Climate crisis to blame for $67bn of Hurricane Harvey damage – study
At least $67bn of the damage caused by Hurricane Harvey in 2017 can be attributed directly to climate breakdown, according to research that could lead to a radical reassessment of the costs of damage from extreme weather.
Harvey ripped through the Caribbean and the US states of Texas and Louisiana, causing at least $90bn of damage to property and livelihoods, and killing scores of people.
Conventional economic estimates attributed only about $20bn of the destruction to the direct impacts of global heating. Climate breakdown is known to be making hurricanes stronger and may make them more likely to occur, but separating the effects of global heating from the natural weather conditions that also cause hurricanes is complex.
In a study published in the journal Climatic Change, researchers used the emerging science of climate change attribution to calculate the odds of such a hurricane happening naturally or under increased carbon dioxide levels, and applied the results to the damage caused.
Similar methods were used in a separate study, published last month in the same journal, that found that droughts in New Zealand between 2007 and 2017 cost the economy about NZ $4.8bn, of which $800m was directly linked to climate change. Floods caused insured losses of about NZ$470m over the same period, of which NZ$140m was linked to the climate.
The researchers say the new tools are a more accurate way of estimating the economic damage caused by climate breakdown.
“We’re pretty sure the climate change-related damages associated with extreme events have been underestimated in most assessments of the social cost of carbon,” said David Frame, a professor of climate change at the Victoria University of Wellington and the lead author of the studies. “We think this line of research, as it matures, should provide a really valuable input.”
Friederike Otto, the director of the Environmental Change Institute at Oxford, who was not involved in the research, said the method could make it possible to generate global estimates of the true cost of climate breakdown, which could have a profound effect on how governments and businesses approach the need to reduce greenhouse gas emissions.
“We have known about the costs of climate change theoretically,” said Otto. “It’s all very well in the abstract, but the global mean temperature does not kill anyone – extreme events cost money and lives. Being able to attribute these impacts to climate change means being able to convey what climate change really means.”
She said it would become possible to compile an inventory of the damage that could be attributed to climate change around the world, which governments and businesses could use to bring about change. “Hopefully this will speed up the process of moving to net zero [carbon].”
Estimating the true costs of the climate crisis could also help developing countries seeking recognition of the loss and damage they face as a result of climate breakdown, which they argue should spur rich countries to provide more assistance. Loss and damage is likely to be one of the most vexed issues at next year’s UN Cop26 climate summit.
Legal actions around the world would also be affected, said Tessa Khan, a co-director of the Climate Litigation Network. Activists and local governments around the world are taking fossil fuel companies to court over their greenhouse gas emissions, arguing that they knowingly caused damage while profiting from raising carbon dioxide levels.
“[The two new studies] are opening to door to stronger evidence to persuade courts that fossil fuel companies should be held accountable for their role,” Khan said. “This will strengthen the legal basis of these lawsuits.”