Time for a global agreement on minerals to fuel the clean energy transition


Damien Giurco, University of Technology Sydney; Nicholas Arndt, Université Grenoble Alpes, and Saleem H. Ali, The University of Queensland

Representatives from around the world are meeting in Bonn this week to discuss progress towards the goals of the Paris climate agreement. A large part of this challenge involves rapidly scaling up the deployment of renewable energy, while curbing fossil fuel use – but little attention has been paid to the minerals that will be needed to build these technologies.

Wind and solar infrastructure, batteries and electric vehicles all require vast amounts of mined (and recycled) resources. These range from copper for wires and electric motors, to lithium and cobalt for batteries, to smaller amounts of rare metals like indium and gallium for solar cells.


Read more: Mining for metals in society’s waste


The problem is that the current system for mining these minerals is not always efficient; it’s polluting and is subject to increased social pressure and public protests. Instead, we need a new international mechanism to coordinate global mineral exploration that looks to our future supply needs.

As technology advances, more and different metals are needed.
Zepf V, Reller A, Rennie C, Ashfield M & Simmons J, BP (2014): Materials critical to the energy industry.

Challenges for minerals supply

While the Paris agreement has created a global framework for managing carbon, nothing similar exists for minerals. This leaves the pursuit of sustainable resource development largely in the hands of mining companies and state-owned enterprises.

Mining these resources generates significant water and air pollution. This problem is increasing: for example, global copper ore quality is declining over time. That means that copper mining now requires excavating twice as much ore as ten years ago to yield the same amount of copper, creating much more mine waste.


Read more: Treasure from trash: how mining waste can be mined a second time


Lower commodity prices have meant that investment in exploring new mine sites has fallen. But it takes a long time to develop new mines – it can often take 20 years to go from finding a metal deposit to beginning mining, and only around 20% of discoveries since 2000 have led to an operating mine.

Lack of investment in exploration is driven by short-term thinking, rather than a long-term plan to supply rising demand.

In parallel, resistance to mining, often at a local level, is increasing worldwide. Environmental catastrophes, of which there have been many examples, erode social trust, often delaying or stopping mine development.

A new global mechanism to more effectively plan resource supply could help rebuild trust in local communities, limit price spikes to ensure equitable access to metal resources, and balance the international tension which arises as industries and governments compete for minerals from a shrinking list of countries able to tolerate and profit from sustaining a mining industry.

A global agreement on mineral resources

Developing a global mechanism will of course be difficult, requiring substantive dialogue and strong leadership. But there are organisations that could step up, such as the United Nations Environment Assembly, or the newly established Intergovernmental Forum on Mining Metals and Sustainable Development.

The global community is well aware of the threat that rising sea levels pose to low-lying countries. We need similar awareness of the crucial role minerals are playing in the energy transition, and the risk that supply problems could derail sustainability goals.

To that end, we need to globally coordinate several crucial aspects of mineral development. To start with, while most detailed information on where minerals are mined and sold is privately held, there is publicly available data that could be used to predict possible imbalances in supply and demand internationally (for example copper, iron, lithium, indium). Publicly-funded institutions have an important role here. They can assess how known supply will meet future demand, and deliver insight into the changing environmental impact.

It should also be entirely possible to develop inventories of recyclable metals, which can be an important supplement to large mining operations.

Compiling inventories of recyclable metals is underway across Europe as part of a move towards a circular economy (where as much waste as possible is repurposed).


Read more: Explainer: what is the circular economy


While recycling for for metals like lithium for less than 1%, around 40% of steel demand is met from scrap recycled during manufacturing and from end-of-life products and infrastructure. Thinking smarter about eventual dismantling of buildings at the time when they are built, can support better use of recycled resources.

Geoscience agencies already offer maps of underground minerals, demonstrating that this kind of co-ordinated perspective is feasible. Extending this approach to recyclables can mitigate environmental impact and ease the social objections to new mines.

A global mechanism for mineral exploration and supply could also be an opportunity to promote best-practice for responsible mining, with a focus on social license and fair and transparent royalty arrangements.

Overcoming resistance

It’s a challenging proposition, especially as many countries display less enthusiasm for international agreements. However, it will be increasingly difficult to meet the Paris targets without tackling this problem.

In the decades ahead, our mineral supply will still need to double or triple to meet the demand for electric vehicles and other technologies required by our growing global population.

