Tag Archives: #climatechange

The Waste Product Which Could Help Mitigate Climate Change (Material Science)

Biochar can boost crop yields in poor soils and help stop the effects of climate change, study finds. So why aren’t we using it more?

A product made from urban, agriculture and forestry waste has the added benefit of reducing the carbon footprint of modern farming, an international review involving UNSW has found.

Visiting Professor in the School of Materials Science and Engineering at UNSW Science, Stephen Joseph, says the study published in GCB Bioenergy provides strong evidence that biochar can contribute to climate change mitigation.

“Biochar can draw down carbon from the atmosphere into the soil and store it for hundreds to thousands of years,” the lead author says.

“This study also found that biochar helps build organic carbon in soil by up to 20 per cent (average 3.8 per cent) and can reduce nitrous oxide emissions from soil by 12 to 50 per cent, which increases the climate change mitigation benefits of biochar.”

The findings are supported by the Intergovernmental Panel on Climate Change’s recent Special Report on Climate Change and Land, which estimated there was important climate change mitigation potential available through biochar.

“The intergovernmental panel found that globally, biochar could mitigate between 300 million to 660 million tonnes of carbon dioxide per year by 2050,” Prof. Joseph says.

“Compare that to Australia’s emissions last year – an estimated 499 million tonnes of carbon dioxide – and you can see that biochar can absorb a lot of emissions. We just need a will to develop and use it.”

Stable charcoal

Biochar is the product of heating biomass residues such as wood chips, animal manures, sludges, compost and green waste, in an oxygen-starved environment – a process called pyrolysis.

The result is stable charcoal which can cut greenhouse emissions, while boosting soil fertility.

The GCB Bioenergy study reviewed approximately 300 papers including 33 meta-analyses that examined many of the 14,000 biochar studies that have been published over the last 20 years.  

“It found average crop yields increased from 10 to 42 per cent, concentrations of heavy metals in plant tissue were reduced by 17 to 39 per cent and phosphorous availability to plants increased too,” Prof. Joseph says.

“Biochar helps plants resist environmental stresses, such as diseases, and helps plants tolerate toxic metals, water stress and organic compounds such as the herbicide atrazine.”

Benefits for plants

The study details for the first time how biochar improves the root zone of a plant.

In the first three weeks, as biochar reacts with the soil it can stimulate seed germination and seedling growth.

During the next six months, reactive surfaces are created on biochar particles, improving nutrient supply to plants.

After three to six months, biochar starts to ‘age’ in the soil and forms microaggregates that protect organic matter from decomposition.

Prof. Joseph says the study found the greatest responses to biochar were in acidic and sandy soils where biochar had been applied together with fertiliser.

“We found the positive effects of biochar were dose dependent and also dependent on matching the properties of the biochar to soil constraints and plant nutrient requirements,” Prof. Joseph says.

“Plants, particularly in low-nutrient, acidic soils common in the tropics and humid subtropics, such as the north coast of NSW and Queensland, could significantly benefit from biochar.

“Sandy soils in Western Australia, Victoria and South Australia, particularly in dryland regions increasingly affected by drought under climate change, would also greatly benefit.”

Stephen Joseph
Professor Stephen Joseph. © Photo: UNSW/Supplied

Prof. Joseph AM is an  expert in producing engineered stable biochar from agriculture, urban and forestry residues.

He has been researching the benefits of biochar in promoting healthy soils and addressing climate change since he was introduced to it by Indigenous Australians in the seventies.

He says biochar has been used for production of crops and for maintaining healthy soils by Indigenous peoples in Australia, Latin America (especially in the Amazon basin) and Africa for many hundreds of years.

Biochar has also been recorded in the 17th Century as a feed supplement for animals.

But while Australian researchers have studied biochar since 2005, it has been relatively slow to take off as a commercial product, with Australia producing around 5000 tonnes a year.

“This is in part due to the small number of large-scale demonstration programs that have been funded, as well as farmers’ and government advisors’ lack of knowledge about biochar, regulatory hurdles, and lack of venture capital and young entrepreneurs to fund and build biochar businesses,” Prof. Joseph says.

In comparison, the US is producing about 50,000 tonnes a year, while China is producing more than 500,000 tonnes a year.

Needs to be economically viable

Prof. Joseph, who has received an Order of Australia for his work in renewable energy and biochar, says to enable widespread adoption of biochar, it needs to be readily integrated with farming operations and be demonstrated to be economically viable.

“We’ve done the science, what we don’t have is enough resources to educate and train people, to establish demonstrations so farmers can see the benefits of using biochar, to develop this new industry,” he says.

However this is slowly changing as large corporations are purchasing carbon dioxide reduction certificates (CORC’s) to offset their emissions, which is boosting the profile of biochar in Australia.

Biochar has potential in a range of applications.

Prof. Joseph co-authored a recent study in International Materials Reviews which detailed the less well-known uses of biochar, such as a construction material, to reduce toxins in soil, grow microorganisms, in animal feed and soil remediation.

UNSW has a collaborative grant with a company and a university in Norway to develop a biochar based anti-microbial coating to kill pathogens in water and find use in air filtration systems, he says.

Read the GCB Bioenergy study.

Featured image: An international review study details for the first time how biochar improves the root zone of a plant. Photo: Shutterstock.


