Great Salt Lake a significant source of greenhouse gas emissions

Newly announced research by Royal Ontario Museum (ROM) examining greenhouse gas emissions from the drying lake bed of Great Salt Lake, Utah, calculates that 4.1 million tons of carbon dioxide and other greenhouse gases were released in 2020. This research suggests that drying lake beds are an overlooked but potentially significant source of greenhouse gases, which may further increase due to climate change. These results were announced in the paper, "A desiccating saline lake bed is a significant source of anthropogenic greenhouse gas emissions," published in the journal One Earth.

"Human-caused desiccation of Great Salt Lake is exposing huge areas of lake bed and releasing massive quantities of greenhouse gases into the atmosphere," said Soren Brothers, who led this research and is ROM's Allan and Helaine Shiff Curator of Climate Change. "The significance of lake desiccation as a driver of climate change needs to be addressed in greater detail and considered in climate change mitigation and watershed planning."

From year to year, Great Salt Lake's water level varies, largely depending on the volume of meltwater that flows into the lake from the surrounding mountains -- from record highs in the 1980s to a record low in 2022. However, it is human-related consumption by agriculture, industry, and municipal uses, that consume ever-increasing amounts of freshwater that, over the years, has depleted the lake. Elsewhere around the world, these same competing uses for water are having a significant impact on lake levels. As iconic saline lakes such as the Aral Sea, Lake Urmia, the Caspian Sea, and Great Salt Lake dry up, they not only destroy critical habitat for biodiversity and create air quality conditions that deteriorate human health, but they also accelerate climate change as newly exposed sediments emit carbon dioxide and methane.

The research team measured carbon dioxide and methane emissions from the exposed sediments of Great Salt Lake, Utah, from April to November 2020, and compared them with aquatic emissions estimates to determine the anthropogenic greenhouse gas emissions associated with desiccation. Calculations based on this sampling indicate the lake bed emitted 4.1 million tons of greenhouse gases to the atmosphere, primarily (94%) as carbon dioxide, constituting an approximately 7% increase to Utah's human-caused greenhouse gas emissions.

Fieldwork was conducted while Soren Brothers was Assistant Professor of Limnology at Utah State University, and lead author, Melissa Cobo, was a master's student at USU. Co-author Tobias Goldhammer is a collaborating researcher at the Leibniz Institute for Freshwater Research (IGB Institute) in Berlin, Germany. Measurements of carbon dioxide and methane gases were made every two weeks from the dried-up lake bed using a portable greenhouse gas analyzer attached to a closed chamber. Seven sites at one location at the south end of the lake were visited repeatedly over the course of the year, and another three locations were sampled during an intensive three-day campaign to determine spatial variability across the lake, which at 1,700 square miles (4,400 square kilometres) is the largest saline lake in the western hemisphere.

As methane is 28 times more powerful a greenhouse gas than carbon dioxide, the global warming impact of these emissions was calculated as "carbon dioxide equivalents" to account for the greater impact of methane. Ultimately, these data indicated that greenhouse gas emissions from the dried lake bed were strongly and positively related to warm temperatures, even at sites that have been exposed for over two decades. To determine whether the lake historically would have been a significant source of greenhouse gases, the team carried out measurements of near-shore greenhouse gas emissions from the lake, as well as analyzing water chemistry collected by the team and government data sets. Together, these analyses showed that the original lake was not likely a significant source of greenhouse gases to the atmosphere, making the dried-up lake bed a novel driver of atmospheric warming.

Read more at Science Daily

Air pollution hides increases in rainfall

We know that greenhouse gas emissions like carbon dioxide should increase rainfall. The emissions heat the atmosphere, causing a one-two punch: warmer oceans make it easier for water to evaporate, and warmer air can hold more water vapor, meaning more moisture is available to fall as rain. But for much of the 20th century, that increase in precipitation didn't clearly show up in the data.

A new study led by researchers at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) finds that the expected increase in rain has been largely offset by the drying effect of aerosols -- emissions like sulfur dioxide that are produced by burning fossil fuels, and commonly thought of as air pollution or smog.

The research is published today in the journal Nature Communications.

"This is the first time that we can really understand what's causing extreme rainfall to change within the continental U.S.," said Mark Risser, a research scientist at Berkeley Lab and one of the lead authors for the study.

He noted that until the 1970s, the expected increases to extreme rainfall were offset by aerosols.

But the Clean Air Act caused a drastic reduction in air pollution in the United States.

"The aerosol masking was turned off quite suddenly. That means rainfall might ramp up much more quickly than we would have otherwise predicted."

Traditional climate models have struggled to confidently predict the human impact on rainfall at scales smaller than a continent -- and that regional level is precisely where most climate change adaptations and mitigations take place.

By using a new method and relying heavily on measurements from rain gauges from 1900 to 2020, researchers were able to more robustly determine how human activities have influenced rainfall in the United States.

"Prior to our study, the Intergovernmental Panel on Climate Change [IPCC] had concluded that the evidence was mixed and inconclusive for changes in U.S. precipitation due to global warming," said Bill Collins, associate laboratory director for the Earth and Environmental Sciences Area at Berkeley Lab and co-lead author on the study.

"We have now provided conclusive evidence for higher rainfall and also helped explain why past studies assessed by the IPCC reached conflicting conclusions."

Specifically, the study isolates how greenhouse gas and aerosol emissions affect both average and extreme rainfall.

Researchers confirmed that increased greenhouse gas emissions, which quickly disperse over the whole planet, cause an increase in rainfall.

The impact from aerosols is more nuanced. Over the long term, aerosols cool the planet, which causes a drying effect.

But they also have a faster, more local response. That fast impact depends on the season, with aerosols generally reducing rainfall in the winter and spring, and amplifying it in summer and fall over much of the United States.

"The seasonality piece is really important," Risser said. "For rainfall, the nature of climate change depends on what season you're talking about, since different kinds of weather systems create precipitation in different parts of the year."

Some of the conflicting studies looking at precipitation trends of the last century can be explained by how the effect of aerosols offsets the effect of greenhouse gases, and how models and simulations factor in these two driving forces.

The researchers noted that tracking aerosols and incorporating them more fully into models and simulations will be important for improving the predictions used for infrastructure design and water resource management.

The United States has already seen examples of recent increases in extreme precipitation, with several intense, record-setting storms in the past few years.

