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I read somewhere that 1,000 square metres of grass absorbs the same amount of carbon dioxide that one person produces. I then think about my small 10ha property. Does that mean that I am covering 100 peoples’ CO₂ emissions every day? What about those large 1,000ha properties then? Do they absorb thousands of tonnes of carbon every year?
In New Zealand, your average carbon footprint will be around four tonnes of carbon, emitted per year (based on the carbon contained in 16.9 tonnes of carbon dioxide equivalent annual per-capita emissions). A 1,000-square-metre area of grass will take up around one tonne of carbon per year. So if you didn’t fly much, lived in a well insulated home, cycled to work etc, you might bring your overall footprint down to around one tonne of carbon per year, the equivalent of what a backyard lawn may take up per year. So far so good.
The big problem (causing tremendous confusion even among scientists) begins right here. In the above, we talk about fluxes, not pools. Using your bank account as an analogy, fluxes are transfers, pools are balances.
With your own carbon emissions, regardless whether they are one or four tonnes per year, you pay into the atmosphere’s account every year. This means that there is more and more carbon in the atmosphere.
That carbon comes from fossil fuels – an entirely different “account”. Regardless of whether you have 1,000 or 100,000 square metres, this is what grass is doing in this analogy: it takes carbon from the atmosphere every year, but that carbon is going straight back to where it was taken from when you mow the lawn and the biomass is broken down and returned to the atmosphere. In other words, your carbon footprint is a flux that leads to a permanent change in a pool (the atmosphere). This is a bit like a weekly salary. You don’t have to pay it back. What your lawn is doing however, is making payments that are returned a few weeks or months later (when you mow the lawn, a cow eats the grass, or when natural turnover takes place).
The bottom line is that short-term fluxes (as large as they might be) don’t matter if they are reciprocated by an equivalent but opposite flux. If you want, let’s do the experiment. You pay $1,000 onto my account ever odd week, and I pay $1,000 onto yours every even week. None of us will care – as little as the atmosphere will worry about the carbon that your grass patch briefly locks away from it.
So your grass won’t lock away carbon dioxide from the atmosphere in the long run. Neither will any grassland in New Zealand.
If you wait long enough, things can become a bit more complicated, namely if my payments back to you start to become a little less or a little more, causing dollars or carbon to accumulate on one account rather than the other. While this is the case in some ecosystems, such as a growing forest, New Zealand grassland is unlikely one of them. So your backyard isn’t helping, there is no way around reducing our greenhouse gas emissions.
Australia’s high rates of forest loss and weakening land clearing laws are increasing bushfire risk, and undermining our ability to meet national targets aimed at curbing climate change.
This dire situation is why we are among the more than 300 scientists and practitioners who have signed a declaration calling for governments to restore, or better strengthen regulations to protect native vegetation.
Land clearing laws have been contentious in several states for years. New South Wales relaxed its land clearing controls in 2017, triggering concerns over irreversible environmental damage. Although it is too early to know the impact of those changes, a recent analysis found that land clearing has increased sharply in some areas since the laws changed.
The Queensland Labor government’s 2018 strengthening of land clearing laws came after years of systematic weakening of these protections. Yet the issue has remained politically divisive. While discussing a federal inquiry into the impact of these policies on farmers, federal agriculture minister David Littleproud suggested that the strenthening of regulations may have worsened Queensland’s December bushfires.
We argue such an assertion is at odds with scientific evidence. And, while the conservation issues associated with widespread land clearing are generally well understood by the public, the consequences for farmers and fire risks are much less so.
Tree loss can increase fire risk
During December’s heatwave in northern Queensland, some regions were at “catastrophic” bushfire risk for the first time since ratings began. Even normally wet rainforests, such as at Eungella National Park inland from Mackay, sustained burns in some areas during “unprecedented” fire conditions.
There is no evidence to support the suggestion that 2018’s land clearing law changes contributed to the fires. No changes were made to how vegetation can be managed to reduce fire risk. This is governed under separate laws, which remained unaltered.
In fact, shortly after the fires, Queensland’s land clearing figures were released. They showed that in the three years to June 2018, an area equivalent to roughly 570,000 Melbourne Cricket Grounds (1,138,000 hectares) of bushland was cleared, including 284,000 hectares of remnant (old-growth) ecosystems.
