How to neutralise your greenhouse gas footprint


Andrew Blakers, Australian National University

With time running out for us to make deep reductions in greenhouse emissions, you may well be wondering what you personally can do to minimise your own greenhouse footprint.

The average greenhouse emissions per Australian are the equivalent of 21 tonnes of carbon dioxide per year. How can you offset or neutralise your personal share of these carbon emissions in the most cost-effective way?




Read more:
We can be a carbon-neutral nation by 2050, if we just get on with it


There are some places where the government is willing to take the necessary action on your behalf. The ACT government, for example, is on track to eliminate greenhouse gas emissions generated within Canberra by 2045, and indeed by 2020 will make its own electricity sector carbon-neutral.

The latter feat was achieved by contracting several new zero-emission solar and wind farms to produce renewable electricity equivalent to Canberra’s consumption. Canberra retail electricity prices continue to be among the lowest in Australia.

Take advantage of solar and wind

If you don’t live in Canberra, you need another way to neutralise your emissions. Fortunately, the cost of solar photovoltaic (PV) and wind power have both fallen rapidly. Australia has long been in the midst of a boom in rooftop PV, and many Gigawatts of ground-mounted PV and wind farms are being built around the country. This has put Australia on track to reach 50% renewable electricity in 2024. Each Megawatt hour (MWh) of electricity generated by renewables reduces electricity from coal by a similar amount, and therefore avoids about 0.9 tonnes of carbon dioxide emissions.

https://datawrapper.dwcdn.net/7Gd1z/2/

The above pie chart, based on federal government data, shows the various sources of Australian greenhouse emissions in 2017. Electricity production is the largest source and can be neutralised by substituting PV and wind for coal and gas. Emissions from electricity use in commerce and industry, the land sector, industrial processes and high temperature heat is largely beyond your control, however, so it’s perhaps best to focus your attention closer to home.

Cost-effective action

However, putting solar panels on your roof, switching to an electric car, and substituting electric heat pumps for gas water and space heating can (or soon will) be cost-effective steps that you can take to reduce your greenhouse footprint. And in the long term, these will either pay for themselves or even end up saving you money.




Read more:
‘Renewable energy breeding’ can stop Australia blowing the carbon budget – if we’re quick


A 10-kilowatt solar PV system installed on your roof will produce about 14 MWh of electricity per year. Since coal power stations produce 0.9 tonnes of carbon dioxide per MWh this save about 12 tonnes of CO2 emissions per year.

To offset your 21 tonnes of CO2 per year, you would therefore need to install 15kW of solar PV capacity for each person who lives in your house. So if four people live in your house, you would need a 60kW solar system.

But a typical rooftop PV system now has a rating of 5-15kW, and many homes lack the roof space needed to install a larger system. Ways to address this are described below.

Road to success

A typical car produces about 190 grams of CO2 per kilometre of travel, and the average Australian car travels 15,500 km per year, thus producing 3 tonnes of CO2.

Moderately priced electric cars are expected to be widely available in the early 2020s, which can travel about 6,000 km for each MWh of electricity consumed.

Once the premium for an electric vehicle drops below about A$10,000, the lifetime cost of an electric car (including buying, maintaining and charging it) will be competitive with conventional cars.

A 2kW PV panel on your house roof will produce enough electricity for 16,000km of electric car driving per year, thus offsetting your entire emissions from motoring (3 tonnes of CO2), assuming you drive an average amount each year and previously drove a conventional model.

Off the gas

Most natural gas use within a home is for water and space heating. Gas can readily be replaced by electric heat pumps, which move heat from the air outside the home into your hot water tank or reverse cycle air conditioning system. Heat pumps typically move four units of heat for each unit of electricity consumed and can be readily powered by rooftop solar panels, supplemented by electricity from the grid.

For the average household, replacement gas with heat pumps can readily reduce household greenhouse gas emissions by up to 5 tonnes per year, at lower lifecycle cost than using gas. Replacement of gas cookers with electric induction cookers allows elimination of gas altogether from the home.

Fly less

Limiting air travel is one of the most effective tactics to cut your personal emissions. Short-haul flights or flights with few passengers increase the emissions intensity per passenger. A mostly full return trip from Australia to London (34,000km) will typically generate about 4 tonnes of CO₂ per passenger.

