TRINDADE ISLAND, Brazil, March 15 (Reuters) - The geology of Brazil's volcanic Trindade Island has fascinated scientists for years, but the discovery of rocks made from plastic debris in this remote turtle refuge is sparking alarm.
Melted plastic has become intertwined with rocks on the island, located 1,140 km (708 miles) from the southeastern state of Espirito Santo, which researchers say is evidence of humans' growing influence over the earth's geological cycles.
"This is new and terrifying at the same time, because pollution has reached geology," said Fernanda Avelar Santos, a geologist at the Federal University of Parana.
Santos and her team ran chemical tests to find out what kind of plastics are in the rocks called "plastiglomerates" because they are made of a mixture of sedimentary granules and other debris held together by plastic.
"We identified (the pollution) mainly comes from fishing nets, which is very common debris on Trinidade Island's beaches," Santos said. "The (nets) are dragged by the marine currents and accumulate on the beach. When the temperature rises, this plastic melts and becomes embedded with the beach's natural material."
First it was the eerie images of barrels leaking on the seafloor not far from Catalina Island. Then the shocking realization that the nation’s largest manufacturer of DDT had once used the ocean as a huge dumping ground — and that as many as half a million barrels of its acid waste had been poured straight into the water.
Now, scientists have discovered that much of the DDT — which had been dumped largely in the 1940s and ’50s — never broke down. The chemical remains in its most potent form in startlingly high concentrations, spread across a wide swath of seafloor larger than the city of San Francisco.
“We still see original DDT on the seafloor from 50, 60, 70 years ago, which tells us that it’s not breaking down the way that [we] once thought it should,” said UC Santa Barbara scientist David Valentine, who shared these preliminary findings Thursday during a research update with more than 90 people working on the issue. “And what we’re seeing now is that there is DDT that has ended up all over the place, not just within this tight little circle on a map that we referred to as Dumpsite Two.”
These revelations confirm some of the science community’s deepest concerns — and further complicate efforts to understand DDT’s toxic and insidious legacy in California. Public calls for action have intensified since The Times reported in 2020 that dichlorodiphenyltrichloroethane, banned in 1972, is still haunting the marine environment today. Significant amounts of DDT-related compounds continue to accumulate in California condors and local dolphin populations, and a recent study linked the presence of this once-popular pesticide to an aggressive cancer in sea lions.
A new generation of scientists have uncovered barrels containing DDT, a toxic pesticide banned decades ago, dumped into the deep ocean.
With a $5.6-million research boost from Congress, at the urging of Sen. Dianne Feinstein (D-Calif.), numerous federal, state and local agencies have since joined with scientists and environmental nonprofits to figure out the extent of the contamination lurking 3,000 feet underwater. (An additional $5.2 million, overseen by California and USC Sea Grant, will be distributed this summer to kick off 18 more months of research.) The findings so far have been one stunning development after another. A preliminary sonar-mapping effort led by the Scripps Institution of Oceanography identified at least 70,000 debris-like objects on the seafloor.
The U.S. Environmental Protection Agency, after combing through thousands of pages of old records, discovered that other toxic chemicals — as well as millions of tons of oil drilling waste — had also been dumped decades ago by other companies in more than a dozen areas off the Southern California coast.
“When the DDT was disposed, it is highly likely that other materials — either from the tanks on the barges, or barrels being pushed over the side of the barges — would have been disposed at the same time,” said John Lyons, acting deputy director of the EPA’s Region 9 Superfund Division. He noted that the new science being shared this week is critical to answering one of the agency’s most burning questions: “Is the contamination moving? And is it moving in a way that threatens the marine environment or human health?”
DDT was banned 50 years ago, but its toxic legacy continues to affect the California marine ecosystem and threaten various animal species.
In recent months, Valentine, whose research team had first brought this decades-old issue back into the public consciousness, has been mapping and collecting samples of the seafloor between the Los Angeles coast and Catalina.
Analysis of the sediment so far shows that the most concentrated layer of DDT is only about 6 centimeters deep — raising questions about just how easily these still-potent chemicals could be remobilized.