Provided by UNSW

Rockets Emit 100 Times More CO₂ Per Passenger Than Flights – Imagine A Whole Industry

The increasing size of the private space industry could be a climate disaster as rockets emit vast quantities of propellant exhaust into the stratosphere and mesosphere, where it can persist for at least two to three years, warns Dr Eloise Marais (UCL Geography).

The commercial race to get tourists to space is heating up between Virgin Group founder Sir Richard Branson and former Amazon CEO Jeff Bezos. On Sunday 11 July, Branson ascended 80 km to reach the edge of space in his piloted Virgin Galactic VSS Unity spaceplane. Bezos’ autonomous Blue Origin rocket is due to launch on July 20, coinciding with the anniversary of the Apollo 11 Moon landing.

Though Bezos loses to Branson in time, he is set to reach higher altitudes (about 120 km). The launch will demonstrate his offering to very wealthy tourists: the opportunity to truly reach outer space. Both tour packages will provide passengers with a brief ten-minute frolic in zero gravity and glimpses of Earth from space. Not to be outdone, Elon Musk’s SpaceX will provide four to five days of orbital travel with its Crew Dragon capsule later in 2021.

What are the environmental consequences of a space tourism industry likely to be? Bezos boasts his Blue Origin rockets are greener than Branson’s VSS Unity. The Blue Engine 3 (BE-3) will launch Bezos, his brother and two guests into space using liquid hydrogen and liquid oxygen propellants. VSS Unity used a hybrid propellant comprised of a solid carbon-based fuel, hydroxyl-terminated polybutadiene (HTPB), and a liquid oxidant, nitrous oxide (laughing gas). The SpaceX Falcon series of reusable rockets will propel the Crew Dragon into orbit using liquid kerosene and liquid oxygen.

Burning these propellants provides the energy needed to launch rockets into space while also generating greenhouse gases and air pollutants. Large quantities of water vapour are produced by burning the BE-3 propellant, while combustion of both the VSS Unity and Falcon fuels produces CO₂, soot and some water vapour. The nitrogen-based oxidant used by VSS Unity also generates nitrogen oxides, compounds that contribute to air pollution closer to Earth.

Roughly two-thirds of the propellant exhaust is released into the stratosphere (12 km-50 km) and mesosphere (50 km-85 km), where it can persist for at least two to three years. The very high temperatures during launch and re-entry (when the protective heat shields of the returning crafts burn up) also convert stable nitrogen in the air into reactive nitrogen oxides.

These gases and particles have many negative effects on the atmosphere. In the stratosphere, nitrogen oxides and chemicals formed from the breakdown of water vapour convert ozone into oxygen, depleting the ozone layer which guards life on Earth against harmful UV radiation. Water vapour also produces stratospheric clouds that provide a surface for this reaction to occur at a faster pace than it otherwise would.

Space tourism and climate change

Exhaust emissions of CO₂ and soot trap heat in the atmosphere, contributing to global warming. Cooling of the atmosphere can also occur, as clouds formed from the emitted water vapour reflect incoming sunlight back to space. A depleted ozone layer would also absorb less incoming sunlight, and so heat the stratosphere less.

Figuring out the overall effect of rocket launches on the atmosphere will require detailed modelling, in order to account for these complex processes and the persistence of these pollutants in the upper atmosphere. Equally important is a clear understanding of how the space tourism industry will develop.

Virgin Galactic anticipates it will offer 400 spaceflights each year to the privileged few who can afford them. Blue Origin and SpaceX have yet to announce their plans. But globally, rocket launches wouldn’t need to increase by much from the current 100 or so performed each year to induce harmful effects that are competitive with other sources, like ozone-depleting chlorofluorocarbons (CFCs), and CO₂ from aircraft.

During launch, rockets can emit between four and ten times more nitrogen oxides than Drax, the largest thermal power plant in the UK, over the same period. CO₂ emissions for the four or so tourists on a space flight will be between 50 and 100 times more than the one to three tonnes per passenger on a long-haul flight.

In order for international regulators to keep up with this nascent industry and control its pollution properly, scientists need a better understanding of the effect these billionaire astronauts will have on our planet’s atmosphere.

This article originally appeared in The Conversation on 19 July 2021.

Featured image: Dr Eloise Marais © UCL


Provided by UCL

Study Finds Ghost Forest ‘Tree Farts’ Contribute to Greenhouse Gas Emissions (Ecology)

 emissions from standing dead trees in coastal wetland forests – colloquially called “tree farts” – need to be accounted for when assessing the environmental impact of so-called “ghost forests.”

In the study, researchers compared the quantity and type of GHG emissions from dead tree snags to emissions from the soil. While snags did not release as much as the soils, they did increase GHG emissions of the overall ecosystem by about 25 percent. Researchers say the findings show snags are important for understanding the total environmental impact of the spread of dead trees in coastal wetlands, known as ghost forests, on GHG emissions.

“Even though these standing dead trees are not emitting as much as the soils, they’re still emitting something, and they definitely need to be accounted for,” said the study’s lead author Melinda Martinez, a graduate student in forestry and environmental resources at NC State. “Even the smallest fart counts.”

In the study, researchers measured emissions of carbon dioxide, methane and nitrous oxide from dead pine and bald cypress snags in five ghost forests on the Albemarle-Pamlico Peninsula in North Carolina, where researchers have been tracking the spread of ghost forests due to sea-level rise.