When you do decide to fly, think about how you can offset the emissions directly. Adding 1kW to your rooftop PV system can offset one return trip to London for one person every 3 years.




Read more:
Why our carbon emission policies don’t work on air travel


Will it pay for itself?

Now that we’ve looked at these various strategies, let’s now consider a family home with three occupants and one car. A 10kW PV system on the roof can make a substantial reduction in their greenhouse footprint by offsetting 14 tonnes of CO2 per year. Switching to an electric car saves 3 tonnes per year and substituting electric heat pumps for gas saves a further 1- 5 tonnes per year.

An additional 5 kW of rooftop PV is needed to neutralise an average amount of air travel, and to power the electric car and heat pumps. This 15kW system would cost about A$20,000 up front and would last 25 years. However, rooftop PV systems are now so cheap compared with the retail electricity tariff that the money invested is generally recovered within 10 years.

The total emissions savings estimated above are about 25 tonnes per year, per household, which is still significantly short of the 63 tonnes (on average) that this family emits. To be fully carbon-neutral, one option is for the family to invest in a wind or solar farm.

The required share of a wind farm or solar farm is about 10 kW or 20 kW respectively per three-person family, noting that a 3MW wind turbine produces nearly double the amount of electricity per year of a 3MW PV farm (single axis tracking), which in turn produces 40% more electricity per year than an equivalent amount of roof-mounted solar panels.

The up-front cost of this investment would be about A$25,000 per family, and it would return a steady income sufficient to repay the initial outlay (with interest) over the 25-year lifetime of the system.

So in summary, assuming that you have the means to meet the (not insubstantial) upfront costs, doing your part to preserve a living and vibrant planet for our children ultimately has a low or even negative net cost.The Conversation

Andrew Blakers, Professor of Engineering, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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For the first time, we can measure the human footprint on Antarctica



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The Casey Station is part of Australia’s permanent outpost in Antarctica.
Shaun Brooks, Author provided

Shaun Brooks, University of Tasmania and Julia Jabour, University of Tasmania

Most people picture Antarctica as a frozen continent of wilderness, but people have been living – and building – there for decades. Now, for the first time, we can reveal the human footprint across the entire continent.

Our research, published today in the journal Nature Sustainability, found that while buildings and disturbance cover a small portion of the whole continent, it has an outsized impact on Antartica’s ecosystem.




Read more:
Explainer: what any country can and can’t do in Antarctica, in the name of science


Our data show 76% of buildings in Antarctica are within just 0.06% of the continent: the ice-free areas within 5km of the coast. This coastal fringe is particularly important as it provides access to the Southern Ocean for penguins and seals, as well as providing a typically wetter climate suitable for plant life.

A hard question to answer

How much land we collectively impact with infrastructure in Antarctica has been a question raised for decades, but until now has been difficult to answer. The good news is it’s a relatively small area. The bigger issue is where it is. Together with our colleagues Dana Bergstrom and John van den Hoff, we have made the first measurement of the “footprint” of buildings and disturbed ice-free ground across Antarctica.

This equates to more than 390,000 square metres of buildings on the icy continent, with a further 5,200,000m² of disturbance just to ice-free land. To put it another way, there is more than 1,100m² of disturbed ground per person in Antarctica at its most populated in summer. This is caused primarily by the 30 nations with infrastructure in Antarctica, along with some presence from the tourism industry.

Figure Building footprint density.
Nature Sustainability

It has taken until now to find the extent of our impact because of difficulty in gathering the data. Because so many countries are active in Antarctica, getting them to provide data on their infrastructure has been very slow. As two-thirds of research stations were built before the adoption of the Protocol on Environmental Protection to the Antarctic Treaty, they did not require environmental impact assessments or monitoring, so it is quite likely many of the operators do not have accessible data on their footprints. In addition, due to the inherent difficulty in accessing Antarctica, and the vast distances between each station, it is not possible to conduct field measurements on a continental scale.

To address these problems, our team took an established approach to measuring a single station’s footprint, and applied it to 158 locations across the continent using satellite imagery. The majority of images used were freely sourced from Google Earth, enabled by continually increasing improvements in resolution and coverage.