“Trawls, cable lays could reintroduce this stuff back up to the surface,” Valentine said. “And animals feeding — if a whale goes down and burrows on the seafloor, that could kick stuff up.”
On a chilly winter morning in between storms, Valentine and a team of students boarded the RV/Yellowfin and set out to collect more seafloor samples along key points of a hot-spot map that they’ve been piecing together.
As his students sliced and cataloged each layer of mud, they gasped in wonder at the tiny worms, snails and sea stars that lived so deep under the sea. They squinted at each tube that came out of the water and laughed apprehensively when asked about all the chemicals they were possibly holding in their hands.
“The goal is to collect as much mud as possible so that we don’t have to come back out every time we have a question,” Valentine explained as the ship’s mechanical pulley churned for the eighth time that day. “We are starting to build a really exceptional data set … that will help us understand the time history of how things were transported, how they were transformed, and what their ultimate fate is.”
Other scientists have also been chipping away at the many pieces to this deep-ocean puzzle.
Thursday’s research updates included plans for the next Scripps mapping expedition, which will scan the seafloor with advanced sonar technology and take hundreds of thousands of photos. Microbiologists shared their latest studies into whether deep-sea microbes could possibly help biodegrade some of the contamination, and chemical oceanographers discussed the many ways they’ve been trying to identify “fingerprints” that could help determine where the DDT is coming from — and how and if it’s moving.
Biological oceanographers, marine ecologists and fisheries scientists also started to connect some dots on the various organisms they’ve found living in the contaminated sediment, as well as the midwater species that could potentially move the chemicals from deeper waters up closer to the surface.
All of them noted that there were uncomfortably high concentrations of DDT and DDT-related compounds in the samples they studied. Even the “control” samples they tried to collect — as a way to compare what a normal sediment or fish sample farther away from the dumping area might look like — ended up riddled with DDT.
“This suggests to us, very preliminarily, that there’s some connection potentially — there’s connectivity in these deep food webs across the basins and across the system,” said Lihini Aluwihare, a marine chemist at Scripps.
On top of all this research, the EPA has been developing its own sampling plan, in collaboration with a number of state and federal agencies, to get a grasp of the many other chemicals that had been dumped into the ocean. The hope, officials said, is that the groundbreaking science now underway on the deep-ocean DDT dumping will ultimately inform how future investigations of other offshore dump sites — whether along the Southern California coast or elsewhere in the country — could be conducted.
Mark Gold, an environmental scientist at the Natural Resources Defense Council who has worked on the DDT problem since the 1990s, said that as he listened to the latest research discoveries, he couldn’t help but think that “our nation’s ocean dumpsites all have horrible contamination problems. And yet they are unmonitored.”
There are also more shallow areas off the Palos Verdes coast and at the mouth of the Dominguez Channel that have been known DDT hot spots for decades. Figuring out how to clean up those contaminated areas in an underwater environment has been its own complicated saga.
For Katherine Pease at Heal the Bay, an environmental group that has been making sure the public remains engaged on this issue in substantive ways, these latest revelations have been eye-opening.
This is, after all, what it truly means to live with a “forever” chemical. After all these decades, scientists are still uncovering new and unsettling surprises about the full extent of the contamination.
“We’re still grappling with this legacy of treating the ocean as a dumping ground,” said Pease, Heal the Bay’s science and policy director. “And the public — whether they’re folks that like to fish ... or people who like to swim and visit the ocean — we all need to understand the history that went on, as well as the impacts. And partly that’s to learn ... to make sure that we’re able to protect our public health, but also to think about how we are treating the ocean now, as well as into the future.”
Thirty years after countries agreed to ease up on the use of chemicals damaging the ozone layer, there are promising signs that the ozone will be fully recovered by the 2060s. But we’re not out of the woods yet. A study published this month in Nature Geoscience shows that emissions from dangerous gases banned in the 1980s are actually on the rise today—with implications not only for the ozone layer but for climate change as well. Even more worryingly, we’re not sure what, exactly, is causing some of these emissions to creep up.
