Expansion, environmental impacts of irrigation by 2050 greatly underestimated


PRINCETON UNIVERSITY

NEWS RELEASE 4-MAY-2020

The amount of farmland around the world that will need to be irrigated in order to feed an estimated global population of 9 billion people by 2050 could be up to several billion acres, far higher than scientists currently project, according to new research. The result would be a far greater strain on aquifers, as well as the likely expansion of agriculture into natural ecosystems as farmers search for water.

Existing irrigation models -- which are widely used to define policies on water and food security, environmental sustainability, and climate change -- suggest that the amount of agricultural land requiring irrigation could extend between 240 million and 450 million hectares (590 million to 1.1 billion acres) during the next 30 years.

But those projections likely underestimate population growth and too confidently assume how much land and water will be available for agriculture without having to find new sources, according to researchers from Princeton University, the University of Reading in the United Kingdom, and the University of Bergen in Norway.

The amount of irrigated land could in fact increase to as high as 1.8 billion hectares (4.4 billion acres), the study authors reported in the journal Geophysical Research Letters, writing, "Policymakers should acknowledge that irrigated areas can grow much more than previously thought in order to avoid underestimating potential environmental costs."

First author Arnald Puy, a postdoctoral researcher in ecology and evolutionary biology at Princeton, said that an expansion of irrigation of this magnitude would have dramatic effects on the environment and other sectors of society. Puy, who is affiliated with the Center for BioComplexity administered by the Princeton Environmental Institute (PEI), worked with co-authors Samuele Lo Piano of the University of Reading and Andrea Saltelli of the University of Bergen.

Irrigation is currently responsible for about 70% of freshwater withdrawals worldwide. About 90% of water taken for residential and industrial uses eventually returns to the aquifer, but only about one-half of the water used for irrigation is reusable. Evaporation, evapotranspiration from plants, and delivery losses such as from leaky pipes forever remove the rest from the water cycle.

"Much larger irrigated areas might mean extending agricultural land toward new ecosystems or non-cultivated areas with the consequent loss of biodiversity, which might also be larger than expected," Puy said. "At the same time, needing more water for irrigation means less water for other sectors and therefore more stress on water resources than expected."

There also could be a much higher amplification of climate change, which current climate models do not account for, Puy said. Previous research has shown that irrigation may influence climate by altering surface temperatures and the amount of water vapor in the atmosphere, both of which are critical components of climate modeling. These factors have an impact on cloud formation and the amount of solar radiation that is either contained within the atmosphere or reflected back into space.

The climate effects of irrigation also include greenhouse gases released through producing and operating irrigation machinery. The most common modern equipment consists of center-pivot systems consisting of wheeled tubes outfitted with spray guns or dripping faucet heads that rotate around a central water source.

"Much larger irrigated areas means that predictions of agricultural gas emissions might also be much lower than they will be in reality," Puy said "More irrigated areas means investing on irrigation machinery and energy consumption, leading to the consumption of fossil-energy reservoirs and the release of CO2."

Finally, irrigated agriculture also increases soil total nitrogen and carbon due to the addition of fertilizers and manure. Nitrate leaching can taint groundwater and ammonia can be volatilized from fertilizers, limiting the availability of potable water, Puy said.

By drawing attention to the underestimation of irrigated land by current models, Puy, Lo Piano and Saltelli hoped to increase the accuracy of all studies that rely on those estimates to project how the climate and environment could be affected by the very real challenge of feeding everyone on Earth -- and how the state of the environment could shape the outcome of that effort.

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The paper, "Current models underestimate future irrigated areas," was published in the April 28 edition of Geophysical Research Letters. The work was supported by a Marie Skodowska-Curie Global Fellowship (grant no. 792178) from the European Commission

URI professor: Climate change increases risk of fisheries conflict

UNIVERSITY OF RHODE ISLAND

 

KINGSTON, R.I. - May 4, 2020 - A team of fisheries scientists and marine policy experts, led by a University of Rhode Island researcher, examined how climate change is affecting the ocean environment and found that the changing conditions will likely result in increased fisheries-related conflicts and create new challenges in the management of global fisheries.

The team's research was published last month in the journal Marine Policy.

Elizabeth Mendenhall, URI assistant professor of marine affairs, said that ocean warming, acidification and sea level rise that are a direct result of climate change are causing populations of fish to shift, making fish increasingly scarce, shifting the boundaries of where nations can legally fish, and increasing the intensity of fishing pressure around the world. The result will be growing conflicts between individual fishermen, fishing communities, fishing nations and fishery managers.

