Hurricanes have plunged the US into a state of national crisis, with Hurricane Harvey now standing as the most costly natural disaster in US history and Hurricane Irma wreaking havoc across Florida, America's most vulnerable state. Texas In just two weeks, the US could rack up hundreds of billions of dollars in losses. Given that more than six million people were ordered to evacuate their homes in Florida because of the danger that Hurricane Irma posed, it's safe to say that getting out seemed to be the safest bet. Moody Analytics, a research firm, has estimated that Hurricane Irma, which hit Florida on Sunday as a Category 4 storm, will cost between $64 billion and $92 billion in damages. That's on top of the $108 billion in estimated damages from Harvey, which made landfall in Texas at the end of August. In all, Irma and Harvey will probably cause between $150 billion and $200 billion in damage, said Mark Zandi, Moody's chief economist. Hurricane Katrina, which battered the Gulf Coast in 2005, caused $160 billion in damage in today's dollars, according to the US National Oceanic and Atmospheric Administration, and at the time was the costliest natural disaster in US history. Even under mandatory evacuation orders, many of the communities that stayed put throughout the devastation of Hurricane Katrina did so because of what they saw as the strength of their local community, preferring to weather the storm with the people they knew. Others made their decisions based on factors such as whether they trusted their local government, the costs of evacuation, or concerns about losing their jobs or the security of their homes in the event of looting. Meanwhile, devastating floods across India, Nepal, Bangladesh, Sierra Leone, Niger, the Democratic Republic of Congo and Nigeria in recent weeks will collectively kill hundreds more than Harvey and Irma combined. A massive complex of wildfires is also burning millions of acres across the American North-West, with a smoke plume stretching coast-to-coast. It looks as if destructive storms like Harvey and Irma will become more common. Accepting that fact, and talking about the radical changes necessary to reverse this trend, are the most important things that can be done right now. Scientists writing in the US government's recent Climate Science Special Report, painstakingly assembled by 13 US federal agencies from the work of thousands of scientists around the world and then leaked to the New York Times, were clear in their view that hurricanes, especially the strongest ones, are going to get worse in the future. Both physics and numerical modelling simulations indicate an increase in tropical cyclone intensity in a warmer world, and the models generally show an increase in the number of very intense tropical cyclones. The frequency of the most intense of these storms is projected to increase in the Atlantic and western North Pacific and in the eastern North Pacific in future years.