Read more at Science Daily

Frequent marine heatwaves in the Arctic Ocean will be the norm

Marine heatwaves will become a regular occurrence in the Arctic in the near future and are a product of higher anthropogenic greenhouse-gas emissions -- as shown in a study just released by Dr. Armineh Barkhordarian from Universität Hamburg's Cluster of Excellence for climate research CLICCS.

Since 2007, conditions in the Arctic have shifted, as confirmed by data recently published in the journal Nature Communications Earth & Environment. Between 2007 and 2021, the marginal zones of the Arctic Ocean experienced 11 marine heatwaves, producing an average temperature rise of 2.2 degrees Celsius above seasonal norm and lasting an average of 37 days.

Since 2015, there have been Arctic marine heatwaves every year.

The most powerful heatwave to date in the Arctic Ocean was in 2020; it continued for 103 days, with peak temperatures intensity that were four degrees Celsius over the long-term average.

The probability of such a heatwave occurring without the influence of anthropogenic greenhouse gases is less than one percent, as calculated by Barkhordarian's team at the Cluster of Excellence CLICCS.

By doing so, they have narrowed down the number of plausible climate scenarios in the Arctic.

According to the study, annual marine heatwaves will be the norm.

The Arctic entered a new phase

In the study, Barkhordarian also proves for the first time that heatwaves are produced when sea ice melts early and rapidly after the winter.

When this happens, considerable heat energy can accumulate in the water by the time maximum solar radiation is reached in July.

"In 2007, a new phase began in the Arctic," says Barkhordarian, an expert on climate statistics.

"There is less and less of the thicker, several-year-old ice, while the percentage of thin, seasonal ice is consistently increasing." However, the thin ice is less durable and melts more quickly, allowing incoming solar radiation to warm the water's surface.

Officially, it is considered to be a marine heatwave when temperatures at the water's surface are higher than 95 percent of the values from the past 30 years for at least five consecutive days.

"Not just the constant loss of sea ice but also warmer waters can have dramatic negative effects on the Arctic ecosystem," says Barkhordarian.

Food chains could collapse, fish stocks could be reduced, and overall biodiversity could decline.

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Diverse forests hold huge carbon potential, as long as we cut emissions

Research results published in the journal, Nature, show that realistic global forest carbon potential is approximately 226 Gigatonnes (Gt) of carbon. The study, which involved hundreds of scientists around the world, highlights the critical importance of forest conservation, restoration, and sustainable management in moving towards international climate and biodiversity targets. The researchers stress that this potential can be achieved by incentivizing community-driven efforts to promote biodiversity.

The forest carbon potential has been a highly controversial topic. Four years ago, a study published in the journal Science found that the restoration of forests could capture over 200 Gt of carbon -- which could draw down approximately 30 percent of excess anthropogenic carbon. While this study elevated a discussion about the role of nature in fighting climate change, it also raised concerns around the adverse environmental impacts of mass tree plantations, carbon offsetting schemes, and greenwashing. While some scientific studies have supported the scale of this finding, others argued that this forest carbon estimate could be up to 4 or 5 times too high.

To address this controversial topic an international team of hundreds of researchers led by the Crowther Lab at ETH Zurich joined forces to build an integrated assessment using a comprehensive range of approaches, including vast ground-sourced data and satellite datasets.

Achieving forest carbon potential

Due to ongoing deforestation, the total amount of carbon stored in forests is ~328 Gt below its natural state. Of course, much of this land is used for extensive human development including urban and agricultural land. However, outside of those areas, researchers found that forests could capture approximately 226 Gt C in regions with a low human footprint if they were allowed to recover. Approximately 61 percent of this potential can be achieved by protecting existing forests, so that they can recover to maturity. The remaining 39 percent can be achieved by reconnecting fragmented forest landscapes through sustainable ecosystem management and restoration.

"Most of the world's forests are highly degraded. In fact, many people have never been in one of the few old growth forests that remain on Earth," said Lidong Mo, a lead author of the study. "To restore global biodiversity, ending deforestation must be a top priority."

The dataset revealed that biodiversity accounts for approximately half of the global forest productivity. As such, the researchers highlighted that, to achieve the full carbon potential, restoration efforts should include a natural diversity of species. In addition, sustainable agricultural, forestry, and restoration practices that promote biodiversity have the greatest potential for carbon capture.

Redefining restoration

The authors stress that responsible restoration is a fundamentally social endeavour. It includes countless actions such as conservation, natural regeneration, rewilding, silviculture, agroforestry, and all other community-driven efforts to promote biodiversity. It requires equitable development, driven by policies that prioritize the rights of local communities and Indigenous people.

"We need to redefine what restoration means to many people," said Thomas Crowther, the senior author of the paper and a professor at ETH Zurich. "Restoration is not about mass tree plantations to offset carbon emissions. Restoration means directing the flow of wealth towards millions of local communities, Indigenous populations, and farmers that promote biodiversity across the globe. Only when healthy biodiversity is the preferred choice for local communities will we get long-term carbon capture as a biproduct."

The researchers conclude that ecologically responsible forest restoration does not include the conversion of other ecosystems that would not naturally contain forests. "Global restoration is not only about trees," said Constantin Zohner, a senior researcher at ETH Zurich. "We have to protect natural biodiversity in all ecosystems including grasslands, peatlands, and wetlands that are equally essential for life on Earth."

Nature for climate

This study brings to light the critical importance of natural, diverse forests in contributing to 30 percent of carbon drawdown potential. However, forests cannot be a substitute for cutting fossil fuel emissions. If emissions continue to rise, the study warns, then on-going droughts, fires, and warming will threaten forests and limit their ability to absorb carbon.

Read more at Science Daily

Climate report: 'Uncharted territory' imperils life on Earth

An international coalition of climate scientists says in a paper published today that the Earth's vital signs have worsened beyond anything humans have yet seen, to the point that life on the planet is imperiled.

William Ripple, a distinguished professor in the Oregon State University College of Forestry, and former OSU postdoctoral researcher Christopher Wolf are the lead authors of the report, and 10 other U.S. and global scientists are co-authors.

"Without actions that address the root problem of humanity taking more from the Earth than it can safely give, we're on our way to the potential collapse of natural and socioeconomic systems and a world with unbearable heat and shortages of food and freshwater," Wolf said.