"These conflicts exist at multiple scales," said Mendenhall, who is writing a book about geopolitics and ocean governance. "Some of it is one boat versus another, sometimes it's one country versus another, and it can get very complicated. It isn't just about overfishing any more. There are other drivers and other dynamics involved."

As warming temperatures shift fish populations to different areas, for instance, the bulk of those stocks may cross the borders of a nations' 200-mile exclusive economic zone, making it illegal for those who have fished those stocks for many years to pursue them any longer.

"We're seeing examples of fishermen crossing borders more often now because the stocks they feel they have a right to have shifted across the border," Mendenhall said.

Among the more challenging questions that climate change is raising for fishing nations is what happens when sea level rise submerges an island. Does that change the nation's maritime boundaries?

"It's an ongoing debate about whether you keep your maritime claim even though you have no land base to manage it from," said Mendenhall. "Or does your claim go away? There are a lot of nations that fish over long distances that are ready to exploit those areas if national boundaries no longer exist."

The tiny Japanese atoll of Okinotorishima is one such case. Located in the southernmost archipelago of Japan, its submergence is raising questions about whether Taiwan and China may legally fish in the area claimed by Japan.

"I argue that as sea level rises, Japan's argument gets weaker," said Mendenhall, noting that the countries have not challenged the boundaries based on the island's submergence yet. "The rules on where you can make your maritime claim are based on where the land is.

"The same problem applies to coastlines," she added. "Low-lying countries like Bangladesh and Vietnam could lose a lot of maritime territory as sea level rises. The outer edge of their claim could move closer to their coastline."

The research team makes a series of recommendations based on its findings designed to improve global fishery management. They recommend greater multilateral fishery monitoring, similar to what is in place off East Africa to combat piracy, which can help deter or catch illegal fishers, thereby reducing the chance that individual fishing boats will take matters into their own hands.

"We also suggest that marine protected areas be used, but it's critical that the area protected is one where habitats are still thriving despite climate change," Mendenhall said. "There is concern, however, that when you protect one area, it may displace the fishers to somewhere else and make the problem worse elsewhere. We need to think about the dynamics that protected areas may cause and account for that in the site selection process."

Finally, the researchers recommend strengthening the global fisheries management regime by taking into account climate change and the new sources of fishery conflict. The management boundaries of many fish stocks were drawn decades ago, and some parts of the open ocean are not managed at all because no productive fish stocks were there many years ago, yet there may be fish stocks there in the future. Most importantly, they suggest that the regional fishery management organizations work together to develop coordinated governance systems to better manage fisheries as environmental conditions change and greater conflicts arise.

"These changes to how [regional fishery management organizations] manage fisheries, and how they coordinate and cooperate with one another, can make high seas fisheries management more resilient to shifts in stocks and users, and changes in relative abundance," the researchers conclude.

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Recent Australian wildfires made worse by logging

UNIVERSITY OF QUEENSLAND

IMAGE: BUSHFIRE view more 

CREDIT: THE UNIVERSITY OF QUEENSLAND

Logging of native forests increases the risk and severity of fire and likely had a profound effect on the recent, catastrophic Australian bushfires, according to new research.

In the wake of the country's worst forest fires in recorded history, University of Queensland researchers have been part of an international collaboration, investigating Australia's historical and contemporary land-use.

UQ Professor and Wildlife Conservation Society Director James Watson said logging regimes have made many forests more fire prone for a host of reasons.

"Logging causes a rise in fuel loads, increases potential drying of wet forests and causes a decrease in forest height," Professor Watson said.

"It can leave up to 450 tonnes of combustible fuel per hectare close to the ground - by any measure, that's an incredibly dangerous level of combustible material in seasonally dry landscapes.

"By allowing these practices to increase fire severity and flammability, we undermine the safety of some of our rural communities.

"It affects wildlife too by creating habitat loss, fragmentation and disturbance for many species, with major negative effects on forest wildlife."

Lead author, Australian National University's Professor David Lindenmayer, said there are land management actions we can take to stop these fires from occurring in the future.

"The first is to prevent logging of moist forests, particularly those close to urban areas," Professor Lindenmayer said.

"We must also reduce forest fragmentation by proactively restoring some previously logged forests.

"In the event of wildfires, land managers must avoid practices such as 'salvage' logging - or logging of burnt forests - which severely reduces recovery of a forest."

