Much has been written about the potential influence of climate change on Superstorm Sandy that recently hit the east coast of the United States with tragic consequences. However, some clear indications of climate change’s influence can be obtained from earlier writings, including its impact on the likelihood and consequences of extreme weather events generally.
In his 2009 book “Storms of my Grandchildren”, NASA’s leading climate scientist, Dr James Hansen indicated what we might expect as a result of climate change. Here are some extracts: 
- Increased warming’s greatest impact on storms will occur through its influence on atmospheric water vapor. The amount of water vapor that the air can hold is a strong function of temperature.
- Even without the chaos that disintegrating ice sheets will bring, the strongest storms will become more powerful this century. That statement is true for storm types that are driven by latent heat. That’s a big deal, because storms fuelled by latent heat include thunderstorms, tornadoes, and tropical storms such as hurricanes and typhoons.
- Latent heat is the energy that water vapor acquires when it evaporates from the liquid state or sublimates from ice.
- When the water vapor condenses, that latent energy is released as heat that is potentially available to fuel a storm.
- . . . the strongest storms of the future will have greater wind velocities. That’s important, because damage caused by winds is a sharp function of wind speed. Just a 10 percent rise in wind speed increases the destructive potential of the wind by about one third.
- . . . one of the requirements for hurricanes is a sufficiently warm sea surface. Thus the region in which tropical storms can form almost surely will expand as sea surface temperatures rise.
As an example of a ratcheting up of storm effects due to global warming, Dr Hansen spoke of a 1993 “Superstorm” that hit North America in March, 1993. The storm “was caused by a collision of a cold Arctic air mass and a moisture-laden low-pressure air mass from the Gulf of Mexico.”
In relation Superstorm Sandy, science and environment writers for Reuters, Julie Steenhuysen and Alister Doyle have said, “Sandy began as a late-season hurricane coming up from the Caribbean in what many experts believe were conditions fueled by unusually warm water temperatures for this time of year. It then joined forces with a large Arctic weather system, which increased its size and transformed it into a winter storm with far more power than would otherwise have been expected.” 
Steenhuysen and Doyle also pointed out that a high pressure system of Canada’s east coast had “blocked Sandy’s escape route. While hurricanes usually turn eastward, the system forced Sandy to make a very sharp left turn and slam into the New Jersey coast.”
In the Sydney Morning Herald on 31 October 2012, Paul McGeogh reported: “That ridge of high pressure pushing down from Canada and Greenland, a blocking high as it is called in the trade, has an intensity that intrigues meteorologists because, they suspect, it is caused by the reduced sea ice in the Arctic - all a part of climate change.” 
In referring to the 1991 Halloween Nor’easter, which brought a 4 meter storm tide and an added storm surge of 1.5 meters to the north-eastern United States (and wave heights of 31 metres two hundred miles off the coast of Nova Scotia), Dr Hansen said: “More powerful Nor’easters and hurricanes will hit the East Coast cities along with higher sea levels – it is not a question of whether, only a question of when. . . . It is not necessary to put the entire island of Manhattan under water to make the city dysfunctional and, given prospects for continuing sea level rise, unsuitable for redevelopment.”
Sea level is yet to reach the magnitude of 1 to 2 meters upon which Dr Hansen’s comments were based. However, he has reported that if ice sheet loss continues to double every 10 years, then sea levels will rise by several metres this century. 
Steenhuysen and Doyle reported that sea levels have risen an average of 20 centimetres in the past 100 years.
According to the Australian Climate Commission : “The impacts of rising sea-level are experienced through ‘high sea-level events’ when a combination of sea-level rise, a high tide and a storm surge or excessive run-off trigger an inundation event. Very modest rises in sea-level, for example, 50 cm, can lead to very high multiplying factors - sometimes 100 times or more - in the frequency of occurrence of high sea-level events.”