Published in BioScience, "The 2023 State of the climate report: Entering uncharted territory" notes that 20 of 35 planetary vital signs the authors use to track climate change are at record extremes.

The authors share new data illustrating that many climate-related records were broken by "enormous margins" in 2023, particularly those relating to ocean temperatures and sea ice. They also note an extraordinary Canadian wildfire season that produced unprecedented carbon dioxide emissions.

The report follows by four years the "World Scientists' Warning of a Climate Emergency" published by Ripple and collaborators in BioScience and co-signed by more than 15,000 scientists in 161 countries.

"Life on our planet is clearly under siege," Ripple said. "The statistical trends show deeply alarming patterns of climate-related variables and disasters. We also found little progress to report as far as humanity combating climate change."

Among the key numbers in the report:
 

• Fossil fuel subsidies -- actions by governments that artificially lower the cost of energy production, raise the price received by producers or lower the price paid by consumers -- roughly doubled between 2021 and 2022, from $531 billion to just over $1 trillion.
• Already this year wildfires in Canada have pumped more than 1 gigaton of carbon dioxide into the atmosphere, greater than Canada's total 2021 greenhouse gas emissions of 0.67 gigatons.
• In 2023, there have already been 38 days with global average temperatures more than 1.5 degrees Celsius above pre-industrial levels. Until this year, such days were a rarity, the authors note.
• The highest average Earth surface temperature ever recorded came this past July, and there's reason to believe it was the highest surface temperature the planet has seen in the last 100,000 years.

"As scientists, we are hugely troubled by the sudden increases in the frequency and severity of climate-related disasters," said Wolf, now a scientist with Corvallis-based Terrestrial Ecosystems Research Associates. "The frequency and severity of those disasters might be outpacing rising temperatures. By the end of the 21st century, as many as 3 to 6 billion people may find themselves outside the Earth's livable regions, meaning they will be encountering severe heat, limited food availability and elevated mortality rates."

The authors say policies are needed that take aim at the underlying issue of "ecological overshoot." When human demand on the Earth's resources is too large, the result in an array of environmental crises, including biodiversity decline. As long as humanity continues to put extreme pressure on the planet, any strategy that focuses only on carbon or climate will simply redistribute the pressure, they note.

"Our goal is to communicate climate facts and make policy recommendations," Ripple said. "It is a moral duty of scientists and our institutions to alert humanity of any potential existential threat and to show leadership in taking action."

The authors urge transitioning to a global economy that prioritizes human well-being and curtails overconsumption and excessive emissions by the rich. Specific recommendations include phasing out fossil fuel subsidies, transitioning toward plant-based diets, scaling up forest protection efforts and adopting international coal elimination and fossil fuel non-proliferation treaties.

Read more at Science Daily

America's wealthiest 10% responsible for 40% of US greenhouse gas emissions

A new study, led by the University of Massachusetts Amherst, reveals that the wealthiest Americans, those whose income places them in the top 10% of earners, are responsible for 40% of the nation's total greenhouse gas emissions. The study, published in  PLOS Climate, is the first to link income, especially income derived from financial investments, to the emissions used in generating that income. The authors suggest that policymakers adopt taxes focused on shareholders and the carbon intensity of investment incomes in order to equitably meet the goal of keeping the global temperature to 1.5 C of warming.

Scientists and environmentalists have long known that consumption -- the amount and kind of food we eat, the vehicles we drive and all the stuff we buy -- is closely linked to greenhouse gas emission. Traditional environmental policy has then sought to either limit consumption or guide it into more environmentally friendly avenues: replacing red meat with plant-based diets or swapping a gas-guzzler for an electric vehicle.

"But," says Jared Starr, a sustainability scientist at UMass Amherst and the lead author of the new study, "consumption-based approaches to limiting greenhouse gas emissions are regressive. They disproportionately punish the poor while having little impact on the extremely wealthy, who tend to save and invest a large share of their income. Consumption-based approaches miss something important: carbon pollution generates income, but when that income is reinvested into stocks, rather than spent on necessities, it isn't subject to a consumption-based carbon tax."

"What happens," Starr asks, "when we focus on how emissions create income, rather than how they enable consumption?"

An answer to that seemingly simple question, however, is fraught with difficulty, because though it's relatively easy to capture a snapshot of wages and salaries -- the main sources of income for 90% of Americans -- it has been very difficult to get a sense of the investment income that makes up a large source of the richest Americans' wealth.

To solve this problem, Starr and his colleagues looked at 30 years' worth of data, drawing first on a database containing over 2.8 billion inter-sectoral financial transfers and following the flow of carbon and income through these transactions. This allowed them to calculate two different values: supplier-based and producer-based greenhouse gas emissions of income.

Supplier-based emissions are those created by industries that supply fossil fuels to the economy. For instance, the operational emissions released by fossil fuel companies are actually quite low, but they make enormous profits by selling oil to others who will burn it.

Producer-based emissions are those directly released by the operation of the business itself -- like a coal-fired power plant.

With these two figures in hand, Starr and his co-authors then linked their emissions data with another database containing detailed demographic and income data for over 5 million Americans. This database parses out income sources differentiating active income -- the wages or salaries earned through employment -- from the passively generated investment income.

Not only did the team find that over 40% of U.S. emissions were attributable with the income flows of the top 10%, they also discovered that the top 1% of earners alone generate 15 -- 17% of the nation's emissions. In general, white, non-Hispanic households had the highest emission-linked income and Black households the lowest. Emissions tended to increase with age, peaking with the 45-54 age group, before declining.

The team also identified "super emitters" with extremely high emissions intensity. These are almost exclusively among the top 0.1% of households, which are overrepresented in the fields of finance, real estate and insurance, manufacturing, and mining and quarrying.

"This research gives us insight into the way that income and investments obscure emissions responsibility," says Starr. "For example, 15 days of income for a top 0.1% household generates as much carbon pollution as a lifetime of income for a household in the bottom 10%. An income-based lens helps us focus in on exactly who is profiting the most from climate-changing carbon pollution, and design policies to shift their behavior."

In particular, Starr and his colleagues point to income and shareholder-based taxation -- rather than taxing consumables.

