire
Commonly used herbicides across the U.S. contain highly toxic undisclosed "inert" ingredients that are lethal to bumblebees, according to a new study published Friday in the Journal of Applied Ecology.
The study reviewed several herbicide products and found that most contained glyphosate, an ingredient best recognized from Roundup products and the most widely used herbicide in the U.S. and worldwide.
While the devastating impacts of glyphosate on bee populations are more broadly recognized, the toxicity levels of inert ingredients are less understood because they are not subjected to the same mandatory testing by the U.S. Environmental Protection Agency (EPA).
"Pesticides are manufactured and sold as formulations that contain a mixture of compounds, including one or more active ingredients and, potentially, many inert ingredients," explained the Center for Food Safety in a statement. "The inert ingredients are added to pesticides to aid in mixing and to enhance the products' ability to stick to plant leaves, among other purposes."
The study found that these inert substances can be highly toxic and even block bees' breathing capacity, essentially causing them to drown. While researchers found that some of the combinations of inert ingredients had no negative impacts on the bees, one of the herbicide formulations killed 96% of the bees within 24 hours.
According to the abstract of the study:
Bees exhibited 94% mortality with Roundup® Ready‐To‐Use® and 30% mortality with Roundup® ProActive®, over 24 hr. Weedol® did not cause significant mortality, demonstrating that the active ingredient, glyphosate, is not the cause of the mortality. The 96% mortality caused by Roundup® No Glyphosate supports this conclusion.
"This important new study exposes a fatal flaw in how pesticide products are regulated here in the U.S.," said Jess Tyler, a staff scientist at the Center for Biological Diversity. "Now the question is, will the Biden administration fix this problem, or will it allow the EPA to continue its past practice of ignoring the real-world harms of pesticides?"
According to the Center for Food Safety, there are currently 1,102 registered formulations that contain the active ingredient glyphosate, each with a proprietary mixture of inert ingredients. In 2017, the group filed a legal petition calling for the EPA to force companies to provide safety data on pesticide formulations that include inert ingredients.
"The EPA must begin requiring tests of every pesticide formulation for bee toxicity, divulge the identity of 'secret' formulation additives so scientists can study them, and prohibit application of Roundup herbicides to flowering plants when bees might be present and killed," said Bill Freese, science director at the Center for Food Safety. "Our legal petition gave the EPA a blueprint for acting on this issue of whole formulations. Now they need to take that blueprint and turn it into action, before it's too late for pollinators."
ATTN @EPA: Undisclosed "inert" ingredients in #pesticide products warrant further scrutiny! ➡️ A new study compared… https://t.co/bdFwXCVHsD— Center 4 Food Safety (@Center 4 Food Safety)1618592343.0
Roundup — also linked to cancer in humans — was originally produced by agrochemical giant Monsanto, which was acquired by the German pharmaceutical and biotech company Bayer in 2018.
The merger of the two companies was condemned by environmentalists and food safety groups who warned it would cultivate the greatest purveyor of genetically modified seeds and toxic pesticides in the world.
Reposted with permission from Common Dreams.
By Ayesha Tandon
New research shows that lake "stratification periods" – a seasonal separation of water into layers – will last longer in a warmer climate.
These longer periods of stratification could have "far-reaching implications" for lake ecosystems, the paper says, and can drive toxic algal blooms, fish die-offs and increased methane emissions.
The study, published in Nature Communications, finds that the average seasonal lake stratification period in the northern hemisphere could last almost two weeks longer by the end of the century, even under a low emission scenario. It finds that stratification could last over a month longer if emissions are extremely high.
If stratification periods continue to lengthen, "we can expect catastrophic changes to some lake ecosystems, which may have irreversible impacts on ecological communities," the lead author of the study tells Carbon Brief.
The study also finds that larger lakes will see more notable changes. For example, the North American Great Lakes, which house "irreplaceable biodiversity" and represent some of the world's largest freshwater ecosystems, are already experiencing "rapid changes" in their stratification periods, according to the study.
As temperatures rise in the spring, many lakes begin the process of "stratification." Warm air heats the surface of the lake, heating the top layer of water, which separates out from the cooler layers of water beneath.
The stratified layers do not mix easily and the greater the temperature difference between the layers, the less mixing there is. Lakes generally stratify between spring and autumn, when hot weather maintains the temperature gradient between warm surface water and colder water deeper down.
