How climate change triggers earthquakes, tsunamis and volcanoes

Devastating hurricane? More than 1,000 lives lost? It must be climate change! Almost inevitably, Hurricane Matthew’s recent rampage across the Caribbean and south-eastern US has been fingered by some as a backlash of global warming driven by humanity’s polluting activities, but does this really stack up?

The short answer is no. Blame for a single storm cannot be laid at climate change’s door, as reinforced by the bigger picture. The current hurricane season is by no means extraordinary, and the last few seasons have actually been very tame. The 2013 season saw no major hurricanes at all and tied with 1982 for the fewest hurricanes since 1930. This, in turn, is no big deal as there is great year-on-year variability in the level of hurricane activity, which responds to various natural factors such as El Niño and the so-called Atlantic Multidecadal Oscillation, as well as the progressive warming of the oceans as climate change bites harder.

The current consensus holds that while a warmer world will not necessarily mean more hurricanes, it will see a rise in the frequency of the most powerful, and therefore more destructive, variety. This view was supported recently by Kerry Emanuel, a hurricane scientist at MIT, who pointed to Matthew as a likely sign of things to come.

Debate within the hurricane science community has in recent decades been almost as hostile as the storms themselves, with researchers, on occasion, even refusing to sit on the same panels at conferences. At the heart of this sometimes acrimonious dispute has been the validity of the Atlantic hurricane record and the robustness of the idea that hurricane activity had been broadly ratcheting up since the 1980s. Now, the weight of evidence looks to have come down on the side of a broad and significant increase in hurricane activity that is primarily driven by progressive warming of the climate. For many, the bottom line is the sea surface temperature, which is a major driver of hurricane activity and storm intensification. Last year saw the warmest sea temperatures on record, so it should not be a surprise. As Michael Mann, an atmospheric scientist at Penn State University, says: “It isn’t a coincidence that we’ve seen the strongest hurricane in both hemispheres [western and eastern] within the last year.” As the Atlantic continues to heat up, the trend is widely expected to be towards more powerful and wetter storms, so that Matthew might seem like pretty small beer when looked back on from the mid-century.

As with hurricanes, Pacific typhoons and the mid-latitude storms that periodically batter the UK and Europe are forecast to follow a similar pattern in an anthropogenically warmed world. Storm numbers may not rise, but there is likely to be an escalation in the frequency of the bigger storm systems, which tend to be the most destructive. An additional concern is that mid-latitude storms may become clustered, bringing the prospect of extended periods of damaging and disruptive winds.

Read more https://www.theguardian.com/world/2016/oct/16/climate-change-triggers-earthquakes-tsunamis-volcanoes

Courtesy of Guardian News & Media Ltd