This process took hours of painstaking “digitisation” – where the spatially accurate images of buildings and disturbed ground were manually mapped within a computer program to create the data.

Davis Station, one of Australia’s three permanent research outposts in Antartica. Researchers used Google Earth images to map the footprint of human infrastructure across the continent.
Shaun Brooks, Author provided

Interestingly, one of the most difficult sites was the United States’ Amundsen-Scott Station. As this station is located on the geographic South Pole, very few satellites pass overhead. This problem was eventually solved by trawling through thousands of aerial images produced by NASA’s Operation IceBridge, where we found their aircraft had flown over the station in 2010. After capturing these data, we then compared our measurements against existing known building sizes and found our accuracy was within 2%.

Unlike buildings, we didn’t have measurements to compare for disturbed ground such as roadways, airstrips, quarries and the like. We believe we have produced a significant underestimate, due to factors including snow cover and insufficient image resolution obscuring smaller features such as walking tracks.




Read more:
Antarctic seas host a surprising mix of lifeforms – and now we can map them


Location, location, location

After mapping the footprint of buildings and ground disturbance our data has yielded some interesting results. For practical reasons, most stations in Antarctica are located within the small ice-free areas spread across the continent, particularly around the coast. In addition to being attractive to us, these areas are essential for much of Antarctica’s biodiversity by providing nesting sites for seabirds and penguins, substrate for mosses, lichens, and two vascular plants, and habitat for the continent’s invertebrate species.

Adelie penguins need ice-free areas to access the ocean.
Shaun Brooks, Author provided

Another interesting finding from these data is what they tell us about wilderness on the continent. Although the current footprint covers a very small fraction of the more than 12 million square kilometres of Antarctica, we found disturbance is present in more than half of all large ice-free areas along the coast. Furthermore, by using the building data we captured, along with existing work by Rupert Summerson, we were also able to estimate the visual footprint, which amounts to an area similar in size to the total ice-free land across the whole continent.

The release of this research is timely, with significant increases in infrastructure proposed for Antarctica. Currently there are new stations proposed by several nations, major rebuilding projects of existing stations underway (including the US’s McMurdo and New Zealand’s Scott Base), and Italy is building a new runway in ice-free areas.

Australia has proposed Antarctica’s first concrete runway, which if built would be the continent’s largest.




Read more:
Why Antarctica’s sea ice cover is so low (and no, it’s not just about climate change)


Until now, decisions on expanding infrastructure have been without the context of how much is already present. We hope informed decisions can now be made by the international community about how much building in Antarctica is appropriate, where it should occur, and how to manage the future of the last great wilderness.The Conversation

Shaun Brooks, PhD Candidate, University of Tasmania and Julia Jabour, Leader, Ocean and Antarctic Governance Research Program, University of Tasmania

This article is republished from The Conversation under a Creative Commons license. Read the original article.

You’ve heard of a carbon footprint – now it’s time to take steps to cut your nitrogen footprint



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Transport and livestock are both significant contributors to nitrogen pollution.
Annalucia/Shutterstock.com

Ee Ling Ng, University of Melbourne; Deli Chen, University of Melbourne, and Xia Liang, University of Melbourne

Nitrogen pollution has significant environmental and human health costs. Yet it is often conflated with other environmental problems, such as climate change, which is exacerbated by nitrous oxide (N₂O) and nitrogen oxides (NOₓ), or particulate smog, to which ammonia (NH₃) also contributes.

One way to understand our nitrogen use is to look at our nitrogen footprint. This is the amount of reactive nitrogen, which is all forms of nitrogen other than inert nitrogen gas, released into the environment from our daily activities that consume resources including food and energy.




Read more:
Nitrogen pollution: the forgotten element of climate change


Our earlier research showed that Australia has a large nitrogen footprint. At up to 47kg of nitrogen per person each year, Australia is far ahead of the US (28kg per person), the second on the leaderboard of per capita reactive nitrogen emissions. Australians’ large nitrogen footprints are created largely by a diet rich in animal protein and high levels of coal use for energy.