Read more at Science Daily

Gloomy climate calculation: Scientists predict a collapse of the Atlantic ocean current to happen mid-century

Important ocean currents that redistribute heat, cold and precipitation between the tropics and the northernmost parts of the Atlantic region will shut down around the year 2060 if current greenhouse gas emissions persist. This is the conclusion based on new calculations from the University of Copenhagen that contradict the latest report from the IPCC.

Contrary to what we may imagine about the impact of climate change in Europe, a colder future may be in store. In a new study, researchers from the University of Copenhagen's Niels Bohr Institute and Department of Mathematical Sciences predict that the system of ocean currents which currently distributes cold and heat between the North Atlantic region and tropics will completely stop if we continue to emit the same levels of greenhouse gases as we do today.

Using advanced statistical tools and ocean temperature data from the last 150 years, the researchers calculated that the ocean current, known as the Thermohaline Circulation or the Atlantic Meridional Overturning Circulation (AMOC), will collapse -- with 95 percent certainty -- between 2025 and 2095. This will most likely occur in 34 years, in 2057, and could result in major challenges, particularly warming in the tropics and increased storminess in the North Atlantic region.

"Shutting down the AMOC can have very serious consequences for Earth's climate, for example, by changing how heat and precipitation are distributed globally. While a cooling of Europe may seem less severe as the globe as a whole becomes warmer and heat waves occur more frequently, this shutdown will contribute to an increased warming of the tropics, where rising temperatures have already given rise to challenging living conditions," says Professor Peter Ditlevsen from the Niels Bohr Institute.

"Our result underscores the importance of reducing global greenhouse gas emissions as soon as possible," says the researcher.

The calculations, just published in the scientific journal, Nature Communications, contradict the message of the latest IPCC report, which, based on climate model simulations, considers an abrupt change in the thermohaline circulation very unlikely during this century.

Early warning signals present

The researchers' prediction is based on observations of early warning signals that ocean currents exhibit as they become unstable. These Early Warning Signals for the Thermohaline Circulation have been reported previously, but only now has the development of advanced statistical methods made it possible to predict just when a collapse will occur.

The researchers analysed sea surface temperatures in a specific area of the North Atlantic from 1870 to present days. These sea surface temperatures are "fingerprints" testifying the strength of the AMOC, which has only been measured directly for the past 15 years.

"Using new and improved statistical tools, we've made calculations that provide a more robust estimate of when a collapse of the Thermohaline Circulation is most likely to occur, something we had not been able to do before," explains Professor Susanne Ditlevsen of UCPH's Department of Mathematical Sciences.

The thermohaline circulation has operated in its present mode since the last ice age, where the circulation was indeed collapsed. Abrupt climate jumps between the present state of the AMOC and the collapsed state has been observed to happen 25 times in connection with iceage climate. These are the famed Dansgaard-Oeschger events first observed in ice cores from the Greenlandic ice sheet. At those events climate changes were extreme with 10-15 degrees changes over a decade, while present days climate change is 1.5 degrees warming over a century.

Read more at Science Daily

Potent greenhouse gas produced by industry could be readily abated with existing technologies

Researchers have found that one method of reducing greenhouse gas emissions is available, affordable, and capable of being implemented right now. Nitrous oxide, a potent greenhouse gas and ozone-depleting substance, could be readily abated with existing technology applied to industrial sources.

"The urgency of climate change requires that all greenhouse gas emissions be abated as quickly as is technologically and economically feasible," said lead author Eric Davidson, a professor with the University of Maryland Center for Environmental Science. "Limiting nitrous oxide in an agricultural context is complicated, but mitigating it in industry is affordable and available right now. Here is a low-hanging fruit that we can pluck quickly."

When greenhouse gases are released into the atmosphere, they trap the heat from the sun, leading to a warming planet. In terms of emissions, nitrous oxide is third among greenhouse gases, topped only by carbon dioxide and methane. Also known as laughing gas, it has a global warming potential nearly 300 times that of carbon dioxide and stays in the atmosphere for more than 100 years. It also destroys the protective ozone layer in the stratosphere, so reducing nitrous oxide emissions provides a double benefit for the environment and humanity.

Nitrous oxide concentration in the atmosphere has increased at an accelerating rate in recent decades, mostly from increasing agricultural emissions, which contribute about two-thirds of the global human-caused nitrous oxide. However, agricultural sources are challenging to reduce. In contrast, for the industry and energy sectors, low-cost technologies already exist to reduce nitrous oxide emissions to nearly zero.

Industrial nitrous oxide emissions from the chemical industry are primarily by-products from the production of adipic acid (used in the production of nylon) and nitric acid (used to make nitrogen fertilizers, adipic acid, and explosives). Emissions also come from fossil fuel combustion used in manufacturing and internal combustion engines used in cars and trucks.

"We know that abatement is feasible and affordable. The European Union's emissions trading system made it financially attractive to companies to remove nitrous oxide emissions in all adipic acid and nitric acid plants," said co-author Wilfried Winiwarter of the International Institute for Applied Systems Analysis. "The German government is also helping to fund abatement of nitrous oxide emissions from nitric acid plants in several low-income and middle-income countries."

The private sector could also play a key role in nitrous oxide emissions reduction, encouraged by trends in consumer preferences for purchasing climate-friendly products. For example, 65% of the nitrous emissions embodied in nylon products globally are used in passenger cars and light vehicles. Automobile manufacturers could require supply chains to source nylon exclusively from plants that deploy efficient nitrous oxide abatement technology.

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Greenhouse gas emissions at 'an all-time high' -- and it is causing an unprecedented rate of global warming, say scientists

Human-caused global warming has continued to increase at an "unprecedented rate" since the last major assessment of the climate system published two years ago, say 50 leading scientists.

One of the researchers said the analysis was a "timely wake-up call" that the pace and scale of climate action has been insufficient, and it comes as climate experts meet in Bonn to prepare the ground for the major COP28 climate conference in the UAE in December, which will include a stocktake of progress towards keeping global warming to 1.5°C by 2050.

Given the speed at which the global climate system is changing, the scientists argue that policymakers, climate negotiators and civil society groups need to have access to up-to-date and robust scientific evidence on which to base decisions.

The authoritative source of scientific information on the state of the climate is the UN's Intergovernmental Panel on Climate Change (IPCC) but the turnaround time for its major assessments is five or ten years, and that creates an "information gap," particularly when climate indicators are changing rapidly.

