November 21, 2017

Hurricanes & Storms: Effects of Irreversible Climate Change

By San Shwe Aung

(Continued from 4-9-2017)

Facts about 2005 Hurricane Katrina
1. Hurricane Katrina was the largest and 3rd strongest hurricane ever recorded to make landfall in the US.
2. In New Orleans, Katrina peaked at a Category 5 hurricane, with winds up to 175 mph.
3. The final death toll was at 1,836, primarily from Louisiana (1,577) and Mississippi (238). More than half of these victims were senior citizens.
4. The storm surge from Katrina was 20-ft (six meters) high.
5. 705 people are reported as still missing as a result of Hurricane Katrina.
6. Hurricane Katrina affected over 15 million people in different ways varying from having to evacuate their homes, rising gas prices, and the economy suffering.
7. An estimated 80% of New Orleans was under water, up to 20 ft deep in places.
8. Hurricane Katrina caused $81 billion in property damages, but it is estimated that the total economic impact in Louisiana and Mississippi may exceed $150 billion, earning the title of costliest hurricane ever in US history.
9. Hurricane Katrina impacted about 90,000 square miles.
10. The region affected by the storm supported roughly 1 million non-farm jobs, and still, hundreds of thousands of local residents were left unemployed by the hurricane.
11. More than 70 countries pledged monetary donations or other assistance after the hurricane. Kuwait made the largest single pledge of $500 million, but Qatar, India, China, Pakistan and Bangladesh made very large donations as well.

Hurricane Harvey (2017).

Hurricane Harvey (2017)
Hurricane Harvey was the first major hurricane to make landfall in the United States since Hurricane Katrina in 2005, ending a record 12-year period with no hurricanes of Category 3 intensity or higher making landfall in the United States. In a four-day period, many areas received more than 40 inches (1,000 mm) of rain as the system moved from here and there over eastern Texas and adjacent waters, causing catastrophic flooding. With peak accumulations of 51.88 in (1,318 mm), Harvey is the wettest tropical cyclone on record in the United States. The resulting floods inundated hundreds of thousands of homes, displaced more than 30,000 people, and prompted more than 13,000 rescues. Harvey is the first major hurricane of the 2017 Atlantic hurricane season. Harvey developed from a tropical wave to the east of the Lesser Antilles, reaching tropical storm status on August 17. The storm crossed through the Windward Islands on the following day, passing just south of Barbados and later near Saint Vincent. Upon entering the Caribbean Sea, Harvey began to weaken due to moderate wind shear and degenerated into a tropical wave north of Colombia early on August 19. The remnants were monitored for regeneration as it continued west-northwestward across the Caribbean and the Yucatán Peninsula, before redeveloping over the Bay of Campeche on August 23. Harvey then began to rapidly intensify on August 24, regaining tropical storm status and becoming a hurricane later that day. While the storm moved generally northwest, Harvey’s intensification phase stalled slightly overnight from August 24–25, however Harvey soon resumed strengthening and became a Category 4 hurricane late on August 25, 2017. Hours later, Harvey made landfall near Rockport, Texas, at peak intensity. Harvey has caused at least 48 confirmed deaths. Catastrophic inland flooding is ongoing in the Greater Houston metropolitan area. Harvey is the worst disaster in Texas history, and expected the recovery to take many years. Preliminary estimates of economic losses range from $10 billion to $160 billion.

Texas & Louisiana
Throughout Texas, more than 300,000 people were left without electricity and billions of dollars of property damage was sustained. By August 29, approximately 13,000 people had been rescued across the state while an estimated 30,000 were displaced. More than 48,700 homes were affected by Harvey throughout the state, including over 1,000 that were completely destroyed and more than 17,000 that sustained major damage; approximately 32,000 sustained minor damage. Nearly 700 businesses were damaged as well. Texas Department of Public Safety stated more than 185,000 homes were damaged and 9,000 destroyed. Heavy rainfall extended eastward into Louisiana, with the state recording up to 14.88 in (37.8 cm) of precipitation, water reached 4 ft (1.2 m) in height, with homes flooded and hundreds of people forced to evacuate in one neighborhood alone. The Louisiana National Guard prepared about 500,000 sandbags and emergency boats and high-water-rescue vehicles were placed on standby should flooding occur. Many locations in the Houston metropolitan area observed at least 30 in (76 cm) of precipitation. This makes Harvey the wettest tropical cyclone on record for Texas, and the United States.

Effects of Climate change
The Gulf of Mexico is known for hurricanes in August, so their incidence alone cannot be attributed to global warming, but the warming climate does influence certain attributes of storms. Studies in this regard show that storms tend to intensify rapidly prior to landfall. Weather events are due to multiple factors, and so cannot be said to be caused by one precondition, but climate change affects aspects of extreme events, and very likely worsened some of the impacts of Harvey. The World Meteorological Organization stated that the quantity of rainfall from Harvey had very likely been increased by climate change. The relationship between climate change and the frequency of hurricanes (or tropical cyclones) is still unclear, and is the subject of continuing research. Harvey approached Houston over sea-surface waters which were significantly above average temperatures. Warm waters provide the main source of energy for hurricanes, and increased ocean heat can result in storms being larger, more intense and longer lasting, in particular bringing greatly increased rainfall.
The recent increases in activity are linked, in part, to higher sea surface temperatures in the region that Atlantic hurricanes form in and move through. Numerous factors have been shown to influence these local sea surface temperatures, including natural variability, human-induced emissions of heat-trapping gases, and pollution. Warmer air can hold more water vapour, in accordance with the Clausius–Clapeyron relation, and there has been a global increase of daily rainfall records. Regional sea surface temperatures around Houston have risen around 0.5° C (0.9° F) in recent decades, which caused a 3–5% increase in moisture in the atmosphere. This had the effect of allowing Harvey to strengthen more than expected. The water temperature of the Gulf of Mexico was above average for this time of the year, and likely to be a factor in Harvey’s impact. The slow movement of Harvey over Texas allowed the storm to drop prolonged heavy rains on the state, as has also happened with earlier storms. Harvey’s stalled position was due to weak prevailing winds linked to a greatly expanded subtropical high pressure system over much of the US at the time, which had pushed the jet stream to the north. Research and model simulations have indicated an association between this pattern and human-caused climate change. Another human-caused effect is due to oil extractions in-land and off shore too. In addition ground water extraction for human use for drinking and economic purposes has caused ground subsiding. Sea level rise along the coast has combined the effects of global warming with subsidence mainly caused by extraction of oil and groundwater for water supplies, resulting in a sea level rise of 6 inches (15 cm) in recent decade.

Political Will
There are several high level international conferences being held in recent years among the countries to deliberate to curb the negative effects & impact on the climate change. Some climate change meetings were attended by many heads of governments & states. Scientists’ warnings & advice on global warming and climate change are theoretically and generally accepted by world leaders but the universal agreement to curb CO2 emission, for example, are hard to materialize. Unless all world leaders have strong political will and commitment to save the world from severe weather patterns, storms, hurricanes, flooding, sea level rise, we people of the world will continue to encounter and suffer from grave impact of Irreversible Global Climate Change. Therefore one of the most important preparations in current time is “Planning for Disaster Risk Reduction”, which must be an integral component of all socio-economic sectors of all nations in the world.

Reference: https://en.wikipedia.org/

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