The nitrogen footprint

Our new research, published in the Journal of Cleaner Production, takes this concept further by measuring the nitrogen footprint of an entire institution, in this case the University of Melbourne.

The institutional nitrogen footprint is the sum of individual activities at the workplace and institutional activities, such as powering laboratories and lecture theatres in the case of a university.

We calculated that the university’s annual nitrogen footprint is 139 tonnes of nitrogen. It is mainly attributable to three factors: food (37%), energy use (32%) and transport (28%).

The University of Melbourne’s nitrogen footprint in 2015 and projections for 2020.

At the university, food plays a dominant role through the meat and dairy consumed. Nitrogen emissions from food occur mainly during its production, whereas emissions from energy use come mainly from coal-powered electricity use and from fuel used during business travel.

Cutting nitrogen

We also modelled the steps that the university could take to reduce its nitrogen footprint. We found that it could be reduced by 60% by taking action to cut emissions from the three main contributing factors: food, energy use, and travel.

The good news is if the university implements all the changes to energy use detailed in its Sustainability Plan – which includes strategies such as adopting clean energy (solar and wind), optimising energy use and buying carbon credits – this would also reduce nitrogen pollution by as much as 29%.

Changing habits of air travel and food choices would be a challenge, as this requires altering the behaviour of people from a culture that places tremendous value on travelling and a love for coffee and meat.

Generally, Australians fly a lot compared to the rest of the world, at significant cost to the environment. We could offset the travel, and we do take that possibility into account, but as others have written before us, we should not make the mistake of assuming that emissions offsets make air travel “sustainable”.

The question that perhaps need to be asked, for work travel, is “to travel or not to travel?” Let’s face it, why are so many academic conferences set in idyllic locations, if not to entice us to attend?

Animal products are major contributors to nitrogen emissions, given the inefficiency of conversion from the feed to milk or meat. Would people be willing to change their latte, flat white or cappuccino to a long black, espresso or macchiato? Or a soy latte?




Read more:
Nitrogen from rock could fuel more plant growth around the world – but not enough to prevent climate change


As 96% of the nitrogen emissions occur outside the university’s boundaries, their detrimental effects are invisible to the person on the ground, while the burden of the pollution is often borne far away, both in time and space.

The ConversationBut, as our study shows for the first time, large institutions with lots of staff are well placed to take steps to cut their large nitrogen footprint.

Ee Ling Ng, Research fellow, University of Melbourne; Deli Chen, Professor, University of Melbourne, and Xia Liang, PhD candidate, University of Melbourne

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

Five ways hospitals can reduce their environmental footprint



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So many hospital items are used once and then thrown away.
from shutterstock.com

Forbes McGain, University of Sydney

Picture the environmental life cycle of many disposable surgical instruments. Iron ore from Western Australia is shipped to China and smelted, fashioned into stainless steel surgical instruments in Pakistan and exported as single-use instruments. In Australia, clinicians use these instruments once, then discard them.

So much that comes into patient contact is routinely used only once. This includes gowns, surgical drapes and covers for patients, anaesthetic breathing equipment, face masks and bed mats.

On top of this, energy is wasted in hospitals because heating, cooling and devices are left on when not in use. It’s not surprising then to learn that health care produces 7% of Australia’s carbon emissions; hospitals produce about half of this.

Here are five ways Australian hospitals can reduce their environmental footprint and improve their financial bottom line.

1. Employ a sustainability officer and get staff involved

A hospital sustainability officer examines ways to reduce energy use and waste, and encourages staff to participate actively in environmental projects. Although an “upfront cost”, in the absence of a sustainability officer activities known to save money and reduce our environmental footprint won’t occur.

At Melbourne’s Western Health, installing LED lights saved around 1,200 megawatt hours (Mwh) per year. This is similar to disconnecting around 165 Victorian houses from the electricity grid. The installation cost was paid back within two years.

Other sustainable activities included alternatively turning off one of the three hospital gas boilers during lull periods and installing large-scale (300kW) solar panels. These produce around 440 Mwh per year.

Since 2007, institutions that have similar daily energy requirements to 3,000 Australian homes or more have been required to annually report their energy use and greenhouse gas emissions to the federal government’s Clean Energy Regulator. Many medium to large hospitals fall into this range.