In short, resource efficiency and jobs of the future depend on an assured mineral supply. This should be a nonpartisan issue, across the global political spectrum.


The ConversationThe authors gratefully acknowledge the contribution of Edmund Nickless, Chair, New Activities Strategic Implementation Committee, International Union of Geological Sciences to this article.

Damien Giurco, Professor of Resource Futures, University of Technology Sydney; Nicholas Arndt, Professor of Geosciences, Université Grenoble Alpes, and Saleem H. Ali, Distinguished Professor of Energy and the Environment, University of Delaware (USA); Professorial Research Fellow, The University of Queensland

This article was originally published on The Conversation. Read the original article.

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Australia emits mercury at double the global average


Robyn Schofield, University of Melbourne

A report released this week by advocacy group Environmental Justice Australia presents a confronting analysis of toxic emissions from Australia’s coal-fired power plants.

The report, which investigated pollutants including fine particles, nitrogen oxides and sulfur dioxide, also highlights our deeply inadequate mercury emissions regulations. In New South Wales the mercury emissions limit is 666 times the US limits, and in Victoria there is no specific mercury limit at all.

This is particularly timely, given that yesterday the Minamata Convention, a United Nations treaty limiting the production and use of mercury, entered into force. Coal-fired power stations and some metal manufacturing are major sources of mercury in our atmosphere, and Australia’s per capita mercury emissions are roughly double the global average.


Read more: Why won’t Australia ratify an international deal to cut mercury pollution?


In fact, Australia is the world’s sixteenth-largest emitter of mercury, and while our government has signed the Minamata convention it has yet to ratify it. According to a 2016 draft impact statement from the Department of Environment and Energy:

Australia’s mercury pollution occurs despite existing regulatory controls, partly because State and Territory laws limit the concentration of mercury in emissions to air […] but there are few incentives to reduce the absolute level of current emissions and releases over time.

Mercury can also enter the atmosphere when biomass is burned (either naturally or by people), but electricity generation and non-ferrous (without iron) metal manufacturing are the major sources of mercury to air in Australia. Electricity generation accounted for 2.8 tonnes of the roughly 18 tonnes emitted in 2015-16.

Mercury in the food web

Mercury is a global pollutant: no matter where it’s emitted, it spreads easily around the world through the atmosphere. In its vaporised form, mercury is largely inert, although inhaling large quantities carries serious health risks. But the health problems really start when mercury enters the food web.

I’ve been involved in research that investigates how mercury moves from the air into the food web of the Southern Ocean. The key is Antartica’s sea ice. Sea salt contains bromine, which builds up on the ice over winter. In spring, when the sun returns, large amounts of bromine is released to the atmosphere and causes dramatically named “bromine explosion events”.

Essentially, very reactive bromine oxide is formed, which then reacts with the elemental mercury in the air. The mercury is then deposited onto the sea ice and ocean, where microbes interact with it, returning some to the atmosphere and methylating the rest.

Once mercury is methylated it can bioaccumulate, and moves up the food chain to apex predators such as tuna – and thence to humans.

As noted by the Australian government in its final impact statement for the Minamata Convention:

Mercury can cause a range of adverse health impacts which include; cognitive impairment (mild mental retardation), permanent damage to the central nervous system, kidney and heart disease, infertility, and respiratory, digestive and immune problems. It is strongly advised that pregnant women, infants, and children in particular avoid exposure.


Read more: Climate change set to increase air pollution deaths by hundreds of thousands


Australia must do better

A major 2009 study estimated that reducing global mercury emissions would carry an economic benefit of between US$1.8 billion and US$2.22 billion (in 2005 dollars). Since then, the US, the European Union and China have begun using the best available technology to reduce their mercury emissions, but Australia remains far behind.

But it doesn’t have to be. Methods like sulfur scrubbing, which remove fine particles and sulfur dioxide, also can capture mercury. Simply limiting sulfur pollutants of our power stations can dramatically reduce mercury levels.

Ratifying the Minamata Convention will mean the federal government must create a plan to reduce our mercury emissions, with significant health and economic benefits. And because mercury travels around the world, action from Australia wouldn’t just help our region: it would be for the global good.


The ConversationIn an earlier version of this article the standfirst referenced a 2006 study stating Australia is the fifth largest global emitter of mercury. Australia is now 16th globally.