Dr Richard Woolway from the European Space Agency is the lead author of the paper, which finds that climate change is driving stratification to begin earlier and end later. He tells Carbon Brief that the impacts of stratification are "widespread and extensive," and that longer periods of stratification could have "irreversible impacts" on ecosystems.
For example, Dr Dominic Vachon – a postdoctoral fellow from the Climate Impacts Research Centre at Umea University, who was not involved in the study – explains that stratification can create a "physical barrier" that makes it harder for dissolved gases and particles to move between the layers of water.
This can prevent the oxygen from the surface of the water from sinking deeper into the lake and can lead to "deoxygenation" in the depths of the water, where oxygen levels are lower and respiration becomes more difficult.
Oxygen depletion can have "fatal consequences for living organisms," according to Dr Bertram Boehrer, a researcher at the Helmholtz Centre for Environmental Research, who was not involved in the study.
Lead author Woolway tells Carbon Brief that the decrease in oxygen levels at deeper depths traps fish in the warmer surface waters:
"Fish often migrate to deeper waters during the summer to escape warmer conditions at the surface – for example during a lake heatwave. A decrease in oxygen at depth will mean that fish will have no thermal refuge, as they often can't survive when oxygen concentrations are too low."
This can be very harmful for lake life and can even increase "fish die-off events" the study notes.
However, the impacts of stratification are not limited to fish. The study notes that a shift to earlier stratification in spring can also encourage communities of phytoplankton – a type of algae – to grow sooner, and can put them out of sync with the species that rely on them for food. This is called a "trophic mismatch."
Prof Catherine O'Reilly, a professor of geography, geology and the environment at Illinois State University, who was not involved in the study, adds that longer stratified periods could also "increase the likelihood of harmful algae blooms."
The impact of climate change on lakes also extends beyond ecosystems. Low oxygen levels in lakes can enhance the production of methane, which is "produced in and emitted from lakes at globally significant rates," according to the study.
Woolway explains that higher levels of warming could therefore create a positive climate feedback in lakes, where rising temperatures mean larger planet-warming emissions:
"Low oxygen levels at depth also promotes methane production in lake sediments, which can then be released to the surface either via bubbles or by diffusion, resulting in a positive feedback to climate change."
Onset and Breakup
In the study, the authors determine historical changes in lake stratification periods using long-term observational data from some of the "best-monitored lakes in the world" and daily simulations from a collection of lake models.
They also run simulations of future changes in lake stratification period under three different emission scenarios, to determine how the process could change in the future. The study focuses on lakes in the northern hemisphere.
The figure below shows the average change in lake stratification days between 1900 and 2099, compared to the 1970-1999 average. The plot shows historical measurements (black), and the low emission RCP2.6 (blue), mid emissions RCP6.0 (yellow) and extremely high emissions RCP8.5 (red) scenarios.
Change in lake stratification duration compared to the 1970-1999 average, for historical measurements (black), the low emission RCP2.6 (blue) moderate emissions RCP6.0 (yellow) and extremely high emissions RCP8.5 (red). Credit: Woolway et al (2021).
The plot shows that the average lake stratification period has already lengthened. However, the study adds that some lakes are seeing more significant impacts than others.
For example, Blelham Tarn – the most well-monitored lake in the English Lake District – is now stratifying 24 days earlier and maintaining its stratification for an extra 18 days compared to its 1963-1972 averages, the study finds. Woolway tells Carbon Brief that as a result, the lake is already showing signs of oxygen depletion.
Climate change is increasing average stratification duration in lakes, the findings show, by moving the onset of stratification earlier and pushing the stratification "breakup" later. The table below shows projected changes in the onset, breakup and overall length of lake stratification under different emission scenarios, compared to a 1970-1999 baseline.
The table shows that even under the low emission scenario, the lake stratification period is expected to be 13 days longer by the end of the century. However, in the extremely high emissions scenario, it could be 33 days longer.
The table also shows that stratification onset has changed more significantly than stratification breakup. The reasons why are revealed by looking at the drivers of stratification more closely.
Warmer Weather and Weaker Winds
The timing of stratification onset and breakup in lakes is driven by two main factors – temperature and wind speed.
