Risk

• High/spring tides and coastal topography can affect storm surges. Locations like the Bay of Bengal have a narrow funnel shape, creating larger waves.
• During Hurricane Katrina, New Orleans in 2005 experienced an 8 meter high storm surge.
• Kiribati: Situated in the middle of the pacific ocean, composed of 33 coral atolls. Most of the population live on the Tarawa where maxim height above sea level is just 3m.
• Kiribati: Climate change is causing bleaching of coral reefs, the health of which is vital for the growth of the islands. Which occurred particularly in 1998, 2002, 2006, 2010 and 2015.
• Bleaching is where additional heat of the ocean produces stress in the coral polyps. This causes them to expel their symbiotic (algae), so losing their food supply.
• Kiribati: Scientists estimate that flooding risk will increase bt 200 times between 2000-80. If sea levels rise slow enough, coral growth may keep pace, depending on "tipping points" like melting of the Greenland ice sheet.
• Kiribati government has looked at buying 23 km2 on Fiji's Vanua Levu Island, to relocate its population, who may become environmental refugees.
• Differences between impacts for developed/developing:

  -Insuring and money G -Coastal defenses vary

  -Spread of disease due to destroyed infrastructure D

  -Have less expensive material and so rebuilding can be quicker and economic damage less G

  -Can be dependent on international aid G
• Sea level rise is predicted to be the greatest in the Philippines, losses of $6.5 billion a year. The rise rate is around 5.8 mm a year, higher than the global average. Analysis has shown that urban areas around Manila bay will be flooded by 2100 with a 1m rise. Up to 2.3 million people could be affected, 62% in metro Manila.
• The country's poverty is a factor (90% of the country's wealth is controlled by 15% ish of the population. Growing populations can lead to over-exploitation and pollution of natural ecosystems like mangroves and coral around the capital Manila. Which reduces their ability to protect the backshore.
• San Fernando: By 2100 the city will lose 300 buildings, over 283000m of land. Property losses are estimated at $2.5 million and land loss at $21 million. Loss of schools, churches and beaches with a recreational value at $95000 a year.
• The bay in San Fernando is used for mooring fishing boats, 130 fisherman earn $12 a week. High unemployment can cause an estimated $168000 welfare loss. Small breakwaters of rip-rap have been constructed to protect government infrastructure like at San Agustin at a cost of $21000.
• In New Zealand, the Pacific Access Category Ballot allows 75 citizens of Kiribati, 75 of Tuvalu and 250 of Tonga to be granted in the country each year. Already 3000 of Tuvalu's 10800 people have moved to New Zealand. In 2014 courts allowed citizenship on the basis of climate refugee status to a family from Tuvalu.
• Dredging along the coastline of California has had long-term implications on the supply of sediment to the Santa Barbara littoral cell.
• • Dredging involves the removal of sediment for use in construction. Removal of the sediment causes the depth of the ocean to increase. This can cause an increase in the occurrence of destructive waves at the coast because they can maintain their energy further towards the shoreline.
• Weathering and mass movement processes combine to increase the rate of coastal recession. Long periods of rainfall weaken rock structure and in turn, leads to mass movement of material.
• During the winter season, the rate of coastal recession tends to be greater than during the summer season. This is because winter brings stormy weather, linked with higher tides and long wave fetch.
• Wind direction controls the movement of waves, influencing the rate of coastal erosion. A dominant wind direction causes powerful destructive waves to attack the coastline.

  • E.g. the south-westerly wind directing waves across the Atlantic Ocean towards Land’s End in Cornwall.
• • Tides are linked to gravitational pull. When the pull is at its strongest, there are high tides. When the pull is at its weakest, there are low tides.
  • During periods of high tide, the rate of coastal recession can increase because waves can reach further towards the shore.
• • Weather systems are influenced by areas of high pressure, creating anticyclones, and areas of low pressure, creating depressions.
  • Increased belts of high pressure reduce the rate of coastal recession because this leads to calmer weather.
  • Belts of low pressure systems cause unsettled weather conditions.
• In Bangladesh, storm surges threaten the lives of those living near the coast. The risk associated with storm surges in the Bay of Bengal is because Bangladesh is so low-lying.
• Climate change is changing the frequency and intensity of low-pressure depressions and tropical storms. Rising global temperatures are causing our oceans to warm, triggering these low-pressure systems. This increases the risk of coastal flooding and creates unusual weather conditions.