This latest SCI Energy Group blog introduces the possible avenues of carbon dioxide utilisation, which entails using carbon dioxide to produce economically valuable products through industrial processes. Broadly, utilisation can be categorised into three applications: chemical use, biological use and direct use. For which, examples of each will be highlighted throughout.
Before proceeding to introduce these, we can first consider utilisation in relation to limiting climate change. As has been discussed in previous blogs, the reduction of carbon dioxide emissions is crucial. Therefore, for carbon dioxide utilisation technologies to have a beneficial impact on climate change, several important factors must be considered and addressed.
1) Energy Source: Often these processes are energy intensive. Therefore, this energy must come from renewable resources or technologies.
2) Scale: Utilisation technologies must exhibit large scaling potential to match the limited timeframe for climate action.
3) Permanence: Technologies which provide permanent removal or displacement of CO2 emissions will be most impactful¹.
Figure 1: CO2 sign
Carbon dioxide, alongside other reactants, can be chemically converted into useful products. Examples of which include urea, methanol, and plastics and polymers. One of the primary uses of urea includes agricultural fertilisers which are pivotal to crop nutrition. Most commonly, methanol is utilised as a chemical feedstock in industrial processes.
Figure 2: Fertilizing soil
One of the key challenges faced with this application of utilisation is the low reactivity of CO2 in its standard conditions. Therefore, to successfully convert it into products of economic value, catalysts are required to significantly lower the molecules activation energy and overall energy consumption of the process. With that being said, it is anticipated that, in future, the chemical conversion of CO2 will have an important role in maintaining a secure supply of fuel and chemical feedstocks such as methanol and methane².
Carbon dioxide is fundamental to plant growth as it provides a source of required organic compounds. For this reason, it can be utilised in greenhouses to promote carbonic fertilisation. By injecting increased levels of CO2 into the air supplied to greenhouses, the yield of plant growth has been seen to increase. Furthermore, CO2 from the flue gas streams of chemical processes has been recognised, in some studies, to be of a quality suitable for direct injection³.
Figure 3: Glass greenhouse planting vegetable greenhouses
These principles are applicable to encouraging the growth of microorganisms too. One example being microalgae which boasts several advantageous properties. Microalgae has been recognised for its ability to grow in diverse environments as well as its ability to be cultured in numerous types of bioreactors. Furthermore, its production rate is considerably high meaning a greater demand for CO2 is exhibited than that from normal plants. Micro-algal biomass can be utilised across a range of industries to form a multitude of products. These include bio-oils, fuels, fertilisers, food products, plant feeds and high value chemicals. However, at present, the efficiency of CO2 fixation, in this application, can be as low as 20-50%.
Figure 4: Illustration of microalgae under the microscope
It is important to note that, at present, there are many mature processes which utilise CO2 directly. Examples of which are shown in the table below.
Many carbon dioxide utilisation technologies exist, across a broad range of industrial applications. For which, some are well-established, and others are more novel. For such technologies to have a positive impact on climate action, several factors need to be addressed such as their energy source, scaling potential and permanence of removal/ displacement of CO2.
The chemistry of carbon dioxide and its role in decarbonisation is a key topic of interest for SCI Energy Group. In the near future, we will be running a webinar concerned with this. Further details of this will be posted on the SCI website in due course.
Energy is critical to life. However, we must work to find solution to source sustainable energy which compliments the UK’s emission targets. This article discusses six interesting facts concerning the UK’s diversified energy supply system and the ways it is shifting towards decarbonised alternatives.
1. In 2015, UK government announced plans to close unabated coal-fired power plants by 2025.
A coal-fired power plant
In recent years, energy generation from coal has dropped significantly. In March 2018, Eggborough power station, North Yorkshire, closed, leaving only seven coal power plants operational in the UK. In May this year, Britain set a record by going one week without coal power. This was the first time since 1882!
2. Over 40% of the UK’s electricity supply comes from gas.
A natural oil and gas production in sea
While it may be a fossil fuel, natural gas releases less carbon dioxide emissions compared to that of coal and oil upon combustion. However, without mechanisms in place to capture and store said carbon dioxide it is still a carbon intensive energy source.