In an initiative being led by the University of Leeds, the scientists have developed an open data, open science platform -- the Indicators of Global Climate Change and website (https://igcc.earth/). It will update information on key climate indicators every year.

Critical decade for climate change

The Indicators of Global Climate Change Project is being co-ordinated by Professor Piers Forster, Director of the Priestley Centre for Climate Futures at Leeds. He said: "This is the critical decade for climate change.

"Decisions made now will have an impact on how much temperatures will rise and the degree and severity of impacts we will see as a result.

"Long-term warming rates are currently at a long-term high, caused by highest-ever levels of greenhouse gas emissions. But there is evidence that the rate of increase in greenhouse gas emissions has slowed.

"We need to be nimble footed in the face of climate change. We need to change policy and approaches in the light of the latest evidence about the state of the climate system. Time is no longer on our side. Access to up-to-date information is vitally important."

Writing in the journal Earth System Science Data, the scientists have revealed how key indicators have changed since the publication of the IPCC's Sixth Assessment Working Group 1 report in 2021- which produced the key data that fed into the subsequent IPCC Sixth Synthesis Report.

What the updated indicators show

Human-induced warming, largely caused by the burning of fossil fuels, reached an average of 1.14°C for the most recent decade (2013 to 2022) above pre-industrial levels. This is up from 1.07°C between 2010 and 2019.

Human-induced warming is now increasing at a pace of over 0.2°C per decade.

The analysis also found that greenhouse gas emissions were "at an all-time high," with human activity resulting in the equivalent of 54 (+/-5.3) gigatonnes (or billion metric tonnes) of carbon dioxide being released into the atmosphere on average every year over the last decade (2012-2021).

There has been positive move away from burning coal, yet this has come at a short-term cost in that it has added to global warming by reducing particulate pollution in the air, which has a cooling effect.

'Indicators critical to address climate crisis'

Professor Maisa Rojas Corradi, Minister of the Environment in Chile, IPCC author and a scientist involved in this study, said: "An annual update of key indicators of global change is critical in helping the international community and countries to keep the urgency of addressing the climate crisis at the top of the agenda and for evidence-based decision-making.

"In line with the "ratchet-mechanism" of increasing ambition envisioned by the Paris Agreement we need scientific information about emissions, concentration, and temperature as often as possible to keep international climate negotiations up to date and to be able to adjust and if necessary correct national policies.

"In the case of Chile, we have a climate change law that aims at aligning government-wide policies with climate action."

Remaining carbon budget

One of the major findings of the analysis is the rate of decline in what is known as the remaining carbon budget, an estimate of how much carbon that can be released into the atmosphere to give a 50% chance of keeping global temperature rise within 1.5°C.

In 2020, the IPCC calculated the remaining carbon budget was around 500 gigatonnes of carbon dioxide. By the start of 2023, the figure was roughly half that at around 250 gigatonnes of carbon dioxide.

The reduction in the estimated remaining carbon budget is due to a combination of continued emissions since 2020 and updated estimates of human-induced warming.

Professor Forster said: "Even though we are not yet at 1.5°C warming, the carbon budget will likely be exhausted in only a few years as we have a triple whammy of heating from very high CO2 emissions, heating from increases in other GHG emissions and heating from reductions in pollution.

"If we don't want to see the 1.5°C goal disappearing in our rearview mirror, the world must work much harder and urgently at bringing emissions down.

"Our aim is for this project to help the key players urgently make that important work happen with up-to-date and timely data at their fingertips."

Dr Valérie Masson-Delmotte, from the Université Paris Saclay who co-chaired Working Group 1 of the IPCC's Sixth Assessment report and was involved in the climate indicators project, said: "This robust update shows intensifying heating of our climate driven by human activities. It is a timely wake up call for the 2023 global stocktake of the Paris Agreement -- the pace and scale of climate action is not sufficient to limit the escalation of climate-related risks."

As recent IPCC reports have conclusively shown, with every further increment of global warming, the frequency and intensity of climate extremes, including hot extremes, heavy rainfall and agricultural droughts, increases.

The Indicators of Global Climate Change (https://igcc.earth/) will have annually updated information on greenhouse gas emissions, human-induced global warming and the remaining carbon budget.

Read more at Science Daily

Tiny microbes could brew big benefits for green biomanufacturing

A research team led by Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley has engineered bacteria to produce new-to-nature carbon products that could provide a powerful route to sustainable biochemicals.

The advance -- which was recently announced in the journal Nature -- uses bacteria to combine natural enzymatic reactions with a new-to-nature reaction called the "carbene transfer reaction." This work could also one day help reduce industrial emissions because it offers sustainable alternatives to chemical manufacturing processes that typically rely on fossil fuels.

"What we showed in this paper is that we can synthesize everything in this reaction -- from natural enzymes to carbenes -- inside the bacterial cell. All you need to add is sugar and the cells do the rest," said Jay Keasling, a principal investigator of the study and CEO of the Department of Energy's Joint BioEnergy Institute (JBEI).

Carbenes are highly reactive carbon-based chemicals that can be used in many different types of reactions. For decades, scientists have wanted to use carbene reactions in the manufacturing of fuels and chemicals, and in drug discovery and synthesis.

But these carbene processes could only be carried out in small batches via test tubes and required expensive chemical substances to drive the reaction.

In the new study, the researchers replaced expensive chemical reactants with natural products that can be produced by an engineered strain of the bacteria Streptomyces. Because the bacteria use sugar to produce chemical products through cellular metabolism, "this work enables us to perform the carbene chemistry without toxic solvents or toxic gases typically used in chemical synthesis," said first author Jing Huang, a Berkeley Lab postdoctoral researcher in the Keasling Lab. "This biological process is much more environmentally friendly than the way chemicals are synthesized today," Huang said.

During experiments at JBEI, the researchers observed the engineered bacterium as it metabolized and converted sugars into the carbene precursor and the alkene substrate. The bacterium also expressed an evolved P450 enzyme that used those chemicals to produce cyclopropanes, high-energy molecules that could potentially be used in the sustainable production of novel bioactive compounds and advanced biofuels. "We can now perform these interesting reactions inside the bacterial cell. The cells produce all of the reagents and the cofactors, which means that you can scale this reaction to very large scales" for mass manufacturing, Keasling said.

