American cities and global climate change

Harvey may have been unprecedented, but it wasn’t unexpected. Houston frequently experiences flooding and experts have repeatedly warned that worse could be to come as the world gets warmer.And yet Houston was shockingly unprepared, not least because its flood control directors think talk of climate change is a plot to prevent development, and its planning system fails to prevent building in the most at-risk areas.

It is only a matter of time before more “unprecedented” flooding hits the US. Next in line could be other major cities such as Miami, New York and Boston. Yet relatively little is being done. In fact, just days before Harvey struck, Donald Trump rescinded rules that mean federal infrastructure projects must take into account flood risks related to climate change.  Global warming may not have caused Hurricane Harvey to form, but it made the storm worse. Abnormally warm waters in the Gulf of Mexico fuelled the hurricane’s rapid intensification, enabling it to pump extraordinary amounts of moisture into the air over Texas.  Sea levels have risen 0.2 metres over the past century due to global warming. This also compounded the situation, slowing the drainage of flood waters and making the storm surge higher.  Finally, Harvey stalled for a long time after coming ashore, so huge amounts of rain fell in one area. This too might be linked to climate change. A growing number of studies suggest this makes weather systems more likely to get “stuck”.All these factors will conspire to increase the number and severity of extreme flooding events as global surface temperatures soar past 2°C above pre-industrial levels in the next few decades.

So who else is in the firing line? In terms of the number of people at risk, populous countries like India, Bangladesh and China naturally come top. Millions in these countries are already affected by river flooding every year. Indeed, this year, abnormally heavy monsoon rains have caused severe flooding across south-east Asia, killing at least 1200 people.However, America features prominently in a list of the coastal cities facing the biggest financial losses from flooding by 2050, according to a 2013 study. The top five are Guangzhou, Miami, New York, New Orleans and Mumbai.  In general, rich cities such as Amsterdam have much better flood protection than poorer cities in developing countries. But many wealthy American cities have low protection levels.  It is clear the US needs to do more. Part of the answer is to stop building homes in harm’s way. This is not just a problem in Houston: since the 1960s, the US has provided cheap, subsidised flood insurance that has encouraged development in high-risk areas. This scheme’s $24 billion debt is set to soar thanks to Harvey. Big infrastructure projects have a part to play, too. Massive barrier schemes similar to the one protecting London have long been considered for protecting places such as New York City, but have yet to get the go-ahead.  But it is simply not feasible to protect many areas, such as the vast swathes of Florida set to disappear under the waves over the next century. Abandoning those areas will be the only solution.  (Michael Le Page, New Scientist)

The problem is a climate of denial. “It cannot happen here; this is the United States of America”. But it can, and has. Parts of the Florida Keys were very badly affected by the recent hurricane, and yet people will still be retiring there and buying houses that should never have been built there and are just a foot or three above sea level. The most beautiful spot in Islamorada is as close to looking like a South Sea Island as you can imagine. We are still waiting to find out whether it is still in business. Last year the sandy beach was washed aeay. This year? For the owner it is a beautiful, but threatened, asset with a limited life.

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