The impact of temperature on lake stratification is based on the fact that warm water is less dense than cool water, Woolway tells Carbon Brief:
"Warming of the water's surface by increasing air temperature causes the density of water to decrease and likewise results in distinct thermal layers within a lake to form – cooler, denser water settles to the bottom of the lake, while warmer, lighter water forms a layer on top."
This means that, as climate change causes temperatures to rise, lakes will begin to stratify earlier and remain stratified for longer. Lakes in higher altitudes are also likely to see greater changes in stratification, Woolway tells Carbon Brief, because "the prolonging of summer is very apparent in high latitude regions."
The figure below shows the expected increase in stratification duration from lakes in the northern hemisphere under the low (left), mid (center), and high (right) emission scenarios. Deeper colors indicate a larger increase in stratification period.
Expected increase in stratification duration in lakes in the northern hemisphere under the low (left), mid (centre) and high (right) emissions scenarios. Credit: Woolway et al (2021).
The figure shows that the expected impact of climate change on stratification duration becomes more pronounced at more northerly high latitudes.
The second factor is wind speed, Woolway explains:
"Wind speed also affects the timing of stratification onset and breakdown, with stronger winds acting to mix the water column, thus acting against the stratifying effect of increasing air temperature."
According to the study, wind speed is expected to decrease slightly as the planet warms. The authors note that the expected changes in near-surface wind speed are "relatively minor" compared to the likely temperature increase, but they add that it may still cause "substantial" changes in stratification.
The study finds that air temperature is the most important factor behind when a lake will begin to stratify. However, when looking at stratification breakup, it finds that wind speed is a more important driver.
Meanwhile, Vachon says that wind speeds also have implications for methane emissions from lakes. He notes that stratification prevents the methane produced on the bottom of the lake from rising and that, when the stratification period ends, methane is allowed to rise to the surface. However, according to Vachon, the speed of stratification breakup will affect how much methane is released into the atmosphere:
"My work has suggested that the amount of accumulated methane in bottom waters that will be finally emitted is related to how quickly the stratification break-up occurs. For example, a slow and progressive stratification break-up will most likely allow water oxygenation and allow the bacteria to oxidise methane into carbon dioxide. However, a stratification break-up that occurs rapidly – for example after storm events with high wind speed – will allow the accumulated methane to be emitted to the atmosphere more efficiently."
Finally, the study finds that large lakes take longer to stratify in spring and typically remain stratified for longer in the autumn – due to their higher volume of water. For example, the authors highlight the North American Great Lakes, which house "irreplaceable biodiversity" and represent some of the world's largest freshwater ecosystems.
These lakes have been stratifying 3.5 days earlier every decade since 1980, the authors find, and their stratification onset can vary by up to 48 days between some extreme years.
O'Reilly tells Carbon Brief that "it's clear that these changes will be moving lakes into uncharted territory" and adds that the paper "provides a framework for thinking about how much lakes will change under future climate scenarios."
Reposted with permission from Carbon Brief.
By Robert Glennon
Interstate water disputes are as American as apple pie. States often think a neighboring state is using more than its fair share from a river, lake or aquifer that crosses borders.
Currently the U.S. Supreme Court has on its docket a case between Texas, New Mexico and Colorado and another one between Mississippi and Tennessee. The court has already ruled this term on cases pitting Texas against New Mexico and Florida against Georgia.
Climate stresses are raising the stakes. Rising temperatures require farmers to use more water to grow the same amount of crops. Prolonged and severe droughts decrease available supplies. Wildfires are burning hotter and lasting longer. Fires bake the soil, reducing forests' ability to hold water, increasing evaporation from barren land and compromising water supplies.
As a longtime observer of interstate water negotiations, I see a basic problem: In some cases, more water rights exist on paper than as wet water – even before factoring in shortages caused by climate change and other stresses. In my view, states should put at least as much effort into reducing water use as they do into litigation, because there are no guaranteed winners in water lawsuits.
Alabama, pay attention to Supreme Court ruling against Florida in water war #Water #SDG6 https://t.co/wIjdoY6Ccr— Noah J. Sabich (@Noah J. Sabich)1617800452.0
Dry Times in the West
The situation is most urgent in California and the Southwest, which currently face "extreme or exceptional" drought conditions. California's reservoirs are half-empty at the end of the rainy season. The Sierra snowpack sits at 60% of normal. In March 2021, federal and state agencies that oversee California's Central Valley Project and State Water Project – regional water systems that each cover hundreds of miles – issued "remarkably bleak warnings" about cutbacks to farmers' water allocations.