Robyn Schofield, Senior Lecturer for Climate System Science and Director of Environmental Science Hub, University of Melbourne

This article was originally published on The Conversation. Read the original article.

Solar is now the most popular form of new electricity generation worldwide


Andrew Blakers, Australian National University

Solar has become the world’s favourite new type of electricity generation, according to global data showing that more solar photovoltaic (PV) capacity is being installed than any other generation technology.

Worldwide, some 73 gigawatts of net new solar PV capacity was installed in 2016. Wind energy came in second place (55GW), with coal relegated to third (52GW), followed by gas (37GW) and hydro (28GW).

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Together, PV and wind represent 5.5% of current energy generation (as at the end of 2016), but crucially they constituted almost half of all net new generation capacity installed worldwide during last year.

It is probable that construction of new coal power stations will decline, possibly quite rapidly, because PV and wind are now cost-competitive almost everywhere.

Hydro is still important in developing countries that still have rivers to dam. Meanwhile, other low-emission technologies such as nuclear, bio-energy, solar thermal and geothermal have small market shares.

PV and wind now have such large advantages in terms of cost, production scale and supply chains that it is difficult to see any other low-emissions technology challenging them within the next decade or so.

That is certainly the case in Australia, where PV and wind comprise virtually all new generation capacity, and where solar PV capacity is set to reach 12GW by 2020. Wind and solar PV are being installed at a combined rate of about 3GW per year, driven largely by the federal government’s Renewable Energy Target (RET).

This is double to triple the rate of recent years, and a welcome return to growth after several years of subdued activity due to political uncertainty over the RET.

If this rate is maintained, then by 2030 more than half of Australian electricity will come from renewable energy and Australia will have met its pledge under the Paris climate agreement purely through emissions savings within the electricity industry.

To take the idea further, if Australia were to double the current combined PV and wind installation rate to 6GW per year, it would reach 100% renewable electricity in about 2033. Modelling by my research group suggests that this would not be difficult, given that these technologies are now cheaper than electricity from new-build coal and gas.

Renewable future in reach

The prescription for an affordable, stable and achievable 100% renewable electricity grid is relatively straightforward:

  1. Use mainly PV and wind. These technologies are cheaper than other low-emission technologies, and Australia has plenty of sunshine and wind, which is why these technologies have already been widely deployed. This means that, compared with other renewables, they have more reliable price projections, and avoid the need for heroic assumptions about the success of more speculative clean energy options.

  2. Distribute generation over a very large area. Spreading wind and PV facilities over wide areas – say a million square kilometres from north Queensland to Tasmania – allows access to a wide range of different weather, and also helps to smooth out peaks in users’ demand.

  3. Build interconnectors. Link up the wide-ranging network of PV and wind with high-voltage power lines of the type already used to move electricity between states.

  4. Add storage. Storage can help match up energy generation with demand patterns. The cheapest option is pumped hydro energy storage (PHES), with support from batteries and demand management.

Australia currently has three PHES systems – Tumut 3, Kangaroo Valley, and Wivenhoe – all of which are on rivers. But there is a vast number of potential off-river sites.

Potential sites for pumped hydro storage in Queensland, alongside development sites for solar PV (yellow) and wind energy (green). Galilee Basin coal prospects are shown in black.
Andrew Blakers/Margaret Blakers, Author provided

In a project funded by the Australian Renewable Energy Agency, we have identified about 5,000 sites in South Australia, Queensland, Tasmania, the Canberra district, and the Alice Springs district that are potentially suitable for pumped hydro storage.

Each of these sites has between 7 and 1,000 times the storage potential of the Tesla battery currently being installed to support the South Australian grid. What’s more, pumped hydro has a lifetime of 50 years, compared with 8-15 years for batteries.

Importantly, most of the prospective PHES sites are located near where people live and where new PV and wind farms are being constructed.

Once the search for sites in New South Wales, Victoria and Western Australia is complete, we expect to uncover 70-100 times more PHES energy storage potential than required to support a 100% renewable electricity grid in Australia.

Potential PHES upper reservoir sites east of Port Augusta, South Australia. The lower reservoirs would be at the western foot of the hills (bottom of the image).
Google Earth/ANU

Managing the grid

Fossil fuel generators currently provide another service to the grid, besides just generating electricity. They help to balance supply and demand, on timescales down to seconds, through the “inertial energy” stored in their heavy spinning generators.