“The transition from forest to marsh from these disturbances is happening quickly, and it’s leaving behind many dead trees,” Martinez said. “We expect these ghost forests will continue to expand as the climate changes.”

Using portable gas analyzers, researchers measured gases emitted by snags and from soils in each forest in 2018 and 2019. Overall average emissions from soils were approximately four times higher than average emissions from snags in both years. And while snags did not contribute as much as soils, researchers said they do contribute significantly to emissions.

In addition to finding that soils emit more GHGs than snags, the work lays the foundation for the researchers’ ongoing work to understand the role snags are playing in emissions – whether they prevent emissions, like corks, or release them like straws. That is an area of future research they’re currently continuing to explore.

“We started off this research wondering: Are these snags straws or corks?” said study co-author Marcelo Ardón, associate professor of forestry and environmental sciences at NC State. “Are they facilitating the release from soils, or are they keeping the gases in? We think that they act as straws, but as a filtered straw. They change those gases, as the gases move through the snags.”

The study, “Drivers of Greenhouse Gas Emissions from Standing Dead Trees in Ghost Forests,” was published online in Biogeochemistry on May 10, 2021. Funding was provided by the National Science Foundation under grant DEB1713592 and a 2019 North Carolina Sea Grant/SpaceGrant Fellowship.

Featured image: Researchers studying “tree farts” from ghost forests in North Carolina. Credit: Melinda Martinez. © NC State


Reference: Melinda Martinez and Marcelo Ardόn, “Drivers of Greenhouse Gas Emissions from Standing Dead Trees in Ghost Forests”, Published online in Biogeochemistry on May 10, 2021. DOI10.1007/s10533-021-00797-5


Provided by NC State

Aluminum May Affect Climate Change by Increasing Ocean’s Carbon Sink Capacity (Earth Science)

Reducing net greenhouse gas emissions to zero as soon as possible and achieving “carbon neutrality” is the key to addressing global warming and climate change. The ocean is the largest active carbon pool on the planet, with huge potential to help achieve negative emissions by serving as a carbon sink. 

Recently, researchers found that adding a small amount of aluminum to achieve concentrations in the 10x nanomolar (nM) range can increase the net fixation of COby marine diatoms and decrease their decomposition, thus improving the ocean’s ability to absorb CO2 and sequester carbon at deep ocean depths. 

The study, published in Limnology and Oceanography on May 3, was conducted by a joint team led by Prof. TAN Yehui from the South China Sea Institute of Oceanology (SCSIO) of the Chinese Academy of Sciences and Prof. Peter G.C. Campbell from the Eau Terre Environnement Research Centre of the National Institute of Scientific Research, Canada.

Estimated effects of aluminum on the export of particulate organic carbon to ocean depths. (Image by ZHOU Linbin)

According to the earlier “iron hypothesis”, adding a small amount of iron to the iron-limited but nutrient-rich oceans could significantly promote the growth of marine phytoplankton (microalgae) and their absorption of CO2, and the consequent burial of organic matter in the ocean. However, the results of artificial iron fertilization experiments did not fully support the “iron hypothesis” and later studies suggested that ignoring the effects of aluminum and other elements may be the reason. 

“In fact, natural iron fertilization, as caused by dust deposition, upwelling and hydrothermal venting, provides the ocean not only iron, but also aluminum and other elements. Aluminum concentrations in the upper ocean are usually one order of magnitude higher than those of iron,” said Prof. TAN. 

Prof. TAN’s team and their collaborators found that aluminum may not only improve the utilization efficiency of iron and dissolved organic phosphorus by marine phytoplankton, thus enhancing carbon fixation in the upper ocean, but may also reduce the decomposition rate of biogenic organic carbon and enhance the export and sequestration of carbon in deep ocean depths. 

They also found a significant negative correlation between aluminum input to the Southern Ocean and atmospheric CO2 concentration over the past 160,000 years. 

Based on their findings about aluminum, they improved the original “iron hypothesis” by proposing the “iron-aluminum hypothesis” to better explain the roles of the two elements in climate change. 

In this study, the researchers used radiocarbon (14C) as a tracer to show that adding aluminum to seawater to achieve trace concentrations (e.g., 40 nM) increased net carbon fixation of marine diatoms 10% to 30%. 

More importantly, this study proved that environmentally relevant low concentrations of aluminum can reduce the daily decomposition rate of marine diatom-produced particulate organic carbon by 50% or more. 

Calculations based on the new data suggest that adding aluminum at a concentration of 40 nM or lower to the ocean may increase the amount of particulate organic carbon exported to depths of 1,000 m and deeper by 1–3 orders of magnitude. This will significantly increase the ocean’s carbon sink capacity and sequester carbon in the ocean for a long time, thus ameliorating climate change.

