extreme weather

A recent study looking into regional tropical cyclone formation conditions in the east and central Pacific has projected that 2 to 3 times more tropical cyclones (Hurricanes) are likely to hit Hawaii in the later part of this century.

NASA image: Rossby Waves of the JetstreamA series of major extreme weather events in the Northern hemisphere including the heatwave in the United States in 2011, the Russian heatwave of 2010, the Pakistani floods of 2010 have now been attributed to a common physical cause. The scientists suggest in a new scientific study that man-made climate change repeatedly disturbs the patterns of atmospheric flow - the atmospheric Rossby waves of the jet stream - around the globe's Northern hemisphere through a subtle resonance mechanism.

"An important part of the global air motion in the mid-latitudes of the Earth normally takes the form of waves wandering around the planet, oscillating between the tropical and the Arctic regions. So when they swing up, these waves suck warm air from the tropics to Europe, Russia, or the US, and when they swing down, they do the same thing with cold air from the Arctic," explains lead author Vladimir Petoukhov.

A worldwide review of global rainfall data led by the University of Adelaide has found that the intensity of the most extreme rainfall events is increasing across the globe as temperatures rise.

Tropical Cyclone Iggy: Image Courtesy NASA, January 2012Cyclone frequency in Indonesia in 2012 is 28 times that for the year 2002, according to the Indonesian Disaster Management Agency BNPB, with the increase attributed to the persistent impact of systemic climate change.

In the three presidential debates between Mitt Romney and Barak Obama climate change was never mentioned, despite it being raised in all previous campaigns going back to 1988. And then came Hurricane Sandy from the Caribbean. A late season category 1 tropical cyclone that combined with a north-easter from the Arctic to pummel the northern eastern coast of the United States, one of the most populous and industrialised areas on earth.

The Hurricane crossed the coast in New Jersey on Monday night, 29 October, at about 8pm not far from Atlantic City. The storm surge caused widespread flooding leaving coastal towns decimated. The winds of the hurricane caused trees to fall and whipped up a massive 3 to 4 metre storm surge. A full moon and a spring tide also exacerbated the storm surge. 10 metre waves were measured just outside New York Harbour entrance. (See Accuweather Superstorm Sandy Stats)

Related: ClimateIMC: Crops devastated, food crisis looms in Haiti from Hurricane Sandy | Skeptical Science - Hurricane Sandy and the Climate Connection | Inside Climate News: 3-D Maps Pictured Sandy's Devastation–Five Years Ago

At least 54 people were killed by Hurricane Sandy in Haiti due to the torrential rains, flooding and destruction of essential bridges and roads. Many Concrete homes and tent camps in Port-au-Prince setup after the 2010 earthquake are largely destroyed leaving up to 18,000 families homeless according to Haitian authorities.

Substantial crop loss occurred due to the Hurricane winds and flooding, threatening hunger and famine in coming weeks and months. Staple crops such as bananas and breadfruit were severely damaged by hurricane Sandy. "We'll have famine in the coming days," Kechner Toussaint, the Abricots mayor, reportedly said. "It's an agricultural disaster."

Related: UN Reliefweb: UN relief agency estimates 1.8 million Haitians have been affected by Hurricane Sandy

The widespread and persistent drought in the US during 2011-2012 has expanded according to the US Drought Monitor as reported on Climate Central. Are we starting to see the signs of a megadrought in the US southwest? Are human influences such as climate change contributing to or causing this widespread extreme weather event?

As of 18 September 2012, 64.82 percent of the contiguous U.S. has been declared as suffering from at least moderate drought - a new record. Extreme drought occurs across 20.74 percent, while the most severe category has ravaged 6.26 per cent of the land. And the seasonal outlook provided by NOAA provides little happy news predicting the drought will persist till the end of the year.

The drought is the worst to occurr since the dustbowl years of the 1930s and comes as North America experiences well above normal temperatures over spring and summer breaking many temperature records with the first half of 2012 being the hottest on record for the United States. July 2012 was the hottest month on record for the continental United States. But Australia and a few other places had abnormally cool month so putting the chill on a hot July for a global record.

An international study led by CSIRO oceanographer Dr Wenju Cai has identified that global warming is causing shifts in the rain band of the South Pacific Convergence Zone causing an increase in extreme weather across the island nation states of the South Pacific. The result of the movement causes drought and higher prevalence of forest fire in some areas while other islands experience extreme floods and increased frequency of tropical cyclones.

"Due to its strong rainfall gradient, a small displacement in the [South Pacific Convergence Zone] SPCZ's position causes drastic changes to hydroclimatic conditions and the frequency of extreme weather events such as droughts, floods and tropical cyclones experienced by vulnerable island countries in the region." says the paper.

Over the weekend the Intergovernmental Panel on Climate Change (IPCC) released The Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX). There were no surprises for anyone who follows climate science, and the report succinctly integrates a discussion of vulnerability, risk management and adaptation strategies for extreme weather disasters.

The report looks at the evidence for each extreme weather event and gives an assessment of probability and confidence value of each weather event assessment and the future trend. It involved some 220 expert authors from 62 countries and involved more than 18,000 review comments.