Home truths on climate change
Climate change – two big words on the world stage, but for every societal shift, big changes await every home and household,
Alistair Hughes decided to go offgrid to save money – but many of his home’s features may soon become necessities as Kiwi households learn to cope with the changing climate.
The Wairarapa homeowner has solar panels on his roof, water tanks in his garden, and a toilet which feeds into a worm farm, producing fertiliser.
In the six years since he moved to selfreliance, he has witnessed the disruptions that droughts and other extreme weather events have caused to water and electrical supplies both around his home, and in Wellington, where he works as a Stuff graphic artist.
‘‘Those systems are becoming less and less reliable now as drought kicks in in the summer time, the availability of electricity is becoming more questionable, the effect on the drainage system is becoming questionable as well,’’ he says.
Many of his home adaptations are now being touted as future essentials for homeowners, who will have to pick up the slack from ageing 20th-century services that were not designed for the weather extremes predicted for this century.
The days when we could rely on uninterrupted water services and electricity from the mains may be numbered, according to environmental planner Iain White, who says solar panels and water tanks will become far more common – if not required by law.
White co-authored a report late last year entitled Climate Change and Stormwater and Wastewater Systems, which found much of the country’s wastewater and stormwater infrastructure was unprepared for the strain of climate change, and could lead to more Edgecumbe-like floods unless billions of dollars are spent on upgrading them.
Those systems are threatened by a double whammy of more droughts, which lead to accumulation of solid waste, and torrential rain, which overloads the pipes.
This week’s West Coast floods highlighted the risks. Greymouth was inundated after 148mm of rain fell on Thursday, less than 24 hours after Grey and Buller districts declared only the second drought in their recorded history.
Homeowners could be faced with three options, White says – do nothing and live with higher risk; pay higher rates to fund infrastructure upgrades; or find a way to ease strain.
The third is likely to be the easiest option, rooftop rainwater collection expected to become commonplace, if not a legal requirement.
‘‘. . . the availability of electricity is becoming more questionable . . .’’ Alistair Hughes
INVESTING IN ELECTRICITY
Mains electricity may also become less reliable in the face of more extreme weather events, as falling trees or debris damage lines, or snow and ice buildups disrupt supply.
Last year there were 50 weatherrelated power outages in the national grid, according to Transpower. This was almost 25 per cent more than average, and up from 36 in 2016, and 29 in 2015.
Commerce Commission figures for the past five years show roughly 37 per cent of outage time experienced by customers was caused by adverse weather, and a further 11 per cent by vegetation, often as a result of high winds.
This may not be a big problem for Wellington, where about two-thirds of power lines are underground. But PowerCo, which supplies 336,000 urban and rural households in the Wairarapa, Taranaki, Wanganui, Rangitikei, and Manawatu regions, has 78 per cent of its lines above ground.
White says homeowners may need to invest in private solar panels and community batteries to increase reliability of supply.
Peer-to-peer power sharing may also become more common.
A GARDENER’S GUIDE
Keith Hammett, president of the Royal New Zealand Institute of Horticulture, lost about 10 per cent of his crop this year – despite working with ornamental plants for 60 years.
‘‘As far as I’m concerned, as a breeder and a grower, this year has been as difficult as I’ve ever known it, because we went for a very long time with exceptionally wet weather . . . then we were thrown into an extremely hot period.’’
Gardeners should keep an eye on myrtle varieties in the backyard, including pohutukawa, ma¯ nuka, eucalyptus, guava and feijoa, as drier air spurs on myrtle rust and similar diseases.
Powdery mildews also benefit from dry air, which could coat the likes of rose leaves and kill plants.
Meanwhile, diseases such as kauri dieback thrive in wet, muddy conditions caused by prolonger wet periods.
Victoria University professor Stephen Hartley says the plants best prepared to survive will probably be those traditionally native to an area.
‘‘I think the best approach is adaptation to how gardens are managed. That might mean keeping the grass a little bit longer, which gives more resilience in a drought, and mulching around existing plants to retain soil moisture.
CHANGES TO WORK
Best estimates from the Ministry for the Environment predict average temperatures will increase up to 1C by 2040, and 3C by 2090.
Accompanying these average rises will be more days when temperatures climb higher, posing a risk to labourers and outdoor workers.
WorkSafe spokesman Simon Humphries says the organisation is already working with businesses to manage work in extreme heat.
Recommendations include doing nonessential work at times when the heat is lowest, rotating jobs, taking extra breaks and reconsidering work hours.
First-aid training to recognise and treat heat-related disorders is also being looked at.
Those working in offices can also expect changes as smart-building features become more common.
Architect Andrew Patterson designed the Geyser Building in Parnell, New Zealand’s first six-star energy-efficient office building.
It has no traditional air conditioning, instead relying on a double layer of glass, which has a greenhouse effect in winter, and can be vented for cooling in summer.
There will be fewer offices built around one central column, Patterson predicts, because these reduce the amount of sunlight entering, which increases demand for electric lighting.
Some of the lessons from the build will translate into homes, he believes, as computers will work out the most efficient ways of regulating internal temperatures.
‘‘The main goal is to make housing increasingly self-sufficient, and with the increasing solar technology, that is becoming more and more achievable.’’