3. Nuclear power accounts for approximately 8% of UK energy supply.
Nuclear power generation is considered a low-carbon process. In 2025, Hinkley Point C nuclear power-plant is scheduled to open in Somerset. With an electricity generation capacity of 3.2GW, it is considerably bigger than a typical power-plant.
In 2018, the total installed capacity of UK renewables increased by 9.7% from the previous year. Out of this, wind power, solar power and plant biomass accounted for 89%.
4. The Irish Sea is home to the world’s largest wind farm, Walney Extension.
The Walney offshore wind farm.
In addition to this, the UK has the third highest total installed wind capacity across Europe. The World Energy Council define an ‘ideal’ wind farm as one which experiences wind speed of over 6.9 metres per second at a height of 80m above ground. As can be seen in the image below, at 100m, the UK is well suited for wind production.
5. Solar power accounted for 29.5% of total renewable electricity capacity in 2018.
This was an increase of 12% from the previous year (2017) and the highest amount to date! Such growth in solar power can be attributed to considerable technology cost reductions and greater average sunlight hours, which increased by up to 0.6 hours per day in 2018.
Currently, the intermittent availability of both solar and wind energy means that fossil fuel reserves are required to balance supply and demand as they can run continuously and are easier to control.
6. In 2018, total UK electricity generation from bioenergy accounted for approximately 32% of all renewable generation.
A biofuel plant in Germany.
This was the largest share of renewable generation per source and increased by 12% from the previous year. As a result of Lynemouth power station, Northumberland, and another unit at Drax, Yorkshire, being converted from fossil fuels to biomass, there was a large increase in plant biomass capacity from 2017.
Throughout the series, you will be introduced to its members through regular features that highlight their roles and major interests in energy. We welcome you to read their series and hope to spark some interesting conversation across all areas of SCI.
The burning of fossil fuels is the biggest contributor to global greenhouse gas emissions.
According to the National Oceanic and Atmospheric Administration (NOAA), by the end of 2018, their observatory at Muana Loa, Hawaii, recorded the fourth-highest annual growth of global CO2 emissions the world has seen in the last 60 years.
Adding even more concern, the Met Office confirmed that this trend is likely to continue and that the annual rise in 2019 could potentially be larger than that seen in the previous two years.
Forecast global CO2 concentration against previous years. Source: Met Office and contains public sector information licensed under the Open Government Licence v1.0.
Large concentrations of CO2 in the atmosphere are a major concern because it is a greenhouse gas. Greenhouse gases absorb infrared radiation from solar energy from the sun and less is emitted back into space. Because the influx of radiation is greater than the outflux, the globe is warmed as a consequence.
Although CO2 emissions can occur naturally through biological processes, the biggest contributor to said emissions is human activities, such as fossil fuel burning and cement production.
Increase of CO2 emissions before and after the Industrial Era. Source: IPCC, AR5 Synthesis Report: Climate Change 2014, Fig. 1.05-01, Page. 3
Weather impacts from climate change include drought and flooding, as well as a noticeable increase in natural disasters.
This warming has resulted in changes to our climate system which has created severe weather impacts that increase human vulnerability. One example of this is the European heat wave and drought which struck in 2003.
The event resulted in an estimated death toll of over 30,000 lives and is recognised as one of the top 10 deadliest natural disasters across Europe within the last century.
In 2015, in an attempt to address this issue, 195 nations from across the globe united to adopt the Paris Agreement which seeks to maintain a global temperature rise of well below 2C, with efforts to limit it even further to 1.5C.
The Paris Climate Change Agreement explained. Video: The Daily Conversation
In their latest special report, the Intergovernmental Panel on Climate Change (IPCC) explained that this would require significant changes in energy, land, infrastructure and industrial systems, all within a rapid timeframe.
In addition, the recently published Emissions Gap report urged that it is crucial that global emissions peak by 2020 if we are to succeed in meeting this ambitious target.
Are we further away then we think?
As well as the Paris Agreement, the UK is committed to the Climate Change Act (2008) which seeks to reduce greenhouse gas emissions by at least 80% by 2050 relative to 1990 baseline levels. Since 1990, the UK has cut emissions by over 40%, while the economy has grown by 72%.
To ensure that we meet our 2050 target, the government has implemented Carbon Budgets, which limit the legal emissions of greenhouse gases within the UK across a five-year period. Currently, these budgets run up to 2032 and the UK is now in the third budget period (2018-2022).