Recruiting bacteria to synthesize chemicals could also play an integral role in reducing carbon emissions, Huang said. According to other Berkeley Lab researchers, close to 50% of greenhouse gas emissions come from the production of chemicals, iron and steel, and cement. Limiting global warming to 1.5 degrees Celsius above pre-industrial levels will require severely cutting greenhouse gas emissions in half by 2030, says a recent report by the Intergovernmental Panel on Climate Change.

Huang said that while this fully integrated system can be envisioned for a large number of carbene donor molecules and alkene substrates, it is not yet ready for commercialization.

"For every new advance, someone needs to take the first step. And in science, it can take years before you succeed. But you have to keep trying -- we can't afford to give up. I hope our work will inspire others to continue searching for greener, sustainable biomanufacturing solutions," Huang said.

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Rationing: A fairer way to fight climate change?

World War II-style rationing could be an effective way to reduce carbon emissions, according to new research from the University of Leeds.

In a paper published today in the journal Ethics, Policy and Environment, academics argue that rationing could help states to reduce greenhouse gas emissions rapidly and fairly.

Policymakers have considered other schemes to reduce emissions, including carbon taxes and personal carbon trading schemes, but the researchers say these favour the wealthy, who could buy the right to pollute if trading were allowed.

The authors argue that carbon rationing would instead allow people to receive an equitable portion of resources based on their needs, therefore sharing out the effort to protect the planet.

The authors were based across the University of Leeds' Inter-Disciplinary Ethics Applied Centre, Sustainability Research Institute and School of History when they conducted the research.

Joint lead author Dr Nathan Wood, who is now a Postdoctoral Fellow at Utrecht University's Fair Energy Consortium, said: "The concept of rationing could help, not only in the mitigation of climate change, but also in reference to a variety of other social and political issues -- such as the current energy crisis."

Lessons from the past

Records from World War II show that compulsory food rationing was more acceptable to the UK public than voluntary changes to diet when resources became scarce. The policy aimed to share goods and burdens more equally, regardless of wealth, which was an important part of its popularity and success.

Historic rationing policies also introduced price controls on goods to keep key resources affordable for most people. As a result, rates of malnutrition went down during World War II, despite the shortages.

A key difference between World War II rationing and the climate crisis is public perception, the researchers say. The availability of thousands of garments, gadgets and goods at the click of a button can give the illusion that resources are available in abundance, but the reality is starkly different.

Dr Rob Lawlor, joint lead author and Lecturer at Leeds' Inter-Disciplinary Ethics Applied Centre, said: "There is a limit to how much we can emit if we are to reduce the catastrophic impacts of climate change. In this sense, the scarcity is very real."

Dr Wood said: "The cost of living crisis has shown what happens when scarcity drives up prices, with energy prices rising steeply and leaving vulnerable groups unable to pay their bills. Currently, those living in energy poverty cannot use anywhere near their fair share of energy supply, whereas the richest in society are free to use as much energy as they can afford."

Dr Lawlor added: "It seems feasible to reduce emissions overall even while the lowest emitters, often the worst off, may be able to increase their emissions -- not despite rationing, but because of rationing and price controls."

What equitable rationing could look like

The researchers suggest that rationing probably wouldn't be the first step. Instead, policy changes could start with stricter regulations and an accompanying information campaign to communicate the benefits of rationing.

Initially, governments could regulate the biggest polluters, such as oil, gas and petrol, long-haul flights and intensive farming, creating scarcity in products that harm the planet. Rationing could then be introduced gradually, to manage the resulting scarcity with the aim of meeting everyone's basic needs.

The academics identified two options for rationing policy. Policymakers could introduce an all-encompassing carbon allowance, giving out 'carbon cards' like bank cards to track and limit usage. Alternatively, governments could ration specifically selected goods, such as flights, petrol, household energy, or even meat or clothing.

Dr Lawlor said: "Many have proposed carbon allowances and carbon cards before. What is new (or old, taking inspiration from World War II) is the idea that the allowances should not be tradable. Another feature of World War II-style rationing is that price controls on rationed goods would prevent prices from rising with increased demand, benefitting those with the least money."

According to the researchers, it's likely that rationing would accelerate the transition from fossil fuels to cleaner energy and more sustainable lifestyles. Dr Wood said: "For example, rationing petrol could encourage greater use of, and investment in, low carbon public transport, such as railways and local trams."

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We need to learn to live with less steel

Steel is one of the most important materials in the world, integral to the cars we drive, the buildings we inhabit, and the infrastructure that allows us to travel from place to place. Steel is also responsible for 7% of global greenhouse gas emissions. In 2021, 45 countries made a commitment to pursue near-zero-emission steel in the next decade. But how possible is it to produce the steel we need in society with zero emissions?

A new study focused on the Japanese steel industry shows that if we are truly committed to reaching zero emissions, we must be prepared for a scenario where the amount of steel we can produce is lower. Japan has set a target for a 46% reduction in emissions from steel by 2030, and zero emissions by 2050. So far, the roadmap for achieving this relies heavily on future innovations in technology. Hope is held out for developments in carbon capture and storage (CCS) and hydrogen-based technologies.

In the study, Dr. Takuma Watari, a researcher at the National Institute for Environmental Studies, Japan, currently working with the University of Cambridge, argues that there is no silver bullet. He says that current plans to cut carbon emissions underestimate how difficult it will be to develop CCS and hydrogen technologies and deploy them widely: "These technologies still face serious technical, economic, and social challenges, and have yet to be implemented at scale. And importantly, it is highly uncertain whether there will be sufficient non-emitting electricity to use these technologies." We need to confront the possibility that technological innovations might not be ready in time to allow us to maintain current levels of steel production whilst cutting emissions to zero.

The research involved mapping the current flows of steel in Japan's industry and using a model to explore how the industry might change if a strict carbon budget were applied in future. Dr. Watari explains that with current practice, the quantity and quality of steel produced would dramatically decrease under a zero-emission carbon budget. This is because of a lack of resources and the practice of downcycling, in which scraps of steel containing impurities are used to make new products. It is difficult to remove these impurities, so the new products have different quality and functionality from the original steel.

According to Dr. Watari, "zero-emission steel production is possible by 2050, but in limited quantity and quality compared to current total production. This is due to the limited availability of zero-emission compatible resources and downcycling practices of scrap steel."