But in the future this service can be performed by similar generators used in pumped hydro systems. And supply and demand can also be matched with the help of fast-response batteries, demand management, and “synthetic inertia” from PV and wind farms.

Wind and PV are delivering ever tougher competition for gas throughout the energy market. The price of large-scale wind and PV in 2016 was A$65-78 per megawatt hour. This is below the current wholesale price of electricity in the National Electricity Market.

Abundant anecdotal evidence suggests that wind and PV energy price has fallen to A$60-70 per MWh this year as the industry takes off. Prices are likely to dip below A$50 per MWh within a few years, to match current international benchmark prices. Thus, the net cost of moving to a 100% renewable electricity system over the next 15 years is zero compared with continuing to build and maintain facilities for the current fossil-fuelled system.

Gas can no longer compete with wind and PV for delivery of electricity. Electric heat pumps are driving gas out of water and space heating. Even for delivery of high-temperature heat for industry, gas must cost less than A$10 per gigajoule to compete with electric furnaces powered by wind and PV power costing A$50 per MWh.

Importantly, the more that low-cost PV and wind is deployed in the current high-cost electricity environment, the more they will reduce prices.

Then there is the issue of other types of energy use besides electricity – such as transport, heating, and industry. The cheapest way to make these energy sources green is to electrify virtually everything, and then plug them into an electricity grid powered by renewables.

A 55% reduction in Australian greenhouse gas emissions can be achieved by conversion of the electricity grid to renewables, together with mass adoption of electric vehicles for land transport and electric heat pumps for heating and cooling. Beyond this, we can develop renewable electric-driven pathways to manufacture hydrocarbon-based fuels and chemicals, primarily through electrolysis of water to obtain hydrogen and carbon capture from the atmosphere, to achieve an 83% reduction in emissions (with the residual 17% of emissions coming mainly from agriculture and land clearing).

Doing all of this would mean tripling the amount of electricity we produce, according to my research group’s preliminary estimate.

The ConversationBut there is no shortage of solar and wind energy to achieve this, and prices are rapidly falling. We can build a clean energy future at modest cost if we want to.

Andrew Blakers, Professor of Engineering, Australian National University

This article was originally published on The Conversation. Read the original article.

How trade policies can support global efforts to curb climate change


File 20170726 23211 sgmupo
Eliminating trade barriers on green technologies could help countries to shift away from fossil fuels.
from www.shutterstock.com, CC BY-ND

Adrian Henry Macey, Victoria University of Wellington

Climate change will have a big impact on the global economy as nations seek to adapt to a warmer world and adopt policies to keep global warming below two degrees. In the wake of the US withdrawal from the Paris Agreement, it is important that policies around trade and investment support national efforts to adapt to global warming while trying to curb it. Four issues stand out:

1. Border tax adjustments

Border tax adjustments, or BTAs, refer to import taxes on goods from countries where companies do not have to pay for their emissions.

This is highly controversial and problematic for practical reasons and difficult to reconcile with World Trade Organisation (WTO) compliance requirements. The arguments in favour rest on punishing free riders and protecting the competitiveness of national firms subject to climate change costs in their home country. Such taxes are also held up as a way of avoiding “carbon leakage” caused by production shifting to countries with more lax climate change policies.

The latter two arguments are similar to those that have been applied in the past to environmental protection regulations. The problem with them is that there is very poor empirical evidence for either competitiveness risk or for carbon leakage.
They also rest on the assumption that combating climate change is always a net cost. This is being increasingly challenged.

The argument against BTAs centres on the potential of unilateral measures being used to coerce developing countries. The sensitivity of such measures is shown by the fact that, until very late in the negotiations of the Paris Agreement, developing countries insisted on including the following clause.

“Developed country parties shall not resort to any form of unilateral measures against goods and services from developing country parties on any grounds related to climate change.”

2. Trade liberalisation in climate-friendly goods and services

Eliminating trade barriers on solar panels and other green technologies could help countries to shift away from fossil fuels. This is fully within the scope of the WTO and indeed the mandate of the current Doha trade round. There are several work streams within the WTO covering this area, though progress is slow.

