Climate Change

Climate change toll from two droughts tops $800m

Two major droughts in recent years led to nearly $5 billion in damages, $800 million of which is directly attributable to climate change, Marc Daalder reports

The true toll of climate change in New Zealand is just beginning to come to light.

New research from a team of Kiwi climate scientists led by Victoria University of Wellington's Dave Frame has found the major 2007 and 2013 droughts - which the Treasury estimates led to $4.8 billion in lost GDP - were seriously exacerbated by climate change.

The study, published in the academic journal Climate Change, proposes a new methodology for quantifying the costs of extreme events that can be directly attributed to climate change. When applied to the New Zealand droughts, the model found $800 million in lost GDP was due to climate change - one sixth of the total damages.

Frame told Newsroom the new methodology estimated far higher climate costs than previous work. When applied to the 2017 Hurricane Harvey, the model found $104 billion of $140 billion in damages was directly attributable to climate change. Previous estimates - which are not directly comparable with the new model, since Frame's work doesn't include some of the accounting the other methodologies do - produced a figure of $20 billion in climate damages for the entire year of 2017 in the United States.

"It's pretty clear that the number you would get if you did make a like-for-like comparison is far higher than the traditional estimate," he said.

"That kind of suggests that the social cost of carbon has been quite badly underestimated."

The pre-existing methodology, called Integrated Assessment Models (IAMs), "have been developed with the premise that the main economic impacts associated with climate change arise from long-term changes to agricultural productivity and practice associated with rising average temperatures," Frame and his team wrote in an article for CarbonBrief.

"They typically assume that the effects of extreme weather events – which are infrequent by definition – are relatively minor."

Frame's team also ran the model on flood insurance payouts in recent years and found the "major-flood insured costs attributable to anthropogenic influence on climate are currently somewhere in the vicinity of $140M for this decade", according to the study.

This figure does not include uninsured costs, lost profits through stalled economic activity or physical or mental health impacts, Frame noted.

The academics are now working with scientists from Australia, the United States and the United Kingdom to further fine-tune to the methodology. They then want to apply it to more events in New Zealand as well as global extreme events like the Australian bushfires, heat waves and major storms.

Frame is hopeful that the new figures could help New Zealanders understand how climate change impacts their daily lives.

"One of the things that I find a little frustrating with New Zealand is that the conversation on climate impacts has been dominated by sea level rise," he said.

"Climate damages are being done now in places like Edgecumbe. If people understand that, then they can adapt their behaviour."

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