Rising Sea Levels | Changing Planet

Summary

The video highlights the growing threat of rising sea levels, caused by global warming and the melting of ice sheets. It explains how 60% of the world's population is at risk, particularly in coastal cities and island nations. Experts like Dr. Benjamin Horton and Dr. David Holland discuss the science behind sea-level rise, the factors contributing to it, and the varying regional impacts. The video also explores how past climate data can inform future strategies to adapt to these changes, emphasizing the need for proactive solutions to address this urgent environmental challenge.

Takeaways

• 😀 Rising sea levels are a major global threat, especially for coastal regions where 60% of the world’s population lives within 60 miles of the shore.
• 🌍 Over the last 100 years, global sea levels have risen by approximately 7 inches (17 cm), and scientists predict this rise could accelerate in the future.
• 🌊 Future projections show that sea levels could rise anywhere from 7 inches to over 3 feet (18 cm to more than 1 meter) by the end of the century.
• ⚠️ A rise greater than 1 meter in sea levels could lead to widespread flooding, erosion, health problems, and socioeconomic instability, particularly in low-lying coastal areas.
• 🏝 Island nations, like the Maldives, fear disappearing due to rising sea levels, and some governments have staged underwater meetings to highlight the threat.
• 🏙 Major cities such as Boston, New York City, Washington DC, Miami, and Los Angeles are also at risk from greater storm surges, flooding, and coastal erosion.
• 📊 Scientists identify two primary causes of rising sea levels: warming oceans causing water expansion, and melting land-based ice sheets and glaciers adding more water to the seas.
• ❄️ Melting marine ice sheets in Greenland and Antarctica contribute significantly to sea level rise, with warm ocean water accelerating ice sheet melting from below.
• 🌐 Since 1993, global sea levels have been rising at an average rate of about 3 millimeters (0.12 inches) per year, with local variations due to regional geology and ocean currents.
• 📜 Historical data from sediment cores taken along coastlines helps scientists understand past sea level changes, aiding predictions and preparations for future challenges.

Q & A

What percentage of the world’s population lives within 60 miles of the coast, making them vulnerable to rising sea levels?

60 percent of the world’s population lives and works within 60 miles of the coast, making them highly vulnerable to the threats posed by rising sea levels.

How much have sea levels risen in the past 100 years, and what is the predicted range for the next 100 years?

Over the past 100 years, global sea levels have risen by about 7 inches (17 centimeters). Scientists predict that in the next 100 years, sea levels could rise anywhere from 7 inches to more than 3 feet (18 centimeters to over 1 meter).

What are some of the potential impacts of rising sea levels mentioned in the transcript?

The potential impacts of rising sea levels include health problems, socioeconomic challenges, biological issues, and even political instability. Coastal areas could also experience greater storm surges, flooding, and coastal erosion.

Which countries and regions are particularly concerned about the threat of rising sea levels?

Island nations are especially concerned about the risk of disappearing due to rising sea levels. In the United States, coastal cities such as Boston, New York City, Washington D.C., Miami, New Orleans, and Los Angeles are also at risk.

What are the two main causes of rising sea levels as identified by scientists?

The two main causes of rising sea levels are the warming climate, which causes the ocean's volume to expand, and the melting of land-based ice sheets and glaciers, which adds more water to the oceans.

How much of the sea level rise is attributed to the warming of the ocean and how much to added water from melting ice sheets?

Of the current sea level rise, one third is due to the warming of the ocean, and two thirds is caused by the addition of water from melting ice sheets and glaciers.

What is the difference between how ice sheets melt from the top and from the bottom?

Ice sheets can melt from the top due to atmospheric warming, but more significantly, they can also melt from the bottom when warm ocean waters reach the ice sheets, which accelerates the melting process.

Why is the melting of marine ice sheets in Greenland and Antarctica particularly concerning for sea level rise?

The melting of marine ice sheets in Greenland and Antarctica is concerning because these ice sheets rest on the ocean floor, and warm ocean waters can accelerate their melting from below, leading to rapid sea level rise.

How do NASA satellites contribute to monitoring sea level rise?

NASA satellites track global sea levels and have shown that since 1993, the average rise has been about 3 millimeters (0.12 inches) per year. They also account for variations in sea level due to local gravity and ocean currents.

What role does the land level play in the rise of sea levels, according to Dr. Benjamin Horton?

Dr. Horton emphasizes that land level changes must also be considered when studying sea level rise, as factors like ice age processes, sediment compaction, and groundwater withdrawal can influence the actual impact on specific regions.