Christopher Allen is senior analyst – model development, working within the Event Response team at RMS, and is based in London. He joined fellow employees from RMS and RMS clients on our annual Impact Trek in Nepal during March this year. This is Chris’s account of his time in Nepal.
On Wednesday, March 21, eight somewhat-still-jetlagged RMS Impact Trekkers left the Summit Hotel in Kathmandu bound for the village of Dhunkharka, three hours’ drive southeast of the capital. We were going to see some of the retrofitting work that was being done by Build Change, a social enterprise partner of RMS that aims to build local capacity for safer construction practices. As we weaved our way through Kathmandu traffic (a chaotic affair at the best of times) we noticed several of the characteristics of the capital’s buildings that had been pointed out to us by Build Change over the past few days: soft story, three-floor brick masonry, new construction sprouting up with reinforced concrete columns, the occasional ground floor still occupied by goats or buffalo…
Climate modeling studies generally agree that anthropogenic climate change will likely cause tropical cyclones globally to be more intense on average, and that the most powerful ones will become more frequent. In response, climatologist Michael Mann (particularly well known for his so-called “hockey-stick” temperature graph) recently advocated the introduction of a sixth category to the Saffir-Simpson Hurricane Wind Scale (SSHWS), in order to better describe the very strongest storms. According to Mann, sturdier construction practices mean that Category 5 storms no longer all cause near-total destruction of human infrastructure and introducing a Category 6 would increase public awareness of the effects climate change is having on tropical cyclone strength. Mann is not the first to propose introducing a Category 6; after powerful tropical cyclones make landfall this is frequently deliberated. Before wading into this debate however, let us look at the SSHWS itself.
What is the El Niño Southern Oscillation? More conveniently known as ENSO, it is the planet’s largest source of natural climate variability on interannual time scales. ENSO describes the interaction between ocean and atmosphere in the equatorial Pacific, but the results of this interaction are global, and can last for many months. There is a good level of ENSO awareness in our industry, such as that warm phases of the oscillation (El Niño) tend to suppress Atlantic hurricane activity, and that cool phases (La Niña) tend to enhance it. But how was ENSO discovered? And how does it work?