Featured image: Diagram of how aluminum may facilitate the uptake of iron and the utilization of dissolved organic phosphorus by marine phytoplankton (Image by ZHOU Linbin) 


Reference: Zhou, L., Liu, F., Liu, Q., Fortin, C., Tan, Y., Huang, L. and Campbell, P.G.C. (2021), Aluminum increases net carbon fixation by marine diatoms and decreases their decomposition: Evidence for the iron–aluminum hypothesis. Limnol Oceanogr. https://doi.org/10.1002/lno.11784


Provided by Chinese Academy of Sciences

How Climate Change Affects Colombia’s Coffee Production? (Agriculture)

If your day started with a cup of coffee, there’s a good chance your morning brew came from Colombia. Home to some of the finest Arabica beans, the country is the world’s third largest coffee producer. Climate change poses new challenges to coffee production in Colombia, as it does to agricultural production anywhere in the world, but a new University of Illinois study shows effects vary widely depending on where the coffee beans grow.

“Colombia is a large country with a very distinct geography. The Andes Mountains cross the country from its southwest to northeast corner. Colombian coffee is currently growing in areas with different altitude levels, and climate impacts will likely be very different for low altitude and high altitude regions,” says Sandy Dall’Erba, professor in the Department of Agricultural and Consumer Economics (ACE) and director of the Regional Economics Applications Laboratory (REAL) at U of I. Dall’Erba is co-author on the study, published in Agricultural Systems.

Other studies on the future of coffee production have either considered the country as a whole, or focused on a few areas within the country.

Dall’Erba and lead author Federico Ceballos-Sierra, who recently obtained a Ph.D. from ACE, look at climate and coffee production for the entire country, broken down into 521 municipalities. This high level of detailed information allows them to identify significant regional variations.

“Colombia is not going to experience reduced productivity overall. But when we look into the impact across municipalities, we see many differences that get lost in the national average. That has important implications for coffee growers who live in one municipality versus another,” Ceballos-Sierra says.

“Low-altitude municipalities will be negatively affected by climate change, and thousands of growers and their families in these areas will see their livelihood jeopardized because productivity is likely to fall below their breakeven point by mid-century,” he states.

The researchers analyze climate data from 2007 to 2013 across Colombia’s 521 coffee-producing municipalities and evaluate how temperature and precipitation affect coffee yield. Subsequently, they model anticipated weather conditions from 2042 to 2061 and future coffee production for each municipal area.   

At the national level, they estimate productivity will increase 7.6% by 2061. But this forecast covers a wide margin of spatial differences, ranging from a 16% increase in high altitude regions (1,500 meters or 5,000 feet above sea level) to a 8.1% decrease in low altitude regions. Rising temperatures will benefit areas that are now marginal for coffee production, while areas that are currently prime coffee growing locations will be too hot and dry in the future.

Ceballos-Sierra grew up on a coffee farm in the Tolima district of Colombia, and he has seen firsthand how changing climate conditions affect production.

“My family’s farm is about 1,900 meters above sea level. Twenty years ago, people would consider that an upper marginal coffee growing area. But now we’re getting significant improvements in yield,” he says.

Meanwhile, coffee growers in lowland areas see decreasing yields, while pests that prey on coffee plants, such as the coffee bean borer, are becoming more aggressive and prevalent.

The research findings have important implications both for coffee growers and policymakers.

“In the future it will be more beneficial to grow coffee higher up in the mountains. So for those who can afford it, buying land in those areas would be a good investment,” Dall’Erba states. “The government might want to consider building infrastructures such as roads, water systems, electricity, and communication towers that would allow farmers in more elevated places to easily access nearby hubs and cities where they can sell their crops. We would expect more settlements and an increasing need for public services in those locations.”

However, because relocation is expensive, it will not necessarily be an option for most of Colombia’s 550,000 smallholder coffee growers, who will need to find other ways to adapt. Farmers might be able to implement new strategies, such as more frequent irrigation, increased use of forest shade, or shifting to different coffee varieties or other crops.

“Our research presents what we anticipate will happen 20 to 40 years from now, given current conditions and practices. Future studies can look into different adaptation strategies and their costs, and evaluate which options are best. Beyond the 40-year horizon we focus on, the prospects might be grimmer without adaptation. Production cannot keep moving to higher levels. Indeed, no mountain top is above 5,800 meters (18,000 feet) in Colombia,” Dall’Erba says.

Colombia’s policymakers can also focus on supporting farmers who no longer will be able to make a living from growing coffee, so they can transition to something else, Ceballos-Sierra states.

“Looking into these regional estimates allows us to make predictions and provide policy suggestions. Specific place-tailored strategies should guide how coffee production adapts to future climate conditions in Colombia,” he concludes.

The researchers say their findings may also apply to other coffee growing locations, including Hawaii, California, and Puerto Rico in the United States.

The Department of Agricultural and Consumer Economics  and the Regional Economics Applications Laboratory (REAL) are in the College of Agricultural, Consumer and Environmental SciencesUniversity of Illinois.

The article, “The effect of climate variability on Colombian coffee productivity: A dynamic panel model approach,” is published in Agricultural Systems. [https://doi.org/10.1016/j.agsy.2021.103126]

Featured image: Federico Ceballos-Sierra surveys coffee plants at his family farm in Colombia. © University of Illinois


Provided by University of Illinois College of Agricultural, Consumer & Environmental Sciences

How Will the Biggest Tropical Trees Respond to Climate Change? (Botany / Nature)

Giant trees in tropical forests, witnesses to centuries of civilization, may be trapped in a dangerous feedback loop according to a new report in Nature Plants from researchers at the Smithsonian Tropical Research Institute (STRI) in Panama and the University of Birmingham, U.K. The biggest trees store half of the carbon in mature tropical forests, but they could be at risk of death as a result of climate change—releasing massive amounts of carbon back into the atmosphere.