The UK has committed to end the sale of all new petrol and diesel cars by 2040.
At present, the UK is on track to outperform both the second and third budget. However, it is not on track to achieve the fourth budget target (2023-2027). To be able to meet this, the Committee on Climate Change (CCC) urge that UK emissions must be reduced annually by at least 3% from this point forward.
We may not be sure which technologies will allow such great emission reductions, but one thing is for certain – decarbonisation is essential, and it must happen now!
How does climate change impact agriculture? Our Agrisciences group will be hosting an event on 6 March to look at just that!
Not only does climate change have a significant impact on agriculture, and the future of food security, but agricultural practices also directly contribute to climate change. Scientists, farmers and policy makers are coming together to find dynamic solutions to the problems caused by climate change in agriculture.
Agriculture provides food. Comprising of a variety of different farming systems, from crops to livestock, agriculture exists in almost every part of the world. Agriculture relies on knowing your geography – its soil properties, local pests and wildlife – but most importantly, the local climate. When these factors start to change, farming becomes a challenge.
We are already experiencing the effects of climate change, and turbulent or extreme weather is becoming more of the norm. As much as environmentalists can try to combat the development of these problems, agriscientists and farmers need to work together to overcome problems.
Consequences of climate change
One of the main consequences of climate change is a temperature increase. Even a slight temperature change can result in a significant effect on crop yields. Further to that, temperature change can result in drought, which affects the soil and plants alike, and lead to a change in pest numbers. An increase in atmospheric CO2 can also affect crops and livestock. Crops that thrive in higher CO2 levels will do better, but others may be negatively affected.
Not only will crop growth be affected directly by the weather, we could see a change in the diversity and number of pests. Image: Pixabay
Extreme weather events are also rapidly increasing in frequency. These include tornadoes, floods, heat waves, all of which can have quickly detrimental effect on farms. The 2018 British summer heat wave significantly affected crop farming in the UK.
As well as being affected by it, agriculture itself contributes to climate change. An estimated 10-20% of greenhouse gases are produced by agriculture, mainly from livestock.
Addressing the challenge
It is easy to consider that the impact of climate change on agriculture is something which can feel beyond our control. However, it is a dynamic challenge, and brings together scientists, academics, farmers, industry and policy makers, to overcome the negative impacts that a changing climate can have on agricultural systems.
Firstly, scientists can work to breed crops that are more resilient to these changes. They can identify genes for traits like heat and drought tolerance, pest resistance and stability under extreme conditions.
Solutions include plant breeding, GM crops, smart crop protection, policy changes and large collaborations across sectors. Image: Pixabay
Livestock farmers can help to curb climate change by introducing new diets that produce less overall methane. Other farmers can make shifts in their farming systems to more sustainable practices.
Policy makers can help with reducing the impact of climate change on agriculture. Not only by supporting environmental policies that potentially reduce the effects of climate change, they can also encourage scientific developments and relevant legislation relating to pest control, GM plants and other key areas.
Alterations to consumer practices can also reduce the impact of agriculture on climate change, and changes need to be made at all levels of the farming and supply chain.
How does climate change affect agriculture? Source: Syngenta
Overall, many parties need to collaborate to help to reduce the impact of agriculture on climate change, and help to overcome the problems that the future might hold, ensuring food security through a changing climate.
Transparent solar cells that can convert invisible light wavelengths into renewable energy could supply 40% of the US’ energy demand, a Michigan State University (MSU) engineering team have reported.
In contrast to the robust, opaque solar panels that take up a large amount of space – whether on rooftops or on designated solar farms – the transparent solar cells can be placed on existing surfaces, such as windows, buildings, phones, and any other object with a clear surface.
Traditional solar panels require large amounts of space.
‘Highly transparent solar cells represent the wave of the future for new solar cell applications,’ says Richard Lunt, Associate Professor of Chemical Engineering and Materials Science at MSU.
‘We analysed their potential and show that by harvesting only invisible light, these devices can provide a similar electricity generation potential as rooftop solar while providing additional functionality to enhance the efficiency of buildings, automobiles, and mobile electronics.’
Solar, or photovoltaic, cells convert the sun’s energy into electricity. Image: Pixabay
Currently, the cells are running at 5% efficiency, says the team, compared to traditional solar panels that have recorded efficiencies between 15-18%. Lunt believes that with further research, the capability of the transparent cells could increase three-fold.
