Wellington could become as hot as Sydney unless action is taken on climate change
The capital could be as hot as Sydney and the Wairarapa could be plagued by droughts by 2090 if greenhouse gas emissions continue unabated.
The changes could even cost Kiwis their favourite Wairarapa pinots, as winemakers turn to varieties that deal better with hotter, drier conditions.
New predictions suggest the number of hot days – classified as days above 25 degrees – will jump from six to 26 for Wellington city, while the Wairarapa's will nearly quadruple from 24 to 94 by 2090.
But the heat in Wellington will be balanced out by a 10 per cent increase in rainfall and more extreme storms likely to hit.
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These are among the key findings of a new climate change report produced by the National Institute of Water and Atmospheric Research (Niwa) and commissioned by the Greater Wellington Regional Council.
Capital residents may welcome the extra sun, but lead author Petra Pearce said it could have detrimental effects on human health, pest control, and farming in eastern areas of the region.
"Cattle get heat-stress over 25 degrees, so that's a real concern for farmers," she said.
Wairarapa's annual rainfall is also expected to fall up to 10 per cent while temperates rise by an average of three degrees by 2090, posing serious threat to pasture, crop growth and water supply.
"The magnitude of these changes is dependant on how fast greenhouse gases increase in the atmosphere," Pearce said.
Ata Rangi winery owner Clive Paton said the changes would not spell the end for wineries, only some varieties of grape.
Despite pinot noir being a Martinborough speciality, for 25 years Paton has been slowly making the transition to grapes more suited to higher temperatures, such as syrah and tempranillo.
"Vineyards are something that last a long time, so whenever you're putting in new blocks or buying something, you're thinking about the future, because quality wines come off older wines."
"In some ways we are expecting to be more like Hawke's Bay down the track," he said.
Whatever the weather, the tourism industry will evolve, says general manager at Destination Wairarapa David Hancock.
"We don't look at trends as far in advance as 2090, but whatever problem any region is faced with, they will evolve to accommodate it," he said.
Wellington city was predicted to heat up by about 2.5 degrees by 2090 if emissions weren't curbed, and rainfall was predicted to rise 10 per cent.
Extreme rain events are expected to become more common, and more severe.
Wellington's sea level fluctuates more rapidly than other parts of the country due to the makeup of its bay, which combined with rising sea levels and more extreme events, may make coastal roads vulnerable.
Regional council chairman Chris Laidlaw said this may mean a managed retreat from the shorelines for homes and infrastructure.
"There is a huge groundswell around the country of people demanding action," he said.
Laidlaw criticised central government, saying New Zealand was doing very little to limit emissions compared to other countries, and local government were screaming out for leadership.
He said a National Policy Statement on climate change would go a long way to directing local government action.
Critics will say the predictions are guess work, but Pearce said Wellington had already warmed by one degree over the past 100 years, and the trend was likely to continue.
"The climate models that run the simulations of future climate are based on very sound principles, and a lot of data, and we are seeing these kind of patterns already play out that these models have been projecting," she said.
Niwa chief scientist Sam Dean said the range of disease-spreading pests, including mosquitoes, was also likely to increase with the warmer temperatures.
"I don't see this as a story of doom and gloom – life will go on, but it puts in front of us the options. The decisions we have as a society to adapt to changes and whether we wish to mitigate and reduce emissions."
David Perks, destination and marketing general manager at the Wellington Regional Economic Development Agency (Wreda), said it didn't have a 70-year tourism plan.
"However, climate change has potential to affect all sectors of the economy in ways which have yet to be determined. It's a global issue that all city's will have to grapple with, and Wellington is no different.
"We certainly hope the world can re-double its efforts to reduce climate change and Wellington is ready to play its part."
Whatever the weather, the tourism industry will evolve says general manager at Destination Wairarapa David Hancock.
"Tourists travel to see something different from what they have home, and we'll always have something that is different, whether it's now or in 2090.
"We don't look at trends as far in advance as 2090, but whatever problem any region is faced with, they will evolve to accommodate it.
"Kaikoura has had a sudden change, but we have seen them evolve to their circumstances - so can we."