The group of pollutants that damage the ozone layer are called chlorofluorocarbons, or CFCs, and they were previously widely used in refrigerants, air conditioners, aerosol cans, and other applications. The Montreal Protocol, the international treaty that went into effect at the end of the 1980s, called for countries to phase out the use of these CFCs. The Protocol is largely considered a historic success in addressing a thorny and global environmental problem.
To get a handle on the global status of CFC emissions, researchers used “atmospheric measurements of CFCs and a model of how gases move around the globe,” study lead author Luke Western, a researcher at the UK’s University of Bristol and the National Oceanic and Atmospheric Administration, told Earther in an email. The CFC measurements were collected from stations around the world.
The study found that emissions from five different types of CFCs were increasing. Three of these CFCs have an explicable cause: a loophole in the Montreal Protocol that allows for some CFC emissions in the production of some hydrofluorocarbons (HFCs), chemicals that were largely used to replace CFCs. While HFCs don’t pack as much of a punch to the ozone layer, they are potent greenhouse gases, with worrying implications for global warming. (The Biden administration signed on to a global amendment to the Montreal Protocol that would eventually phase out HFC use in September.)
The research done by Western and his team isn’t able to concretely pin emissions to a specific region or factory—but we can make some guesses. China has, historically, been the world’s largest producer of HFCs. As InsideClimate News reported, outside of China, the largest producer of the HFCs whose byproducts were tracked by the study is a Honeywell factory located in Louisiana.
While we can guess about some of the chemicals in the study, the other two CFCs measured are, weirdly, a mystery. Neither of the chemicals are approved for any sort of use, and while it’s possible that they could be connected to a number of industrial processes, more work and consultations with the chemical industry are needed.
“We really have no clue,” said Western’s co-author, Martin Vollmer, an atmospheric chemist at the Swiss Federal Laboratories for Materials Science and Technology in Dübendorf, during a press conference last month. “We don’t know of any chemical process where [these chemicals] will show up as a by-product.”
The rise of these chemicals are concerning not only for the efficacy of the Montreal Protocol but also for climate change. “CFCs are potent greenhouse gases, with global warming potentials many thousand times greater than CO2,” Western said. “The emissions in 2020 of these five CFCs are roughly the same as the CO2 emissions from a country like Switzerland.”
The levels of CFC emissions detected may be relatively small compared to pre-Montreal Protocol levels—but it’s still good to be aware of what’s going on.
“We’re hoping to give an early warning so that others are aware of these emissions,” Western said.
More than half of the world’s largest lakes and reservoirs have lost significant amounts of water over the last three decades, according to a new study, which pins the blame largely on climate change and excessive water use.
Roughly one-quarter of the world’s population lives in the basin of a drying lake, according to the study by a team of international scientists, published Thursday in the journal Science.
While lakes cover only around 3% of the planet, they hold nearly 90% of its liquid surface freshwater and are essential sources of drinking water, irrigation and power, and they provide vital habitats for animals and plants.
But they’re in trouble.
Lake water levels fluctuate in response to natural climate variations in rain and snowfall, but they are increasingly affected by human actions.
Across the world, the most significant lakes are seeing sharp declines. The Colorado River’s Lake Mead in Southwest US has receded dramatically amid a megadrought and decades of overuse. The Caspian Sea, between Asia and Europe – the world’s largest inland body of water – has long been declining due to climate change and water use.
The shrinking of many lakes has been well documented, but the extent of change – and the reasons behind it – have been less thoroughly examined, said Fangfang Yao, the study’s lead author and a visiting scholar at the Cooperative
The researchers used satellite measurements of nearly 2,000 of the world’s largest lakes and reservoirs, which together represent 95% of Earth’s total lake water storage.
Examining more than 250,000 satellite images spanning from 1992 to 2020, along with climate models, they were able to reconstruct the history of the lakes going back decades.
The results were “staggering,” the report authors said.