Tree clearing can worsen fire risk in several ways. It can affect the regional climate. In parts of eastern Australia, tree cover reductions are estimated to have increased summer surface temperatures by up to 2℃ and southwest Western Australia by 0.4–0.8℃, reduced rainfall in southeast Australia, and made droughts hotter and longer.
Removing forest vegetation depletes soil moisture. Large, intact areas of forest typically have cooler, wetter microclimates buffered from extreme temperatures. Over time, some forest types can even become fire-resistant, but smaller patches of trees are typically drier and more flammable.
Trees also form a natural windbreak that can slow the spread of bushfires. An analysis of the 2005 Wangary fire in South Australia found that fires spread most rapidly through paddocks, rather than through areas lined with native trees.
Extensive tree clearing also leads to problems for farmers, including rising salinity, reduced water quality, and soil erosion. Governments and rural communities spend significant money and labour redressing the aftermath of excessive clearing.
Sensible regulation of native vegetation removal does not restrict existing agriculture, but rather seeks to support sustainable production. Retained trees can help deal with many environmental risks that hamper agricultural productivity, including animal health, long-term pasture productivity, risks to the water cycle, pest control, and human well-being.
Rampant tree clearing is undoing climate policy too. Much of the federal government’s A$2.55 billion Emissions Reduction Fund has gone towards tree planting. But it would take almost this entire sum just to replace the trees cleared in Queensland since 2012.
In 2019, Australians might reasonably expect that our relatively wealthy and well-educated country has moved beyond a frontier-style reliance on continued deforestation, and we would do well to better acknowledge and learn lessons from Indigenous Australians with respect to their land management practices.
Yet the periodic weakening of land clearing laws in many parts of Australia has accelerated the problem. The negative impacts on industry, society and wildlife are numerous and well established. They should not be ignored.
2017 was the worst year on record for hurricane damage in Texas, Florida and the Caribbean from Harvey, Irma and Maria. We had hoped for a reprieve this year, but less than a month after Hurricane Florence devastated communities across the Carolinas, Hurricane Michael has struck Florida.
Coastlines are being developed rapidly and intensely in the United States and worldwide. The population of central and south Florida, for example, has grown by 6 million since 1990. Many of these cities and towns face the brunt of damage from hurricanes. In addition, rapid coastal development is destroying natural ecosystems like marshes, mangroves, oyster reefs and coral reefs – resources that help protect us from catastrophes.
In a unique partnership funded by Lloyd’s of London, we worked with colleagues in academia, environmental organizations and the insurance industry to calculate the financial benefits that coastal wetlands provide by reducing storm surge damages from hurricanes. Our study, published in 2017, found that this function is enormously valuable to local communities. It offers new evidence that protecting natural ecosystems is an effective way to reduce risks from coastal storms and flooding.
The economic value of flood protection from wetlands
Although there is broad understanding that wetlands can protect coastlines, researchers have not explicitly measured how and where these benefits translate into dollar values in terms of reduced risks to people and property. To answer this question, our group worked with experts who understand risk best: insurers and risk modelers.
Using the industry’s storm surge models, we compared the flooding and property damages that occurred with wetlands present during Hurricane Sandy to the damages that would have occurred if these wetlands were lost. First we compared the extent and severity of flooding during Sandy to the flooding that would have happened in a scenario where all coastal wetlands were lost. Then, using high-resolution data on assets in the flooded locations, we measured the property damages for both simulations. The difference in damages – with wetlands and without – gave us an estimate of damages avoided due to the presence of these ecosystems.
Our paper shows that during Hurricane Sandy in 2012, coastal wetlands prevented more than US$625 million in direct property damages by buffering coasts against its storm surge. Across 12 coastal states from Maine to North Carolina, wetlands and marshes reduced damages by an average of 11 percent.
These benefits varied widely by location at the local and state level. In Maryland, wetlands reduced damages by 30 percent. In highly urban areas like New York and New Jersey, they provided hundreds of millions of dollars in flood protection.