Such events are defined as “inundation events associated with high tides and storm surges, amplified by the slow rise in sea level”. The report states that “such events are very sensitive to small increases in sea level, and the probability of these events rises in a highly nonlinear way with rising sea level”.
Of course, every storm system is unique. A key factor in considering the implications of Superstorm Sandy is the increased likelihood of extreme weather events as a result of climate change, including examples referred to above.
In Time Science & Space on 10 May, 2012, Paul Tullis reported on a paper by James Hansen, Makiko Sato and Reto Reudy , which considered the variability of extreme weather events over time. Tullis wrote: “In the paper . . . the authors show that extreme outliers of more than three standard deviations above the mean temperature covered between six and thirteen percent of the globe during the years 2003 to 2008. If they were normally distributed and similar to the climactic record, that should have been just a 0.1-to-0.2 percent frequency of an extreme heat event. (That’s about exactly as often as a perfect bell curve predicts they would occur.) Hansen dubs this difference a ‘three-sigma anomaly’ for the Greek-letter symbol for standard deviation. And in the world of statistics, these anomalies represent a stunning 10-fold increase in extreme weather events.” [Underline added here for emphasis.]
The paper was based on decades of readings from more than 1,000 weather stations world-wide, as well as satellite observations and measurements from Antarctic research stations.
The following chart is based on the work of Hansen and Sato, and shows the change in the distribution of northern hemisphere temperatures from 1951 to 2011 (although only shown to 2010 here). The bell curve has moved to the right, indicating general warming. At the same time, it has become broader and flatter, with more extreme weather events, including temperatures that are colder than average. Each bell curve shown through the time series represents the distribution of anomalies over an 11-year period. 
Here are some key estimates of the increase in likelihood of extreme weather events, from various sources, as a result of climate change:
- 10-fold increase in extreme weather events generally (referred to above)
- 2011 Texas drought 20 times more likely to have occurred than in the 1960s 
- November 2011 heat wave in England 62 times more likely to have occurred than in the 1960s. 
- European heatwave of 2003 (with over 30,000 deaths and 13 billion Euros in losses) around 6 times more likely than it would otherwise have been. 
- 100-fold increase in the frequency of occurrence of high sea-level events with a 50 centimetre rise in sea levels (referred to above).
In his 2011 book, “The God Species – How Humans really can save the planet”, Mark Lynas said, “The catastrophic flooding events that hit Pakistan in August 2010 and Australia in January 2011 are exactly the kind of hydrological disasters that will be striking with deadly effect more often in a warmer world.” 
Consistent with that view, Professor David Karoly of Melbourne University has pointed out that the total precipitable water in the atmosphere around Melbourne, Australia, on 13 January 2011 was 65.0 mm, which was 20% above the previous record of 54.5 mm. 
Of note is the ever-increasing use of the word “unprecedented” to describe significant weather events.
Specifically in relation to North Atlantic tropical storms, the following chart from the Pew Center on Global Climate Change (ending at 2007) paints a sobering picture:
The Pew Center reports: "This figure shows the number of named tropical storms in the North Atlantic, per year, smoothed out over a 10-year running average to minimize the noise in year-to-year variation. Since 1996, tropical storm frequency has exceeded by 40% the old historic maximum of the mid-1950s, previously considered extreme. Recent peer-reviewed studies suggest a link between higher sea surface temperature and storm frequency. Extreme weather events are a projected impact of global climate change. " 
It is difficult to dispute the words of Barack Obama on climate change in 2006, before becoming president: “Not only is it real, it's here, and its effects are giving rise to a frighteningly new global phenomenon: the man-made natural disaster.” 
It is clear that we cannot continue to add to global warming without impunity. Urgent action is required if we are to have any chance of preventing future catastrophes such as Superstorm Sandy.
The National Hurricane Center's official name for the storm is "Post Tropical Cyclone Sandy". Many media outlets adopted the term "Superstorm Sandy" after it reached land, weakened and was downgraded from hurricane status. 