The Colorado River Basin is mired in a drought that began in 2000. Experts disagree as to how long it could last. What's certain is that the "Law of the River" – the body of rules, regulations and laws governing the Colorado River – has allocated more water to the states than the river reliably provides.
The 1922 Colorado River Compact allocated 7.5 million acre-feet (one acre-foot is roughly 325,000 gallons) to California, Nevada and Arizona, and another 7.5 million acre-feet to Utah, Wyoming, Colorado and New Mexico. A treaty with Mexico secured that country 1.5 million acre-feet, for a total of 16.5 million acre-feet. However, estimates based on tree ring analysis have determined that the actual yearly flow of the river over the last 1,200 years is roughly 14.6 million acre-feet.
The inevitable train wreck has not yet happened, for two reasons. First, Lakes Mead and Powell – the two largest reservoirs on the Colorado – can hold a combined 56 million acre-feet, roughly four times the river's annual flow.
But diversions and increased evaporation due to drought are reducing water levels in the reservoirs. As of Dec. 16, 2020, both lakes were less than half full.
Second, the Upper Basin states – Utah, Wyoming, Colorado and New Mexico – have never used their full allotment. Now, however, they want to use more water. Wyoming has several new dams on the drawing board. So does Colorado, which is also planning a new diversion from the headwaters of the Colorado River to Denver and other cities on the Rocky Mountains' east slope.
Utah Stakes a Claim
The most controversial proposal comes from one of the nation's fastest-growing areas: St. George, Utah, home to approximately 90,000 residents and lots of golf courses. St. George has very high water consumption rates and very low water prices. The city is proposing to augment its water supply with a 140-mile pipeline from Lake Powell, which would carry 86,000 acre-feet per year.
Truth be told, that's not a lot of water, and it would not exceed Utah's unused allocation from the Colorado River. But the six other Colorado River Basin states have protested as though St. George were asking for their firstborn child.
In a joint letter dated Sept. 8, 2020, the other states implored the Interior Department to refrain from issuing a final environmental review of the pipeline until all seven states could "reach consensus regarding legal and operational concerns." The letter explicitly threatened a high "probability of multi-year litigation."
Utah blinked. Having earlier insisted on an expedited pipeline review, the state asked federal officials on Sept. 24, 2020 to delay a decision. But Utah has not given up: In March 2021, Gov. Spencer Cox signed a bill creating a Colorado River Authority of Utah, armed with a $9 million legal defense fund, to protect Utah's share of Colorado River water. One observer predicted "huge, huge litigation."
How huge could it be? In 1930, Arizona sued California in an epic battle that did not end until 2006. Arizona prevailed by finally securing a fixed allocation from the water apportioned to California, Nevada and Arizona.
Litigation or Conservation
Before Utah takes the precipitous step of appealing to the Supreme Court under the court's original jurisdiction over disputes between states, it might explore other solutions. Water conservation and reuse make obvious sense in St. George, where per-person water consumption is among the nation's highest.
St. George could emulate its neighbor, Las Vegas, which has paid residents up to $3 per square foot to rip out lawns and replace them with native desert landscaping. In April 2021 Las Vegas went further, asking the Nevada Legislature to outlaw ornamental grass.
The Southern Nevada Water Authority estimates that the Las Vegas metropolitan area has eight square miles of "nonfunctional turf" – grass that no one ever walks on except the person who cuts it. Removing it would reduce the region's water consumption by 15%.
Water rights litigation is fraught with uncertainty. Just ask Florida, which thought it had a strong case that Georgia's water diversions from the Apalachicola-Chattahoochee-Flint River Basin were harming its oyster fishery downstream.
That case extended over 20 years before the U.S. Supreme Court ended the final chapter in April 2021. The court used a procedural rule that places the burden on plaintiffs to provide "clear and convincing evidence." Florida failed to convince the court, and walked away with nothing.
Robert Glennon is a Regents Professor and Morris K. Udall Professor of Law & Public Policy, University of Arizona.
Disclosure statement: Robert Glennon received funding from the National Science Foundation in the 1990s and 2000s.
Reposted with permission from The Conversation.