Wetlands reduced damages in most locations, but not everywhere. In some parts of North Carolina and the Chesapeake Bay, wetlands redirected the surge in ways that protected properties directly behind them, but caused greater flooding to other properties, mainly in front of the marshes. Just as we would not build in front of a seawall or a levee, it is important to be aware of the impacts of building near wetlands.
Wetlands reduce flood losses from storms every year, not just during single catastrophic events. We examined the effects of marshes across 2,000 storms in Barnegat Bay, New Jersey. These marshes reduced flood losses annually by an average of 16 percent, and up to 70 percent in some locations.
In related research, our team has also shown that coastal ecosystems can be highly cost-effective for risk reduction and adaptation along the U.S. Gulf Coast, particularly as part of a portfolio of green (natural) and gray (engineered) solutions.
Reducing risk through conservation
Our research shows that we can measure the reduction in flood risks that coastal ecosystems provide. This is a central concern for the risk and insurance industry and for coastal managers. We have shown that these risk reduction benefits are significant, and that there is a strong case for conserving and protecting our coastal ecosystems.
There is often a strong desire to return to the status quo after a disaster. More often than not, this means rebuilding seawalls and concrete barriers. But these structures are expensive, will need constant upgrades as as sea levels rise, and can damage coastal ecosystems.
Even after suffering years of damage, Florida’s mangrove wetlands and coral reefs play crucial roles in protecting the state from hurricane surges and waves. And yet, over the last six decades urban development has eliminated half of Florida’s historic mangrove habitat. Losses are still occurring across the state from the Keys to Tampa Bay and Miami.
Protecting and nurturing these natural first lines of defense could help Florida homeowners reduce property damage during future storms. In the past two years our team has worked with the private sector and government agencies to help translate these risk reduction benefits into action for rebuilding natural defenses.
Across the United States, the Caribbean and Southeast Asia, coastal communities face a crucial question: Can they rebuild in ways that make them better prepared for the next storm, while also conserving the natural resources that make these locations so valuable? Our work shows that the answer is yes.
This is an updated version of an article originally published on Sept. 25, 2017.
On average, renovating a home generates far more waste than building a new one from scratch.
This waste goes straight to landfill, damaging the environment. It also hurts your budget: first you have to pay for demolition, then the new materials, and then disposal of leftover building products.
By keeping waste in mind from the start and following some simple guidelines, you can reduce the waste created by your home renovation.
Waste is often treated as inevitable, factored into a building budget with no serious attempt to reduce it.
By raising the issue early with your architect, designer or builder, they can make decisions at the design stage that reduce waste later. Often the designers and architects don’t see their decisions contributing to waste – or rather, they don’t really think about it.
During my research on reducing construction waste, I asked one architect what he thought happens to the waste generated. He laughed with a glint in his eyes and said, “I think it disappears into pixie dust!”
One simple early decision that dramatically reduces waste is designing with material sizes in mind. If you have a ceiling height that does not match the plasterboard sheet, you end up with a tiny little strip that has to be cut out of a full sheet. In the case of bricks, not matching the ceiling height is even more wasteful.
Obviously not all materials will work together at their standard sizes (and you need to fit your renovation to the existing house). But sensitive design can make intelligent trade-offs, reducing overall waste.
When I asked architects why they don’t design zero-waste buildings more often, they said clients don’t ask for it. Make it part of your brief, and ask the architect how they can save money by using the materials efficiently.
2. Get your builder involved early
If you’re using an architect for your renovation, it’s common to have very little collaboration between them and the builder. Any errors or issues are usually spotted after construction has begun, requiring expensive and wasteful rework.
Instead, ask your architect and builder to collaborate on a waste management plan. Such integrated approaches have worked well in Australia and the United States.
This means clients, engineers and builders are collaborating, rather than taking adversarial roles. For such contracts to work, it’s important to involve all parties early in the project, and to encourage cooperation.
The briefing stage is an opportunity for architects, quantity surveyors and builders to work together to identify a waste minimisation target.
3. Whatever you do, don’t change your mind
One the biggest contributions to waste on sites is late design changes. Client-led design changes are identified in all literature as having far-reaching implications on waste.
