29 October 2012


Courtesy: AP
     Nicknamed "Frankenstorm", there is a climate change component to this story. Dr Kevin Trenberth of the US National Center for Atmospheric Research says it’s not a matter of attributing this or that particular storm to global warming but recognising there is a systematic influence on weather events:
It’s not the right question to ask if this storm or that storm is due to global warming, or is it natural variability. Nowadays, there’s always an element of both... there is a systematic influence on all of these weather events now-a-days because of the fact that there is this extra water vapour lurking around in the atmosphere than there used to be say 30 years ago.
Four uncontroversial facts help put Hurricane Sandy in context:
More extremes

The past few years have been marked by unusually severe extreme weather characteristic of climate change. A new study by Munich Re shows that North America has been most affected by weather-related extreme events in recent decades. "Severe weather in North America" analyzes all kinds of weather perils and their trends. It reports and shows that the continent has experienced the largest increases in weather-related loss events.
     Previously the NOAA had reported on the stream of extreme weather in the USA In 2011, when  new records were set in the US for tornadoes, drought, wind, floods, and wildfires. Heat records were set in every state. At one time in the 2011 summer, nearly half of the country’s population was under a heat advisory or heat warning. In late November, hurricane-force winds hit parts of Wyoming, Utah, Nevada, Arizona, New Mexico, and California, with winds reaching 97 mph in Pasaden. The number of events that produced on the order of $1 billion or more in damages in 2011 is the largest since tracking of that statistic began in 1980, even after damages are adjusted for inflation. NOAA estimates that there were at least 14 such events in 2011. (The previous record was nine, set in 2008; an average year would see three or four.) Collectively, the 14 events resulted in approximately $55 billion in damage. Furthermore, many events produced less than $1 billion in damage, but are not included in the tally, although they collectively represent additional significant financial losses.Weather- and climate-related disasters in the US claimed more than 1000 lives in 2011, almost double the yearly average.
     “Climate is what you expect; weather is what you get,” says Dr Jeff Masters, Weather Underground director of meteorology and former hurricane hunter.
     Connecting the dots between extreme weather and global warming, Masters told Climate Progress in February this year:
 I like to think of the weather as a game of dice. Mother Nature rolls the dice each day to determine the weather, and the rolls fall within the boundaries of what the climate will allow. The extreme events that happen at the boundaries of what are possible are what people tend to notice the most. When the climate changes, those boundaries change. Thus, the main way people will tend to notice climate change is through a change in the extreme events that occur at the boundaries of what is possible.
     The natural weather rhythms I’ve grown used to during my 30 years as a meteorologist have become disrupted over the past few years. Many of Earth’s major atmospheric circulation patterns have seen significant shifts and unprecedented behavior; new patterns that were unknown have emerged; extreme weather events were incredibly intense and numerous during 2010 – 2011. The laws of physics demand that the huge amount of heat-trapping gases humans are pumping into the atmosphere must be significantly altering the fundamental large-scale circulation pattern of the atmosphere. Unprecedented behavior like we’ve witnessed in the configuration of the winter jet stream over North America–with the four most extreme years since 1865 occurring since 2006–could very well be due to human-caused climate change.

Sources: AP, Climate Progress,Connecting the Dots, Climate Signals, 350.org