‘That is what we are working towards,’ says Lunt. ‘Traditional solar applications have been actively researched for over five decades, yet we have only been working on these highly transparent solar cells for about five years.’
The cells can be added to any existing transparent surface, including mobile phones. Image: Max Pixel
While solar panels may be more efficient at converting energy than the group’s transparent cells, Lunt says that the latter can be easily applied to more surfaces and therefore a larger surface area, increasing the overall amount of energy produced by the cells.
‘Ultimately,’ he says, ‘this technology offers a promising route to inexpensive, widespread solar adoption on small and large surfaces that were previously inaccessible.’
Transparent solar cells. Video: Michigan State University
Together, and with further work on its efficiency, the authors of the paper believe that their see-through cells and traditional solar panels could fulfil the US’ energy needs.
‘The complimentary deployment of both technologies could get us close to 100% of our demand if we also improve energy storage,’ Lunt says.
Renewables outstripped coal power for the first time in electricity generation in Europe in 2017, according to a new report. The European Power Sector in 2017 – by think-tanks Sandbag and Agora Energiewende – predicts renewables could provide half of Europe’s electricity by 2030.
Wind, solar and biomass generation collectively rose by 12% in 2017 – to 679 Terawatt hours – generating 21% of Europe’s electricity and contributing to 30% of the energy mix. ‘This is incredible progress considering just five years ago coal generation was more than twice that of wind, solar and biomass,’ the report says.
Hydroelectric power is the most popular renewable energy source worldwide. Image: PxHere
However, growth is variable. The UK and Germany alone contributed to 56% of the expansion in the past three years. There is also a ‘bias’ for wind, with a 19% increase in 2017, due to good wind conditions and huge investments, the report says.
‘This is good news now the biomass boom is over, but bad news in that solar was responsible for just 14% of the renewables growth in 2014 to 2017.’
New analysis by trade group WindEurope backs up the findings on wind power, showing that countries across Europe installed more offshore capacity than ever before: 3.14GW. This corresponds to 560 new offshore wind turbines across 17 wind farms. Fourteen projects were fully completed and connected to the grid, including the first floating offshore wind farm. Europe now has a total installed offshore wind capacity of 15.78GW.
The EU’s 2030 goals for climate and energy. Video: European Commission
Germany remains top of the European league, with the largest total installed wind-power capacity; worth 42% of the EU’s new capacity in 2017, followed by Spain, the UK, and France. Denmark boasts the largest share of wind in its power mix at 44% of electricity demand.
Renewable energy has long been known as a greener alternative to fossil fuels, but that doesn’t mean that the former has no negative environmental impacts. Hydropower, for instance, has been known to reduce biodiversity in the land used for its systems.
Now, a team of Norwegian-based researchers have developed a methodology that quantifies the environmental effects of hydropower electricity production.
Ulla-Førre – Norway’s largest hydropower station.
Martin Dorber, PhD candidate in Industrial Ecology at the Norwegian University of Science and Technology (NTNU), is part of the team that developed the analytic tool. ‘Some hydropower reservoirs may look natural at first. However, they are human-influenced and if land has been flooded for their creation, this may impact terrestrial ecosystems,’ he said,
The Life Cycle Assessment, or LCA, can be used by industry and policymakers to identify the trade-offs associated with current and future hydropower projects. Norway is one of the top hydropower producers in the world, with 95% of its domestic electricity production coming from hydropower.
Generations inside the Hoover Dam station. Image: Richard Martin/Flickr
Many hydropower facilities include a dam – many purpose-built for hydropower generation – which stores fresh water from lakes or rivers in a reservoir.
Reducing biodiversity in the areas where hydropower development is being considered is one of the main disadvantages of the renewable source. Reduced freshwater habitats and water quality, and land flooding are among the damaging effects – all of which are difficult to assess, says the team.
‘Land use and land use change is a key issue, as it is one of the biggest drivers of biodiversity loss, because it leads to loss and degradation of habitat for many species,’ said Dorber.