3.International carbon trading and offsets

The Kyoto Protocol includes several mechanisms (Clean Development Mechanism, Joint Implementation and Emissions Trading) that can be used by countries that have tabled a 2020 target (European countries and Australia).

International market mechanisms beyond 2020 have not yet been created under the Paris Agreement but its Article 6 foresees them. Such mechanisms are being developed bottom-up by groups of countries, which can make much faster progress than is possible within the United Nations Framework Convention on Climate Change (UNFCCC).

However, any new mechanisms are likely to be linked in some way to the UNFCCC. There is no coverage of carbon trading under the WTO at present and there appears to be no appetite for bringing it within WTO disciplines.

4. Compatibility of climate measures and trade rules

One fear is that WTO rules will have a chilling effect on climate change measures such as subsidies, technical regulations or bans on certain products. However, Article 3.5 of the UNFCCC (which applies to the Paris Agreement as it does to the earlier Kyoto Protocol) is clear.

It uses WTO language to state that “measures taken to combat climate change, including unilateral ones, should not constitute a means of arbitrary or unjustifiable discrimination or a disguised restriction on international trade”. The UNFCCC, like the WTO, acknowledges the legitimate purpose of climate measures, including that they may involve restrictions on trade.

There is ample and growing WTO jurisprudence on measures taken for environmental purposes which confirms their legitimacy in WTO law. The jurisprudence is not static; it evolves with international thinking as expressed in treaties and less formal agreements.

Helpfully the WTO Treaty (1994) included an objective relating to protection and preservation of the environment that went further than the earlier General Agreement on Tariffs and Trade (GATT). This provision has already been used in interpretation by the highest WTO jurisdiction, the Appellate Body.

Conclusions

I expect that some carbon markets will develop amongst carbon clubs. Trading rules will be determined by those countries involved and will rest on the environmental integrity of the units traded.

Border tax adjustments (BTAs) are problematic. Some commentators have predicted a climate change trade war, arguing that countries are vulnerable if their climate measures are seen as inadequate.

This is now an improbable scenario. Any attempt to impose BTAs against countries which have signed up to the Paris Agreement would face enormous practical difficulties. It would also risk undoing the international consensus.

Transparency, peer review and naming and shaming of countries with inadequate pledges (Nationally Determined Contribution or NDCs), or countries that fail to implement an adequate one, may prove more effective than any of these unilateral measures. Evidence from the climate change negotiations is that countries do care about their reputation.

A further resource to encourage countries to act would be carbon clubs, where countries wanting to accelerate their transition to a low-carbon economy would link their climate measures through a common carbon price via their emissions trading schemes.

The threat of BTAs – clearly foreseen by major American companies after the Trump Administration’s decision to leave the Paris Agreement – may be a useful political lever to gain cooperation. But there are other ways of achieving similar ends.

The ConversationOne example is to require all goods, domestic or imported, to meet sustainability standards. This is potentially allowable under the WTO Technical Barriers to Trade agreement (TBT) as a type of processing and production method. But even if not, the existence of the Paris Agreement – a universal agreement with clear objectives and requirements on all parties to act on climate change – would be a useful reference in any dispute settlement proceedings.

Adrian Henry Macey, Senior Associate, Institute for Governance and Policy Studies; Adjunct Professor, New Zealand Climate Change Research Institute. , Victoria University of Wellington

This article was originally published on The Conversation. Read the original article.

Australia can’t lose in the global race for cheaper, cleaner energy


Paul Graham, CSIRO

Despite our sometimes heated national debate about our energy future, Australia is well positioned to benefit from innovative low emission technologies. No matter which avenue we take to cleaner energy, our energy-rich resources means there are opportunities for Australian businesses – and cheaper energy for Australian consumers.

That’s the conclusion reached by CSIRO in our Low Emissions Technology Roadmap, which outlines potential pathways for the energy sector to contribute to Australia’s emissions reduction target.

Our target under the Paris climate agreement calls for a 26-28% reduction of emissions by 2030 from 2005 levels. Our analysis also considers how the energy sector could meet the more ambitious aspiration of avoiding 1.5-2℃ global warming.

Looking past the political wrangling

Perhaps one of the reasons the energy debate in Australia is so vehement is that, with the exception of oil, we are rich in energy resources. While we cannot wait indefinitely, the lack of resource constraints means we can monitor and test what options emerge as the most cost effective. Technology neutrality is often called upon as a key policy design principle.