The Federal Government has launched a Royal Commission to find ways to improve Australia's preparedness, resilience, and response to natural disasters.

Researcher Michelle Ward, from UQ's School of Earth and Environmental Sciences, said it was time for government to act.

"We urge policy makers to recognise and account for the critical values of intact, undisturbed native forests, not only for the protection of biodiversity, but for human safety," Ms Ward said.

"Let's act strongly and swiftly for the sake of our communities, the species they house, our climate and Australia's wild heritage."

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The study was undertaken by a team from ANU, Macquarie University, UQ, and the Wildlife Conservation Society.

It has been published in Nature Ecology and Evolution (DOI: 10.1038/s41559-020-1195-5).

Surf and turf: Green new deal should be a 'teal new deal'

Incorporating the oceans into climate policy is essential, scientists say in a new paper

SAN DIEGO STATE UNIVERSITY

IMAGE: TERRESTRIAL AND OCEAN-BASED CLIMATE SOLUTIONS GO HAND-IN-HAND. view more 

CREDIT: AUTHORS OF THE PAPER

Debates around the Green New Deal have largely centered around climate change concerns on land. But a group of scientists are calling on policymakers to include oceans in the deal.

The Green New Deal is a legislative proposal to tackle climate change and boost the economy, while also supporting equity and social justice.

"There is an opportunity to enact policy that can make meaningful change to help our country both economically and environmentally," said San Diego State University ecologist Rebecca Lewison, one of the co-authors of a new paper on the subject. "It's critical that oceans are part of that policy framework."

"Integrating Oceans into Climate Policy: Any Green New Deal Needs a Splash of Blue" was published in April in Conservation Letters. Lead authors are Lewison, whose work focuses on sustainable resource and land use, and Arielle Levine, an SDSU geographer specializing in human-environment interactions in marine and coastal systems, in collaboration with Oregon State University environmental economist Steven Dundas.

The authors recommend a policy that integrates terrestrial and ocean approaches to create a robust portfolio of climate adaptation and mitigation measures supporting communities, the environment and the economy.

"As we come out of this pandemic, policymakers will be looking for ways to jump start the economy, and we have a unique opportunity to develop policies that promote economic development in an environmentally sustainable manner," Levine said. "Including the oceans in Green New Deal policies will expand opportunities for sustainable economic development in both inland and coastal communities, while addressing the ongoing threat of climate change that we can't ignore."

Their proposals focus on renewable energy, sustainable transportation, food security and habitat restoration, and include:

Harnessing offshore energy

A push to expand offshore renewables will complement the push for renewable energy on land, the scientists said. As ocean winds pick up in the evening, they can supplement energy sources especially during the critical evening peak hours from 4 to 9 p.m.

"Developing offshore renewable energy will help states build a stronger, more adaptable and sustainable energy portfolio," Lewison said.

Reducing emissions from ships, freighters, ports

As with energy, climate-ready sustainable transport can and should include maritime shipping, since more than 80% of global merchandise travels by sea and ships are responsible for about 3% of greenhouse gas emissions.

Reducing ship speed is one measure that can reduce emissions. This will mean it takes ships longer to reach destinations, but it's a strategy shipping companies already use voluntarily when fuel prices are high.

"Policies to reduce speed, modifications to ship design and improved fuel efficiency standards for new ships can help significantly reduce emissions," Levine said. "Another way to reduce emissions is to have ships hook up to land-based energy sources while at port, which can also improve local air quality."

The European Union and the International Maritime Organization have set goals to reduce ship emissions by half by 2050. However, "the incentives need to be stronger, with specific targets along the way, to ensure this goal is met," Levine said.

Boosting food security

The oceans feed more people on the planet than any other source.

Sustainable wild-caught fish harvest paired with other approaches like aquaculture -- the process of 'farming' or growing seafood -- are needed to feed a hungry planet of 7.7 billion people. Aside from being a food source, cultivated seaweed can also help absorb carbon emissions.

"Properly executed aquaculture, paired with sustainable fisheries, has the potential to enhance food supply, decrease the carbon footprint of protein sources and sequester carbon at the same time," Dundas said.

To that end, the authors recommend more flexible, transboundary management structures that harness the best science and technology to meet global food demand, from seaweed to tuna.

Supporting sustainable fisheries and aquaculture does much more than support coastal economies. The food and money from seafood industries and markets support inland economies as well. New applications of ocean-based fertilizers can boost production on farms far from the coast, supplying nitrogen and phosphorus, which are necessary nutrients for agriculture but can be harmful when present in high concentrations in coastal waters.