Hydropower development can be damaging to freshwater habitats. Image: Pexels
Using reservoir surface area data from the Norwegian Water Resources and Water Resources Directorate and satellite images from the NASA-USGS Global Land Survey, the team were able to create a life cycle inventory that showed the amount of land needed to produce a kilowatt-hour of electricity.
‘By dividing the inundated land area with the annual electricity production of each hydropower reservoir, we calculated site-specific net land occupation values for the life cycle inventory,’ said Dorber.
‘While it’s beyond the scope of this work, our approach is a crucial step towards quantifying impacts of hydropower electricity production on biodiversity for life cycle analysis.’
While this study is exclusive to hydropower reservoirs in Norway, the team believe this analysis could be adopted by other nations looking to extend their hydropower development and assess the potential consequences.
Pumped-storage hydropower. Video: Statkraft
‘We have shown that remote sensing data can be used to quantify the land use change caused by hydropower reservoirs,’ said Dorber. ‘At the same time our results show that the land use change differs between hydropower reservoirs.’
‘More reservoir-specific land use change assessment is a key component that is needed to quantify the potential environmental impacts.’
Researchers at the University of Waterloo, Canada, have developed an innovative method for capturing renewable natural gas from cow and pig manure for use as a fuel for heating homes, powering industry, and even as a replacement for diesel fuel in trucks.
It is based on a process called methanation. Biogas from manure is mixed with hydrogen, then run through a catalytic converter, producing methane from carbon dioxide in the biogas through a chemical reaction.
A biogas plant. Image: Pixabay
The researchers claim that power could be taken from the grid at times of low demand or generated on-site via wind or solar power to produce the hydrogen.
The renewable natural gas produced would yield a large percentage of the manure’s energy potential and efficiently store electricity, while emitting a fraction of the gases produced when the manure is used as a fertiliser.
‘The potential is huge,’ said David Simakov, Professor of Chemical Engineering at Waterloo. 'There are multiple ways we can benefit from this single approach.’
See a Farm Convert Pig Poop Into Electricity. Video: National Geographic
Using a computer model of a 2,000-head dairy farm in Ontario, which already collects manure and converts it into biogas in anaerobic digesters before burning it in generators, the researchers tested the concept.
They estimated that a $5-million investment in a methanation system would have a five-year payback period, taking government subsidies for renewable natural gas into account.
'This is how we can make the transition from fossil-based energy to renewable energy using existing infrastructure, which is a tremendous advantage,’ Simakov said.
It’s well known that the oceans are becoming more acidic as they absorb increasing amounts of CO2 from the atmosphere. Now, German researchers say they have found the first evidence that this is happening in freshwaters, too, with potentially widespread effects on ecosystems.
‘Many current investigations describe tremendous effects of rising CO2 levels on marine ecosystems,’ says Linda Weiss at Ruhr-University Bochum: acidic oceans can have major impacts on marine food webs, nutrient cycles, overall productivity and biodiversity. ‘However, freshwater ecosystems have been largely overlooked,’ she adds.
Waters with high acidity have reduced biodiversity.
Weiss and colleagues looked at four freshwater reservoirs in Germany. Their analysis of data over 35 years – from 1981 to 2015 – confirmed a continuous increase in CO2, measured as the partial pressure or pCO2, and an associated decrease in pH of about 0.3, suggesting that freshwaters may acidify at a faster rate than the oceans.
In lab studies, the team also investigated the effects of higher acidity on two species of freshwater crustaceans called Daphnia, or water fleas. Daphnia found in lakes, ponds and reservoirs are an important primary food source for many larger animals.
Daphnia are an essential part of the freshwater food chain. Image: Faculty of Natural Sciences at Norwegian University of Science and Technology/Flickr
When Daphnia sense that predators are around, they respond by producing ‘helmets’ and spikes that make them harder to eat. Weiss found that high levels of CO2 reduce Daphnia’s ability to detect predators. ‘This reduces the expression of morphological defences, rendering them more vulnerable,’ she says.
The team suggest that CO2 alters chemical communication between species, which could have knock-on effects throughout the whole ecosystem. Many fish learn to use chemical cues from injured species to detect predatory threats and move away from danger, for example.
Ocean acidification - the evil twin of climate change | Triona McGrath | TEDxFulbrightDublin. Video: TEDx Talks
Cory Suski, an ecologist at the University of Illinois at Urbana-Champaign, US, says he is not aware of many other data sets showing trends in CO2 abundance in freshwater over an extended time. Also, he notes: ‘A lot of the work to date in this area has revolved around behavioural or physiological responses to elevated CO2, so a morphological change is novel.’