They found that 53% of the lakes and reservoirs had lost significant amounts of water, with a net decline of around 22 billion metric tons a year – an amount the report authors compared to the volume of 17 Lake Meads.
More than half of the net loss of water volume in natural lakes can be attributed to human activities and climate change, the report found.
The report found losses in lake water storage everywhere, including in the humid tropics and the cold Arctic. This suggests “drying trends worldwide are more extensive than previously thought,” Yao said.
Different lakes were affected by different drivers.
Unsustainable water consumption is the predominant reason behind the shriveling of the Aral Sea in Uzbekistan and California’s Salton Sea, while changes in rainfall and runoff have driven the decline of the Great Salt Lake, the report found.
In the Arctic, lakes have been shrinking due to a combination of changes in temperature, precipitation, evaporation and runoff.
“Many of the human and climate change footprints on lake water losses were previously unknown,” Yao said, “such as the desiccations of Lake Good-e-Zareh in Afghanistan and Lake Mar Chiquita in Argentina.”
Climate change can have an array of impacts on lakes. The most obvious, Yao said, is to increase evaporation.
As lakes shrink, this can also contribute to an “aridification” of the surrounding watershed, the study found, which in turn increases evaporation and accelerates their decline.
For lakes in colder parts of the world, winter evaporation is an increasing problem as warmer temperatures melt the ice that usually covers them, leaving the water exposed to the atmosphere.
These changes can have cascading effects, including a decrease in water quality, an increase in toxic algal blooms and a loss of aquatic life.
“An important aspect that is not often recognized is the degradation in water quality of the lakes from a warmer climate, which puts stress on water supply for communities that rely on them,” Yao said.
For reservoirs, the report found that the biggest factor in their decline is sedimentation, where sediment flows into the water, clogging it up and reducing space. It’s a “creeping disaster,” Yao said, happening over the course of years and decades.
Lake Powell, for instance – the second-largest human-made reservoir in the US – has lost nearly 7% of its storage capacity due to sediment build-up.
Sedimentation can be affected by climate change, he added. Wildfires, for example, which are becoming more intense as the world warms, burn through forests and destabilize the soil, helping to increase the flow of sediment into lakes and reservoirs.
“The result of sedimentation will be that reservoirs will be able to store less water, thereby becoming less reliable for freshwater and hydroelectric energy supply, particularly for us here in the US, given that our nation’s reservoirs are pretty old,” Yao said.
Not all lakes are declining; around a third of lake declines were offset by increases elsewhere, the report found.
Some lakes have been growing, with 24% seeing significant increases in water storage. These tended to be lakes in less populated regions, the report found, including areas in the Northern Great Plains of North America and the inner Tibetan Plateau.
The fingerprints of climate change are on some of these gains, as melting glaciers fill lakes, posing potential risks to people living downstream from them.
In terms of reservoirs, while nearly two thirds experienced significant water loss, overall there was a net increase due to more than 180 newly filled reservoirs, the report found.
Catherine O’Reilly, professor of geology at Illinois State University, who was not involved with the study, said this new research provides a useful long term data set that helps untangle the relative importance of the factors driving the decline of lakes.
“This study really highlights the impact of climate in ways that bring it close to home – how much water do we have access to, and what are the options to increase water storage?” she told CNN.
“It’s a little scary to see how many freshwater systems are unable to store as much water as they used to,” she added.
As many parts of the world become hotter and drier, lakes must be managed properly. Otherwise climate change and human activities “can lead to drying sooner than we think,” Yao said.
Earth has pushed past seven out of eight scientifically established safety limits and into “the danger zone,” not just for an overheating planet that’s losing its natural areas, but for the well-being of people living on it, according to a new study.
The study looks not just at guardrails for the planetary ecosystem but for the first time it includes measures of “justice,” which is mostly about preventing harm for countries, ethnicities and genders.
The study by the international scientist group Earth Commission published in Wednesday’s journal Nature looks at climate, air pollution, phosphorus and nitrogen contamination of water from fertilizer overuse, groundwater supplies, fresh surface water, the unbuilt natural environment and the overall natural and human-built environment. Only air pollution wasn’t quite at the danger point globally.