Restoring wetlands, sea kelp, mangroves

When it comes to habitat restoration and climate change, replanting trees and forests are what come to mind most often. But the Teal Deal would also include restoration of wetlands, mangroves, seagrass and kelp, because coastal and ocean habitats need to stay intact to mitigate climate change, the paper notes.

"The perfect example is Hurricane Katrina -- one reason it was so devastating was that wetland and other coastal habitats have been lost to development," Lewison said.

A National Oceanic and Atmospheric Administration study found that each $1 million investment in wetland restoration creates an average of 17 jobs, in addition to providing a buffer for storm events.

"A Teal Deal combines land and ocean approaches to address climate change, generating economic benefits to communities everywhere," Lewison said. "The COVID-19 pandemic has shown us that rapid, responsive and coordinated efforts across sectors can stop a crisis. The climate change crisis is ongoing and an integrated policy offers the same opportunity -- to develop a responsive and coordinated multi-sectoral plan for climate resilience."

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Oceans should have a place in climate 'green new deal' policies, scientists suggest

OREGON STATE UNIVERSITY

 

CORVALLIS, Ore. - The world's oceans play a critical role in climate regulation, mitigation and adaptation and should be integrated into comprehensive "green new deal" proposals being promoted by elected officials and agency policymakers, a group of ocean scientists suggests in a new paper.

"The 'green new deal' has been the headline, but very few have been talking about the oceans in those conversations," said Steven Dundas, an environmental and resource economist in Oregon State University's College of Agricultural Sciences and the Coastal Oregon Marine Experiment Station in Newport, Oregon.

"We think it's important to add a touch of ocean blue to this conversation because the oceans play an important role in efforts to mitigate effects of climate change," he said. "Our proposed 'teal deal' is an integrated approach that is more likely to generate cost-effective and equitable solutions to this global threat."

Dundas is one of three senior authors of the paper, which was published recently by the journal Conservation Letters. The other senior authors are Arielle Levine and Rebecca Lewison of San Diego State University. Additional authors include OSU's Angee Doerr, Ana Spalding and Will White.

The scientists highlight four areas of investment commonly touted in "green new deal" proposals that also apply to the world's oceans: energy, transportation, food security and habitat restoration.

"Adding the oceans to climate policy doesn't mean you're ignoring the terrestrial approaches to climate change mitigation," Dundas said. "It means adopting a portfolio approach that includes both. We hope this paper and our recommendations broaden the policy options needed to meet the grand challenge of climate change."

The concept of a green new deal emerged last year as a way to address climate change. International environmental leaders are now suggesting that coronavirus recovery plans present an opportunity to address climate change.

In the renewable energy sector, the ocean's winds, waves and currents represent a significant source of clean energy that could reduce emissions, meet demand for electricity and spur economic growth through new industry. But many hurdles remain, since offshore energy projects are subject to a range of regulatory policies from the local to the national level, the researchers said.

In the transportation sector, 80% of merchandise around the globe is transported by sea, contributing about 3% of human-made emissions. Growth in world trade is predicted to increase emissions by 150 to 250% by 2050. But measures to address and improve maritime emissions reductions are largely absent from international efforts. Modifying hull designs, relying more on biofuels or wind power and other steps could reduce shipping emissions, the researchers suggested.

In the area of food security, marine fisheries remain one of the most sustainable sources of protein for human consumption, with a lower total carbon footprint than many land-based food sources.

As climate change impacts the size and distribution of marine resources, fishing communities are faced with a few options: following the fish, which could increase costs and emissions; finding an alternative livelihood, which is often not feasible; and switching to a new species, which also could come with increased costs and requires careful fisheries management, the researchers said.

Aquaculture - the term for commercially raising fish or growing seafood products - also holds potential for growth at a relatively low emissions cost, researchers said. For example, seaweed aquaculture could mitigate hundreds of tons of emissions each year.

"Properly executed aquaculture, paired with sustainable fisheries, has the potential to enhance the food supply, decrease the carbon footprint of protein sources and sequester carbon at the same time," said Lewison.

In the area of habitat restoration, investment in projects that restore coastal habitats such as mangroves, tidal wetlands, kelp forests and seagrasses should be a key component of climate policy, the researchers suggest. These habitats currently store up to 25 billion metric tons of carbon, and further restoration could increase that storage capability.