But he points out that it is difficult to predict how this change could impact aquatic ecosystems, or whether this may be a global phenomenon, simply because of the complex nature of CO2 in freshwater. The amount of CO2 in freshwater is driven by a number of factors including geology, land use, water chemistry, precipitation patterns and aquatic respiration.
English wine is on the rise. In 50 years, production has increased by more than three orders of magnitude, from a negligible 1,500 bottles/year to a respectable 5.3 million.
Meanwhile, on the other side of the English Channel, grapes are harvested around two weeks before the traditional dates. In the Champagne region, harvest kicked off on 26 August 2017, while the average date for previous years was 10 September. In Burgoyne, home of Beaujolais wines, harvest began on 23 August, also two weeks ahead of schedule. Harvest workers in that area are also doing night shifts to reduce heat stress for the sensitive grapes.
French vineyards are struggling with the changes to traditional harvests. Image: Max Pixel
Both phenomena – the success of English wine and the earlier harvests in France – are linked to climate change. In a few decades, the favourable wine-growing conditions historically enjoyed by the Champagne region may have migrated to England.
As the life cycle of the grapevine – and therefore quality and quantity of the wine obtained – is extremely sensitive to temperature and weather extremes, wine growers have already been noticing the effects of climate change for years. Researchers have detailed how conditions have changed, how they are likely to change further, and what vineyards can do to adapt.
All agricultural products are likely to be affected by climate change at some point, but wine occupies a special position due to its high value. Therefore, wine growers have always watched the weather and its effects on their vineyards very closely, and recorded their observations.
Climate scientist Benjamin Cook from Columbia University at New York and ecologist Elizabeth Wolkovich from Harvard University, have analysed harvest data spanning more than 400 years, from 1600 to 2007, from European regions, together with the weather data.
While many studies have covered the last few decades, this one reaches back to the time before the Industrial Revolution.
Higher temperatures in spring and summer generally speed the whole process and lead to earlier harvests, like the one in 2017, while cool and rainy summers can delay the phrenology and thus the harvest time. Traditionally, the observation was that a warm summer and a period of drought just before grape picking is the best recipe for an early harvest.
Grape picking is easiest after a warm summer. Image: Pixabay
‘Our research, and other work, has clearly and unequivocally demonstrated that climate change is already affecting viticulture worldwide,’ explains Cook, adding that: ‘There are lots of opportunities for adaptation in various locations, such as planting different varieties, but the most important thing is for people to starting planning for the next several decades, when conditions are likely to get even warmer still.’
Adapt or move?
So, what could be changed? Short of pulling up Pinot Noir vines in Champagne and replanting them in Dorset, there are some steps wine-makers can take to ensure a good harvest.
The Chemistry of Wine. Video: Reactions
For instance, growers could add a few days to the ripening cycle by delaying the spring pruning, or by allowing the vines to grow higher above the ground, where the air is slightly cooler than just above the soil. While these changes are benign, other measures, such as reducing the leaf area, may have complex consequences that could interfere with the quality of the wine.
In selecting the plant material, growers could reverse the trends of the 20th Century, when it made sense to select rapidly ripening varieties. Simply by adapting the choice of variety from among the range of varieties already used in a given region to the changing climate, growers can to some extent mitigate the anticipated effects.
Alternatively, wine production could migrate closer to the poles. Wines now coming from California may be produced in Washington State, and the premium fizz we now call Champagne may one day be known as Devon or Kent.
In 1942 the Leverhulme Trust endowed a lecture in memory of the first Viscount Leverhulme, founder of the Lever Brothers
The Lecture is given every three years before the Liverpool and North West Regional Group to promote chemical or technological research or education.
Prof Maitland is the 20th recipient of this prestigious award and gave his lecture on ‘Avoiding catastrophic climate change; Paris 2015 set the targets, can the UK deliver?’.
Read our full write-up on the lecture here.