There aren’t any mandated requirements to reduce energy use or greenhouse gas emissions, but the reporting allows hospitals to gauge changes over time and strive to improve. In the absence of a hospital sustainability officer, hospitals hire expensive contractors to ensure the reporting requirements are met.

Hospital equipment should be switched off when not in use.
from shutterstock.com

Although some hospital staff are interested in workplace sustainability and want to make a difference, there are many barriers to doing so – both physical and psychological. Local sustainability action plans can be put in place to help staff work together to improve hospital sustainability. Activities can include staff in operating rooms being involved in lighting “switch-offs”, recycling different items and sending unused, out-of-date equipment to less advantaged countries.

2. Reuse surgical equipment where possible

Single-use medical equipment often costs more money than reusable equipment. Studies conducted at Western Health and Yale-New Haven Medical Center in
the US found reusable anaesthetic equipment in operating theatres saved around A$5,000 a year per operating theatre.

The environmental footprint will vary according to the source of electricity. In the above studies, cleaning reusable anaesthetic equipment in Australia resulted in a slightly higher carbon footprint. This is because sterilisers and washers use a lot of electricity, which is derived mainly from coal in Australia. In the US, electricity is sourced from a less carbon-polluting energy mix (more natural gas in particular).

Research in Australia and Germany has shown reusing the standard breathing circuits used by anaesthetists to deliver oxygen and gases to anaesthetised patients does not increase the risk of microbiological contamination. Also, reusing these yearly for a six-theatre operating suite saved around A$5,500 and the equivalent electricity and water savings of one entire Australian household.

3. Recycle better

It is feasible to increase the amount of total recyclable hospital waste from very little to 35%, which saves money even in operating theatres. The most obvious first step to increase recycling rates begins with cardboard and paper products, which surprisingly even now may not be recycled.

It is also important to separate expensive hospital infectious waste from other less expensive, non-infectious waste.

Plastic from IV bags and oxygen tubes could be recycled.
from shutterstock.com

Several plastic types from hospitals can be recycled relatively easily, including PVC plastic. Some manufacturers in Melbourne are working with hospitals to convert PVC plastic from IV bags, face masks and oxygen tubes into agricultural pipes and children’s play equipment. More than 130 hospitals in Australia and New Zealand are involved.

All recycling efforts require collaboration between clinical staff, infection prevention, environmental services and recyclers.

4. Avoid potent anaesthetic greenhouse gases

Anaesthetic gases are hundreds to thousands of times more potent greenhouse gases than CO₂. Desflurane and nitrous oxide are the most problematic, but can be substituted without altering patient care.

These gases do have more rapid anaesthetic onset and offset durations, but other, less environmentally harmful gases can be used just as effectively. Due to familiarity and perhaps drug marketing, desflurane and nitrous oxide remain in common use by anaesthetists.

Several Australian hospitals have saved A$30,000 and hundreds of tonnes of CO₂ annually by substituting desflurane with other anaesthetic gases. Victoria’s health system alone could save hundreds of thousands of dollars a year by such substitution.

5. Advocate and collaborate towards a low-carbon, low-waste system

It’s important to minimise patients’ need for care in a hospital as much as possible. This will involve increasing the role of general practitioners, public health care and disease prevention. We should also avoid unnecessary and potentially harmful tests, such as performing a variety of common blood tests on all pre-operative patients (even those who don’t need them).

The health-care system can’t become low carbon and low waste without leadership, incentives and direction. In 2008 the UK Climate Change Act legislated for an 80% reduction in CO₂ emissions by 2050 and formed the Sustainable Development Unit – a national body charged with reducing health care’s CO₂ emissions. By 2017 there was an 18% increase in UK health-care activity, yet an 11% reduction in CO₂ emissions. Nothing like this exists in Australia.

Australia’s current ad hoc, piecemeal approach by engaged clinicians to improve hospital sustainability and translate this to all hospitals is not working. The federal government, which funds around half of all health care, could promote environmental sustainability by:

The ConversationIt’s time for more sustainable use of health care’s financial, environmental and social resources. Our health depends on it.