The research indicates that with a carbon budget of zero emissions, the production of steel goods would be dramatically restricted compared to today, reaching about half the current levels at best. In this case, higher-quality steel production (e.g., sheet steel) would be especially hard hit.

The implication is clear. It is not enough to rely on a technological silver bullet materialising to transform the supply of steel. We also need to look seriously at strategies to reduce demand by shifting our culture of steel use and improving our material efficiency. We also need to pursue upcycling to produce high-grade steel from scrap steel.

This will require collaboration from those who use steel as well as those who produce it. Steel products could be made more resource efficient if they are designed to last longer or to be lightweight. Once steel products reach the end of their life, upcycling could be achieved through advanced sorting and shredding to remove impurities from scrap steel. As a society, Japan may also have to become less steel-dependent and shift to a model of 'service use' rather than ownership of products. Unlike today, when steel is abundant and cheap, a net-zero future will require us to use scarcer, more expensive steel resources with greater efficiency. 

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Limiting global warming now can preserve valuable freshwater resource

Snowcapped mountains not only look majestic -- They're vital to a delicate ecosystem that has existed for tens of thousands of years. Mountain water runoff and snowmelt flows down to streams, rivers, lakes, and oceans -- and today, around a quarter of the world depends on these natural "water towers" to replenish downstream reservoirs and groundwater aquifers for urban water supplies, agricultural irrigation, and ecosystem support.

But this valuable freshwater resource is in danger of disappearing. The planet is now around 1.1 degrees Celsius (1.9 degrees Fahrenheit) warmer than pre-industrial levels, and mountain snowpacks are shrinking. Last year, a study co-led by Alan Rhoades and Erica Siirila-Woodburn, research scientists in the Earth and Environmental Sciences Area of Lawrence Berkeley National Laboratory (Berkeley Lab), found that if global warming continues along the high-emissions scenario, low-to-no-snow winters will become a regular occurrence in the mountain ranges of the western U.S. in 35 to 60 years.

Now, in a recent Nature Climate Change study, a research team led by Rhoades found that if global warming reaches around 2.5 degrees Celsius compared to pre-industrial levels, mountain ranges in the southern midlatitudes, the Andean region of Chile in particular, will face a low-to-no-snow future between the years 2046 and 2051 -- or 20 years earlier than mountain ranges in the northern midlatitudes such as the Sierra Nevada or Rockies. (Low-to-no-snow occurs when the annual maximum water stored as snowpack is within the bottom 30% of historical conditions for a decade or more.) The researchers also found that low-to-no-snow conditions would emerge in the southern midlatitudes at a third of the warming than in the northern midlatitudes.

"These findings are pretty shocking. We assumed that both regions in the southern and northern hemispheres would respond similarly to climate change, and that the Andes would be more resilient given its high elevation," said Alan Rhoades, a hydroclimate research scientist in Berkeley Lab's Earth and Environmental Sciences Area and lead author of the new study. "This shows that not every degree of warming has the same effect in one region as another."

In another major finding, the researchers learned that such a low-to-no-snow future coincides with roughly 10% less mountain runoff in both hemispheres, during wet and dry years.

"If you expect 10% less runoff, that means there's at least 10% less water available every year to refill reservoirs in the summer months when agriculture and mountain ecosystems most need it," Rhoades said.

Such diminished runoff would be particularly devastating for agricultural regions already parched by multiyear droughts.

California's current drought is entering its fourth year. According to the U.S. Drought Monitor, more than 94 percent of the state is in severe, extreme, or exceptional drought. Shrinking groundwater supplies and municipal wells throughout the state are severely impacting the San Joaquin Valley, the state's agricultural heartland.

And Chile -- which exports approximately 30% of its fresh fruit production every year, with much of it shipped to the United States -- is in the midst of a historic 13-year drought.

Saving snow, freshwater by curbing greenhouse gas emissions

But the new study also suggests that low-to-no-snow in both the northern and southern midlatitude mountain ranges can be prevented if global warming is limited to essentially 2.5 degrees Celsius (4.5 degrees Fahrenheit), the researchers said.

Their analysis is based on Earth system models that simulate the various components of the climate, such as the atmosphere and land surface, to identify how mountain water cycles could continue to change through the 21st century, and what warming levels might give rise to a widespread and persistent low-to-no-snow future across the American Cordillera -- a chain of mountain ranges spanning the western "backbone" of North America, Central America, and South America.

The researchers used computing resources at Berkeley Lab's National Energy Research Scientific Computing Center (NERSC) to process and analyze data collected by climate researchers from all over the world through the Department of Energy's CASCADE (Calibrated & Systematic Characterization, Attribution, & Detection of Extremes) project. (Post-analysis data from the study is available to the research community at NERSC.)

The closest to what Rhoades and his team considered to be "episodic low-to-no snow" conditions occurred in California between 2012 to 2016. The lack of snow and drought conditions in these years demonstrated the vulnerability of our water supply and, in part, led to the passing of the California Sustainable Groundwater Management Act, new approaches to water and agricultural management practices, and mandatory water cuts, Rhoades said

Persistent low-to-no snow (10 years in a row) has yet to occur, but Rhoades said that water managers are already thinking about such a future. "They're collaborating with scientists to come up with strategies to proactively rather than reactively manage water resources for the worst-case scenarios if we can't mitigate greenhouse gas emissions to avoid certain warming levels. But the better strategy would be to prevent further warming by cutting greenhouse gas emissions," he said.

For future studies, Rhoades plans to continue to examine and run new Earth system model simulations at even higher resolution "to give more spatial context of when and where snow loss might occur and what causes it," he said, and investigate how every degree of warming might change other key drivers of the mountain-water cycle, such as the landfall location and intensity of atmospheric rivers, and mountain ecosystem responses.

He also plans to continue to work with water managers through the Department of Energy-funded HyperFACETS project to identify ways we can better prepare for a low-to-no snow future through new management strategies such as infrastructure hardening against drought and floods and managed aquifer recharge.

Rhoades is optimistic, citing research from another Berkeley Lab-led study that found reaching zero net emissions of carbon dioxide from energy and industry by 2050 can be accomplished by rebuilding the U.S. energy infrastructure to run primarily on renewable energy.

"It just requires the will and initiative to invest financial resources at the level of urgency that climate change demands, which means we need to start doing this today," he said.