These are mostly due to owners changing their mind once something is built. Reworking any part of a building due to design changes can account for as much as 50% of the cost overrun, as well as causing delays and generating waste.
The early work with your design and construction team outlined in the first steps gives you the chance to make sure you’re committed to your original design. Skimping in the planning stage can end up costing you far more in the long run.
4. Deconstruction, not demolition
Ask your builder not to demolish the building, but to deconstruct it. Deconstruction means taking a building apart and recovering materials for recycling and reuse. This provides opportunities for sorting materials on site.
Salvaged materials can be resold to the community or reused in the renovations. It greatly reduces the tip fees which are usually higher for mixed waste (typical from demolition process) and lower for sorted waste.
Of course this takes more time and has an additional cost. Therefore you do have to balance the cost of deconstruction against the savings.
Denmark, which recycles 86% of its construction waste, has made it mandatory for all government buildings to undergo selective demolition and sorting of construction waste. A good place to start in Australia is your state environment department, which may have guidelines on what is involved.
5. Choose materials carefully
Good-quality materials last longer, reducing maintenance later. Choosing manufacturers that use minimal packaging also reduces waste (be careful here to check the difference between “minimal” and “inadequate” packaging, as the latter can mean your material breaks).
Reusing materials from your renovation may also be an option (you will need to discuss this with architect and builder at the beginning of the project). Finally, using materials with recycled content is a great option, and boosts our recycling industry.
In March 2017 the Housing Industry Association released data suggesting the Australian residential building industry will increasingly become more dependent on renovation work rather than new construction,
If you’re renovating your home, making efficiency and low waste a priority helps cut costs and reduce landfill.
The One Billion Trees Programme promises to deliver combined benefits, not only by offsetting greenhouse gas emissions, but also reducing erosion on marginal land. However, unless funding is closely tied to successful outcomes, this public investment risks failing in its environmental and political ambitions.
We have developed a results-based bond financing scheme that would remove the risk from forest planting and could be applied to forest and landscape restoration initiatives elsewhere in the world.
Globally, we face a major financing gap to fund the infrastructure required to mitigate the causes of climate change and to adapt to the consequences. The scale of global investment isn’t equal to the scale of the challenge. The Global Commission on the Economy and Climate estimates that core infrastructure investment needs to nearly double to about $6 trillion annually up until 2030.
The barriers to investment are many, but one is simply the risk of failure. I call this “the Coldplay conundrum”, after the British soft-rock band’s attempt to offset the greenhouse gas emissions created by their second album, A Rush of Blood to the Head. Money was transferred to southern India for the planting of 10,000 mango trees, yet, some years later, much of it hadn’t made it to landowners and, as a result, few trees survived. Coldplay, for all their green ambitions, ended up with egg on their face.
Politicians face the same risk when they embark on projects to deliver environmental outcomes. Although voters expect governments to deliver various public goods, there is also an expectation that public money will be managed effectively, efficiently and responsibly in doing so. Failing on either front could attract the wrath of the electorate.
The New Zealand government faces just this conundrum over its plan to plant a billion trees over the coming decade. It already manages various grants schemes, such as the Afforestation Grant Scheme and Erosion Control Funding Programme. But upscaling these could produce poor results if funding isn’t closely tied to successful outcomes.
A better solution
Results-based financing helps to manage this political risk. The idea is that governments only hand over the money once the desired outcomes are successfully delivered. The New Zealand government might guarantee to pay for trees that are successfully established, thereby attracting private and social sector parties to do this work – and to do it well. This contrasts with more common funding models, such as grants or output-based contracts, which might lead to success, but might also go the way of Coldplay.
My collaborator, investment specialist Sam Lindsay, and I have designed the Native Forest Bond Scheme, a results-based financing structure that would take the risk out of forest planting for the government, to enable innovation over business-as-usual. It is specifically designed to address the challenge of establishing continuous native forest on erosion-prone marginal land.
This is one of New Zealand’s most pressing environmental challenges. About 11% of the country’s total land area is mildly to severely erosion-prone but currently in pasture. Extreme weather events – which are expected to increase as a consequence of climate change – can trigger mass erosion, with costly damage to public and private property. Pastoral land, or land where forest was recently cleared, is particularly vulnerable.