Forbes McGain, Associate Professor, University of Sydney

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

The carbon footprint of tourism revealed (it’s bigger than we thought)


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Travel is getting cheaper, but more carbon-intensive.
Renato Podestá Castilho/Flickr, CC BY-SA

Dr Arunima Malik, University of Sydney and Dr Ya-Yen Sun, The University of Queensland

The carbon footprint of tourism is about four times larger than previously thought, according to a world-first study published today in Nature Climate Change.

Researchers from the University of Sydney, University of Queensland and National Cheng Kung University – including ourselves – worked together to assess the entire supply chain of tourism. This includes transportation, accommodation, food and beverages, souvenirs, clothing, cosmetics and other goods.

Put together, global tourism produces about 8% of global greenhouse gas emissions, much more than previous estimates.

Adding it all up

Tourism is a trillion-dollar industry, and is growing faster than international trade.

To determine the true emissions produced by tourism, we scanned over a billion supply chains of a range of commodities consumed by tourists. By combining a detailed international trade database with accounts tracking what goods and services tourists bought, we identified carbon flows between 160 countries from 2009 to 2013.

Our results show that tourism-related emissions increased by around 15% over that period, from 3.9 gigatonnes (Gt) of carbon-dioxide equivalent (CO₂-e) to 4.5Gt. This rise primarily came from tourist spending on transport, shopping and food.

World map showing bilateral embodied carbon movements. In 2013, international travel was responsible for 23% of the global carbon footprint of tourism.
[The carbon footprint of global tourism] (http://dx.doi.org/10.1038/s41558-018-0141-x)

We estimate that our growing appetite for travel and a business-as-usual scenario would increase carbon emissions from global tourism to about 6.5Gt by 2025. This increase is largely driven by rising incomes, making tourism highly income-elastic and carbon-intensive.

Whose responsibility is it?

In the study, we compared two perspectives for allocating responsibility for these emissions: residence-based accounting and destination-based accounting. The former perspective allocates emissions to the country of residence of tourists, the latter to the country of destination. Put simply, are tourism-related carbon emissions the responsibility of travellers or tourist destinations?

If responsibility lies with the travellers, then we should identify the countries that send the most tourists out into the world, and find ways to reduce the carbon footprint of their travel.




Read more:
Can you be a sustainable tourist without giving up flying?


On the other hand, destination-based accounting can offer insights into tourism spots (like popular islands) that would benefit most from technology improvements and regulations for reducing the carbon footprint of tourism.

Tracking emissions under destination-based accounting over a specific period could help researchers and policymakers to answer questions about the success of incentive schemes and regulations, and to assess the speed of decarbonisation of tourism-related sectors.




Read more:
Sustainable shopping: is it possible to fly sustainably?


So how do countries rank under the two accounting perspectives? The United States is responsible for the majority of tourism-related emissions under both perspectives – many people travel both from and to the US – followed by China, Germany and India.

But on a per-capita basis, the situation looks rather different. Small island destinations have the highest per-capita destination-based footprints. Maldives tops the list – 95% of the island’s tourism-related emissions come from international visitors.

Tourists are responsible for 30-80% of the national emissions of island economies. These findings bring up the question of the impact of tourism on small island states.

Islands as tourist destinations

Small islands depend on income from tourists. At the same time, these very tourists threaten the native biodiversity of the islands.

Small island states typically do not have the capacity to embrace technology improvements due to their small economies of scale and isolated locations.

Sustainable tourism on islands.
Author provided

Can we lend a helping hand? Directing financial and technical support to these islands could potentially help with efforts to decarbonise their infrastructure. This support would be a reflection of the share of consumer responsibility, especially from developed nations that are “net travellers”.

Maldives, Mauritius and other small islands are actively exploring ways of building their renewable energy capacity to reduce the carbon intensity of local hotels, transport and recreational spots.

Creating awareness at multiple levels

We hope that our study provides a starting point for conversations between the public, companies and policymakers about sustainable tourism.




Read more:
‘Sustainable tourism’ is not working – here’s how we can change that


The ConversationUltimately real change will come from implementing regulations and incentives together to encourage low-carbon operations. At a personal level, though, it’s worth looking at the carbon-cost of your flights, choosing to offset your emissions where possible and supporting tourism companies that aim to operate sustainably.