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Scientists crack upcycling plastics to reduce greenhouse gas emissions

Scientists from the University of Illinois Urbana-Champaign, University of California, Santa Barbara, and Dow have developed a breakthrough process to transform the most widely produced plastic -- polyethylene (PE) -- into the second-most widely produced plastic, polypropylene (PP), which could reduce greenhouse gas emissions (GHG).

"The world needs more and better options for extracting the energy and molecular value from its waste plastics," said co-lead author Susannah Scott, Distinguished Professor and Mellichamp Chair of Sustainable Catalytic Processing at UC Santa Barbara. Conventional plastic recycling methods result in low-value plastic molecules and, thus, offer little incentive to recycle the mountains of plastic waste that have accumulated over the past several decades. But, Scott added, "turning polyethylene into propylene, which can then be used to make a new polymer, is how we start to build a circular economy for plastics."

"We started by conceptualizing this approach and demonstrated its promise first through theoretical modeling -- now we have proved that it can be done experimentally in a way that is scalable and potentially applicable to current industry demands," said co-lead author Damien Guironnet, a professor of chemical and biomolecular engineering at Illinois, who published the first study outlining the necessary catalytic reactions in 2020.

The new study published in the Journal of the American Chemical Society announces a series of coupled catalytic reactions that transform PE, which is #2 and #4 plastic that make up 29% of the world's plastic consumption, into the building block propylene that is the key ingredient to produce PP, also known as #5 plastic that accounts for close to 25% of the world's plastic consumption.

This study establishes a proof-of-concept for upcycling PE plastic with more than 95% selectivity into propylene. The researchers have built a reactor that creates a continuous flow of propylene that can be converted into PP easily using current technology -- making this discovery scalable and rapidly implementable.

"Our preliminary analysis suggests that if just 20% of the world's PE could be recovered and converted via this route, it could represent a potential savings of GHG emissions comparable to taking 3 million cars off the road," said Garrett Strong, a graduate student associated with the project.

The goal is to cut each very long PE molecule many times to obtain many small pieces, which are the propylene molecules. First, a catalyst removes hydrogen from the PE, creating a reactive location on the chain. Next, the chain is split in two at this location using a second catalyst, which caps the ends using ethylene. Finally, a third catalyst moves the reactive site along the PE chain so the process can be repeated. Eventually, all that is left are a large number of propylene molecules.

"Think of cutting a baguette in half, and then cutting precisely-sized pieces off the end of each half -- where the speed at which you cut controls the size of each slice," Guironnet said.

"Now that we have established the proof of concept, we can start to improve the efficiency of the process by designing catalysts that are faster and more productive, making it possible to scale up," Scott said. "Since our end-product is already compatible with current industry separation processes, better catalysts will make it possible to implement this breakthrough rapidly."

The work presented in this publication is highly complementary to a paper published in Science last week. Both groups used virgin plastics and similar chemistries. However, the Science team used a different process in an enclosed batch reactor, requiring much higher pressure -- which is energy intensive -- and the need to recycle more ethylene.

"If we are to upcycle a significant fraction of the over 100 million tons of plastic waste we generate each year, we need solutions that are highly scalable," Guironnet said. "Our team demonstrated the chemistry in a flow reactor we developed to produce propylene highly selectively and continuously. This is a key advance to address the immense volume of the problem that we are facing."

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System to create bioplastics

A team of Texas A&M AgriLife Research scientists has developed a system that uses carbon dioxide, CO2, to produce biodegradable plastics, or bioplastics, that could replace the nondegradable plastics used today. The research addresses two challenges: the accumulation of nondegradable plastics and the remediation of greenhouse gas emissions.

Published Sept. 28 in Chem, the research was a collaboration of Susie Dai, Ph.D., associate professor in the Texas A&M Department of Plant Pathology and Microbiology, and Joshua Yuan, Ph.D., formerly with the Texas A&M Department of Plant Pathology and Microbiology as chair for synthetic biology and renewable products and now Lopata professor and chair in the Washington University in St. Louis Department of Energy, Environmental and Chemical Engineering.

The research was made possible by the John '90 and Sally '92 Hood Fund for Sustainability and Renewable Products, Texas A&M AgriLife and Texas A&M University.

Creating bioplastics

Dai said today's petroleum-based plastics do not degrade easily and create a massive issue in the ecosystems and, ultimately, oceans.

To address these issues, the Texas A&M College of Agriculture and Life Sciences researchers and their teams worked for almost two years to develop an integrated system that uses CO2 as a feedstock for bacteria to grow in a nutrient solution and produce bioplastics. Peng Zhang, Ph.D., postdoctoral research associate, and Kainan Chen, doctoral student, both in the Texas A&M Department of Plant Pathology and Microbiology, contributed to the work. The Texas A&M University System has filed a patent application for the integrated system.

"Carbon dioxide has been used in concert with bacteria to produce many chemicals, including bioplastics, but this design produces a highly efficient, smooth flow through our carbon dioxide-to-bioplastics pipeline," Dai said.

"In theory, it is kind of like a train with units connected to each other," Dai said. "The first unit uses electricity to convert the carbon dioxide to ethanol and other two-carbon molecules -- a process called electrocatalysis. In the second unit, the bacteria consume the ethanol and carbon molecules to become a machine to produce bioplastics, which are different from petroleum-based plastic polymers that are harder to degrade."

Capturing and re-using CO2 waste

Using CO2 in the process could also help reduce greenhouse gas emissions. Many manufacturing processes emit CO2 as a waste product.

"If we can capture the waste carbon dioxide, we reduce greenhouse gas emission and can use it as a feedstock to produce something," Dai said. "This new platform has great potential to address sustainability challenges and transform the future design of carbon dioxide reduction."

The major strength of the new platform is a much faster reaction rate than photosynthesis and higher energy efficiency.

"We are expanding the capacity of this platform to broad product areas such as fuels, commodity chemicals and diverse materials," Dai said. "The study demonstrated the blueprint for 'decarbonized biomanufacturing' that could transform our manufacturing sector."

Expanding future impacts

Dai said currently, bioplastics are more expensive than petroleum-based plastics. But if the technology is successful enough to produce bioplastics at an economic scale, industries could replace traditional plastic products with ones that have fewer negative environmental impacts. In addition, mitigating CO2 emissions from energy sectors such as gas and electric facilities would also be a benefit.

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