Air pollution is dangerous at local and regional levels, while climate was beyond the harmful levels for humans in groups but not quite past the safety guideline for the planet as a system, the study from the Swedish group said.
The study found “hotspots” of problem areas throughout Eastern Europe, South Asia, the Middle East, Southeast Asia, parts of Africa and much of Brazil, Mexico, China and some of the U.S. West — much of it from climate change. About two-thirds of Earth don’t meet the criteria for freshwater safety, scientists said as an example.
“We are in a danger zone for most of the Earth system boundaries,” said study co-author Kristie Ebi, a professor of climate and public health at the University of Washington.
If planet Earth just got an annual checkup, similar to a person’s physical, “our doctor would say that the Earth is really quite sick right now and it is sick in terms of many different areas or systems and this sickness is also affecting the people living on Earth,” Earth Commission co-chair Joyeeta Gupta, a professor of environment at the University of Amsterdam, said at a press conference.
It’s not a terminal diagnosis. The planet can recover if it changes, including its use of coal, oil and natural gas and the way it treats the land and water, the scientists said.
But “we are moving in the wrong direction on basically all of these,” said study lead author Johan Rockstrom, director of the Potsdam Institute for Climate Impact Research in Germany.
“This is a compelling and provocative paper – scientifically sound in methodology and important for identifying the dimensions in which the planet is nearing the edge of boundaries that would launch us into irreversible states,” Indy Burke, dean of the Yale School of the Environment said in an email. She wasn’t part of the study.
The team of about 40 scientists created quantifiable boundaries for each environmental category, both for what’s safe for the planet and for the point at which it becomes harmful for groups of people, which the researchers termed a justice issue.
Rockstrom said he thinks of those points as setting up “a safety fence” outside of which the risks become higher, but not necessarily fatal.
Rockstrom and other scientists have attempted in the past this type of holistic measuring of Earth’s various interlocking ecosystems. The big difference in this attempt is that scientists also looked at local and regional levels and they added the element of justice.
The justice part includes fairness between young and old generations, different nations and even different species. Frequently, it applies to conditions that harm people more than the planet.
An example of that is climate change.
The report uses the same boundary of 1.5 degree Celsius (2.7 degrees Fahrenheit) of warming since pre-industrial times that international leaders agreed upon in the 2015 Paris climate agreement. The world has so far warmed about 1.1 degrees Celsius (2 degrees Fahrenheit), so it hasn’t crossed that safety fence, Rockstrom and Gupta said, but that doesn’t mean people aren’t being hurt.
“What we are trying to show through our paper is that event at 1 degree Centigrade (1.8 degrees Fahrenheit) there is a huge amount of damage taking place,” Gupta said, pointing to tens of millions of people exposed to extreme hot temperatures.
The planetary safety guardrail of 1.5 degrees hasn’t been breached, but the “just” boundary where people are hurt of 1 degree has been.
“Sustainability and justice are inseparable,” said Stanford environmental studies chief Chris Field, who wasn’t part of the research. He said he would want even more stringent boundaries. “Unsafe conditions do not need to cover a large fraction of Earth’s area to be unacceptable, especially if the unsafe conditions are concentrated in and near poor and vulnerable communities.”
Another outside expert, Dr. Lynn Goldman, an environment health professor and dean of George Washington University’s public health school, said the study was “kind of bold,” but she wasn’t optimistic that it would result in much action.
Arizona has determined that there is not enough groundwater for all of the housing construction that has already been approved in the Phoenix area, and will stop developers from building some new subdivisions, a sign of looming trouble in the West and other places where overuse, drought and climate change are straining water supplies.
The decision by state officials very likely means the beginning of the end to the explosive development that has made the Phoenix area the fastest growing metropolitan region in the country.
The state said it would not revoke building permits that have already been issued and is instead counting on new water conservation measures and alternative sources to produce the water necessary for housing developments that have already been approved.