Dr Arunima Malik, Lecturer in Sustainability, University of Sydney and Dr Ya-Yen Sun, Senior Lecturer, The University of Queensland

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

Three ways to improve commercial shipping’s environmental footprint



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A man stretches his leg on the bank of the Han River as a ship passes by amid thick haze. Tens of thousands of premature deaths in east Asia every year are caused by shipping pollution.
REUTERS/Stringer

Martina Doblin, University of Technology Sydney

Do you wear runners, drink coffee or own a mobile phone? The chances are that these products cruised to you on a ship. In 2015, the global merchant fleet carried a record 10 billion tonnes of cargo, a 2.1% increase from the previous year. The Conversation

However, while it’s an essential part of international trade, shipping also poses serious risks to the environment. Apart from damage caused by dredging shipping channels and the spread of marine pests around the world, there is also growing concern about pollution. According to a report from the European Union, international shipping contributes 2.5% of global greenhouse gas emissions annually. This is predicted to rise by between 50% and 250% by 2050.

As well as contributing to global warming, ship pollution includes toxic compounds and particles that cause a host of other health hazards. A 2016 Chinese-led study found the shipping boom in east Asia has caused tens of thousands of premature deaths a year, largely from heart and lung disease and cancer.

Commercial ships are designed to be used for a long time. As a result, their engines are typically older and less efficient than those used in many other industries, and replacing them is prohibitively expensive. But there are some immediate solutions to this problem that use existing technology: increasing fuel quality, treating engine emissions, and adopting other energy-conservation measures so that ships burn less fuel.

Improve fuel quality

When diesel ship engines burn poor-quality fuel, their smoke stacks release oxides of nitrogen and sulfur as well as carbon. These pollutants, as well as contributing to greenhouse warming, are highly toxic. Sulfur dioxide readily dissolves in water, creating acid rain that causes harm to both people and the environment.

Refinement of crude oil removes sulfur, which reduces the amount of sulfur dioxide produced when the fuel is burned. Higher-grade diesel also reduces the volume of heat-trapping nitrous oxide, but is more expensive to produce because it requires more purification at the refinery.

The International Maritime Organization, the UN body that regulates the safety and security of shipping, is planning to reduce the amount of sulfur allowed in fuel. However, it is currently considering whether the change will take place in 2020 or will be deferred to 2025.

Install exhaust scrubbers

Clean fuel is an important part of reducing emissions, but the higher cost of low-sulfur fuel will deter many companies. Another way for ships to meet clean-air requirements is by capturing engine exhaust and passing it through scrubbers. These scrubbers convert nitrous oxide gases into harmless nitrogen and water.

This process requires retrofitting older ships, and updating the design of new ship exhaust systems. One advantage of this approach is that it allows ships to meet the different pollution regulations around the world without having to swap fuels.

Another way to reduce production of nitrous oxide is by reducing the temperature at which diesel fuel burns, but this leads to decreased fuel efficiency and increased fuel consumption. Scrubbers are potentially a cheaper and more accessible option.

Reduce energy use overall

Ships don’t just burn diesel fuel to propel themselves through the water. Fuel also generates electricity so that people on board can do things like use computers and read at night.

To increase fuel efficiency, other energy conservation measures can be adopted so that ships burn less fuel and decrease their emissions. The US Navy’s Green Fleet has, for example, replaced their old light fixtures with energy-saving LEDs.

They have also undertaken a temperature control initiative, where thermostats have been checked to ensure they are in proper working order and faulty parts in their water cooling systems replaced. Some ships have gone further, and installed stern flaps that modify the flow of water under the ship’s hull to reduce drag, thus increasing fuel efficiency.

All of this means the shipping industry can lower its fuel bill through conserving energy, and at the same time reduce its negative impacts on the health of humans and the planet. With more than 20,000 ships in the global fleet, these immediate solutions to reducing greenhouse gas emissions and other types of pollution will make a real difference.

Martina Doblin, Senior Research Fellow, Plant Functional Biology & Climate Change, University of Technology Sydney

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