In 2009, he prepared Vegetarian Victoria’s submission to the Victorian State Government in response to its Climate Change Green Paper. His question on animal agriculture and climate change finished second in polling for The Sunday Age’s 2011 "Climate Agenda", and prompted an article prior to the close of polling and another subsequently.
Paul has had around fifty letters published in The Age and The Sunday Age since 2008 and is a regular contributor to the Viva la Vegan website on climate change issues. He is also contributing to the land use component of “ZCA 2020”, a joint project between Beyond Zero Emissions and The University of Melbourne. His work is also featured on the websites of BCCAG and LIVE.
Hurricane Sandy Subway Alert | © Colleen Sturtevant | Dreamstime.com
Bell curve “Shifting Distribution of Northern Hemisphere Summer Temperature Anomalies, 1951-2011”: Refer below
"North Atlantic Tropical Storms": Refer below
 Hansen, J., “Storms of my grandchildren”, Bloomsbury, 2009, pp. 253-257
 Steenhuysen, J and Doyle, A “Experts weigh Sandy's causes”, Climate Spectator, 2 Nov 2012, http://www.climatespectator.com.au/commentary/experts-weigh-sandys-causes
 McGeough, P. “Huge Arctic melt added extra bite”, Sydney Morning Herald, 31 October 2012, http://www.smh.com.au/world/huge-arctic-melt-added-extra-bite-20121030-28hsw.html
 Hansen, ibid, p. 287
 Steffen, W, “The Critical Decade: Climate Science, risks and responses”, Climate Commission, pp. 23 & 26, http://climatecommission.gov.au/topics/the-critical-decade/
 Hansen, J., Sato, M. & Ruedy, R. “Climate Variability and Climate Change: The New Climate Dice” (Preliminary Draft), 10 Nov 2011, http://www.columbia.edu/~jeh1/mailings/2011/20111110_NewClimateDice.pdf
 Tullis, P. “Global Warming: An Exclusive Look at James Hansen’s Scary New Math”, Time Science & Space, 10 May, 2012, http://science.time.com/2012/05/10/global-warming-an-exclusive-look-at-james-hansens-scary-new-math/
 Goddard Space Flight Center Scientific Visualization Studio, 2 Aug 2012 “Shifting Distribution of Northern Hemisphere Summer Temperature Anomalies, 1951-2011”, Animation No. 3975, http://svs.gsfc.nasa.gov/goto?3975
 American Meteorological Society, cited in Skirble, R., "US Drought Linked to Climate Change", Voice of America, 27 July 2012, http://www.voanews.com/content/us-drought-linked-to-climate-change/1447839.html
 Dr Myles Allen and colleagues, Oxford University, cited in “Cuts in emissions are at a premium” by Liam Phelan lecturer in environmental studies at the University of Newcastle, Sydney Morning Herald, 25 January, 2011, http://www.smh.com.au/opinion/society-and-culture/cuts-in-emissions-are-at-a-premium-20110124-1a2ul.html
 Lynas, M., “The God Species – How Humans really can save the planet”, Fourth Estate, 2011, p. 55
 Karoly, Prof. David, School of Earth Sciences, University of Melbourne, “The recent extreme weather in eastern Australia: A sign of climate change or the response to La Niña?”, 23rd April, 2011 at Firbank Grammar, Brighton
 Pew Center on Global Climate Change, "North Atlantic Tropical Storms", http://web.archive.org/web/20100814083531/http://www.pewclimate.org/global-warming-basics/facts_and_figures/impacts/storms.cfm
 Obama, B. “Energy Independence and the Safety of Our Planet”, 3 April, 2006, http://obamaspeeches.com/060-Energy-Independence-and-the-Safety-of-Our-Planet-Obama-Speech.htm
 Sharp, T. "Superstorm Sandy: Facts about the Frankenstorm", Live Science, 1 Nov 2012, http://www.livescience.com/24380-hurricane-sandy-status-data.html
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