A new NIWA programme that can attribute climate change’s contribution to extreme weather events weeks later will show Kiwis the effects of the climate crisis are already here, its principal climate scientist says.
Dr Sam Dean told Breakfast that over the last 10 years, it’s estimated that at least $940 million is directly attributable to climate change.
“That’s costs we wouldn’t have had if there wasn’t already climate change, that’s quite a significant underestimate,” he said.
The area of work is called attribution science and works out the “likelihood or risk of an extreme weather event, so we’ve looked at floods, we’ve looked at droughts, we’ve looked at heatwaves”, Dean said.
“Some of those events like those warm winters, warm summers we’ve had, some of them that we’ve had couldn’t have happened at all without climate change, the probability was so small they’re next to impossible,” he said.
“Other events like floods aren’t so clear cut, they’re very different around the country, depends whether they’re in the north or the south.”
Dean says the quick turnaround of this research means it will be brought home to Kiwis that “their experience in climate change here and now”.
“New Zealand has changed a lot we’ve already had a degree of warming, this is a very different country from when people arrived here.”
Establishing the costs of climate change will be key as New Zealand looks to implement recommendations from the Climate Commission.
“When you’re having conversations about doing the things the Climate Commission is asking for, you’ve got to think about what it’s already costing you today,” he said.
Dean says the cost of the recent Canterbury floods would be incredibly high, but people shouldn’t expect the climate contribution figure for them to be as high as that for the 2014 Northland floods.
“Because it’s in the south it’s not going to be as dramatic in terms of its climate change contribution.”
“Costs for this event will be extraordinarily high, this was an exceptional amount of rainfall, we’re talking about a one-in-200 year for the foothills and one-in-40 for the coast in terms of rainfall,” he said.
“Floods are a little more complicated, how dry the conditions were before the rain fell may have been a factor in terms of how much water goes down the rivers and causes the flooding.
“There will definitely be a factor and we should come out with that in the next week or so.”