Mowers and sneezers struggle as climate change pushes grass skywards

You don’t need a dwindling glacier to see the effects of climate change – just head down for a frolic in the long grass. Achoo.

Wellington was not alone in recording its wettest winter on record in 2022 and, even before summer had started, November was confirmed as the hottest on record nationwide.

Niwa last week confirmed 2022 had overtaken 2021 as the hottest on record. It was news that landed as Cyclone Hale drenched huge parts of the country.

While climate change has long been picked to harm food supply as droughts and extreme weather events become more common, it seems that some plants are flourishing in the damper, warmer conditions – and it is not always for the good.

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At Wellington’s Krull St play area on Sunday, as New Zealand hit the midway point of summer, the steep bank above the playground is usually brown, dry grass by this time of the season, making for a popular box-sliding spot. But this summer has left the grass long, plush, and often too green to slide.

Wellington City Council spokesman Richard MacLean confirmed the council’s mowing team was struggling to stay on top of spring-like growth.

“Normally by this time of the year things have started to dry out. Clearly it has not been the case. Our mowing teams are really under the pump.”

Victoria University climate scientist James Renwick said some weather events would have happened with or without human-made climate change but climate change made them worse.

The extra heat and rain generally was down to climate change, he said.

Grass generally stopped growing – or notably slowed down – over winter but the grass growing season would likely extend as climate change worsened.

“As you warm up the climate the grass will grow longer and will eventually grow all year,” he said.

Royal New Zealand College of GPs medical director Dr Bryan Betty said it was turning out to be a “particularly bad year” for hay fever as the humid wet weather increased grass growth and pollens.

“The symptoms can be quite disabling,” he said.

Dr Daniel Collins, an independent water resource and climate change specialist with Pūtahi Research, said climate change could alter plant growth in a number of ways. Fewer frosts and more carbon dioxide encouraged growth but water was the “wild card”.

“During the warmer months, as the climate continues to change, it is fair to anticipate both greater water demand and lower water availability from our rivers and aquifers – a double whammy for water stress.”

But there were adaptions we could make such as shifting how we used water, to choosing what plants to grow, to water use charges and changing out aesthetic expectations so that brown grass wasn’t undesirable.

At Twigland Gardeners World in Glenside, northern Wellington, shop worker Sarah Hooker said the heat and rain had made for superb growing conditions.

“We are still getting good moisture around so it’s not drying out as much.”

It meant that heat-loving plants – such as zucchini, aubergines, and chillis – that would usually be too late to plant could still be planted with the expectation of a crop this year.

But there was one issue – the increased humidity was leading to more fungal disease, she said.