Despite Harvey’s battering, US political and opinion leaders are holding fast to the idea that extreme events are unrelated to man-made climate change.
Deluged with news from Texas, we can be forgiven for thinking that Hurricane Harvey was the worst global weather event ever.
Measured in lives and livelihoods lost, it didn’t come near last week’s monsoonal flooding across Pakistan, India, Nepal and Bangladesh that has crippled food production over vast acreages and killed over 1200 people.
Many other recent rain events in (among other places) southern and eastern Asia, the Philippines, central and South America and Africa – too many to list here – have had a more devastating impact on lives and economies than Harvey. But they weren’t in a developed western country.
It’s a sad reality that global news puts far less focus on poor places than rich ones. Houston is a big, bustling, wealthy city, supported by one of the biggest ports in the US and large chemical and research industries. That made Harvey very big news.
Nearly all of Houston’s Fortune 500 companies (it has more of them than any US city except New York) are involved in some way with oil and gas. Needless to say, they’ve so far had nothing to say about whether their industry might have contributed to the storm that wrecked the city.
It’s true, as many people are keen to point out, that human-induced climate change and weather events are different phenomena, and that rain events have always happened and will continue to do so regardless of what we put into the atmosphere.
In 2005 Al Gore pointed out that a warmer world breeds stronger storms, believing that the drowning of New Orleans by Hurricane Katrina might alert his country to dangerous climate change. He thought the same of ex-Hurricane Sandy when it smashed into New York in 2012.
But the only lesson learned from these events seems to be that people and governments don’t like to dwell on bad memories. Many senior politicians, including the Texas governor, Greg Abbott, have claimed that big wind and rain events have no connection with climate change, man-made or not.
Recent events like Typhoon Haiyan (which killed over 6000 people in 2013) and our own Cyclones Yasi (2011) and Monica (2015) had an apocalyptic feel to them. But while not always reliable, old records have turned up a few storms in the distant past that seemed comparable in size.
Commentators like me have learned to be wary of attributing big weather events to changing climate. I’ve found it useful to avoid such discussion while focusing on the bleeding obvious – higher average temperatures, melting polar ice sheets and the like.
The social and political tensions in play during storm events inhibit talk about attribution. Raising the topic of man-made climate change when homes have been inundated and people drowned (or when wildfires have incinerated homes and people) is, as they say, playing with fire.
But scientific method finds a way around inhibitions. Since Hurricane Sandy, various studies have identified extended polar jet streams as a major reason for storm systems staying stalled for long periods, allowing them time to take up more water from the sea and to dump more of it over land.
Add to that very warm, energising Gulf waters along with warm air above (warm air can hold more moisture) and you have a recipe for Houston’s third “500-year flood” in three years, and by far its most damaging wind-and-rain event on record.
A 2015 US-Korean study found that while warmer ocean water inhibited formation of tropical cyclones overall, leading to fewer storms, it also increased the intensity of those that did form. In the same year a European study found a 12 per cent rise since 1980 in record-breaking rain events.
Across the continental divide in California at the weekend a crisis of an entirely different kind was playing out, the biggest forest fire in memory besieging the city of Los Angeles, while up the coast San Francisco baked in its hottest day on record. It was the opposite face of the same stalled weather systems that caused the Houston floods.
Unlike devastated parts of south Asia, Houston is a rich city in a rich country. But with nearly 200,000 homes damaged or destroyed, 80 per cent of which lack flood insurance, the damage bill may be as high as $150 billion, far ahead of any past natural disaster in the US.
Add to that the economic cost of closing 10 Gulf coast refineries accounting for about 17 per cent of US refining capacity, and it’s unsurprising that governor Abbott is calling for more national help.
In the past, Abbott has taken out law suits against federal climate regulations, and when campaigning to be governor in 2014 he railed about “political demagogues using climate change as an excuse to remake the American economy.”
Harvey, which is having a fair shot on its own at remaking the economy, ought to change Abbott’s mind about climate change, but that’s unlikely given the powerful resistance across southern US states to identifying underlying causes of extreme weather events.
“I don’t believe Hurricane Harvey is God’s punishment for Houston electing a lesbian mayor,” said widely-syndicated conservative commentator Ann Coulter on Twitter last week. “But that is more credible than ‘climate change’.”
She offered no basis for her bald assertion. I suggest it’s based on faith alone bolstered by 1.7 million Twitter followers, and with numbers like that behind you, who needs facts?