Coastal habitat restoration also can increase flood and erosion protection and mitigate storm impacts, reducing the vulnerability of coastal populations to extreme weather impacts and reducing costs of disaster aid.

"Investing in these four sectors can benefit communities across the United States," said Levine. "The impacts and the benefits go far beyond coastal communities."

The researchers hope to use the paper and their argument to encourage policymakers to consider the oceans in "green new deal" proposals moving forward.

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Aviation industry opposes leaving middle seat empty

Credit: CC0 Public Domain

The global aviation body said Tuesday that the risk of catching COVID-19 on a plane was low and there was no need to leave the middle seat empty once the industry takes off again.


The International Air Transport Association backed the wearing of masks by both passengers and crew but said it did not support physical distancing measures that would leave the middle seat empty in a row of three.

There would be "dramatic cost increases" if such seats were left empty, IATA said in a statement, warning that airlines might otherwise go bust if they struggled to break even.

The aviation industry has taken a big hit in the coronavirus crisis, as lockdown measures and travel restrictions bite.

IATA said that evidence so far—which it admitted was limited—suggested the risk of virus transmission on a plane was already low.

Cabin environment

It said the reasons why this could be include the fact that passengers face forwards, with limited face-to-face interaction, while seats provide a barrier to the person in front.

It said the air flow downwards from the ceiling to the floor further reduces the potential for transmission, while air flow rates are not high and "not conducive to droplet spread" as in regular indoor environments.

Meanwhile, High Efficiency Particulate Air (HEPA) filters on modern aircraft clean cabin air to hospital operating theatre quality, said IATA.

"The cabin environment naturally makes transmission of viruses difficult," said IATA chief Alexandre de Juniac.

"Our aim is to make the cabin environment even safer with effective measures so that passengers and crew can return to travel with confidence.

"Screening, face coverings and masks are among the many layers of measures that we are recommending. Leaving the middle seat empty, however, is not."

Besides everyone adopting masks on board, proposed temporary measures to reduce the risk of infection include temperature screening of passengers, airport workers and passengers, and limiting movement in the cabin mid-flight.

More frequent and deeper cleaning measures are being considered, along with boarding and disembarking processes that reduce contact.

Immunity passports and testing for the novel coronavirus could also be included, in time.

Struggle to break even

Geneva-based IATA said that physical distancing measures on planes would "fundamentally shift the economics of aviation".

It said the maximum load factor would be cut to 62 percent—well below the industry's break-even figure of 77 percent.

Ticket costs would therefore have to go up by between 43 percent and 54 percent just to cover costs, said IATA.

"Airlines are fighting for their survival. Eliminating the middle seat will raise costs. If that can be offset with higher fares, the era of affordable travel will come to an end," said Juniac.

"On the other hand, if airlines can't recoup the costs in higher fares, airlines will go bust.

"Neither is a good option when the world will need strong connectivity to help kick-start the recovery from COVID-19's economic devastation."


Explore furtherAirline revenues to nosedive by 55% in 2020: IATA

© 2020 AFP

Fossil fuel-free jet propulsion with air plasmas

by American Institute of Physics

A schematic diagram of a prototype microwave air plasma thruster and the images of the bright plasma jet at different microwave powers. This device consists of a microwave power supply, an air compressor, a compressed microwave waveguide and a flame ignitor. Credit: Jau Tang and Jun Li

Humans depend on fossil fuels as their primary energy source, especially in transportation. However, fossil fuels are both unsustainable and unsafe, serving as the largest source of greenhouse gas emissions and leading to adverse respiratory effects and devastation due to global warming.


A team of researchers at the Institute of Technological Sciences at Wuhan University has demonstrated a prototype device that uses microwave air plasmas for jet propulsion. They describe the engine in the journal AIP Advances.

"The motivation of our work is to help solve the global warming problems owing to humans' use of fossil fuel combustion engines to power machinery, such as cars and airplanes," said author Jau Tang, a professor at Wuhan University. "There is no need for fossil fuel with our design, and therefore, there is no carbon emission to cause greenhouse effects and global warming."

Beyond solid, liquid and gas, plasma is the fourth state of matter, consisting of an aggregate of charged ions. It exists naturally in places like the sun's surface and Earth's lightning, but it can also be generated. The researchers created a plasma jet by compressing air into high pressures and using a microwave to ionize the pressurized air stream.

This method differs from previous attempts to create plasma jet thrusters in one key way. Other plasma jet thrusters, like NASA's Dawn space probe, use xenon plasma, which cannot overcome the friction in Earth's atmosphere, and are therefore not powerful enough for use in air transportation. Instead, the authors' plasma jet thruster generates the high-temperature, high-pressure plasma in situ using only injected air and electricity.