Evan Gora, STRI Tupper postdoctoral fellow, studies the role of lightning in tropical forests. Adriane Esquivel-Muelbert, lecturer at the University of Birmingham, studies the effects of climate change in the Amazon. The two teamed up to find out what kills big tropical trees. But as they sleuthed through hundreds of papers, they discovered that nearly nothing is known about the biggest trees and how they die because they are extremely rare in field surveys.

“Big trees are hard to measure,” said Esquivel-Muelbert. “They are the pain in a field campaign because we always have to go back with a ladder to climb up to find a place to measure the circumference above the buttresses. It takes a long time. Studies focusing on the reasons trees die don’t have enough information for the biggest trees and often end up excluding them from their analysis.”

 “Because we generally lack the data necessary to tell us what kills trees that are above approximately 50 centimeters in diameter, that leaves out half of the forest biomass in most forests,” Gora said.

Only about 1% of trees in mature tropical forests make it to this size. Others wait their turn in the shade below.

The other thing that makes tropical forests so special—high biodiversity—also makes it difficult to study big trees: There are so many different species, and many of them are extremely rare.

“Because only 1–2% of big trees in a forest die every year, researchers need to sample hundreds of individuals of a given species to understand why they are dying,” Gora said. “That may involve looking for trees across a huge area.”

Imagine a study of blood pressure in people who have lived to be 103. One would have to locate and test seniors from cities and towns around the world: a time-consuming, logistically complex and expensive proposition.

A large body of evidence shows that trees are dying faster in tropical forests than ever before. This is affecting the ability of forests to function and in particular, to capture and store carbon dioxide.

“We know the deaths of largest and oldest trees are more consequential than the death of smaller trees,” Gora said. “Big trees may be at particular risk because the factors that kill them appear to be increasing more rapidly than the factors that seem to be important for smaller-tree mortality.”

In large parts of the tropics, climate change is resulting in more severe storms and more frequent and intense droughts. Because big trees tower above the rest, they may be more likely to be hit by lightning, or damaged by wind. Because they have to pull ground water higher than other trees, they are most likely to be affected by drought.

Hoping to better understand what is happening to big trees, Gora and Esquivel-Muelbert identified three glaring knowledge gaps. First, almost nothing is known about disease, insects and other biological causes of death in big trees. Second, because big trees are often left out of analyses, the relationship between cause of death and size is not clear. And, finally, almost all of the detailed studies of big tropical trees are from a few locations like Manaus in Brazil and Barro Colorado Island in Panama.

To understand how big trees die, there is a trade-off between putting effort into measuring large numbers of trees and measuring them often enough to identify the cause of death. Gora and Esquivel-Muelbert agree that a combination of drone technology and satellite views of the forest will help to find out how these big trees die, but this approach will only work if it is combined with intense, standardized, on-the-ground observations, such as those used by the Smithsonian’s international ForestGEO network of study sites.

Esquivel-Muelbert hopes that the impetus for this research will come from a shared appreciation for these mysterious living monuments:

“I think they are fascinating to everyone,” she said. “When you see one of those giants in the forest, they are so big. My colleague and Amazonian researcher, Carolina Levis, says that they are the monuments we have in the Amazon where we don’t have big pyramids or old buildings.…That is the feeling, that they have been through so much. They are fascinating, not just in the scientific sense but also in another way. It moves you somehow.”

Funding for this study was from STRI, the U.S. National Science Foundation and the TreeMort project as part of the EU Framework Programme for Research and Innovation.

The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The institute furthers the understanding of tropical biodiversity and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Promo video.

Featured image: Tropical trees may grow to be more than 250 feet (77 meters) tall. Note person in red on the forest floor, below. Credit: Evan Gora, STRI


Reference: Gora, E.M. and Esquivel-Muelbert, A. 2021. Implications of size-dependent tree mortality for tropical forest carbon dynamics. Nature Plants. doi: 10.1038/s41477-021-00879-0 https://www.nature.com/articles/s41477-021-00879-0


Provided by Smithsonian

How India’s Rice Production Can Adapt to Climate Change Challenges? (Agriculture)

As the global population grows, the demand for food increases while arable land shrinks. A new University of Illinois study investigates how rice production in India can meet future needs by adapting to changing climate conditions and water availability. 

“Rice is the primary crop in India, China, and other countries in Southeast Asia. Rice consumption is also growing in the U.S. and elsewhere in the world,” says Prasanta Kalita, professor in the Department of Agricultural and Biological Engineering at U of I and lead author on the study.

“If you look at where they traditionally grow rice, it is countries that have plenty of water, or at least they used to. They have tropical weather with heavy rainfall they depend on for rice production. Overall, about 4,000 liters of water go into production and processing per kilogram of rice,” he states.

Climate change is likely to affect future water availability, and rice farmers must implement new management practices to sustain production and increase yield, Kalita says.

The United Nations’ Food and Agriculture Organization (FAO) estimates the world population will grow by two billion people by 2050, and food demand will increase by 60%.

“We will need multiple efforts to meet that demand,” Kalita states. “And with two billion more people, we will also need more water for crop production, drinking water, and industrial use.”