Geoffrey Maitland (second left) receives his award from Alan Bayliss, Chair of the Board of Trustees, with Trevor Rhodes (left), Chair of SCI’s Liverpool and North West Group, and Sharon Todd, SCI’s Executive Director. Image: Mike Halliday
Reace Edwards, from Chester University, collects her award from Prof Maitland. She is the top scoring second year student on the BEng/MEng Chemical Engineering degree course. Image: Mike Halliday
Oliver Stanfield won his award for highest-achieving third year student on the BSc Chemistry with Industrial Experience course at the University of Bangor. Image: Mike Halliday
Aaisha Patel, from Liverpool John Moores University, is the best second year student on the BSc (Hons) Chemical and Pharmaceutical Science programme. Image: Mike Halliday
On average, 10% of all crop production is lost annually to drought and extreme heat, with the situation getting worse year on year. Heat stress happens over short-time periods, but drought happens over longer timescales and is linked to drier soils. Maize and wheat are especially hard hit, with yields falling by up to 50% if drought hits.
On the High Plains, the largest US wheat-growing region, drought is a possibility every season. ‘Drought stress can be a key concern, especially in dry lands, but even in irrigated areas we can’t expect the same levels of water in future and farmers face restrictions,’ says Chris Souder at Monsanto.
So, this is not simply a developing world problem. Pedram Rowhani, University of Sussex, UK, found cereals in more technically developed agricultural systems of North America, Europe, and Australia suffered most from droughts. Yield losses due to drought were 19.9% in the US compared to almost no effect in Latin America.
Crop breeders in the past paid a great deal of attention to yield, but not enough to resilience to extreme events such as drought, Rowhani says, but this is changing. Growers increasingly want built-in drought resilience and plant scientists are looking for novel solutions. New, unconventional approaches based on novel insights from basic science might be necessary.
Hundreds of genes and proteins are involved in the complex trait of drought resistance. Plants avoid drought stress by shortening their life cycle with accelerated flowering, or cut down water loss by closing leaf pores called stomata. One approach by breeders is to target specific traits by crossing individual plants that perform best under drought conditions.
Stomata are found of the underside of leaves and are used for gas exchange. Image: Pixabay
‘About 97% of plant water loss occurs through the stomata. If you want to regulate the amount of water a plant uses, regulate the stomata,’ says Julie Gray, University of Sheffield, UK. Gray has been genetically tweaking wheat, barley, and rice plants so they have fewer of these pores.
She believes rising CO2 levels in the atmosphere means that they do not suffer from less carbon dioxide from opening their stomata. ‘CO2 levels have gone up 40% over the last 200 years. It’s quite possible they are producing more stomata than they need,’ says Gray.
Power plant in Tihange, Belgium. CO2emissions continue to increase. Image: Hullie@Wikimedia Commons
Gray reports that plants grown at 450ppm CO2 with reduced stomatal density, but increased stomatal size, had larger biomass and increased growth tolerance when water was limited. ‘Plants can operate with perhaps half as many stomata before you see significant effects on photosynthesis, so you can definitely reduce water loss this way,’ says Gray.
Root of the issue
At the other end of the plant plumbing system are roots. Susannah Tringe, Joint Genome Institute, UK, is seeking microbes that can gift stress-tolerance to their plant hosts. ‘The microbes associated with plants are likely to be just as important for plant growth and health as the microbiome of humans,’ says Tringe.
Though a lot of work has focused on finding the ‘magic microbe,’ Tringe believes whole communities will be necessary in real field conditions, whereas a single strain could be out-muscled by competitors.
Regular bouts of drought are leading to famine in developing countries. Video: Food and Agriculture Organization of the United Nations
Sugar and drought
‘Drought is probably the most widespread abiotic stress that limits food production worldwide. There is always need to improve drought tolerance,’ says Matthew Paul, Rothamsted Research Institute, UK.
‘Sucrose is produced in photosynthesis,’ Paul explains. ‘During drought conditions, plants will withhold sucrose from the grain, as a survival mechanism’. This can terminate reproductive structures and abort seed formation, even if drought is short-lived, greatly compromising yield.
A plant scientist studying rice plants. Image: IRRI Photos@Flickr
Rothamsted researchers have looked at modifying plants so sugar keeps flowing. ‘If you can get more sugar going to where you want it […] then this could improve yields and yield resilience,’ enthuses Paul. Field studies show that GM maize improved yields from 31 to 123% under severe drought, when compared with non-transgenic maize plants.