Coastal Hazards and Human Impacts

Summary

This lecture focuses on coastal hazards and their impact on human populations, particularly in coastal cities, which are prone to both natural and human-made dangers. It covers the unpredictable nature of tsunamis, the environmental threat of pollution and oil spills, and the growing issue of sea level rise. The lecture highlights the risks to infrastructure, livelihoods, and ecosystems in coastal areas, emphasizing the varying effects on different regions based on wealth and resources. It also discusses mitigation strategies such as sea walls, barriers, and advanced technologies to combat these challenges.

Takeaways

• 😀 Over 70% of the human population lives near coastal environments, benefiting from resources like fisheries, trade, and moderated climate.
• 🌊 Tsunamis are caused by seismic waves due to undersea earthquakes or volcanic eruptions, and they are one of the most dangerous natural hazards that we cannot control.
• 🌍 The 2011 Japan tsunami and the 2004 Indian Ocean tsunami are two of the most devastating tsunamis of the 21st century, impacting large populations in coastal areas.
• 🌊 Tsunami waves are fast (up to 500 mph) but initially low in height in deep waters, often unnoticed, only to increase dramatically as they approach shallow coastal areas.
• 🛢️ Pollution in the oceans, including plastics and oil spills, is a major environmental issue, with plastics taking centuries to decompose and harming marine life and human health.
• 🛢️ Oil spills from offshore drilling, like the 2010 Deepwater Horizon disaster, contaminate marine ecosystems and enter the food chain, impacting both wildlife and human health.
• 🌿 Microplastics from synthetic clothing fibers are another significant source of ocean pollution, as they enter the water system from washing machines and accumulate in marine life.
• 🌎 Studies show that fish in remote areas like the Mariana Trench are consuming plastic, highlighting the widespread impact of ocean pollution even in the most isolated ecosystems.
• 🌊 Global sea levels have been rising due to climate change, leading to coastal flooding, shoreline erosion, and threats to infrastructure and livelihoods.
• 💰 Wealthier countries, like the United States, have more resources to mitigate the impacts of sea level rise, while poorer countries, like the Solomon Islands, face greater challenges in addressing these threats.

Q & A

What are the advantages of living in coastal environments?

Coastal environments offer several advantages including a moderated climate, trade opportunities, ports, and resources like fisheries.

What is the primary natural hazard discussed in the lecture that we cannot control?

The primary natural hazard discussed in the lecture that we cannot control is tsunamis, which are caused by sudden, dramatic motions in the sea floor, often from earthquakes or undersea volcanic eruptions.

How fast can tsunamis travel in deep sea, and what is their characteristic when approaching the coast?

Tsunamis can travel at speeds up to 500 miles per hour in deep sea. As they approach the coast, the wave height increases dramatically due to the shallow water, sometimes reaching 50 feet or more.

What is the significance of the 2011 Japanese tsunami in relation to human impacts?

The 2011 Japanese tsunami had a significant impact, causing widespread destruction by picking up cars and homes, and is used as an example of the devastating effect of tsunamis on populated coastal areas.

How does plastic pollution affect marine life and human health?

Plastic pollution can be ingested by marine life, entering the food chain. Microplastics in fish can eventually be consumed by humans, raising concerns about both environmental and human health risks.

What are the dangers of oil spills in the ocean?

Oil spills pose serious environmental threats, including the contamination of water and food sources, as well as the long-term impact of toxic substances in the marine ecosystem.

How long can plastic waste persist in the ocean?

Plastic waste can persist in the ocean for hundreds to thousands of years, with items like plastic bottles taking 450 years to decompose, and some plastics potentially never fully breaking down.

What role do washing machines play in the spread of microplastics?

Washing machines contribute to the spread of microplastics by releasing tiny synthetic fibers from clothing (such as polyester or nylon) that are not filtered out and enter the water system.

How is sea level rise expected to impact coastal populations and infrastructure?

Sea level rise is expected to lead to increased flooding, shoreline erosion, and habitat loss, with infrastructure such as homes, roads, and bridges being threatened, particularly in densely populated coastal areas.

How do wealthy and less wealthy countries differ in their approach to mitigating sea level rise?

Wealthy countries, like the United States, have more resources to allocate towards mitigation efforts, including the construction of sea walls and technological solutions. In contrast, poorer countries, such as the Solomon Islands, face more challenges in addressing the impacts of sea level rise.