Kalita and his colleagues conducted the study at the Borlaug Institute for South Asia’s research farm in Bihar, India. Farmers in the region grow rice during the monsoon season, when heavy rainfall sustains the crop.

The researchers collected data on rice yield and climate conditions, then used computer simulations to model future scenarios based on four global climate models. The purpose of the study was to estimate rice yield and water demand by 2050, and evaluate how farmers can adapt to the effects of climate change.

“As the weather changes, it affects temperature, rainfall, and carbon dioxide concentration. These are essential ingredients for crop growth, especially for rice. It’s a complicated system, and effects are difficult to evaluate and manage,” Kalita states.

“Our modeling results show the crop growth stage is shrinking. The time for total maturity from the day you plant to the day you harvest is getting shorter. The crops are maturing faster, and as a result, you don’t get the full potential of the yield.”

If farmers maintain current practices, rice yield will decrease substantially by 2050, the study shows. But various management strategies can mitigate the effects of climate change, and the researchers provide a series of recommendations.

Traditional rice farming involves flooding the fields with water. Rice transplants need about six inches of standing water. If fields aren’t level, it requires even more water to cover the crops, Kalita says. However, if farmers use direct-seeded rice instead of transplants, they can increase production while using significantly less water.

Another practice involves soil conservation technology. “The soil surface continuously loses water because of temperature, humidity, and wind. If you keep crop residue on the ground, it reduces the evaporation and preserves water. Furthermore, when the crop residue decomposes, it will help increase soil quality,” Kalita explains.

The researchers also suggest implementing strategies to prevent post-harvest crop losses. FAO estimates about 30% of crops are lost or wasted after harvest, so efforts to reduce those losses can further increase crop availability and food security.

Overall, the best approach to achieve a 60% increase in rice production while minimizing additional irrigation needs is a combination of conservation strategies and a 30% reduction in post-harvest loss, the researchers conclude.

The Department of Agricultural and Biological Engineering is in the College of Agricultural, Consumer and Environmental Sciences and the Grainger College of EngineeringUniversity of Illinois.

The article, “Predicting the water requirement for rice production as affected by projected climate change in Bihar, India” is published in Water. [https://doi.org/10.3390/w12123312]

Authors are Ranjeet Jha, Prasanta Kalita, Richard Cooke, Praveen Kumar, Paul Davidson, and Rajkumar Jat.

This research was partly funded by the University of Illinois at Urbana-Champaign and USDA National Institute of Food and Agriculture.

Featured image: Farm workers plant rice transplants at the Borlaug Institute for South Asia’s research farm in Bihar, India. © University of Illinois


Provided by University of Illinois

Flower Colors Change in Response To Temperature And Aridity Fluctuations (Botany)

Clemson University scientists have linked climatic fluctuations over the past one and a quarter-century with flower color changes.

Researchers combined descriptions of flower color from museum flower specimens dating back to 1895 with longitudinal- and latitudinal-specific climate data to link changes in temperature and aridity with color change in the human-visible spectrum (white to purple).

The study, which was published in the journal Proceedings of the Royal Society B, showed the change varied across taxa.

“Species experiencing larger increases in temperature tended to decline in pigmentation, but those experiencing larger increases in aridity tended to increase in pigmentation,” said Cierra Sullivan, a graduate student in the College of Science’s Department of Biological Sciences and lead author of the paper titled “The effects of climate change on floral anthocyanin polymorphisms.”

Matthew Koski, an assistant professor of biological sciences, co-authored the paper.

“Seing changes is not necessarily bad, but it’s something to which we should pay attention.”

— CIERRA SULLIVAN

Previous research by Koski and his team, including Sullivan, showed that the ultraviolet-absorbing pigmentation of flowers increased globally over the past 75 years in response to a rapidly degraded ozone layer. That study discussed how flower color changes could influence the behavior of pollinators, which have UV photoreceptors that enable them to detect patterns not visible to human eyes. This study discusses plant color change visible to humans.

“Although we see these changes in flower color, that doesn’t inherently mean it’s doomsday because the forest, plants and animals naturally respond to what’s going on in their environment,” said Sullivan, who hails from Chesapeake, Virginia. “Seeing changes is not necessarily bad, but it’s something to which we should pay attention.”

A dozen flowers

Researchers selected 12 species with reported floral color polymorphisms in North America, representing eight families and 10 genera. 

Graduate student Cierra Sullivan used herbarium specimen data in her research linking temperature and aridity changes to flower color change over the past 124 years. © Clemson

Sullivan obtained herbarium specimen data from the Southeast Regional Network of Expertise and Collections (SRNEC)Consortium of Pacific Northwest HerbariaConsortium of California Herbaria and the Consortium of Northeastern Herbaria. She also checked Clemson University Herbarium’s physical collection for specimens not already represented in SERNEC. 

After researchers retrieved the date of specimen collection and latitudinal and longitudinal coordinates, they obtained historical bioclimatic data from the year and month that the plant was collected. That data included monthly precipitation, minimum, maximum and mean temperature, minimum and maximum vapor pressure deficit (VPD), and dew point temperature. Vapor pressure deficit is the difference between how much moisture is in the air and the amount of moisture that can be held when the air is saturated. It has implications for drought stress in plants — higher VPD means more water loss from plants.