The prototype plasma jet device can lift a 1-kilogram steel ball over a 24-millimeter diameter quartz tube, where the high-pressure air is converted into a plasma jet by passing through a microwave ionization chamber. To scale, the corresponding thrusting pressure is comparable to a commercial airplane jet engine.

By building a large array of these thrusters with high-power microwave sources, the prototype design can be scaled up to a full-sized jet. The authors are working on improving the efficiency of the device toward this goal.

"Our results demonstrated that such a jet engine based on microwave air plasma can be a potentially viable alternative to the conventional fossil fuel jet engine," Tang said.


Explore furtherIntense microwave pulse ionizes its own channel through plasma
More information: "Jet propulsion by microwave air plasma in the atmosphere," AIP Advances (2020). DOI: 10.1063/5.0005814
Journal information: AIP Advances


Provided by American Institute of Physics

Will our clean air last after COVID-19? Study says it's possible
by Lauren Miura, University of California, Los Angeles
 

UCLA researchers show how taking bold action on climate change will benefit local residents. Credit: Nurit Katz/UCLA

Since millions of Californians began staying at home and off the roads in March, air quality in the Golden State has visibly improved. Once life returns to normal, however, air pollution levels are likely to return to their prepandemic levels.

A team of UCLA researchers argues this does not have to be our fate.

In a peer-reviewed study published May 4 in the journal Nature Sustainability, they describe a pathway for California to dramatically cut greenhouse gas emissions and air pollution by 2050. Taken together, these actions would prevent about 14,000 premature deaths from air pollution–related illnesses each year, all while helping to reduce climate change, the researchers say.

Air pollution is linked to a host of health problems, including respiratory and cardiovascular diseases, neurological problems, cancers, and adverse pregnancy outcomes. People exposed to elevated levels of air pollution also have a higher chance of getting sick with influenza and are more vulnerable to COVID-19.

"It doesn't need to take a global pandemic to create cleaner air and healthier lives," said Yifang Zhu, one of the study's lead authors and a professor at the UCLA Fielding School of Public Health. "Climate action directly benefits people at a local and regional scale by creating cleaner air. The public health benefits are both immediate and long-term, and we can save the economy billions each year."

To limit the rise in global temperature to 3.6 degrees Fahrenheit (2 degrees Celsius) above preindustrial levels by 2100—the threshold for avoiding the most severe effects of global warming—the United Nations' Intergovernmental Panel on Climate Change warns that human-caused emissions will need to be reduced to nearly zero, and any remaining emissions will need to be captured and stored. This is known as net-zero emissions, or carbon neutrality.

Achieving this globally is no easy feat, but the study shows how it can be done in California—creating the first-ever roadmap for the state to get there by 2050 using existing policies and technologies.

"Nothing we are suggesting is science fiction, but it will take a lot more than what we're doing now," said study co-author Tony Wang, an engineer with the California Air Resources Board who recently received a doctorate in environmental science and engineering from UCLA.

Collaborators from the UCLA Joint Institute for Regional Earth System Science and Engineering contributed state-of-the-art modeling to analyze how ambient air quality would change under a net-zero emissions scenario. Then, the researchers combined the model with epidemiological data and information to estimate the impact of cleaner air on public health.

In addition to the finding that approximately 14,000 premature deaths could be avoided each year in California by 2050, achieving net-zero emissions could also:
Reduce acute respiratory symptoms in 8.4 million adults.
Reduce asthma exacerbation in 1 million children.
Decrease the number of lost work days by 1.4 million.
Decrease cardiovascular hospital admissions by 4,500.

While all communities would benefit, the state's top 25% most-polluted census tracts would receive approximately 35% of the health benefits resulting from the projected improvements in air quality, according to the study.

"We were happy to see that when you cut down on these emissions, you bring disproportionately higher levels of air-quality benefits to disadvantaged communities," Zhu said.

Unlike with the current COVID-19 crisis, achieving net-zero emissions postpandemic would benefit the economy. By 2050, the monetary savings of greenhouse gas reductions will exceed the cost by $109 billion a year, the study found.

The study's authors intend for their research to help state and local policymakers visualize how taking bold action on climate change will directly benefit people.