On Thursday, Governor Katie Hobbs, a Democrat, said Arizona was not immediately running dry and that new construction would continue in major cities like Phoenix. The analysis prepared by the state looked at groundwater levels over the next 100 years.
“We’re going to manage this situation,” she said at a news conference. “We are not out of water and we will not be running out of water.”
Maricopa County, which includes Phoenix and its suburbs, gets more than half its water supply from groundwater. Most of the rest comes from rivers and aqueducts as well as recycled wastewater. In practical terms, groundwater is a finite resource; it can take thousands of years or longer to be replenished.
The announcement of a groundwater shortage means Arizona would no longer give developers in some areas of Maricopa County new permits to construct homes that rely on wells for water.
Phoenix and nearby large cities, which must obtain separate permission from state officials for their development plans every 10 to 15 years, would also be denied approval for any homes that rely on groundwater beyond what the state has already authorized.
The decision means cities and developers must look for alternative sources of water to support future development — for example, by trying to buy access to river water from farmers or Native American tribes, many of whom are facing their own shortages. That rush to buy water is likely to rattle the real estate market in Arizona, making homes more expensive and threatening the relatively low housing costs that had made the region a magnet for people from across the country.
“Housing affordability will be a challenge moving forward,” said Spencer Kamps, vice president of legislative affairs for the Home Builders Association of Central Arizona, an industry group. He noted that even as the state limits home construction, commercial buildings, factories and other kinds of development can continue.
Even so, the change will act as a signal to developers, said Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University. “We see the horizon for the end of sprawl,” she said.
A groundwater shortage would likely not derail the planned growth in the short term in major cities like Phoenix, Scottsdale and Mesa, Ms. Porter said.
“There is still capacity for development within designated cities,” Ms. Porter said, referring to cities whose growth plans had already been approved by state water officials. Those cities would not be able to get approval to build any homes that rely on groundwater beyond that amount.
The new restrictions would be felt hardest and most immediately in small towns and unincorporated swaths of desert along the fringes of the Phoenix metro area — where most lower-cost homes tend to get built. “Those have been hot spots for growth,” Ms. Porter said.
The announcement is the latest example of how climate change is reshaping the American Southwest. A 23-year drought and rising temperatures have lowered the level of the Colorado River, threatening the 40 million Americans in Arizona and six other states who rely on it — including residents of Phoenix, which gets water from the Colorado by aqueduct.
Rising temperatures have increased the rate of evaporation from the river, even as crops require more water to survive those higher temperatures. The water that Arizona receives from the Colorado River has already been cut significantly through a voluntary agreement among the seven states. Last month, Arizona agreed to conservation measures that would further reduce its supply.
The result is that Arizona’s water supply is being squeezed from both directions: disappearing ground water as well as the shrinking Colorado River.
And the water shortage could be more severe than the state’s analysis shows because it assumes that Arizona’s supply from the Colorado would remain constant over the next 100 years, something that is uncertain at best.
The Phoenix area occupies a valley in southern Arizona, cradled by mountain ridges and sliced by the Salt and Gila rivers. The landscape is filled with lush golf courses, baseball diamonds, farm fields and swimming pools, contrasted against rocky brown terrain that surrounds it.
The county uses some 2.2 billion gallons of water a day — more than twice as much as New York City, despite having half as many people.
Arizona’s water problems have begun to percolate through the state’s politics. When she took office in January, Governor Hobbs pledged in her first major address to tighten controls on groundwater use around the state.
As evidence of that commitment, Governor Hobbs released a report that she said had been suppressed by the previous administration, which was Republican-led. It showed that an area west of Phoenix, called the Hassayampa sub-basin, doesn’t have enough water for new wells. As a result, the Arizona Department of Water Resources said it would no longer issue new permits in that region for the construction of homes that would rely on groundwater.
But Hassayampa is just one of several sub-basins that make up the larger groundwater basin underneath metropolitan Phoenix. The state’s announcement on Thursday essentially extends that finding across the Phoenix area.
One of the places very likely to feel the impact of the new restrictions is Queen Creek.
