Photo: Water NZ

Climate emissions pose a fearsome threat to our drinking water, and the draft Three Waters reform bill doesn’t help.

Opinion: Tackling climate change emissions needs to be a cornerstone of the Government’s Three Waters Reforms. The reforms provide a much-needed opportunity to pave the way for real action to reduce emissions from the water sector. However, the Government’s recently-released exposure drafts appear to miss the opportunity for the sector to be an active participant in emissions reduction, focusing instead on the need for climate change mitigation and adaptation.

Emissions reduction needs to be a critical part of the future.

The proposed Three Waters reforms may be the biggest shake up in a generation, but whatever the outcome, they are dwarfed by the challenge of climate change. No other sector or industry in the country is more involved or at risk of climate than water.

Our best-case scenario still on the table at the recent COP-26 meeting in Glasgow is that we keep global warming to a close as possible to 1.5 degrees. Unfortunately, that’s not the most likely outcome, given that we’ve already seen a global temperature rise of 1.2C above pre-industrial times.

But even if we can keep global warming to this level, it will still mean a sea level rise of 40cm. 1.5C also means an annual loss of 1.5 million tonnes of marine fisheries and a decline of between 70 and 90 percent of coral reefs. The UN is currently predicting a 40 percent shortfall in freshwater resources by 2030.

At a recent launch of Water NZ’s low emissions guide, Navigating to Net Zero, Aotearoa’s water sector low carbon journey, water industry leaders agreed the outlook was “scary”.

– water industry leaders on climate threat

Here in Aotearoa New Zealand, the risk climate change poses to drinking water has been rated as our number one risk in our national climate risk assessment. This recognises that increased drought and flooding will badly affect our source water. It will mean water shortages and increased contamination.

This will have a massive effect on agriculture as well as many towns and communities. Source water risks are one of many in a long list of climate risks which include asset inundation, increased asset deterioration, and supply chain interruptions.

The Three Waters Reforms are driven by the need to find an affordable way to meet future demand and growth, upgrade ageing infrastructure, and at the same time improve water quality.

With a whopping $120b to $185b capital investment needed in the next 30 years to address decades of under-investment and support housing and population growth, it’s vital that this new infrastructure boom not only increases our capacity, but at the same time, reduces and offsets emissions from the sector.

How we reduce emissions and tackle climate change has huge consequences for all of us.

Currently, the water sector is a net greenhouse gas emitter. Energy and chemicals are consumed in the treatment and conveyance of water and there’s considerable inbuilt carbon dioxide created in building new infrastructure. Our wastewater treatment plant processes also release methane and nitrous oxide from their processes, both potent greenhouse gases.

The opportunities are there not only to reduce emissions but to start acting as carbon sinks.

But that’s where we get to one of the roadblocks. We need better understanding of wastewater emissions and their causes.

Nitrogen removal is a core goal of wastewater treatment plants, it prevents eutrophication of our waterways.  Without this treatment, nutrient overload in waterways leads to algal blooms, choking our rivers and disrupting aquatic food webs.

What is not well understood is what this means for greenhouse gas emissions.

During treatment, nitrogen is converted into the potent greenhouse gas nitrous oxide. What is not yet understood are the exact volumes or drivers of nitrous oxide during their processes. Do we have to trade off our waterways for our atmosphere? Science does not yet have the answers.

We do know that the emissions differ across processes, across time, and even within wastewater treatment plants. So, we need to get the right solutions. But direct measurement of greenhouse gasses is expensive. Consequently, we’re left estimating emissions instead of measuring.

Only once we understand our emissions can we be confident about solutions – many of which will involve highly technical innovations and, as with most infrastructure, planning needs to happen today if it is to be implemented tomorrow.

The Three Waters Reforms could provide an opportunity to embed the drivers and structure to drive real action. Mandatory climate-related disclosures are being seen by many as a catalyst for climate action in the finance industry. In the same way bringing transparency to water sector greenhouse gas emissions and climate risks lays the foundation for targets and processes to drive down emissions and adapt to change.

Opportunities to reduce emissions fall into three broad categories. Driving down operational emissions through more energy efficient blowers and pumps is one example.  Other examples include reducing embodied carbon in new assets by repurposing old assets and adopting new materials such as low carbon concrete.

Finally, the exciting stuff. Recapturing the many bi-products of wastewater and repurposing these as part of a circular economy.

Internationally this work is already well underway, with many wastewater treatment plants around the world being increasingly viewed as resource recovery facilities. Already in New Zealand we have 16 of our wastewater treatment plants producing biogas. Introducing other organic waste can help divert organic wastes from landfill and increase biogas production.

Biogas is but one of many fuel sources that innovative wastewater treatment plants are producing.  In Australia researchers are working at scale to develop technologies to produce hydrogen fuel from wastewater. Closer to home, the solid fraction of wastewater known as biosolids is being run through vermi-composting, large scale industrial worm farms, to produce soil conditioner. These are a rich source of carbon and nutrients and a natural alternative to imported fossil fuels.

The Government has committed to a net emissions reduction of all greenhouse gases (except biogenic methane) to zero by 2050. A less ambitious biogenic methane emissions target – 10 percent by 2030 and somewhere between 24-47 percent below 2017 levels by 2050, have yet to be reconciled with New Zealand signing on to an international agreement to reduce methane by thirty percent in the same time frame.

Right now, reducing carbon, lowering energy consumption, and adapting to climate change need to be front of mind.

Despite the lack of overall policy framework, some of our water utilities have taken up the challenge and set their own carbon reduction targets.

Watercare and Auckland Council aim to achieve net zero by 2050 with an earlier target of 50 percent reduction by 2030, while Christchurch City Council has a net zero by 2045.

In Watercare’s case, its journey to zero emissions has already begun – getting runs on the board through reducing electricity usage and switching to solar where possible, changing vehicle fleet to EV and working out where and how to reduce built-in carbon by using low-carbon concrete. But Watercare admits the next stages will get more difficult.

This will involve a combination of continued public education and more technology and planning. By looking at ways of reducing water usage, biosolid re-use and more nature-based stormwater solutions, it is possible to turn the water sector from a net emitter of carbon to one which re-captures carbon.

There is also the opportunity to reduce emissions from infrastructure and wastewater by-products that can generate energy and reduce reliance on imported fertilisers.

Achieving New Zealand’s emissions targets is going to be a huge undertaking. Water is a critical enabler for renewable energy supplies, agricultural systems, and climate friendly cities.

Keeping water services factored into climate change emission reduction will unlock a broad range of opportunities to help achieve our carbon reduction goals.

As chief executive of Water New Zealand, Gillian Blythe leads a not-for-profit member organisation promoting and enabling the sustainable management and development of the water environment.

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