"Reducing greenhouse gas emissions in our state will not only slow down global climate change, but more importantly, will improve the air quality and protect people's health in our local community," said co-author Bin Zhao, a former UCLA researcher who is now an earth scientist at Pacific Northwest National Laboratory.


Explore further  Concrete solutions that lower both emissions and air pollution

More information: Tianyang Wang et al. Health co-benefits of achieving sustainable net-zero greenhouse gas emissions in California, Nature Sustainability (2020). DOI: 10.1038/s41893-020-0520-y

Journal information: Nature Sustainability


Provided by University of California, Los Angeles

April 2020 tied for warmest on record: EU climate service
by Marlowe Hood
The five last years have been the hottest on record, as was the decade from 2010-2019

Last month tied 2016 for the hottest April on record worldwide, with particularly high temperatures over western Europe and north-central Asia, the European Union's climate monitoring network said Tuesday.


Temperatures were also well above average over parts of Greenland and Antarctica, accelerating the disintegration of kilometres-thick ice sheets that have become the main drivers of sea level rise, the Copernicus Climate Change Service (C3S) reported.

April 2020 was a statistically insignificant 0.01 degrees Celsius cooler than the same month in 2016, the warmest April registered since the late 19th century, when reliable records began.

"The average temperature for the 12 months to April 2020 is close to 1.3C above the pre-industrial level," the benchmark by which global warming is often measured, Copernicus said.

Under the 2015 Paris Agreement, nearly 200 countries have pledged to cap the rise in Earth average surface temperature to "well below" 2C, and to 1.5C if possible.

The country that probably saw the warmest April compared to the past was Switzerland, where the thermometer last month rose a blistering 5C above the 1871-1900 average.

Siberia, central and northwest Africa, western Australia and Mexico all saw a warmer-than-usual April, as did the Arctic Ocean and the coast of Alaska.

By contrast, southern and southeast Asia were cooler than usual, while temperatures were especially chilly in central Canada.

The five last years have been the hottest on record, as was the decade from 2010-2019.

2019—the second warmest year ever—was only 0.04C below 2016, when temperatures were boosted by a powerful El Nino, a periodic natural weather phenomenon over the Pacific Ocean.

Overall, global temperatures have risen more than one degree Celsius since mid-19th century levels, driven mostly by the burning fossil fuels. They have increased by about 0.2C per decade since the 1970s.

Atmospheric concentrations of CO2—which causes global warming—are now at their highest level in at least 800,000 years.

The United Nations said last year that manmade greenhouse gas emissions needed to tumble 7.6 percent annually over the next decade to cap global warming at 1.5C.

Current pledges to cut emissions put Earth on a path of several degrees warming by the end of the century.


Explore furtherJanuary 2020 warmest on record: EU climate service

Culling and carcass removal key to containing African swine fever, model shows

by Sarah McDaid, Heriot-Watt University

Credit: CC0 Public Domain

While countries like Denmark are building walls to prevent the spread of African swine fever, a new mathematical model has identified two effective tactics.


A team of scientists in Scotland and Spain has reported that culling and fast removal of animal carcasses are critical for the eradication of the disease.

Professor Andy White and his Heriot-Watt University mathematics research team worked with the SaBio group of the Spanish Game Resources Institute (IREC), UCLM & CSIC (Ciudad Real, Spain) to develop the new model.

African swine fever is a highly infectious virus that causes severe, usually fatal disease in domestic pigs and wild boar. There is no treatment or vaccine.

African swine fever is not a threat to humans, but the virus can have a profound socioeconomic impact on areas with outbreaks.

Wild boar are free-ranging and can carry and spread ASF.

Professor Andy White said: "African swine fever can rapidly devastate pig populations, there are outbreaks in China, Poland, Belgium and the Baltic states at the moment. In China, it has wiped out around 40% of the country's pig population.

"Wild boar transmit the disease and their numbers are on the rise in Europe. There are several populations in the UK and here too numbers are increasing.

"Our mathematical model was used to understand the different ways that the virus could be transmitted.

"To match the data, we showed that infection needed to occur in three ways. Through contact between susceptible and infected wild boar, through contact between susceptible wild boar and infected carcasses and via individuals that survive the initial infection, but succumb to the disease after several months.

"Our new model also considered biosecurity measures that can help mitigate the spread of an outbreak.

"A combination of culling and the removal of infected carcasses is the most effective way to eradicate the virus without also eradicating the host population.

"It is important to act quickly: early implementation of these measures will reduce infection levels while maintaining a higher host population density. In some cases, this could prevent the virus from establishing in a wild boar population."