When Arizona created its groundwater rules more than 40 years ago, Queen Creek was still mostly peach and citrus groves and expansive farmland. Today, it is one of the fastest-growing places in Arizona, where families go fishing at an “oasis” lake fed by recycled wastewater. The town’s population of 75,000 is projected to grow to 175,000 by the time it is built out decades from now.
But to do any of that, the town needs to find more water.
“We’re in search of about 30,000 acre feet,” or about 9.8 billion gallons per year, said Paul Gardner, Queen Creek’s utility director.
Since there isn’t enough groundwater to supply its needs for future growth, Queen Creek is hunting for water anywhere it can, exploring proposals such as transferring it via canal from western Arizona, expanding the Bartlett Lake reservoir by joining other cities in a project to build a higher dam.
Unlike Phoenix, Queen Creek doesn’t have a “designation” from the state — essentially, a determination that the city has enough water to support new homes. Without that designation, each proposed development must prove to the state it has a 100-year supply. Developers without that seal of approval would now have to find sources other than groundwater.
Even as the state takes steps to try to slow depletion, the Kyl Center has warned that Arizona is still pumping too much groundwater. New industrial projects are sucking up groundwater without restrictions, and demand for water is outpacing any gains from conservation efforts, the center found in a 2021 report.
Despite the increasingly dire warnings from the state and water experts, some developers note that construction will not stop anytime soon. The Arizona water agency has given permission for construction on about 80,000 housing lots that have yet to be built, a state official said.
Cynthia Campbell, Phoenix’s water-resources management adviser, said the city largely relies on river water, and groundwater represents only about 2 percent of its water supply. But that could change drastically if Arizona were hit with drastic cuts in its Colorado River allotments, forcing the city to pump more groundwater.
Many outlying developments and towns in Maricopa County’s sprawl have been able to build by enrolling in a state-authorized program that lets subdivisions suck up groundwater in one place if they pump it back into the ground elsewhere in the basin.
Ms. Campbell said the idea that you could balance water supplies like that had always been a “legal fiction,” one that now appears to be unraveling as the state takes a harder look at where the groundwater supplies are coming up short.
“This is the hydrologic disconnect coming home to roost,” Ms. Campbell said.
In outlying areas, “a lot of the developers are really worried, they’re freaked,” Ms. Campbell said. “The reality is, it all came back to catch us.”
The British Antarctic Survey has released its new maps and they are a stark visual depiction of the retreat of ice at our poles.
Just as stark is the warning from the secretary general of the United Nations' World Meteorological Organisation, Professor Petteri Taalas.
In an interview with Sky News, he emphasised that the melted ice will never return, remarking that the planet has "lost this glacier melting game and sea level rise game".
He said: "Thanks to an already high concentration of carbon dioxide, we have lost this glacier melting game and sea level rise game.
"It may continue for the coming thousands of years because the natural removal of carbon dioxide from the atmosphere is very slow.
"There's no return to the climate that we used to have in the last century, so that's gone... and we will live with these consequences and higher temperatures."
Professor Taalas's unusually blunt language reflects growing concern about the Arctic and Antarctic ice.
The Arctic region in particular is warming up to three times faster than the rest of the world, and one recent study suggested it could be sea-ice free in the summer by the 2030s, which is a decade earlier than previous predictions.
This matters because the poles essentially function as the planet's refrigerators.
As they shrink, the heat reflecting white surface is replaced by darker water, which absorbs heat, accelerating warming.
The warming drives further melting, and as the ice melts into the oceans, sea levels rise.
This worsens coastal erosion and exacerbates the effects of storm surges.
Alongside these impacts, the loss of ice means the loss of precious habitats for wildlife, and a disruption of delicate ecosystems, ocean currents and weather patterns.
And the melting of permafrost, or ground which has previously been permanently frozen, is one of the things that most worries climate scientists.
Permafrost covers 25% of the Northern Hemisphere's land surface and accounts for nearly half of all organic carbon stored in the planet's soil.
For all of these reasons, what happens in the poles will matter well beyond them.