Another reason for caution is that technological change is inherently unpredictable. For example, at the start of this century, few would have expected solar photovoltaics to be one of the lowest cost sources of electricity. Current expectations of sourcing cost-effective bulk electricity storage would have seemed even less likely at the time.

However, there are two key choices that will determine how we reduce greenhouse gases, and the shape of our energy future.

First, we must decide how much weight we give to improving energy productivity, versus decarbonising our energy supply. This is essentially a policy decision: should we use our existing energy more intelligently and efficiently in our buildings, industries and transport, or aggressively pursue new technology?

Whatever strategy we pick, we also need to choose what technology we emphasise: dispatchable power, from flexible and responsive energy generation, or variable renewable energy (from sources like solar, wind and wave), supported with storage.

From these choices four pathways are derived: Energy productivity plus, Variable renewable energy, Dispatchable power and Unconstrained.

There are four broad pathways to cheaper, cleaner energy. (Click to view larger image.)
CSIRO

Our electricity market modelling found the different pathways lead to comparable household electricity bills. High energy productivity scenarios tend to delay generation investment and reduce energy use, leading to slightly lower bills in 2030 (including the cost of high efficiency equipment).

Weighing risk

The main attribute that separates the pathways is the mix of risks they face. We’ve grouped risks into three categories: technology, commercial and market risk, social licence risk and stakeholder coordination risk.

Risks identified with each pathway to cheaper renewable energy. (Click to view larger image.)
CSIRO

Energy productivity plus combines mature existing low emissions technology with gas, so there’s no significant market risk. However there is a social license risk, as many will protest a stronger reliance on expanding gas supplies.

Gas-fired generation is high in this scenario. If improved energy productivity reduces emissions elsewhere, the electricity sector will have less pressure to phase out highly polluting generators.

This scenario would also require a high degree of cooperation between government, companies and customers. We would need to coordinate, to make sure incentives and programs work together to bring down household and business energy use.

Variable renewable energy invites more technical and commercial risk, as our electricity grid will need to be transformed to accept a high level of energy from fluctuating sources like wind. There’s also considerable community concern around the reliability of variable renewables.

While the evolution towards a secure system with very high variable renewable generation has been modelled in detail for the Roadmap, its final costs will remain uncertain until demonstrated at scale. Whether stakeholders will have the appetite to demonstrate such a system (with some risk to supply security and electricity prices) represents a coordination risk for this pathway.

Dispatchable power is perhaps the most risky option. Solar thermal, geothermal, carbon capture and storage and nuclear power are all relatively new to Australia (although other countries have explored them further). Developing them here will mean taking some technological and commercial gambles.

Carbon capture and storage and nuclear power are also deeply unpopular, and there’s a risk of dividing community consensus even further.

While solar thermal – and potentially nuclear power – could be deployed as small modules, in general the technologies in this category require high up-front capital investment. These projects may need strong government guarantees to achieve financing.

Unconstrained would mean both improving energy productivity and investing in a wide range of generation options: solar, efficient fossil fuels and carbon capture and storage.

Unfortunately there is no objective way of weighing the risks of one pathway against another. However, we can narrow risks over time through research, development and demonstration.

Between now and 2030 we are likely to rely on a narrow set of mature technologies to reduce greenhouse gases: solar photovoltaics, wind, natural gas and storage.

The ConversationAs the world, and Australia’s, greenhouse gas reduction targets ramp up after 2030, we’ll be well positioned to adapt, with the capacity to incorporate a broader range of options.

Paul Graham, Chief economist, CSIRO energy, CSIRO

This article was originally published on The Conversation. Read the original article.

As global food demand rises, climate change is hitting our staple crops



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Farmers face falling crop yields and growing food demand.
Shutterstock

Andrew Borrell, The University of Queensland

Climate change and extreme weather events are already impacting our food, from meat and vegetables, right through to wine. In our series on the Climate and Food, we’re looking at what this means for the food chain. The Conversation


While increases in population and wealth will lift global demand for food by up to 70% by 2050, agriculture is already feeling the effects of climate change. This is expected to continue in coming decades.

Scientists and farmers will need to act on multiple fronts to counter falling crop yields and feed more people. As with previous agricultural revolutions, we need a new set of plant characteristics to meet the challenge.