Recent events in the Tasman District and Tolaga Bay, where torrents of sediment and forestry debris were flushed out of vulnerable catchments onto neighbouring properties and waterways, are a hint of the adaptation challenges to come.
Establishing permanent forest on this land is a no-brainer. It would increase land resilience and create large carbon stocks to offset emissions from elsewhere in New Zealand’s economy. A succession of reports, most recently by Vivid Economics and the Productivity Commission, have all highlighted the essential role of afforestation in meeting New Zealand’s Paris Agreement commitments. But landowners need help, because they often lack the cash, time or expertise to establish forests successfully.
Riding the global trend
The Native Forest Bond Scheme brings together parties around this common cause. Government provides the guarantee to pay for successful forest outcomes that generate significant public value through erosion control, carbon sequestration, meaningful regional jobs and greater biodiversity. Investors provide upfront capital for forest planting by purchasing the bond.
If outcome targets are successfully met, then investors are rewarded with interest payments, but if the planting programme underperforms, then investors bear the risk of project failure. By reallocating risks and incentives, the scheme enables parties to do what otherwise might not have been done.
Globally, other organisations are turning to results-based financing to create greener landscapes. At the city level, DC Water successfully issued such a bond to establish green infrastructure in Washington D.C., purchased by Goldman Sachs and the Calvert Foundation. At the international level, The Nature Conservancy and Climate Bonds Initiative are exploring the feasibility of sustainable land bonds, where developing countries would issue bonds to raise capital for land use change, and developed countries would then offset the interest payments as long as these changes are successful.
The Native Forest Bond Scheme is a tool for more effective financing of environmental outcomes. By tying funding to results, it creates a more credible commitment to the expectations of the Paris Agreement and UN Sustainable Development Goals. Without rethinking public investment, noble ambitions may ring hollow.
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.
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.
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.
It is also important to separate expensive hospital infectious waste from other less expensive, non-infectious waste.
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:
Humans may be Earth’s apex predator, but the fleeting shadow of a vulture or the glimpse of a big cat can cause instinctive fear and disdain. But new evidence suggests that predators and scavengers are much more beneficial to humans than commonly believed, and that their loss may have greater consequences than we have imagined.
In a recent paper in Nature Ecology & Evolution, we summarised recent studies across the globe looking at the services predators and scavengers can provide, from waste disposal to reducing car crashes.
The many roles our fanged friends play
Animals that eat meat play vital roles in our ecosystems. One of the most outstanding examples we found was that of agricultural services by flying predators, such as insectivorous birds and bats.
We found studies that showed bats saving US corn farmers over US$1 billion in pest control because they consume pest moths and beetles. Similarly, we found that without birds and bats in coffee plantations of Sulawesi, coffee profits are reduced by US$730 per hectare.
It’s not just birds and bats that help farmers. In Australia, dingoes increase cattle productivity by reducing kangaroo populations that compete for rangeland grasses (even when accounting for dingoes eating cattle calves).
This challenges the notion that dingoes are solely vermin. Rather, they provide a mixture of both costs and benefits, and in some cases their benefits outweigh the costs. This is particularly important as dingoes have been a source of conflict for decades.
One piece of research showed that if mountain lions were recolonised in the eastern United States, they would prey on enough deer to reduce deer-vehicle collisions by 22% a year. This would save 150 lives and more than US$2 billion in damages.
Weighing up the costs and benefits
Although these species provide clear benefits, there are well known costs associated with predators and scavengers as well. Many predators and scavengers are a source of conflict, whether it is perceived or real; particularly pertinent in Australia is the ongoing debate over the risk of shark attacks.
These drastic costs of predators and scavengers are rare, yet they attract rapt media attention. Nevertheless, many predators and scavengers are rapidly declining due to their poor reputation, habitat loss and a changing climate.
It’s time for a change in the conservation conversation to move from simply discussing the societal costs of predators and scavengers to a serious discussion of the important services that these animals provide in areas we share. Even though we may rightly or wrongly fear these species, there’s no doubt that we need them.
The authors would like to acknowledge the contributions of Dr Hawthorne Beyer and Alexander Braczkowski.