In the new study, led by Imperial College London and published today in Science, researchers ranked 90% of global net-zero greenhouse gas emissions pledges as providing low confidence in their full implementation.
The researchers recommend nations make their targets legally binding and back them up with long-term plans and short-term implementation policies to increase the likelihood of avoiding the worst impacts of climate change.
Lead researcher Professor Joeri Rogelj, director of research for the Grantham Institute at Imperial, said: "Climate policy is moving from setting ambitious targets to implementing them. However, our analysis shows most countries do not provide high confidence that they will deliver on their commitments. The world is still on a high-risk climate track, and we are far from delivering a safe climate future.”
Assigning confidence
Climate goals set out in the Paris Agreement include keeping temperature rises well below 2°C above the average temperature before the industrial revolution and ideally below 1.5°C. The main way to achieve this is the reach ‘net-zero’ greenhouse gas emissions as soon as possible, where any remaining emissions are effectively offset.
Most countries have set net-zero goals and Nationally Determined Contributions (NDCs) – non-binding national plans proposing climate actions. Taking these plans at face value, and assuming they will all be fully implemented, gives the world a chance of keeping warming to 1.5-2?C. But taking current policies only, with no implementation of net-zero pledges, means models predict temperature rises could be as much as 2.5-3?C by 2100, with warming still increasing.
To reduce the uncertainty in which of these scenarios is likely to happen, the team, including researchers from the UK, Austria, USA, Netherlands, Germany, and Brazil, assigned a ‘confidence’ to each net-zero policy. They assessed 35 net zero targets, covering every country with more than 0.1% of current global greenhouse gas emissions.
The confidence assessment was based on three policy characteristics: whether the policy was legally binding, whether there was a credible policy plan guiding implementation, and whether short-term plans would already put emissions on a downward path over the next decade.
Based on this, policies were given ‘higher’, ‘lower’ or ‘much lower’ confidence of being fully implemented. Some regions scored highly, including the European Union, the United Kingdom and New Zealand, but around 90% scored ‘lower’ or ‘much lower’ confidence, including China and the US, which together account for more than 35% of current emissions.
Modelling emissions
From this assessment, the team modelled five scenarios of future greenhouse gas emissions and resulting temperatures. These were: considering only current policies (the most conservative scenario); only adding in policies that have a high confidence of being implemented; adding policies with high and low confidence; adding all policies regardless of confidence as if they are implemented; and a scenario where all policies are fully implemented and all NDCs are met (the most forgiving scenario).
The most conservative scenario had the largest uncertainty, with a range of 1.7-3°C and a median estimate of 2.6°C. The most optimistic scenario has a range of 1.6-2.1, with a median estimate of 1.7°C. This might suggest that, if all net-zero policies are fully implemented, the Paris Agreement goals are withing reach. However, with so many policies ranked in the low-confidence end of the scale, this would be wishful thinking in absence of further efforts.
Co-author Taryn Fransen, from the World Resources Institute in Washington DC, and the Energy and Resources Group at the University of California–Berkeley, said: “Climate change targets are by their nature ambitious – there’s no point in setting a target for a foregone conclusion. But implementation must follow.”
Catalysing action
Only twelve out of 35 net zero policies are currently legally binding, and the researchers say increasing this number would help ensure the policies survive long-term and catalyse action. Countries also need clear implementation pathways for different sectors, outlining exactly what changes are needed and where the responsibility lies.
Co-author Dr Robin Lamboll, from the Centre for Environmental Policy at Imperial, said: “Making targets legally binding is crucial to ensure long-term plans are adopted. We need to see concrete legislation in order to trust that action will follow from promises.”
The team included researchers from Imperial College London (UK) the International Institute for Applied Systems Analysis (Austria), the World Resources Institute (US), the University of California–Berkeley (US), the Netherlands Environmental Assessment Agency, the Institute for Environmental Studies (Netherlands), the NewClimate Institute (Germany), the Copernicus Institute of Sustainable Development (Netherlands), and the Universidade Federal do Rio de Janeiro (Brazil).