The model also suggests that it may be easier to control ASF in warmer climates.

"Higher temperatures lead to faster degradation of infected carcasses, which also reduces the severity of an outbreak."

In some regions, wild boar are supplementary fed to increase their density. The model suggests this should be avoided when ASF is a threat, as it leads to a more pronounced epidemic outbreak and persistence of the disease in the long-term.

The scientists reported the findings of their new model in Scientific Reports.

Explore further   African swine fever kills more than 20 wild boar in Poland

More information: Xander O'Neill et al. Modelling the transmission and persistence of African swine fever in wild boar in contrasting European scenarios, Scientific Reports (2020). DOI: 10.1038/s41598-020-62736-y

Journal information: Scientific Reports 

Provided by Heriot-Watt University

New book shows how ancient Greek writing helps us understand today's environmental crises

by Jodi Heckel, University of Illinois at Urbana-Champaign

Credit: University of Illinois at Urbana-Champaign

The way ancient Greeks thought about the natural environment and their relationship to it is relevant to how we respond to environmental crises today. In her new book, "Other Natures," Clara Bosak-Schroeder, a classics professor at the University of Illinois at Urbana-Champaign, looks at how the ethnographies written by ancient Greeks reveal how they explored ideas about consumption and their use of natural resources.

The book focuses on two Greek writers, Herodotus, writing in the 5th century B.C., and Diodorus, writing a few centuries later, and considers their work from the perspective of concern about our current climate emergency. Their ethnographies were the travel writing of their day, describing the habits and customs of people in other places—Africa, India and parts of the Middle East—and how they used natural resources.

"What I found was these Greek and Roman writers weren't doing this kind of reflection on natural resources when they were writing about their own homelands," Bosak-Schroeder said.

One of their major concerns was diet and the connection between diet and health.

"When they looked at other people, they saw them eating very different types of foods, and they were curious about how those foods could promote health and the ways they might be superior to the Greek diet," Bosak-Schroeder said.

Their writing also was a window into systems of consumption and how people are involved in growing food and killing animals, she said. Herodotus and Diodorus were particularly interested in how people related to animals, and their stories reflect that. Diodorus wrote about an African community with a close relationship to seals, where humans and seals hunted together and shared childcare.

While the story is fabricated, "it helps to see that the writers were curious about boundaries between humans and animals, and whether it is possible to have some sort of shared community," Bosak-Schroeder said. "I saw the Greek writers experimenting with how to live with other species, perhaps in more productive ways."

Diodorus also wrote about ancient Egyptians who honored their sacred animals by giving them rich, refined foods—a way to worship the animals with the side effect that Egyptians stayed healthier by not eating that food themselves.

"The idea underlying the story is that we can live richer, fuller lives if we take the well-being of other species into account," Bosak-Schroeder said. "The Greek writers were not environmentalists and not interested in animal welfare for its own sake, but they saw humans depending on other species. It was a pragmatic approach to their own well-being that was connected to other beings on the planet."

They also expressed concerns about consumption, she said.

"Even though they weren't living in a global environmental crisis the way we are, they still seem to be anxious about their consumption of luxury items and whether they should be importing things from other places. They didn't cast those questions exactly in environmental terms, but they saw that their choices could have bigger, unintended consequences," she said.

The writers focused on the role of women and their perspectives on the world as something different and valuable, with insights into what is possible. Diodorus wrote about an Assyrian queen who invaded India, then realized she could not conquer the country because Indians had war elephants. She had huge elephant puppets made from wooden frameworks covered in ox skins, and they were drawn up to the battle lines to fool the Indians.

That idea of listening to diverse viewpoints translates to looking for solutions to climate change, as well as holding leaders accountable for finding a centralized approach to big problems, Bosak-Schroeder said.

"That's a powerful idea right now when a lot of environmental work is being done by people in marginalized communities," she said. "The parts of the world already experiencing climate change have this perspective that we in richer, more industrialized nations really need to listen to."

The final part of "Other Natures" moves from ancient Greece to modern museums of natural history and looks at the way people are educated about environmental issues when they go to museums. Bosak-Schroeder studied exhibits at the Field Museum of Natural History in Chicago and other natural history museums throughout the country. She suggests they can take a cue from the ancient writers in how they display their collections of artifacts and plant and animal specimens by integrating their stories.

"Museums can do more to show how humans relate to other species and are interdependent with them, and they can do that in the way they put collections together," she said. "They have really great practices that can help people understand our climate emergency."

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