Sea level rise is so much more than melting ice

Summary

This video explores the complex factors behind sea level rise, using New York City as a key example. Climate change is causing oceans to warm and ice sheets to melt, contributing to rising sea levels. However, local variations, such as the Earth's uneven gravitational pull and shifting ocean currents like the Gulf Stream, explain why New York's sea level is rising faster than the global average. Additionally, land movements, including sinking and uplifting, play a crucial role in this process. The video highlights the interconnected nature of these forces and the uncertainty of future projections.

Takeaways

• 😀 Sea level rise is happening faster in some places, like New York City, at 1.5 times the global average.
• 🌍 Global warming is causing ice sheets and glaciers to melt, contributing to rising sea levels.
• 🌊 Melting ice and warming oceans cause thermal expansion, both contributing to sea level rise.
• 🗺️ The ocean surface is not flat; it has hills and valleys, which means sea level rise is uneven across the globe.
• 🌎 Earth's mass is not evenly distributed, and large landmasses and ice sheets exert a gravitational pull that affects water distribution.
• ❄️ As ice sheets melt, their gravitational pull weakens, causing the sea level to rise farther away from the melting ice, like in New York.
• 🌊 The Gulf Stream current plays a major role in transferring water across the Atlantic; melting ice affects its flow and causes water to pile up on the East Coast.
• 🔄 Slowing of the Gulf Stream due to fresh water from melting glaciers is expected to result in higher sea levels along the U.S. East Coast.
• 🏝️ Land sinking, such as in New York and Louisiana, also causes the relative sea level to rise in those areas.
• 🛋️ The Earth’s crust, like a couch cushion, rises and sinks over long periods of time due to the melting of ice sheets from the last ice age, and this continues today.
• 🔮 Scientists understand the mechanisms behind sea level rise but remain uncertain about the future due to accelerating climate change.

Q & A

Why is sea level rise happening faster in New York City than the global average?

Sea level rise in New York City is occurring at 1.5 times the global average due to a combination of factors, including melting ice, ocean currents, and the unique geological features of the region. Specifically, changes in gravitational forces and shifting ocean currents contribute to the faster rise in this area.

How does the Earth's gravity affect sea level rise?

The Earth's gravity is not evenly distributed. Large ice sheets, like those in Antarctica, have a strong gravitational pull that draws ocean water towards them, raising sea levels nearby. As the ice melts, its gravitational pull weakens, causing the water level to decrease near the ice sheet but rise farther away, such as along the East Coast of the U.S.

What role do ocean currents play in sea level rise, particularly in New York?

Ocean currents, especially the Gulf Stream, play a significant role in the movement of water along the Atlantic. The Gulf Stream acts like a conveyor belt, moving warm water away from the U.S. East Coast. As the ice melts and fresh water is added, the density of the water decreases, slowing the current and causing water to pile up along the coast, contributing to rising sea levels.

Why are currents like the Gulf Stream slowing down, and what does this mean for coastal regions like New York?

As the planet warms and ice melts, large amounts of fresh water are introduced into the oceans, lowering the density of seawater. This disrupts the Gulf Stream's ability to sink and continue its conveyor-like movement, causing it to slow down. The result is that more water accumulates along the U.S. East Coast, raising sea levels in coastal regions like New York.

How does the concept of 'land sinking' contribute to sea level rise?

Land subsidence, or sinking, can increase the relative sea level in a region. This occurs due to various factors, such as tectonic shifts, the weight of accumulated sediments (like in Louisiana), or even the melting of glaciers. As the land sinks, the sea appears to rise, contributing to the overall effect of sea level rise.

How does the land beneath New York City contribute to the rise in sea levels?

The land beneath New York City is slowly sinking due to a process that began at the end of the last ice age. Thousands of years ago, the weight of an ice sheet pushed down on the Earth's mantle, causing the surrounding land to rise. As the ice melted, the land began to sink back to its natural level, a process that is still occurring today, contributing to rising sea levels in the region.

What analogy does Dr. Andrea Dutton use to explain the Earth's shifting land and sea levels?

Dr. Dutton compares the Earth's shifting land to sitting on a couch. When you sit down, the cushion in the middle sinks, but the edges push up. Similarly, when the weight of ice melts, the land that was pushed down slowly rises, and the land that was pushed outwards sinks, affecting sea levels.

What are some of the challenges scientists face when measuring sea level rise?

While scientists understand the factors driving sea level rise, accurately measuring it remains complex. The interplay of melting ice, ocean currents, gravitational pull, and land subsidence means that sea level rise can vary greatly from place to place, making it difficult to predict future changes with precision.

What is the primary cause of sea level rise as described in the script?

The primary causes of sea level rise are the warming of the planet, which melts ice sheets and glaciers, and the thermal expansion of seawater as it absorbs heat. These factors contribute to the rising ocean levels globally and locally, with additional regional variations influenced by local conditions like gravitational pull and ocean currents.

Why is it difficult to predict the future impacts of sea level rise?

The future impacts of sea level rise are difficult to predict because of uncertainties in how climate change will progress, how much more ice will melt, and how ocean currents will behave. The complexities of the Earth's dynamic systems make it challenging to forecast sea level rise with high accuracy, especially in the long term.