Researchers were able to get complete data sets for 1,944 herbarium specimens.

They found variation among the 12 species. Some increased in pigmentation, while others declined in color over the past century.

“It was all tightly linked to how much climatic variation they experienced over time across their range,” Koski said. 

Multiple implications

Two of the species that tended to get lighter in pigmentation are found in the western parts of North America that experienced more dramatic temperature changes than the species in the eastern United States, which had more moderate temperature increases.

Matthew Koski © Clemson

“This study documents that flower color that is visually more obvious to humans is also responding to global change but is responding to different factors such as temperature and drought,” Koski said. 

He said such flower color changes are likely to affect plant-pollinator and plant-herbivore interactions and warrant further study. Continued research will help give insight to how species will respond to the various aspects of climate change and which species are the most vulnerable to future climate projections,” he said.

This research was supported by the National Science Foundation Division of Environmental Biology Grant 174590 and Clemson University. The content is solely the responsibility of the authors and does not necessarily represent the views of the funders.


Reference: Cierra N. Sullivan and Matthew H. Koski, “The effects of climate change on floral anthocyanin polymorphisms”, Royal Society Publishing B, 2021. https://doi.org/10.1098/rspb.2020.2693


Provided by Clemson

Ancient Relic Points to a Turning Point in Earth’s History 42,000 Years Ago (Earth Science)

Just like in The Hitchhiker’s Guide to the Galaxy, the answer was 42.

The temporary breakdown of Earth’s magnetic field 42,000 years ago sparked major climate shifts that led to global environmental change and mass extinctions, a new international study co-led by UNSW Sydney and the South Australian Museum shows.

This dramatic turning point in Earth’s history – laced with electrical storms, widespread auroras, and cosmic radiation – was triggered by the reversal of Earth’s magnetic poles and changing solar winds.

The researchers dubbed this danger period the ‘Adams Transitional Geomagnetic Event’, or ‘Adams Event’ for short – a tribute to science fiction writer Douglas Adams, who wrote in The Hitchhiker’s Guide to the Galaxy that ‘42’ was the answer to life, the universe, and everything.

The findings are published today in Science.

“For the first time ever, we have been able to precisely date the timing and environmental impacts of the last magnetic pole switch,” says Chris Turney, a professor at UNSW Science and co-lead author of the study. 

This ancient kauri tree found in Ngāwhā, New Zealand, was alive during the Adams Event. Photo: Nelson Parker

“The findings were made possible with ancient New Zealand kauri trees, which have been preserved in sediments for over 40,000 years.

“Using the ancient trees we could measure, and date, the spike in atmospheric radiocarbon levels caused by the collapse of Earth’s magnetic field.”

While scientists already knew the magnetic poles temporarily flipped around 41-42,000 years ago (known as the ‘Laschamps Excursion’), they didn’t know exactly how it impacted life on Earth – if at all. 

But the researchers were able to create a detailed timescale of how Earth’s atmosphere changed over this time by analysing rings on the ancient kauri trees.

“The kauri trees are like the Rosetta Stone, helping us tie together records of environmental change in caves, ice cores and peat bogs around the world,” says co-lead Professor Alan Cooper, Honorary Researcher at the South Australian Museum.

The researchers compared the newly-created timescale with records from sites across the Pacific and used it in global climate modelling, finding that the growth of ice sheets and glaciers over North America and large shifts in major wind belts and tropical storm systems could be traced back to the Adams Event.

One of their first clues was that megafauna across mainland Australia and Tasmania went through simultaneous extinctions 42,000 years ago.

“This had never seemed right, because it was long after Aboriginal people arrived, but around the same time that the Australian environment shifted to the current arid state,” says Prof. Cooper.

The paper suggests that the Adams Event could explain a lot of other evolutionary mysteries, like the extinction of Neandertals and the sudden widespread appearance of figurative art in caves around the world.

“It’s the most surprising and important discovery I’ve ever been involved in,” says Prof. Cooper.

Video: Watch as Stephen Fry brings to life the story of the ‘Adams event’. Video: UNSW Sydney.

The perfect (cosmic) storm

The magnetic north pole – that is, the direction a compass needle points to – doesn’t have a fixed location. It usually wobbles close to the North Pole (the northern-most point of Earth’s axis) over time due to dynamic movements within the Earth’s core, just like the magnetic south pole. 

Sometimes, for reasons that aren’t clear, the magnetic poles’ movements can be more drastic. Around 41,000-42,000 years ago they swapped places entirely.

“The Laschamps Excursion was the last time the magnetic poles flipped,” says Prof. Turney. “They swapped places for about 800 years before changing their minds and swapping back again.” 

Until now, scientific research has focused on changes that happened while the magnetic poles were reversed, when the magnetic field was weakened to about 28 per cent of its present-day strength. 

But according to the team’s findings, the most dramatic part was the lead-up to the reversal, when the poles were migrating across the Earth.

“Earth’s magnetic field dropped to only 0-6 per cent strength during the Adams Event,” says Prof. Turney. 

“We essentially had no magnetic field at all – our cosmic radiation shield was totally gone.”

During the magnetic field breakdown, the Sun experienced several ‘Grand Solar Minima’ (GSM), long-term periods of quiet solar activity.