When it comes to the staple crops – wheat, rice, maize, soybean, barley and sorghum – research has found changes in rainfall and temperature explain about 30% of the yearly variation in agricultural yields. All six crops responded negatively to increasing temperatures – most likely associated with increases in crop development rates and water stress. In particular, wheat, maize and barley show a negative response to increased temperatures. But, overall, rainfall trends had only minor effects on crop yields in these studies.

Since 1950, average global temperatures have risen by roughly 0.13°C per decade. An even faster rate of roughly 0.2°C of warming per decade is expected over the next few decades.

As temperatures rise, rainfall patterns change. Increased heat also leads to greater evaporation and surface drying, which further intensifies and prolongs droughts.

A warmer atmosphere can also hold more water – about 7% more water vapour for every 1°C increase in temperature. This ultimately results in storms with more intense rainfall. A review of rainfall patterns shows changes in the amount of rainfall everywhere.

Maize yields are predicted to decline with climate change.
Shutterstock

Falling yields

Crop yields around Australia have been hard hit by recent weather. Last year, for instance, the outlook for mungbeans was excellent. But the hot, dry weather has hurt growers. The extreme conditions have reduced average yields from an expected 1-1.5 tonnes per hectare to just 0.1-0.5 tonnes per hectare.

Sorghum and cotton crops fared little better, due to depleted soil water, lack of in-crop rainfall, and extreme heat. Fruit and vegetables, from strawberries to lettuce, were also hit hard.

But the story is larger than this. Globally, production of maize and wheat between 1980 and 2008 was 3.8% and 5.5% below what we would have expected without temperature increases. One model, which combines historical crop production and weather data, projects significant reductions in production of several key African crops. For maize, the predicted decline is as much as 22% by 2050.

Feeding more people in these changing conditions is the challenge before us. It will require crops that are highly adapted to dry and hot environments. The so-called “Green Revolution” of the 1960s and 1970s created plants with short stature and enhanced responsiveness to nitrogen fertilizer.

Now, a new set of plant characteristics is needed to further increase crop yield, by making plants resilient to the challenges of a water-scarce planet.

Developing resilient crops for a highly variable climate

Resilient crops will require significant research and action on multiple fronts – to create adaptation to drought and waterlogging, and tolerance to cold, heat and salinity. Whatever we do, we also need to factor in that agriculture contributes significantly to greenhouse gas emissions (GHGs).

Scientists are meeting this challenge by creating a framework for adapting to climate change. We are identifying favourable combinations of crop varieties (genotypes) and management practices (agronomy) to work together in a complex system.

We can mitigate the effects of some climate variations with good management practices. For example, to tackle drought, we can alter planting dates, fertilizer, irrigation, row spacing, population and cropping systems.

Genotypic solutions can bolster this approach. The challenge is to identify favourable combinations of genotypes (G) and management (M) practices in a variable environment (E). Understanding the interaction between genotypes, management and the environment (GxMxE) is critical to improving grain yield under hot and dry conditions.

Genetic and management solutions can be used to develop climate-resilient crops for highly variable environments in Australia and globally. Sorghum is a great example. It is the dietary staple for over 500 million people in more than 30 countries, making it the world’s fifth-most-important crop for human consumption after rice, wheat, maize and potatoes.

‘Stay-green’ in sorghum is an example of a genetic solution to drought that has been deployed in Australia, India and sub-Saharan Africa. Crops with stay-green maintain greener stems and leaves during drought, resulting in increased stem strength, grain size and yield. This genetic solution can be combined with a management solution (e.g. reduced plant population) to optimise production and food security in highly variable and water-limited environments.

Other projects in India have found that alternate wetting and drying (AWD) irrigation in rice, compared with normal flooded production, can reduce water use by about 32%. And, by maintaining an aerobic environment in the soil, it reduces methane emissions five-fold.

Climate change, water, agriculture and food security form a critical nexus for the 21st century. We need to create and implement practices that will increase yields, while overcoming changing conditions and limiting the emissions from the agricultural sector. There is no room for complacency here.

Andrew Borrell, Associate Professor, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland; Centre Leader, Hermitage Research Facility; College of Experts, Global Change Institute, The University of Queensland

This article was originally published on The Conversation. Read the original article.