Even though a GSM means less activity on the Sun’s surface, the weakening of its magnetic field can mean more space weather – like solar flares and galactic cosmic rays – could head Earth’s way. 

“Unfiltered radiation from space ripped apart air particles in Earth’s atmosphere, separating electrons and emitting light – a process called ionisation,” says Prof. Turney.

“The ionised air ‘fried’ the Ozone layer, triggering a ripple of climate change across the globe.” 

From auroras to lightning storms, the sky would have put on quite a show during the Adams Event. Photo: Unsplash.

Into the caves

Dazzling light shows would have been frequent in the sky during the Adams Event.

Aurora borealis and aurora australis, also known as the northern and southern lights, are caused by solar winds hitting the Earth’s atmosphere. 

Usually confined to the polar northern and southern parts of the globe, the colourful sights would have been widespread during the breakdown of Earth’s magnetic field.

“Early humans around the world would have seen amazing auroras, shimmering veils and sheets across the sky,” says Prof. Cooper. 

Ionised air – which is a great conductor for electricity – would have also increased the frequency of electrical storms. 

“It must have seemed like the end of days,” says Prof. Cooper.

The researchers theorise that the dramatic environmental changes may have caused early humans to seek more shelter. This could explain the sudden appearance of cave art around the world roughly 42,000 years ago.

“We think that the sharp increases in UV levels, particularly during solar flares, would suddenly make caves very valuable shelters,” says Prof. Cooper. “The common cave art motif of red ochre handprints may signal it was being used as sunscreen, a technique still used today by some groups. 

“The amazing images created in the caves during this time have been preserved, while other art out in open areas has since eroded, making it appear that art suddenly starts 42,000 years ago.”

The centre of this cave art from El Castillo Cave in Spain is believed to be almost 42,000 years old – the same age as the Adams Event. Photo: Paul Pettitt, courtesy Gobierno de Cantabria

Uncovering ancient clues

These findings come two years after a particularly important ancient kauri tree was uncovered at Ngāwhā, Northland. 

The massive tree – with a trunk spanning over two and a half metres – was alive during the Laschamps. 

“Like other entombed kauri logs, the wood of the Ngāwhā tree is so well preserved that the bark is still attached,” says UNSW’s Dr Jonathan Palmer, a specialist in dating tree-rings (dendrochronology). Dr Palmer studied cross sections of the trees at UNSW Science’s Chronos 14Carbon-Cycle Facility

Using radiocarbon dating – a technique to date ancient relics or events – the team tracked the changes in radiocarbon levels during the magnetic pole reversal. This data was charted alongside the trees’ annual growth rings, which acts as an accurate, natural timestamp. 

The new timescale helped reveal the picture of this dramatic period in Earth’s history. The team were able to reconstruct the chain of environmental and extinction events using climate modelling. 

“The more we looked at the data, the more everything pointed to 42,” says Prof. Turney. “It was uncanny. 

“Douglas Adams was clearly on to something, after all.”

Video: The ancient kauri trees were key to the findings, explain Prof. Chris Turney and Prof. Alan Cooper. Video: UNSW Sydney.

An accelerant like no other

While the magnetic poles often wander, some scientists are concerned about the current rapid movement of the north magnetic pole across the Northern Hemisphere. 

“This speed – alongside the weakening of Earth’s magnetic field by around nine per cent in the past 170 years – could indicate an upcoming reversal,” says Prof. Cooper.

“If a similar event happened today, the consequences would be huge for modern society. Incoming cosmic radiation would destroy our electric power grids and satellite networks.”

Prof. Turney says the human-induced climate crisis is catastrophic enough without throwing major solar changes or a pole reversal in the mix.  

“Our atmosphere is already filled with carbon at levels never seen by humanity before,” he says. “A magnetic pole reversal or extreme change in Sun activity would be unprecedented climate change accelerants.

“We urgently need to get carbon emissions down before such a random event happens again.”

This work was made possible by funding from an Australian Research Council Discovery Project Grant, support from Ngāpuhi iwi and Top Energy, the University of Waikato Radiocarbon Laboratory, and many other national and international partners.

Featured image: This dramatic paleoclimate change – which was hallmarked with widespread auroras – could help explain other evolutionary mysteries, like the extinction of Neandertals. Photo: Unsplash.


Reference: Alan Cooper, Chris S. M. Turney, Jonathan Palmer, Alan Hogg, Matt McGlone, Janet Wilmshurst, Andrew M. Lorrey, Timothy J. Heaton, James M. Russell, Ken McCracken, Julien G. Anet, Eugene Rozanov, Marina Friedel, Ivo Suter, Thomas Peter, Raimund Muscheler, Florian Adolphi, Anthony Dosseto, J. Tyler Faith, Pavla Fenwick, Christopher J. Fogwill, Konrad Hughen, Mathew Lipson, Jiabo Liu, Norbert Nowaczyk, Eleanor Rainsley, Christopher Bronk Ramsey, Paolo Sebastianelli, Yassine Souilmi, Janelle Stevenson, Zoë Thomas, Raymond Tobler, Roland Zech, “A global environmental crisis 42,000 years ago”, Science 19 Feb 2021: Vol. 371, Issue 6531, pp. 811-818 DOI: 10.1126/science.abb8677


Provided by UNSW